CN112406836A - Brake-by-wire system with backup function and control method thereof - Google Patents

Brake-by-wire system with backup function and control method thereof Download PDF

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Publication number
CN112406836A
CN112406836A CN202011454370.4A CN202011454370A CN112406836A CN 112406836 A CN112406836 A CN 112406836A CN 202011454370 A CN202011454370 A CN 202011454370A CN 112406836 A CN112406836 A CN 112406836A
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China
Prior art keywords
brake
piston
master cylinder
electric hydraulic
simulator
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CN202011454370.4A
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Chinese (zh)
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CN112406836B (en
Inventor
初亮
李世博
许炎武
赵迪
常城
陈超一
聂荣真
睢岩
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Jilin University
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Jilin University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
    • B60T13/142—Systems with master cylinder
    • B60T13/147—In combination with distributor valve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
    • B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
    • B60T13/746—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive and mechanical transmission of the braking action
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/02—Brake-action initiating means for personal initiation
    • B60T7/04—Brake-action initiating means for personal initiation foot actuated
    • B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or force sensors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
    • B60T8/4081—Systems with stroke simulating devices for driver input
    • B60T8/409—Systems with stroke simulating devices for driver input characterised by details of the stroke simulating device

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)

Abstract

The invention discloses a brake-by-wire system with a backup function and a control method thereof, wherein the brake-by-wire system comprises a brake control mechanism, an active brake pedal stroke simulator, a main energy supply device and a hydraulic adjusting unit; brake master cylinder's I cavity liquid outlet A among the brake operating mechanism, II cavity liquid outlet B, III cavity inlet C respectively with active brake pedal stroke simulator's inlet D, inlet E, liquid outlet F tube coupling, the liquid outlet G of active brake pedal stroke simulator, liquid outlet H respectively with hydraulic pressure regulating unit's inlet M, inlet L tube coupling, main energy supply device's liquid outlet I, liquid outlet J respectively with hydraulic pressure regulating unit's inlet M, inlet L tube coupling, main energy supply device's inlet K and hydraulic pressure regulating unit's liquid outlet R all with the brake operating mechanism in the liquid outlet D tube coupling of liquid storage pot. The invention also provides a control method of the brake-by-wire system with the backup function.

Description

Brake-by-wire system with backup function and control method thereof
Technical Field
The invention relates to a brake-by-wire system applied to the field of automobile brake systems, in particular to a brake-by-wire system with a backup function and a control method thereof.
Background
In recent years, with the progress of artificial intelligence technology, it has become possible to use a robot instead of a human to complete a driving task, an unmanned vehicle will inevitably become one of the development trends of future automobile technology, and an intelligent driving system will eventually replace a human to drive an automobile. The emergence of intelligent driving systems puts new and higher demands on braking systems, the newly introduced intelligent driving functions require that the braking systems can realize brake-by-wire through commands, the braking systems are ensured to have higher availability, and all key functions including brake-by-wire have redundant backup and are not limited to traditional conventional braking mechanical backup. To meet these needs, the brake-by-wire system should have a redundant backup function, and in addition, should have a higher pressure regulation capability, and at the same time, should add a pedal stroke simulation function, so that the brake pedal of the brake-by-wire system still has a pedal feel close to that of the conventional brake pedal.
Several patent applications have been searched for in connection with the present invention:
the invention relates to a brake-by-wire system and a vehicle, which are named as 'brake-by-wire system' and 'vehicle' with the application number of 201710885196.0, wherein the publication number of Chinese patent is CN109552287A and publication number of 2019.04.02. The brake system executing mechanism designed by the invention comprises two electric brakes and two hydraulic brakes which are respectively controlled by a motor and a hydraulic unit and are respectively applied to a front shaft and a rear shaft. The invention has the disadvantage that the brake-by-wire system lacks a redundant backup function.
The invention relates to an electronic mechanical brake system with a backup brake system, which is named as 'an electronic mechanical brake system with a backup brake system' with the application number of 201811553147.8, and the Chinese patent publication number is CN109606340A and publication number 2019.04.12. The invention provides an electronic brake system which uses hydraulic pressure to simulate pedal feeling and uses electronic braking as a main braking mode and simultaneously reserves a hydraulic pipeline as a backup unit. The invention has the disadvantages that the backup brake system has insensitive response, difficult implementation and limited brake capacity, the electronic brake system actuating mechanism has complex structure and great control difficulty, and the four wheels adopt repeated actuating mechanisms, thereby greatly improving the cost of the brake system.
The Chinese patent publication No. CN110525409A, publication No. 2019.12.03, entitled redundant service brake System of vehicle, and application No. 201910753378.1. The design of the invention adopts the motor hydraulic pump as a power source of the backup braking system, and realizes the mode switching between the main braking system and the backup braking system through the electromagnetic valve. The invention has the defects that more electromagnetic valves need to be controlled, and the performance requirement of the backup braking system on the motor hydraulic pump is too high to exceed the self capacity.
Disclosure of Invention
The invention aims to solve the technical problems that the performance requirement of a brake-by-wire system in the prior art exceeds the capability of the existing product, the structure is complex, the control difficulty is high, the braking capability of a redundant backup system is limited, and the pedal feel is inconsistent with that of the traditional vehicle, and provides the brake-by-wire system with the backup function and the control method thereof.
In order to solve the technical problems, the invention is realized by adopting the following technical scheme:
the brake-by-wire system with the backup function comprises a brake control mechanism, an active brake pedal stroke simulator, a main energy supply device and a hydraulic adjusting unit;
the brake control mechanism comprises a brake master cylinder and a liquid storage tank; the brake master cylinder is internally provided with three chambers which are arranged in series, namely a first chamber, a second chamber and a third chamber from left to right;
brake master cylinder's I cavity liquid outlet A and active brake pedal stroke simulator's inlet D brake pipe connection, brake master cylinder's II cavity liquid outlet B and active brake pedal stroke simulator's inlet E brake pipe connection, brake master cylinder's III cavity inlet C and active brake pedal stroke simulator's liquid outlet F brake pipe connection, active brake pedal stroke simulator's liquid outlet G and main energy supply device's liquid outlet I all with hydraulic pressure regulating unit's inlet M brake pipe connection, active brake pedal stroke simulator's liquid outlet H and main energy supply device's liquid outlet J all with hydraulic pressure regulating unit's inlet L brake pipe connection, main energy supply device's inlet K and hydraulic pressure regulating unit's liquid outlet R all with the liquid outlet D brake pipe connection of liquid storage pot.
The brake master cylinder in the technical scheme comprises a brake master cylinder body, a brake master cylinder first piston, a brake master cylinder second piston, a brake master cylinder first piston spring, a brake master cylinder second piston spring and a brake master cylinder push rod; the brake master cylinder body is a cylindrical structural member, the left end of the brake master cylinder body is closed, the right end of the brake master cylinder body is opened, a flange plate is arranged on the right end face of the brake master cylinder, and six liquid inlet and outlet ports which are threaded holes are arranged on the outer cylindrical surface of the brake master cylinder body; the brake master cylinder first piston spring, the brake master cylinder first piston, the brake master cylinder second piston spring, the brake master cylinder second piston and the brake master cylinder push rod are sequentially arranged in the brake master cylinder body, the brake master cylinder first piston, the brake master cylinder second piston and the brake master cylinder body are in sliding connection, and the rotation axes of the brake master cylinder first piston spring, the brake master cylinder first piston, the brake master cylinder second piston, the brake master cylinder push rod and the brake master cylinder body are collinear; the brake master cylinder is internally provided with three chambers which are isolated by a first piston of the brake master cylinder and a second piston of the brake master cylinder and can independently generate high-pressure brake fluid, the three chambers are arranged in series, a first chamber, a second chamber and a third chamber are sequentially arranged from left to right, and a mechanical inlet of the brake master cylinder is a push rod of the brake master cylinder; the brake master cylinder is fixed on the vehicle body through a flange.
In the technical scheme, the liquid storage tank is provided with four liquid outlets which are respectively a liquid outlet f, a liquid outlet r, a liquid outlet t and a liquid outlet d, the liquid outlet f, the liquid outlet r and the liquid outlet t are respectively connected with a liquid inlet a of a first cavity of the brake main cylinder, a liquid inlet b of a second cavity of the brake main cylinder and a liquid inlet c of a third cavity of the brake main cylinder through pipelines, and the liquid storage tank is arranged above the brake main cylinder.
The brake control mechanism in the technical scheme further comprises a brake pedal, a pedal displacement sensor and a brake master cylinder one-way valve; the brake pedal is installed below the front part of a driver in a carriage, the top end of a rotating part in the brake pedal is fixed on a pedal support through a pin shaft, the pedal support is fixed on a vehicle body through a bolt, the left side surface of the middle end of the rotating part in the brake pedal is in contact connection with the right end surface of a brake main cylinder push rod in a brake main cylinder, a pedal displacement sensor is fixed on the pedal support connected with the vehicle body, a movable arm of the pedal displacement sensor is connected with the rotating part in the brake pedal, a brake main cylinder check valve is installed between a liquid storage tank liquid outlet t and a brake main cylinder III cavity liquid inlet c, a port of the brake main cylinder check valve is connected with a liquid storage tank liquid outlet t hydraulic pipeline, and a port of the brake main cylinder check valve is connected with a brake main cylinder.
The active brake pedal stroke simulator comprises a motor controller, a motor, a driving gear, a toothed internal circulation nut, a ball, a screw mandrel ejector rod, a limit switch, a rear cover, a partition plate, a first thrust bearing, a second piston spring, a second piston sealing ring, a first piston spring, a third piston spring seat retainer ring, a third piston sealing ring, a simulator cylinder body, a simulator one-way valve, a simulator third liquid outlet electromagnetic valve, a simulator first liquid outlet electromagnetic valve, a simulator second liquid outlet electromagnetic valve and a brake main cylinder pressure sensor;
the simulator cylinder body is a cylindrical structural member, the left end and the right end of the simulator cylinder body are both opened, a flange plate for mounting is arranged on the outer cylindrical surface of a left end cylinder opening, three bolt holes are uniformly distributed on the flange plate, a three-section cylindrical stepped hole is machined along the central axis of the simulator cylinder body, the diameter of the three-section stepped hole is gradually reduced from left to right, and the three-section stepped hole is a first-section stepped hole, a second-section stepped hole and a third-section stepped hole in sequence, wherein a second piston and a second piston spring are installed in the first-section stepped hole, the first piston and the first piston spring are installed in the second-section stepped hole, the third-section stepped hole is an oil inlet and outlet hole of the simulator cylinder body and is machined into an internal threaded hole, the cylindrical wall of the first-section stepped hole is also machined with an air;
the third piston is a two-section stepped shaft, the right end shaft diameter is larger, an annular groove for placing a sealing ring is processed on the cylindrical surface of the right end shaft, the left end shaft diameter is smaller and used for mounting a third piston spring, a circular groove for placing a third piston spring seat check ring is processed on the cylindrical surface of the left end shaft, a circular hole is processed on the left end shaft along the rotation center line of the stepped shaft, and the diameter of the circular hole is slightly larger than that of a right end slide bar of the screw mandrel push rod; the first piston is a two-section stepped shaft, the right end shaft diameter is larger, the left end shaft diameter is smaller, the left end shaft diameter is used for mounting a third piston spring, an annular boss is arranged on the left end face of the shaft with the larger diameter and used for mounting the first piston spring, a circular stepped hole is machined along the rotation center line of the stepped shaft, the diameter of the right end of the stepped hole is larger and equal to the shaft diameter of the right end of the third piston, and the diameter of the left end of the stepped hole is smaller and equal to the shaft diameter of the left end of the third piston; the second piston is a two-section stepped shaft, the right end shaft diameter is larger, a circular boss is arranged on the right end surface and used for mounting a first piston spring, an annular groove used for placing a sealing ring is processed on the cylindrical surface of the right end shaft, the left end shaft diameter is smaller and used for mounting a second piston spring, a circular through hole is processed along the rotation center line of the stepped shaft, and the diameter of the through hole is slightly larger than the left end shaft diameter of the first piston;
the simulator comprises a simulator cylinder body, a back cover, a toothed internal circulation nut, a screw mandrel ejector rod, a screw roller path, a screw mandrel ejector rod, a third piston, a second piston, a first piston and a second piston, wherein the simulator cylinder body is arranged on the right end surface of a partition plate through a bolt, the back cover is arranged on the left end surface of the partition plate through a rivet, the toothed internal circulation nut is arranged between the back cover and the partition plate through a first thrust bearing and a second thrust bearing, the left end surface and the right end surface of the first thrust bearing are respectively in contact connection with the back cover and the toothed internal circulation nut, the left end surface and the right end surface of the second thrust bearing are respectively in contact connection with the toothed internal circulation nut and the partition plate, the screw mandrel ejector rod is arranged in a spiral roller path of a central hole of the toothed internal circulation nut through balls and is in rolling connection, the right end surface of the screw mandrel ejector rod is inserted into a stepped hole of the simulator cylinder, the first piston spring is sleeved on a circular boss on the second end face of the left side of the first piston, the second piston spring and the third piston spring are respectively arranged on a left end shaft of the second piston and a left end shaft of the third piston, a third piston spring seat is sleeved on the left end of the third piston in a transition fit manner, a third piston spring seat check ring is arranged in a circular groove at the left end of the third piston, the left end face of the third piston spring seat is in contact connection with the right end face of the third piston spring seat check ring, a second piston sealing ring and a third piston sealing ring are respectively sleeved in annular grooves of the second piston and the third piston, the motor is arranged on the right end face of a partition plate below a simulator cylinder body, a driving gear is sleeved on an output shaft of the motor in an interference fit manner and is connected with a toothed internal circulation nut in a meshing manner, a motor controller is arranged on the right end face of the motor shell, the limit switch is arranged at the central position of the rear cover and is connected with the motor controller by a limit switch signal wire, the port a of the simulator electromagnetic valve, the port p of the third liquid outlet electromagnetic valve of the simulator and the port a of the one-way valve of the simulator are all connected with oil inlet and outlet hole hydraulic pipelines on the simulator cylinder body, the port p of the simulator electromagnetic valve and the port p of the first liquid outlet electromagnetic valve of the simulator are all connected with a D port hydraulic pipeline of the active brake pedal stroke simulator, the port a of the first liquid outlet electromagnetic valve of the simulator is connected with a G port hydraulic pipeline of the active brake pedal stroke simulator, the port p of the second liquid outlet electromagnetic valve of the simulator and a brake master cylinder pressure sensor are all connected with an E port hydraulic pipeline of the active brake pedal stroke simulator, the port a of the second liquid outlet electromagnetic valve of the simulator is connected with an H port hydraulic pipeline of the active brake pedal stroke simulator, and the port a of the third liquid outlet electromagnetic valve of the simulator are connected with, And ports p of the simulator one-way valves are connected with a port F of the active brake pedal stroke simulator through hydraulic pipelines.
The main energy supply device in the technical scheme comprises an electric hydraulic cylinder, an electric hydraulic cylinder pressure sensor, an electric hydraulic cylinder first liquid outlet electromagnetic valve and an electric hydraulic cylinder second liquid outlet electromagnetic valve;
the electric hydraulic cylinder comprises an electric hydraulic cylinder body, an electric hydraulic cylinder piston spring, an electric hydraulic cylinder piston, an electric hydraulic cylinder ball screw and an electric hydraulic cylinder motor; the cylinder body of the electric hydraulic cylinder is a cylindrical structural member, the left end and the right end of the cylinder body are both provided with holes, the diameter of the left end opening is smaller and is processed into a threaded hole, the hole is an oil inlet and outlet hole a of the electric hydraulic cylinder, the diameter of the right end opening is larger, and an oil inlet and outlet hole p is arranged on the outer cylindrical surface of the cylinder body of the electric hydraulic cylinder; a center hole is formed in the center of the right end of the electric hydraulic cylinder piston, a spiral raceway for mounting balls is arranged on the inner cylindrical surface of the center hole, and a ball screw of the electric hydraulic cylinder is provided with a spiral raceway matched with the spiral raceway of the electric hydraulic cylinder piston; the electric hydraulic cylinder piston spring and the electric hydraulic cylinder piston are sequentially arranged in the electric hydraulic cylinder body, the electric hydraulic cylinder piston is in sliding connection with the electric hydraulic cylinder body, the left end of the electric hydraulic cylinder ball screw is arranged in a central hole at the right end of the electric hydraulic cylinder piston and is in rolling connection, the right end of the electric hydraulic cylinder ball screw is connected with the electric hydraulic cylinder motor through a transmission mechanism, and the electric hydraulic cylinder ball screw can convert the rotary motion of the electric hydraulic cylinder motor into the linear motion of the electric hydraulic cylinder piston;
the first liquid solenoid valve of hydraulic cylinder's p mouth, the electric cylinder second goes out the p mouth of liquid solenoid valve, electric cylinder pressure sensor all with electric cylinder business turn over oilhole a hydraulic line connection, the first liquid solenoid valve's of electric cylinder a mouth and the I mouth hydraulic line connection of main energy supply device, the electric cylinder second goes out the liquid solenoid valve's an mouth and the J mouth hydraulic line connection of main energy supply device, electric cylinder business turn over oilhole p and the K mouth hydraulic line connection of main energy supply device.
The hydraulic adjusting unit in the technical scheme comprises a right rear wheel check valve, a right rear wheel liquid inlet electromagnetic valve, a left front wheel check valve, a left front wheel liquid inlet electromagnetic valve, a right front wheel check valve, a right front wheel liquid inlet electromagnetic valve, a left rear wheel check valve, a left rear wheel liquid inlet electromagnetic valve, a right rear wheel liquid outlet electromagnetic valve, a left front wheel liquid outlet electromagnetic valve, a right front wheel liquid outlet electromagnetic valve and a left rear wheel liquid outlet electromagnetic valve;
an opening a of the right rear wheel check valve, an opening P of the right rear wheel liquid inlet electromagnetic valve, an opening a of the left front wheel check valve and an opening P of the left front wheel liquid inlet electromagnetic valve are all connected with an M opening hydraulic pipeline of the hydraulic adjusting unit, an opening a of the right front wheel check valve, an opening P of the right front wheel liquid inlet electromagnetic valve, an opening a of the left rear wheel check valve and an opening P of the left rear wheel liquid inlet electromagnetic valve are all connected with an L opening hydraulic pipeline of the hydraulic adjusting unit, an opening P of the right rear wheel check valve, an opening a of the right rear wheel liquid inlet electromagnetic valve and an opening P of the right rear wheel liquid outlet electromagnetic valve are all connected with a Q opening hydraulic pipeline of the hydraulic adjusting unit, an opening P of the left front wheel check valve, an opening a of the left front wheel liquid inlet electromagnetic valve and an opening P of the left front wheel liquid outlet electromagnetic valve are all connected with a P opening hydraulic pipeline of the hydraulic adjusting unit, an opening P of the right front wheel check valve, an opening a opening of the right front wheel liquid inlet electromagnetic valve and a, the port a of the right rear wheel liquid outlet electromagnetic valve, the port a of the left front wheel liquid outlet electromagnetic valve, the port a of the right front wheel liquid outlet electromagnetic valve and the port a of the left rear wheel liquid outlet electromagnetic valve are all connected with the port R hydraulic pipeline of the hydraulic adjusting unit.
The control method of the brake-by-wire system with the backup function comprises the following steps:
1) detecting whether the displacement of the brake pedal is 0 or not, receiving a pedal displacement signal transmitted by a pedal displacement sensor by a brake controller, and entering a step 2 if the pedal displacement is 0); otherwise, entering step 3);
2) when the pedal displacement is 0, the working state command sent by the brake controller to the simulator motor controller is in an idle state, so that the active brake pedal stroke simulator is in the idle state, when the screw mandrel is in an initial position, the motor does not work, when the screw mandrel is not in the initial position, the motor controller drives the motor to rotate reversely, the motor converts the rotary motion of the motor into the linear motion of the screw mandrel through the driving gear, the toothed internal circulation nut, the ball and the screw mandrel, so that the screw mandrel moves leftwards until the left end of the sliding rod of the screw mandrel is contacted with the limit switch, the limit switch transmits the acquired signal to the motor controller through a limit switch signal wire, and at the moment, the screw mandrel is considered to be in the initial position; meanwhile, the main energy supply device is also in an idle state, when the piston of the electric hydraulic cylinder is in an initial position, the motor of the electric hydraulic cylinder does not work, when the piston of the electric hydraulic cylinder is not in the initial position, the motor of the electric hydraulic cylinder is driven to rotate reversely, the motor of the electric hydraulic cylinder converts the rotary motion into the linear motion of the piston of the electric hydraulic cylinder through the ball screw of the electric hydraulic cylinder, so that the piston of the electric hydraulic cylinder moves rightwards to the initial position, whether the piston of the electric hydraulic cylinder returns or not is judged through the rotating speed of the motor of the electric hydraulic cylinder, when the rotating speed of the motor of the electric hydraulic cylinder is lower than a threshold value; when the pedal displacement is 0 and the screw mandrel ejector rod in the active brake pedal stroke simulator and the electric hydraulic cylinder piston in the main energy supply device are both returned, the brake system does not work;
3) calculating a target master cylinder pressure P when the pedal displacement is greater than 0Master cylinder tarThe brake controller receives a pedal displacement signal transmitted by the pedal displacement sensor, and obtains a target main cylinder pressure P under corresponding pedal displacement according to a relation curve of the traditional automobile pedal displacement and the main cylinder pressure measured by a testMaster cylinder tar；
4) The working state command sent by the brake controller to the simulator motor controller is a pedal stroke simulation state, so that the active brake pedal stroke simulator is in the pedal stroke simulation state, when the screw mandrel is in the initial position, the motor does not work, and when the screw mandrel is not in the initial position, the motor controller drives the motor to rotate reversely, so that the screw mandrel moves to the initial position; after that, the electromagnetic valve of the simulator is opened, the first liquid outlet electromagnetic valve of the simulator, the second liquid outlet electromagnetic valve of the simulator and the third liquid outlet electromagnetic valve of the simulator are all closed, the brake fluid of the front axle completely enters the active brake pedal stroke simulator, and the pedal feeling is completely provided by the brake pedal stroke simulator; in order to make the pedal feel consistent with the traditional brake pedal feel, parameters of a first piston spring, a second piston spring, a first piston and a second piston of an active brake pedal travel simulator need to be matched, so that the brake pedal travel simulator can accurately simulate the pressure volume characteristic of a wheel cylinder, and the pedal feel is guaranteed; the first liquid outlet electromagnetic valve of the electric hydraulic cylinder and the second liquid outlet electromagnetic valve of the electric hydraulic cylinder are both opened, and at the moment, the wheel cylinder pressure is completely provided by the main energy supply device;
5) the brake controller receives a pressure signal P of a main energy supply device transmitted by a pressure sensor of the electric hydraulic cylinderElectric hydraulic cylinder act(ii) a If the pressure signal P of the main energy supply deviceElectric hydraulic cylinder actLess than target master cylinder pressure PMaster cylinder tarEntering step 6); if the pressure signal P of the main energy supply deviceElectric hydraulic cylinder actEqual to target master cylinder pressure PMaster cylinder tarEntering step 7); otherwise, entering step 8);
6) pressure signal P of main energy supply deviceElectric hydraulic cylinder actLess than target master cylinder pressure PMaster cylinder tarWhen the electric hydraulic cylinder piston moves to the oil inlet and outlet hole p of the electric hydraulic cylinder, the main energy supply device starts to build pressure and the actual pressure gradually rises;
7) pressure signal P of main energy supply deviceElectric hydraulic cylinder actEqual to target master cylinder pressure PMaster cylinder tarWhen the main energy supply device is in a pressure maintaining state, the electric hydraulic cylinder motor is static, and the ball screw of the electric hydraulic cylinder and the piston of the electric hydraulic cylinder keep the original position unchanged, so that the actual pressure of the main energy supply device is kept unchanged;
8) pressure signal P of main energy supply deviceElectric hydraulic cylinder actGreater than target master cylinder pressure PMaster cylinder tarWhen the electric hydraulic cylinder piston returns to the oil inlet and outlet hole p of the electric hydraulic cylinder, the actual pressure of the main energy supply device is reduced to 0, and after the electric hydraulic cylinder piston returns, the pressure reduction process is finished;
9) the brake controller receives the pressure signal P of the main energy supply device transmitted by the pressure sensor of the electric hydraulic cylinder againElectric hydraulic cylinder actJudging whether the main energy supply device fails, if so, entering the step 10), otherwise, returning to the step 1);
10) the first liquid outlet electromagnetic valve of the electric hydraulic cylinder, the second liquid outlet electromagnetic valve of the electric hydraulic cylinder are closed, the electromagnetic valve of the simulator is closed, the first liquid outlet electromagnetic valve of the simulator, the second liquid outlet electromagnetic valve of the simulator and the third liquid outlet electromagnetic valve of the simulator are opened, and at the moment, the wheel cylinder pressure is completely provided by the brake master cylinder;
11) the brake controller receives a brake master cylinder pressure signal P transmitted by a brake master cylinder pressure sensorBrake master cylinder act(ii) a If the master cylinder pressure signal PBrake master cylinder actLess than target master cylinder pressure PMaster cylinder tarStep 12) is entered; if the master cylinder pressure signal PBrake master cylinder actEqual to target master cylinder pressure PMaster cylinder tarEntering step 13); otherwise go to step 14);
12) pressure signal P of brake master cylinderBrake master cylinder actLess than target master cylinder pressure PMaster cylinder tarWhen the brake pedal stroke simulator is in a pressurization state, the brake controller sends a working state command to the simulator motor controller to enable the active brake pedal stroke simulator to be in the pressurization state, the motor controller sends a control command to enable the motor to rotate in the forward direction, the motor converts the rotary motion into the linear motion of the screw mandrel through the driving gear, the toothed internal circulation nut, the ball and the screw mandrel, when the screw mandrel moves to be in contact with a third piston, the third piston starts to move rightwards relative to the first piston, the pressurization process starts, the third piston is continuously pushed along with the screw mandrel, and the pressurization process is continuously carried out; brake fluid enters a third cavity of the brake master cylinder through the simulator oil inlet and outlet hole and a third liquid outlet electromagnetic valve of the simulator, active pressurization and pedal feeling simulation work is completed by adjusting the active brake pedal stroke simulator in real time, and the actual pressure of the brake master cylinder is gradually increased;
13) pressure signal P of brake master cylinderBrake master cylinder actEqual to target master cylinder pressure PMaster cylinder tarWhen the pressure of the brake master cylinder is maintained, the working state instruction sent to the simulator motor controller by the brake controller is a pressure maintaining state, so that the active brake pedal stroke simulator is in the pressure maintaining state, the motor controller sends a control instruction to enable the motor to be static, and the screw mandrel and the third piston keep the original position to be fixed, so that the actual pressure of the brake master cylinder is kept unchanged;
14) pressure signal P of brake master cylinderBrake master cylinder actGreater than target master cylinder pressure PMaster cylinder tarWhen the brake master cylinder is in a decompression state, the working state command sent by the brake controller to the simulator motor controller is in the decompression state, the active brake pedal stroke simulator is in the decompression state, the motor controller sends a control command to enable the motor to rotate reversely, the motor converts the rotary motion into the linear motion of the screw mandrel through the driving gear, the toothed internal circulation nut, the ball and the screw mandrel until the screw mandrel moves to be in contact with the limit switch, the screw mandrel returns to the initial position, the third piston moves leftwards relative to the first piston under the action of a third piston spring and high-pressure brake fluid until the third piston returns to the original position, and brake fluid in a third cavity of the brake master cylinder flows back to the active brake pedal stroke simulator through the simulator one-way valve and the simulator oil inlet and outlet holeThe active brake pedal stroke simulator is adjusted in real time to complete the work of active pressure reduction and pedal feeling simulation, and the actual pressure of the brake master cylinder is gradually reduced until the pressure reduction process is finished;
15) return to step 1).
Compared with the prior art, the invention has the beneficial effects that:
1. the brake-by-wire system with the backup function has a simple hardware structure, only an active brake pedal stroke simulator needs to be additionally arranged on the basis of the brake-by-wire system, only a small amount of electromagnetic valves and the active brake pedal stroke simulator need to be controlled in the conventional braking process and the redundant backup braking process, and the control difficulty is low.
2. The active brake pedal stroke simulator in the brake-by-wire system with the backup function integrates the pedal feeling simulation function and the pressure regulation function integrating active pressurization, pressure maintaining and active depressurization, and makes up the deficiency of the pressure regulation capability of the traditional hydraulic regulation unit.
3. The brake-by-wire system with the backup function can simulate the pedal feeling through the active brake pedal stroke simulator when the main energy supply device works, and can dynamically regulate the pressure of the brake master cylinder and the pedal feeling through the active pressure regulating function of the active brake pedal stroke simulator after the main energy supply device fails, so that the redundant backup design of the brake system is realized while the brake pedal feeling is ensured to be consistent with that of a traditional automobile, and the driving safety is ensured to the maximum extent.
4. The brake-by-wire system with the backup function can be installed in a hybrid electric vehicle and an electric vehicle, can enable hydraulic braking and motor braking to be better matched through accurate braking pressure adjustment, exerts the regenerative braking capacity of the motor to the maximum extent, and greatly improves the trafficability of the hybrid electric vehicle and the electric vehicle.
Drawings
The invention is further described with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of the structural components of a brake-by-wire system with backup function according to the present invention;
FIG. 2 is a schematic diagram of the structural components of an active brake pedal travel simulator in a brake-by-wire system with a backup function according to the present invention;
FIG. 3 is a right side view of a simulator body of an active brake pedal travel simulator in a brake-by-wire system with backup function according to the present invention;
FIG. 4 is a schematic diagram of the structural components of a main energy supply device in a brake-by-wire system with a backup function according to the present invention;
fig. 5 is a schematic diagram illustrating the structural composition of a hydraulic pressure adjusting unit in a brake-by-wire system with a backup function according to the present invention;
FIG. 6 is a flow chart of a control method of a brake-by-wire system with a backup function according to the present invention;
in the figure: 1. a brake control mechanism, 2, a liquid storage tank, 3, a brake master cylinder check valve, 4, a brake master cylinder push rod, 5, a pedal displacement sensor, 6, a brake pedal, 7, a brake master cylinder body, 8, a brake master cylinder second piston, 9, a brake master cylinder second piston spring, 10, a brake master cylinder first piston, 11, a brake master cylinder first piston spring, 12, an active brake pedal stroke simulator, 13, a main energy supply device, 14, a hydraulic pressure adjusting unit, 15, a right rear wheel, 16, a left front wheel, 17, a right front wheel, 18, a left rear wheel, 19, a toothed internal circulation nut, 20, a second thrust bearing, 21, a first thrust bearing, 22, a limit switch, 23, a screw rod ejector rod, 24, a ball, 25, a driving gear, 26, a limit switch signal line, 27, a first motor fixing bolt, 28, a motor, 29, a motor controller, 30, a second piston sealing ring, 31. a simulator cylinder, 32, a third piston seal ring, 33, an oil inlet and outlet hole, 34, a first piston, 35, a third piston, 36, a first piston spring, 37, a third piston spring, 38, a third piston spring seat, 39, a third piston spring seat retainer ring, 40, a second piston, 41, a second piston spring, 42, a vent hole, 43, a second partition connecting bolt, 44, a partition, 45, a fourth rear cover connecting rivet, 46, a rear cover, 47, a simulator check valve, 48, a simulator third liquid outlet electromagnetic valve, 49, a simulator electromagnetic valve, 50, a simulator first liquid outlet electromagnetic valve, 51, a simulator second liquid outlet electromagnetic valve, 52, a brake master cylinder pressure sensor, 53, a second motor fixing bolt, 54, a seventh rear cover connecting rivet, 55, a third partition connecting bolt, 56, a sixth rear cover connecting rivet, 57, a fifth rear cover connecting rivet, 58. the hydraulic control system comprises a third rear cover connecting rivet, 59, a second rear cover connecting rivet, 60, a first partition connecting bolt, 61, a first rear cover connecting rivet, 62, an electric hydraulic cylinder pressure sensor, 63, an electric hydraulic cylinder first liquid outlet electromagnetic valve, 64, an electric hydraulic cylinder second liquid outlet electromagnetic valve, 65, an electric hydraulic cylinder body, 66, an electric hydraulic cylinder piston spring, 67, an electric hydraulic cylinder piston, 68, an electric hydraulic cylinder ball screw, 69, an electric hydraulic cylinder motor, 70, a right rear wheel check valve, 71, a right rear wheel liquid inlet electromagnetic valve, 72, a left front wheel check valve, 73, a left front wheel liquid inlet electromagnetic valve, 74, a right front wheel check valve, 75, a right front wheel liquid inlet electromagnetic valve, 76, a left rear wheel check valve, 77, a left rear wheel liquid inlet electromagnetic valve, 78, a right rear wheel liquid outlet electromagnetic valve, 79, 80, a right front wheel liquid outlet electromagnetic valve, 81, and a left rear wheel liquid outlet electromagnetic valve.
Detailed Description
The invention is described in detail below with reference to the attached drawing figures:
the brake-by-wire system with the backup function comprises a brake control mechanism 1, an active brake pedal stroke simulator 12, a main energy supply device 13 and a hydraulic pressure adjusting unit 14.
Referring to fig. 1, the brake operating mechanism 1 includes a master cylinder, a reservoir 2, a brake pedal 6, a pedal displacement sensor 5, and a master cylinder check valve 3.
The brake master cylinder comprises a brake master cylinder body 7, a brake master cylinder first piston 10, a brake master cylinder second piston 8, a brake master cylinder first piston spring 11, a brake master cylinder second piston spring 9 and a brake master cylinder push rod 4; the brake main cylinder body 7 is a cylindrical structural member, the left end of the brake main cylinder body is closed, the right end of the brake main cylinder body is opened, a flange plate is arranged on the right end face of the brake main cylinder, and six liquid inlet and outlet ports which are threaded holes are arranged on the outer cylindrical surface of the brake main cylinder body 7; the brake master cylinder first piston spring 11, the brake master cylinder first piston 10, the brake master cylinder second piston spring 9, the brake master cylinder second piston 8 and the brake master cylinder push rod 4 are sequentially arranged in the brake master cylinder body 7, the brake master cylinder first piston 10, the brake master cylinder second piston 8 and the brake master cylinder body 7 are in sliding connection, and the rotation axes of the brake master cylinder first piston spring 11, the brake master cylinder first piston 10, the brake master cylinder second piston spring 9, the brake master cylinder second piston 8, the brake master cylinder push rod 4 and the brake master cylinder body 7 are collinear; the brake master cylinder is internally provided with three chambers which are isolated by a first piston 10 of the brake master cylinder and a second piston 8 of the brake master cylinder and can independently generate high-pressure brake fluid, the three chambers are arranged in series, a first chamber, a second chamber and a third chamber are sequentially arranged from left to right, and a mechanical inlet of the brake master cylinder is a push rod 4 of the brake master cylinder, so that mechanical energy input by a pedal of a driver can be converted into hydraulic energy.
The liquid storage tank 2 is generally made of hard plastic materials, and has four liquid outlets, namely a liquid outlet f, a liquid outlet r, a liquid outlet t and a liquid outlet d, and the liquid storage tank 2 is used for storing brake fluid and detecting the residual amount of the brake fluid.
The brake pedal 6 comprises a rotating part and a pedal support, the rotating part is installed on the pedal support through a pin shaft through hole in the top end of the rotating part and a pin shaft, the rotating part is rotatably connected with the pedal support, the pedal support is fixed with a vehicle body through a bolt, and the brake pedal 6 amplifies the pedal force operated by a driver through the lever principle and can reflect the braking intention of the driver.
The pedal displacement sensor 5 adopts a pull-wire type displacement sensor of CLM series of ASM company of Germany, and a movable arm on the pedal displacement sensor 5 can measure the angular displacement of the brake pedal 6 and feed the angular displacement back to the brake controller, so that the pedal displacement sensor is used for acquiring the pedal displacement information of a driver when the braking energy of the automobile is recovered.
The brake master cylinder check valve 3 adopts a straight-through type check valve, the forward opening pressure is 0.04MPa, and the brake master cylinder check valve 3 is used for controlling the flow direction of brake fluid, so that the brake fluid can only flow from the port p to the port a of the brake master cylinder check valve 3, but the brake fluid cannot flow back.
The position and the connection mode of the specific components are as follows: the brake pedal 6 is installed below the front part of a driver in a carriage, the top end of a rotating part in the brake pedal 6 is fixed on a pedal support through a pin shaft, the pedal support is fixed on the vehicle body through a bolt, and the left side surface of the middle end of the rotating part in the brake pedal 6 is in contact connection with the right end surface of a brake master cylinder push rod 4 in a brake master cylinder. The pedal displacement sensor 5 is fixed on a pedal bracket connected with the vehicle body, the pedal displacement sensor 5 is fixed on the pedal bracket connected with the vehicle body, and a movable arm of the pedal displacement sensor 5 is connected with a rotating part in the brake pedal 6. The brake master cylinder is fixed on the vehicle body through a flange plate, a liquid outlet A of a first cavity of the brake master cylinder is connected with a brake pipeline of a liquid inlet D of the active brake pedal stroke simulator 12, a liquid outlet B of a second cavity of the brake master cylinder is connected with a brake pipeline of a liquid inlet E of the active brake pedal stroke simulator 12, and a liquid inlet C of a third cavity of the brake master cylinder is connected with a brake pipeline of a liquid outlet F of the active brake pedal stroke simulator 12. The liquid outlet f, the liquid outlet r and the liquid outlet t of the liquid storage tank 2 are respectively connected with a liquid inlet a of a first cavity of the brake master cylinder, a liquid inlet b of a second cavity of the brake master cylinder and a liquid inlet c of a third cavity of the brake master cylinder through pipelines, and the liquid storage tank 2 is arranged above the brake master cylinder. The brake master cylinder check valve 3 is arranged between a liquid outlet t of the liquid storage tank 2 and a liquid inlet c of a III cavity of the brake master cylinder, a p port of the brake master cylinder check valve 3 is connected with a hydraulic pipeline of the liquid outlet t of the liquid storage tank 2, and an a port of the brake master cylinder check valve 3 is connected with a hydraulic pipeline of the liquid inlet c of the III cavity of the brake master cylinder.
Referring to fig. 2 and 3, the active brake pedal stroke simulator 12 includes a toothed internal circulation nut 19, a second thrust bearing 20, a first thrust bearing 21, a limit switch 22, a screw rod carrier 23, a ball 24, a driving gear 25, a limit switch signal line 26, a first motor fixing bolt 27, a motor 28, a motor controller 29, a partition 44, a fourth rear cover connecting rivet 45, a rear cover 46, a second motor fixing bolt 53, a seventh rear cover connecting rivet 54, a sixth rear cover connecting rivet 56, a fifth rear cover connecting rivet 57, a third rear cover connecting rivet 58, a second rear cover connecting rivet 59, a first rear cover connecting rivet 61, a second piston seal 30, a simulator cylinder 31, a third piston seal 32, an oil inlet/outlet hole 33, a first piston 34, a third piston 35, a first piston spring 36, a third piston spring 37, a third piston spring 38, a third piston spring seat, a fourth piston spring seat, a, The hydraulic brake system comprises a third piston spring seat retainer ring 39, a second piston 40, a second piston spring 41, a vent hole 42, a second partition plate connecting bolt 43, a third partition plate connecting bolt 55, a first partition plate connecting bolt 60, a simulator one-way valve 47, a simulator third liquid outlet electromagnetic valve 48, a simulator electromagnetic valve 49, a simulator first liquid outlet electromagnetic valve 50, a simulator second liquid outlet electromagnetic valve 51 and a brake master cylinder pressure sensor 52.
The specific specifications and functions are as follows: the active brake pedal stroke simulator 12 mainly plays a role in simulating pedal feel and serving as a backup energy supply device to realize active pressurization, pressure maintaining and active pressure reduction when the main energy supply device 13 fails.
The toothed internal circulation nut 19 is a disc-type structural member, a cylindrical boss is arranged at the right end of the toothed internal circulation nut 19, the circle center of the boss is overlapped with the center of the toothed internal circulation nut 19, teeth meshed with the driving gear 25 are arranged on the outer cylindrical surface of the periphery of the toothed internal circulation nut 19, a central through hole is formed in the center of the toothed internal circulation nut 19, and a spiral raceway for mounting the ball 24 is arranged on the inner cylindrical surface of the central through hole.
The screw mandrel 23 consists of a left section and a right section, the left section is a screw mandrel which is provided with a spiral raceway and matched with a central through hole of the toothed internal circulation nut 19 and a ball 24, the right section is a cylindrical sliding rod with a smooth surface, and the screw mandrel 23 plays a role in converting the rotary motion of the toothed internal circulation nut 19 into linear motion.
The first thrust bearing 21 and the second thrust bearing 20 can adopt a thrust ball bearing or a thrust cylindrical roller bearing, and the first thrust bearing 21 and the second thrust bearing 20 can bear the radial acting force of the toothed internal circulation nut 19 and can limit the axial displacement of the toothed internal circulation nut 19.
The simulator cylinder body 31 is a cylindrical structural member, the left end and the right end of the simulator cylinder body are both open, a flange plate for installation is arranged on the outer cylindrical surface of the left end cylinder opening, three bolt holes are uniformly distributed in the flange plate, a three-section cylindrical stepped hole is machined along the central axis of the simulator cylinder body 31, the diameter of the three-section stepped hole gradually decreases from left to right, and sequentially comprises a first section of stepped hole, a second section of stepped hole and a third section of stepped hole, wherein a second piston 40 and a second piston spring 41 are installed in the first section of stepped hole, a first piston 34 and a first piston spring 36 are installed in the second section of stepped hole, the third section of stepped hole is an oil inlet and outlet hole 33 of the simulator cylinder body 31 and is machined into an internal threaded hole, a vent hole 42 is further machined in the cylindrical wall of the first section of stepped hole, and the three-section cylindrical.
The partition plate 44 is a disc-type structural member, an outer contour line of an outer circular surface of the partition plate 44 is composed of two eccentric circles and two outer tangent lines of the two eccentric circles, the diameter of an upper eccentric circle on the partition plate 44 is large, the diameter of a lower eccentric circle on the partition plate 44 is small, two central through holes are processed in the center of the two eccentric circles of the partition plate 44, three uniformly-distributed bolt holes, two uniformly-distributed bolt holes and seven rivet holes are further processed on the plane of the partition plate 44, the three uniformly-distributed threaded hole distribution circles are concentrically arranged with the upper eccentric circle on the partition plate 44, the two uniformly-distributed threaded hole distribution circles are concentrically arranged with the lower eccentric circle on the partition plate 44, the seven rivet hole distribution circles are concentrically arranged with the upper eccentric circle on the partition plate 44, the diameter of the three uniformly-distributed threaded hole distribution circles is small, the diameter of the seven rivet holes distribution circles is large.
The rear cover 46 is a stepped cylindrical structural member, the left end of the structural member is closed, the right end of the structural member is open, a central through hole for mounting the limit switch 22 is processed at the left end, the outer contour of the outer circular surface of the cylinder opening at the right end is the same as that of the outer circular surface of the partition plate 44, a flange plate for mounting is arranged on the outer circular surface of the cylinder opening at the right end, and seven rivet holes are arranged on the flange plate and matched with the seven rivet holes on the partition plate 44 for use; two stepped holes are formed in the rear cover 46, the left-end stepped hole is a central circular hole and has a smaller diameter, the inner contour of the right-end stepped hole has the same shape as the outer contour of the outer circumferential surface of the partition 44, the two stepped holes are communicated with each other, the rotating shaft of the left-end stepped hole and the upper eccentric circular rotating shaft of the right-end stepped hole are collinear, and a circular boss for mounting the first thrust bearing 21 is arranged on the left end surface of the right-end stepped hole.
The third piston 35 is a two-section stepped shaft, the right end shaft diameter is large, an annular groove for placing a third piston sealing ring 32 is processed on the cylindrical surface of the right end shaft, the left end shaft diameter is small for installing a third piston spring 37, a circular groove for placing a third piston spring seat retaining ring 39 is processed on the cylindrical surface of the left end shaft, a circular hole is processed on the left end shaft along the rotation center line of the stepped shaft, and the diameter of the circular hole is slightly larger than that of the slide bar of the screw mandrel ejector rod 23.
First piston 34 be two segmentation step shafts, the right-hand member shaft diameter is great, the left end shaft diameter is less, the left end shaft diameter is used for installing third piston spring 37, be provided with ring shape boss on the left end face of the diameter great axle for install first piston spring 36, along the processing of step shaft centre of rotation line there is circular shoulder hole, the shoulder hole right-hand member diameter is great, equals with third piston 35 right-hand member shaft diameter, the shoulder hole left end diameter is less, equals with third piston 35 left end shaft diameter.
The second piston 40 is a two-section stepped shaft, the right end shaft diameter is larger, a circular ring-shaped boss is arranged on the right end face and used for mounting the first piston spring 36, an annular groove used for placing the second piston sealing ring 30 is processed on the cylindrical surface of the right end shaft, the left end shaft diameter is smaller and used for mounting the second piston spring 41, a circular through hole is processed along the rotation center line of the stepped shaft, and the diameter of the through hole is slightly larger than that of the left end shaft diameter of the first piston 34.
The first piston spring 36 adopts a cylindrical spiral spring, has low rigidity, and mainly simulates the pressure volume characteristic of a wheel cylinder during low-intensity braking in a pedal stroke simulation state; the second piston spring 41 is a cylindrical coil spring with high rigidity, and mainly simulates the pressure volume characteristic of a wheel cylinder during high-intensity braking in a pedal stroke simulation state, and the third piston spring 37 is a cylindrical coil spring with high rigidity, and mainly enables the third piston 35 to move towards the direction of the screw mandrel 23 (namely leftwards relative to the second piston 40) in a pressure reduction state so as to realize the function of active pressure reduction.
The third piston spring seat 38 is a circular ring-shaped structural member and is used for mounting and fixing the third piston spring 37.
Third piston spring seat retaining ring 39 be the ring form structure, adopt aluminum alloy material, for convenient installation, processing is jagged on the ring. The third piston spring seat retainer ring 39 functions to limit the axial displacement of the third piston spring seat 38.
The second piston seal ring 30 and the third piston seal ring 32 are both O-shaped seal rings, and are used for sealing brake fluid.
The first rear cover connecting rivet 61, the second rear cover connecting rivet 59, the third rear cover connecting rivet 58, the fourth rear cover connecting rivet 45, the fifth rear cover connecting rivet 57, the sixth rear cover connecting rivet 56 and the seventh rear cover connecting rivet 54 are half-head rivets for connecting the rear cover 46 and the partition 44.
The first partition plate connecting bolt 60, the second partition plate connecting bolt 43 and the third partition plate connecting bolt 55 adopt common fine-thread hexagon bolts and are used for connecting the simulator cylinder body 31 and the partition plate 44; the first motor fixing bolt 27 and the second motor fixing bolt 53 are ordinary fine hexagonal bolts for connecting the motor 28 and the partition plate 44.
The motor 28 is a brush direct current permanent magnet motor, and the motor 28 is a power source of the active brake pedal stroke simulator 12.
The brake master cylinder pressure sensor 52 adopts an active pressure sensor with the model number 303 produced by BOSCH company, and the pressure of the brake master cylinder can be measured by inputting 5V power supply voltage.
The first simulator liquid outlet electromagnetic valve 50 and the second simulator liquid outlet electromagnetic valve 51 are two-position two-way normally open electromagnetic valves, can realize bidirectional flow of brake fluid, and are used for controlling the on-off of the brake master cylinder and the hydraulic pressure adjusting unit 14.
The simulator solenoid valve 49 and the simulator third liquid outlet solenoid valve 48 are two-position two-way normally closed solenoid valves, and can realize bidirectional flow of brake fluid when electrified, so as to control the on-off of the brake master cylinder and the active brake pedal stroke simulator 12.
The simulator check valve 47 adopts a straight-through type check valve, the forward opening pressure is 0.04MPa, and the simulator check valve 47 is used for controlling the flow direction of brake fluid, so that the brake fluid can only flow from the port p to the port a of the simulator check valve 47, but the brake fluid cannot flow back.
The position and the connection mode of the concrete components are as follows:
the first piston 34 and the second piston 40 are sequentially arranged in the first section stepped hole and the second section stepped hole of the simulator cylinder 31 and are in sliding connection, the second piston sealing ring 30 is sleeved in the annular groove of the second piston 40, the third piston 35 is sleeved in the first piston 34 and is in sliding connection, and the third piston sealing ring 32 is sleeved in the annular groove of the third piston 35. The first piston spring 36 is sleeved on the circular boss on the second end face on the left side of the first piston 34, the left end face of the first piston spring 36 is in contact connection with the bottom face of the circular boss on the right end face of the second piston 40, and the right end face of the first piston spring 36 is in contact connection with the bottom face of the circular boss on the left end face of the first piston 34; a second piston spring 41 and a third piston spring 37 are respectively arranged on left end shafts of a second piston 40 and a third piston 35, the left end surface of the second piston spring 41 is in contact connection with the right end surface of a partition plate 44, the right end surface of the second piston spring 41 is in contact connection with the left end surface of a large-diameter shaft of the second piston 40, a third piston spring seat 38 is sleeved at the left end of the third piston 35 in a transition fit manner, the left end surface of the third piston spring 37 is in contact connection with the right end surface of the third piston spring seat 38, and the right end surface of the third piston spring 37 is in contact connection with the left end surface of a small-diameter shaft of the first piston 34; the pretension of the second piston spring 41 is greater than the pretension of the first piston spring 36. The third piston spring seat retainer 39 is mounted in a circular groove at the left end of the third piston 35, and the left end surface of the third piston spring seat 38 is in contact connection with the right end surface of the third piston spring seat retainer 39. The motor 28 is mounted on the right end surface of the partition plate 44 below the simulator cylinder 31 by the first motor fixing bolt 27 and the second motor fixing bolt 53. The motor controller 29 is mounted on the right end face of the housing of the electric motor 28, the terminal of the electric motor 28 is connected to the drive output terminal of the motor controller 29, and the motor controller 29 is connected to the brake system controller to receive commands from the brake system controller. The limit switch 22 is installed at the central position of the rear cover 46, the limit switch 22 transmits the collected signal to the motor controller 29 through a limit switch signal wire 26, the limit switch 22 is a small-stroke microswitch, and when the screw mandrel 23 returns to the initial position, the screw mandrel 23 contacts with the limit switch 22 to generate a corresponding signal. The driving gear 25 is sleeved on an output shaft of the motor 28 and is in interference fit connection, and the driving gear 25 is in tooth meshing connection with the toothed internal circulation nut 19 on the outer circumferential surface. The toothed internal circulation nut 19 is sleeved on a screw rod at the left end of the screw rod ejector rod 23, a ball 24 is arranged in a spiral raceway on a central through hole of the toothed internal circulation nut 19 and a spiral raceway on the screw rod in the screw rod ejector rod 23, the ball 24 can circulate through a circulation raceway (not shown in the figure) in the toothed internal circulation nut 19, and the rotary motion of the toothed internal circulation nut 19 is converted into the linear motion of the screw rod ejector rod 23 through the ball 24. The toothed internal circulation nut 19 is installed between the rear cover 46 and the partition plate 44 through the first thrust bearing 21 and the second thrust bearing 20, a second thrust bearing 20 is sleeved on a boss at the right end of the toothed internal circulation nut 19 and is in contact connection, the right end face of the toothed internal circulation nut 19 is in contact connection with the left end face of the second thrust bearing 20, the second thrust bearing 20 is sleeved on a circular boss at the left end face of the partition plate 44 and is in contact connection, the right end face of the second thrust bearing 20 is in contact connection with the left end face of the partition plate 44, the left end face of the toothed internal circulation nut 19 is in contact connection with the right end face of the first thrust bearing 21, the first thrust bearing 21 is sleeved on a circular boss at the inner side of the rear cover 46 and is in contact connection, and the left end. The right slide bar part of the screw mandrel 23 passes through the upper eccentric circular hole on the partition 44 and the circular hole on the third piston 35, and has a certain clearance with the two. The screw mandrel 23 can contact the third piston 35 during pressurization, but does not contact the partition 44. When the screw jack 23 returns to the initial position, there is no interference with the movement of the third piston 35. The simulator cylinder 31 is mounted on the right end face of the partition 44 by three bolts, the left end face of the simulator cylinder 31 is in contact connection with the right end face of the partition 44, and the three bolts are a first partition connecting bolt 60, a second partition connecting bolt 43 and a third partition connecting bolt 55, respectively. The rear cover 46 is mounted on the left end surface of the partition 44 by seven rivets, the right end surface of the rear cover 46 is in contact connection with the left end surface of the partition 44, and the seven rivets are a first rear cover connecting rivet 61, a second rear cover connecting rivet 59, a third rear cover connecting rivet 58, a fourth rear cover connecting rivet 45, a fifth rear cover connecting rivet 57, a sixth rear cover connecting rivet 56, and a seventh rear cover connecting rivet 54, respectively. Wherein: the rotation axes of the first piston 34, the second piston 40, the third piston 35, the third piston spring seat 38, the lead screw ejector rod 23, the toothed internal circulation nut 19, the first thrust bearing 21, the second thrust bearing 20 and the simulator cylinder 31 are collinear, the rotation axis of the output shaft of the motor 28 is collinear with the rotation axis of the driving gear 25, and the rotation axis of the output shaft of the motor 28 is parallel to the rotation axes of the first piston 34, the second piston 40, the third piston 35, the third piston spring seat 38, the lead screw ejector rod 23, the toothed internal circulation nut 19, the first thrust bearing 21, the second thrust bearing 20 and the simulator cylinder 31. The port a of the simulator electromagnetic valve 49, the port p of the simulator third liquid outlet electromagnetic valve 48 and the port a of the simulator one-way valve 47 are all connected with the oil inlet and outlet hole 33 hydraulic pipeline on the simulator cylinder 31, a port p of the simulator electromagnetic valve 49 and a port p of the simulator first liquid outlet electromagnetic valve 50 are connected with a port D hydraulic pipeline of the active brake pedal stroke simulator 12, a port a of the simulator first liquid outlet electromagnetic valve 50 is connected with a port G hydraulic pipeline of the active brake pedal stroke simulator 12, a port p of the simulator second liquid outlet electromagnetic valve 51 and a brake master cylinder pressure sensor 52 are connected with a port E hydraulic pipeline of the active brake pedal stroke simulator 12, a port a of the simulator second liquid outlet electromagnetic valve 51 is connected with a port H hydraulic pipeline of the active brake pedal stroke simulator 12, and a port a of the simulator third liquid outlet electromagnetic valve 48 and a port p of the simulator one-way valve 47 are connected with a port F hydraulic pipeline of the active brake pedal stroke simulator 12.
Referring to fig. 4, the main power supply device 13 includes an electric hydraulic cylinder, an electric hydraulic cylinder pressure sensor 62, an electric hydraulic cylinder first liquid outlet electromagnetic valve 63, and an electric hydraulic cylinder second liquid outlet electromagnetic valve 64.
The specific specifications and functions are as follows: the main energy supply device 13 is mainly used as a brake system energy supply device to realize the functions of active pressurization, pressure maintaining and active pressure reduction.
The electric hydraulic cylinder comprises an electric hydraulic cylinder body 65, an electric hydraulic cylinder piston spring 66, an electric hydraulic cylinder piston 67, an electric hydraulic cylinder ball screw 68 and an electric hydraulic cylinder motor 69; the cylinder body 65 of the electric hydraulic cylinder is a cylindrical structural member, the left end and the right end of the cylinder body are both provided with holes, the diameter of the left end opening is smaller and is processed into a threaded hole, the hole is an oil inlet and outlet hole a of the electric hydraulic cylinder, the diameter of the right end opening is larger, and an oil inlet and outlet hole p is formed in the outer cylindrical surface of the cylinder body 65 of the electric hydraulic cylinder; a center hole is formed in the center of the right end of the electric hydraulic cylinder piston 67, a spiral raceway for mounting balls is formed in the inner cylindrical surface of the center hole, and a spiral raceway matched with the spiral raceway of the electric hydraulic cylinder piston 67 is formed in the electric hydraulic cylinder ball screw 68; the electric hydraulic cylinder piston spring 66 and the electric hydraulic cylinder piston 67 are sequentially arranged in the electric hydraulic cylinder body 65, the electric hydraulic cylinder piston 67 is in sliding connection with the electric hydraulic cylinder body 65, the left end of the electric hydraulic cylinder ball screw 68 is arranged in a central hole at the right end of the electric hydraulic cylinder piston 67 and is in rolling connection, the right end of the electric hydraulic cylinder ball screw 68 is connected with an electric hydraulic cylinder motor 69 through a transmission mechanism (not shown in the figure), and the electric hydraulic cylinder ball screw 68 can convert the rotary motion of the electric hydraulic cylinder motor 69 into the linear motion of the electric hydraulic cylinder piston 67.
The electric hydraulic cylinder pressure sensor 62 adopts an active pressure sensor of type 303 manufactured by BOSCH company, needs to input a supply voltage of 5V, and can measure the pressure of the primary energy supply device 13.
The first liquid outlet electromagnetic valve 63 and the second liquid outlet electromagnetic valve 64 of the electric hydraulic cylinder are two-position two-way normally closed electromagnetic valves, so that the bidirectional flow of brake liquid can be realized, and the two-position two-way normally closed electromagnetic valves are used for controlling the on-off of the main energy supply device 13 and the hydraulic pressure adjusting unit 14.
The position and the connection mode of the specific parts are as follows: the port p of the first liquid outlet electromagnetic valve 63 of the electric hydraulic cylinder, the port p of the second liquid outlet electromagnetic valve 64 of the electric hydraulic cylinder, and the electric hydraulic cylinder pressure sensor 62 are all connected with the hydraulic pipeline a of the oil inlet and outlet hole of the electric hydraulic cylinder, the port a of the first liquid outlet electromagnetic valve 63 of the electric hydraulic cylinder is connected with the hydraulic pipeline I of the main energy supply device 13, the port a of the second liquid outlet electromagnetic valve 64 of the electric hydraulic cylinder is connected with the hydraulic pipeline J of the main energy supply device 13, and the oil inlet and outlet hole p of the electric hydraulic cylinder is connected with the hydraulic pipeline K of the main energy supply device 13.
Referring to fig. 5, the hydraulic pressure adjusting unit 14 includes a right rear wheel check valve 70, a right rear wheel liquid inlet solenoid valve 71, a left front wheel check valve 72, a left front wheel liquid inlet solenoid valve 73, a right front wheel check valve 74, a right front wheel liquid inlet solenoid valve 75, a left rear wheel check valve 76, a left rear wheel liquid inlet solenoid valve 77, a right rear wheel liquid outlet solenoid valve 78, a left front wheel liquid outlet solenoid valve 79, a right front wheel liquid outlet solenoid valve 80, and a left rear wheel liquid outlet solenoid valve 81.
The specific specifications and functions are as follows: the hydraulic pressure adjusting unit 14 has a function of adjusting the brake cylinder pressure.
The right rear wheel liquid inlet electromagnetic valve 71, the left front wheel liquid inlet electromagnetic valve 73, the right front wheel liquid inlet electromagnetic valve 75 and the left rear wheel liquid inlet electromagnetic valve 77 are two-position two-way normally open electromagnetic valves and respectively control the pressurization of the right rear wheel 15, the left front wheel 16, the right front wheel 17 and the left rear wheel 18.
The right rear wheel liquid outlet electromagnetic valve 78, the left front wheel liquid outlet electromagnetic valve 79, the right front wheel liquid outlet electromagnetic valve 80 and the left rear wheel liquid outlet electromagnetic valve 81 are two-position two-way normally closed electromagnetic valves and respectively control the pressure reduction of the right rear wheel 15, the left front wheel 16, the right front wheel 17 and the left rear wheel 18.
The right rear wheel check valve 70, the left front wheel check valve 72, the right front wheel check valve 74, and the left rear wheel check valve 76 define that the brake fluid can flow only in one direction.
The position and the connection mode of the specific parts are as follows: an opening a of the right rear wheel check valve 70, an opening P of the right rear wheel liquid inlet electromagnetic valve 71, an opening a of the left front wheel check valve 72 and an opening P of the left front wheel liquid inlet electromagnetic valve 73 are all connected with an M-opening hydraulic pipeline of the hydraulic adjusting unit 14, an opening a of the right front wheel check valve 74, an opening P of the right front wheel liquid inlet electromagnetic valve 75, an opening a of the left rear wheel check valve 76 and an opening P of the left rear wheel liquid inlet electromagnetic valve 77 are all connected with an L-opening hydraulic pipeline of the hydraulic adjusting unit 14, an opening P of the right rear wheel check valve 70, an opening a of the right rear wheel liquid inlet electromagnetic valve 71 and an opening P of the right rear wheel liquid outlet electromagnetic valve 78 are all connected with a Q-opening hydraulic pipeline of the hydraulic adjusting unit 14, an opening P of the left front wheel check valve 72, an opening a opening of the left front wheel liquid inlet electromagnetic valve 73 and an opening P of the left front wheel liquid outlet electromagnetic valve 79 are all connected with a P-opening hydraulic pipeline of the hydraulic adjusting unit 14, an opening P of the, The p port of the right front wheel liquid outlet electromagnetic valve 80 is connected with an O port hydraulic pipeline of the hydraulic adjusting unit 14, the p port of the left rear wheel check valve 76, the a port of the left rear wheel liquid inlet electromagnetic valve 77 and the p port of the left rear wheel liquid outlet electromagnetic valve 81 are connected with an N port hydraulic pipeline of the hydraulic adjusting unit 14, and the a port of the right rear wheel liquid outlet electromagnetic valve 78, the a port of the left front wheel liquid outlet electromagnetic valve 79, the a port of the right front wheel liquid outlet electromagnetic valve 80 and the a port of the left rear wheel liquid outlet electromagnetic valve 81 are connected with an R port hydraulic pipeline of the hydraulic adjusting unit 14.
The connection relationship among the brake control mechanism 1, the active brake pedal stroke simulator 12, the main energy supply device 13 and the hydraulic pressure adjusting unit 14 of the brake-by-wire system with the backup function is as follows: the driver directly controls the brake control mechanism 1, finally the hydraulic adjusting unit 14 controls the wheels to brake, and an active brake pedal stroke simulator 12 and a main energy supply device 13 are arranged between the output end of the brake control mechanism 1 and the input end of the hydraulic adjusting unit 14 in parallel. The output end of the brake control mechanism 1 comprises a first cavity liquid outlet A of the brake master cylinder, a second cavity liquid outlet B of the brake master cylinder and a third cavity liquid inlet C of the brake master cylinder, the first cavity liquid outlet A of the brake master cylinder is connected with a liquid inlet D brake pipeline of the active brake pedal stroke simulator 12, the second cavity liquid outlet B of the brake master cylinder is connected with a liquid inlet E brake pipeline of the active brake pedal stroke simulator 12, a third cavity liquid inlet C of the brake master cylinder is connected with a liquid outlet F brake pipeline of the active brake pedal stroke simulator 12, a liquid outlet G of the active brake pedal stroke simulator 12 and a liquid outlet I of the main energy supply device 13 are both connected with a liquid inlet M brake pipeline of the hydraulic adjusting unit 14, a liquid outlet H of the active brake pedal stroke simulator 12 and a liquid outlet J of the main energy supply device 13 are both connected with a liquid inlet L brake pipeline of the hydraulic adjusting unit 14, the liquid inlet K of the main energy supply device 13 and the liquid outlet R of the hydraulic adjusting unit 14 are connected with the liquid outlet d of the liquid storage tank 2 through brake pipelines.
The brake-by-wire system with the backup function can simulate the pedal feeling through the active brake pedal stroke simulator 12 when the main energy supply device 13 works (pressure regulation), and can dynamically regulate the pressure of a brake master cylinder and the pedal feeling through the active pressure regulation function of the active brake pedal stroke simulator 12 after the main energy supply device 13 fails, so that the redundant backup design of the brake system is realized while the brake pedal feeling is ensured to be consistent with that of a traditional automobile, and the driving safety is ensured to the maximum extent.
Referring to fig. 6, the control method of the brake-by-wire system with backup function according to the present invention is as follows:
the method comprises the following steps: whether the displacement of the brake pedal 6 is 0 or not is detected, and the brake controller receives a pedal displacement signal transmitted from the pedal displacement sensor 5. And if the pedal displacement is 0, entering a step two, otherwise, entering a step three.
Step two: when the pedal displacement is 0, the working state command sent by the brake controller to the simulator motor controller 29 is in an idle state, so that the active brake pedal stroke simulator 12 is in the idle state, when the screw mandrel 23 is already at the initial position, the motor 28 does not work, when the screw mandrel 23 is not at the initial position, the motor controller 29 drives the motor 28 to rotate reversely, the motor 28 converts the rotary motion of the motor 28 into the linear motion of the screw mandrel 23 through the driving gear 25, the toothed internal circulation nut 19, the ball 24 and the screw mandrel 23, so that the screw mandrel 23 moves leftwards until the left end of the sliding rod of the screw mandrel 23 is contacted with the limit switch 22, the limit switch 22 transmits the acquired signal to the motor controller 29 through the limit switch signal wire 26, and at this time, the screw mandrel 23 is considered to be at the initial position. Meanwhile, the main energy supply device 13 is also in an idle state, when the electric hydraulic cylinder piston 67 is in an initial position, the electric hydraulic cylinder motor 69 does not work, when the electric hydraulic cylinder piston 67 is not in the initial position, the electric hydraulic cylinder motor 69 is driven to rotate reversely, the electric hydraulic cylinder motor 69 converts the rotary motion into the linear motion of the electric hydraulic cylinder piston 67 through the electric hydraulic cylinder ball screw 68, so that the electric hydraulic cylinder piston 67 moves rightwards to the initial position, whether the electric hydraulic cylinder piston 67 returns or not is judged through the rotating speed of the electric hydraulic cylinder motor 69, when the rotating speed of the electric hydraulic cylinder motor 69 is lower than a threshold value w, the electric hydraulic cylinder piston 67 is considered to return, and the threshold value w needs to be obtained through; when the pedal displacement is 0 and the screw mandrel 23 in the active brake pedal stroke simulator 12 and the electric hydraulic cylinder piston 67 in the main energy supply device 13 are both returned, the brake system does not work.
Step three: calculating a target master cylinder pressure P when the pedal displacement is greater than 0Master cylinder tarThe brake controller receives the pedal displacement signal transmitted by the pedal displacement sensor 5, and obtains the target master cylinder pressure P under the corresponding pedal displacement according to the relation curve of the traditional automobile pedal displacement and the master cylinder pressure measured by the testMaster cylinder tar。
Step four: the working state command sent by the brake controller to the simulator motor controller 29 is a pedal stroke simulation state, so that the active brake pedal stroke simulator 12 is in the pedal stroke simulation state, when the screw mandrel 23 is already at the initial position, the motor 28 does not work, and when the screw mandrel 23 is not at the initial position, the motor controller 29 drives the motor 28 to rotate reversely, so that the screw mandrel 23 runs to the initial position. After that, the simulator solenoid valve 49 is opened, the first simulator fluid outlet solenoid valve 50, the second simulator fluid outlet solenoid valve 51 and the third simulator fluid outlet solenoid valve 48 are all closed, the front axle brake fluid completely enters the active brake pedal stroke simulator 12, and the pedal feel is completely provided by the active brake pedal stroke simulator 12. In order to make the pedal feel consistent with the conventional brake pedal feel, the parameters of the first piston spring 36, the second piston spring 41, the first piston 34 and the second piston 40 of the active brake pedal stroke simulator 12 need to be matched, so that the brake pedal stroke simulator can accurately simulate the pressure-volume characteristics of the wheel cylinder, and the pedal feel is guaranteed. The first hydraulic cylinder outlet electromagnetic valve 63 and the second hydraulic cylinder outlet electromagnetic valve 64 are both opened, and at the moment, the wheel cylinder pressure is completely provided by the main energy supply device 13.
Step five: the brake controller receives the pressure signal P of the main energy supply device 13 transmitted by the electric hydraulic cylinder pressure sensor 62Electric hydraulic cylinder act. If the pressure signal P of the main energy supply device 13Electric hydraulic cylinder actLess than target master cylinder pressure PMaster cylinder tarEntering the step six; if the pressure signal P of the main energy supply device 13Electric hydraulic cylinder actEqual to target master cylinder pressure PMaster cylinder tarEntering a seventh step; otherwise, entering step eight.
Step six: pressure signal P of main energy supply device 13Electric hydraulic cylinder actLess than target master cylinder pressure PMaster cylinder tarWhen the main energy supply device 13 is in a pressurization state, the electric hydraulic cylinder motor 69 is driven to rotate in the forward direction, the electric hydraulic cylinder motor 69 converts the rotation motion into the linear motion of the electric hydraulic cylinder piston 67 through the electric hydraulic cylinder ball screw 68, the electric hydraulic cylinder piston 67 moves leftwards, and when the electric hydraulic cylinder piston 67 moves to the electric hydraulic cylinder oil inlet and outlet hole p, the main energy supply device 13 starts to build pressure and the actual pressure gradually rises.
Step seven: pressure signal P of main energy supply device 13Electric hydraulic cylinder actEqual to target master cylinder pressure PMaster cylinder tarWhen the main energy supply device 13 is in a pressure maintaining state, the electric hydraulic cylinder motor 69 is static, and the electric hydraulic cylinder ball screw 68 and the electric hydraulic cylinder piston 67 keep the original position, so that the actual pressure of the main energy supply device 13 is kept unchanged.
Step eight: pressure signal P of main energy supply device 13Electric hydraulic cylinder actGreater than target master cylinder pressure PMaster cylinder tarWhen the main energy supply device 13 is in a decompression state, the electric hydraulic cylinder motor 69 is driven to rotate reversely, the electric hydraulic cylinder motor 69 converts the rotation motion into the linear motion of the electric hydraulic cylinder piston 67 through the electric hydraulic cylinder ball screw 68, the electric hydraulic cylinder piston 67 moves rightwards, the actual pressure of the main energy supply device 13 is gradually reduced, after the electric hydraulic cylinder piston 67 returns to the electric hydraulic cylinder oil inlet and outlet hole p, the actual pressure of the main energy supply device 13 is reduced to 0, and after the electric hydraulic cylinder piston 67 returns to the original position, the decompression process is finished.
Step nine: the brake controller receives the pressure signal P of the main energy supply device 13 transmitted by the electric hydraulic cylinder pressure sensor 62 againElectric hydraulic cylinder actAnd judging whether the main energy supply device 13 fails, if so, entering the step ten, and if not, returning to the step one.
Step ten: the first hydraulic cylinder liquid outlet electromagnetic valve 63 and the second hydraulic cylinder liquid outlet electromagnetic valve 64 are closed, the simulator electromagnetic valve 49 is closed, the first simulator liquid outlet electromagnetic valve 50, the second simulator liquid outlet electromagnetic valve 51 and the third simulator liquid outlet electromagnetic valve 48 are opened, and at the moment, the wheel cylinder pressure is completely provided by the brake master cylinder.
Step eleven: the brake controller receives the master cylinder pressure signal P from the master cylinder pressure sensor 52Brake master cylinder act. If the master cylinder pressure signal PBrake master cylinder actLess than target master cylinder pressure PMaster cylinder tarEntering step twelve; if the master cylinder pressure signal PBrake master cylinder actEqual to target master cylinder pressure PMaster cylinder tarEntering a step thirteen; otherwise go to step fourteen.
Step twelve: pressure signal P of brake master cylinderBrake master cylinder actLess than target master cylinder pressure PMaster cylinder tarWhen the brake controller sends a working state command to the simulator motor controller 29 to be a pressurization state, so that the active brake pedal stroke simulator 12 is in the pressurization state, the motor controller 29 sends a control command to enable the motor 28 to rotate in the forward direction, the motor 28 converts the rotary motion into the linear motion of the screw rod ejector 23 through the driving gear 25, the toothed internal circulation nut 19, the ball 24 and the screw rod ejector 23, when the screw rod ejector 23 moves to be in contact with the third piston 35, the third piston 35 starts to move rightwards relative to the first piston 34, the pressurization process starts, the third piston 35 is continuously pushed by the screw rod ejector 23, and the pressurization process is continuously carried out. Brake fluid enters a third cavity of the brake master cylinder through the simulator oil inlet and outlet hole 33 and the simulator third liquid outlet electromagnetic valve 48, active pressurization and pedal feeling simulation work is completed by adjusting the active brake pedal stroke simulator 12 in real time, and the actual pressure of the brake master cylinder is gradually increased.
Step thirteen: pressure signal P of brake master cylinderBrake master cylinder actEqual to target master cylinder pressure PMaster cylinder tarWhen the working state command sent by the brake controller to the simulator motor controller 29 is a pressure maintaining state, the active brake pedal stroke simulator 12 is in the pressure maintaining state, and the motor controller 29 sends a control command to enable the active brake pedal stroke simulator to be in the pressure maintaining stateThe motor 28 is static, the screw mandrel 23 and the third piston 35 keep the original position, so that the actual pressure of the brake master cylinder is kept unchanged.
Fourteen steps: pressure signal P of brake master cylinderBrake master cylinder actGreater than target master cylinder pressure PMaster cylinder tarWhen the working state command sent by the brake controller to the simulator motor controller 29 is a decompression state, so that the active brake pedal stroke simulator 12 is in the decompression state, the motor controller 29 sends a control command to enable the motor 28 to rotate reversely, the motor 28 converts the rotary motion into the linear motion of the screw rod ejector 23 through the driving gear 25, the toothed internal circulation nut 19, the ball 24 and the screw rod ejector 23 until the screw rod ejector 23 moves to be in contact with the limit switch 22, the screw rod ejector 23 returns to the initial position, the third piston 35 moves leftwards relative to the first piston 34 under the action of the third piston spring 37 and high-pressure brake fluid until the third piston 35 returns, the brake fluid in the third chamber of the brake master cylinder flows back to the active brake pedal stroke simulator 12 through the simulator one-way valve 47 and the simulator oil inlet and outlet hole 33, and the active brake pedal stroke simulator 12 is adjusted in real time, and finishing the work of active pressure reduction and pedal feeling simulation, and gradually reducing the actual pressure of the brake master cylinder until the pressure reduction process is finished.
Step fifteen: and returning to the first step.

Claims (8)

1. The brake-by-wire system with the backup function is characterized by comprising a brake control mechanism (1), an active brake pedal stroke simulator (12), a main energy supply device (13) and a hydraulic pressure adjusting unit (14);
the brake control mechanism (1) comprises a brake master cylinder and a liquid storage tank (2);
the brake master cylinder is internally provided with three cavities which are arranged in series, namely a cavity I, a cavity II and a cavity III from left to right, wherein a cavity I liquid outlet A of the cavity I of the brake master cylinder is connected with a brake pipeline of a liquid inlet D of the active brake pedal stroke simulator (12), a cavity II liquid outlet B of the brake master cylinder is connected with a brake pipeline of a liquid inlet E of the active brake pedal stroke simulator (12), a cavity III liquid inlet C of the brake master cylinder is connected with a brake pipeline of a liquid outlet F of the active brake pedal stroke simulator (12), a liquid outlet G of the active brake pedal stroke simulator (12) and a liquid outlet I of the main energy supply device (13) are both connected with a brake pipeline of a liquid inlet M of the hydraulic adjusting unit (14), a liquid outlet H of the active brake pedal stroke simulator (12) and a liquid outlet J of the main energy supply device (13) are both connected with a brake pipeline of a liquid inlet L of the hydraulic adjusting unit (14), a liquid inlet K of the main energy supply device (13) and a liquid outlet R of the hydraulic adjusting unit (14) are both connected with a liquid outlet d of the liquid storage tank (2) through a brake pipeline.
2. The brake-by-wire system with backup function according to claim 1, wherein the brake master cylinder comprises a brake master cylinder body (7), a brake master cylinder first piston (10), a brake master cylinder second piston (8), a brake master cylinder first piston spring (11), a brake master cylinder second piston spring (9) and a brake master cylinder push rod (4), the brake master cylinder body (7) is a cylindrical structural member, the left end of the brake master cylinder body is closed, the right end of the brake master cylinder body is opened, a flange plate is arranged on the right end surface of the brake master cylinder, six liquid inlet and outlet ports are arranged on the outer cylindrical surface of the brake master cylinder body (7) and are all threaded holes, the brake master cylinder first piston spring (11), the brake master cylinder first piston (10), the brake master cylinder second piston spring (9), the brake master cylinder second piston (8) and the brake master cylinder push rod (4) are sequentially arranged in the brake master cylinder body (7, the brake master cylinder comprises a first piston (10) of the brake master cylinder, a second piston (8) of the brake master cylinder and a cylinder body (7) of the brake master cylinder, wherein the first piston spring (11) of the brake master cylinder, the first piston (10) of the brake master cylinder, a second piston spring (9) of the brake master cylinder, the second piston (8) of the brake master cylinder, a push rod (4) of the brake master cylinder and the rotation axis of the cylinder body (7) of the brake master cylinder are collinear, three chambers which are isolated by the first piston (10) of the brake master cylinder and the second piston (8) of the brake master cylinder and can independently generate high-pressure brake fluid are arranged in the brake master cylinder in a series manner, and are a first chamber, a second chamber and a third chamber from left to right in sequence, a push rod (4) of the brake master cylinder is arranged at a mechanical inlet of;
liquid storage pot (2) total four liquid outlets, be liquid outlet f, liquid outlet r, liquid outlet t and liquid outlet d respectively, liquid outlet f, liquid outlet r, liquid outlet t are connected through pipeline and I cavity inlet a of brake master cylinder, II cavity inlet b of brake master cylinder, III cavity inlet c of brake master cylinder respectively, liquid storage pot (2) are installed in the top of brake master cylinder.
3. The brake-by-wire system with backup function according to claim 1, wherein said brake operating mechanism (1) further comprises a brake pedal (6), a pedal displacement sensor (5), a master cylinder check valve (3);
brake pedal (6) install driver front portion below in the carriage, the top of rotation part is fixed on the pedal support through the round pin axle in brake pedal (6), the pedal support passes through the bolt fastening on the automobile body, the middle-end left surface of rotation part is connected with the right-hand member face contact of brake master cylinder push rod (4) in the brake master cylinder in brake pedal (6), pedal displacement sensor (5) are fixed on the pedal support of being connected with the automobile body, the digging arm of pedal displacement sensor (5) is connected with the rotation part in brake pedal (6), install between liquid storage pot (2) liquid outlet t and brake master cylinder III cavity inlet c brake master cylinder check valve (3), the p mouth and the liquid storage pot (2) liquid outlet t hydraulic line connection of brake master cylinder check valve (3), the a mouth and the hydraulic line connection of brake master cylinder III cavity inlet c of brake master cylinder check valve (3).
4. The brake-by-wire system with a backup function according to claim 1, wherein the active brake pedal stroke simulator (12) comprises a motor controller (29), a motor (28), a driving gear (25), a toothed internal circulation nut (19), a ball (24), a screw rod ejector rod (23), a limit switch (22), a rear cover (46), a partition plate (44), a first thrust bearing (21), a second thrust bearing (20), a second piston (40), a second piston spring (41), a second piston sealing ring (30), a first piston (34), a first piston spring (36), a third piston (35), a third piston spring (37), a third piston spring seat (38), a third piston spring seat retainer ring (39), a third piston sealing ring (32), a simulator cylinder body (31), a simulator check valve (47), a first piston spring, a second piston spring (35), a third piston spring (37), a simulator cylinder seat (38), a simulator check valve (47), and a second piston sealing ring (, A simulator third liquid outlet electromagnetic valve (48), a simulator electromagnetic valve (49), a simulator first liquid outlet electromagnetic valve (50), a simulator second liquid outlet electromagnetic valve (51) and a brake master cylinder pressure sensor (52);
the simulator is characterized in that the simulator cylinder body (31) is installed on the right end face of the partition plate (44) through a bolt, the rear cover (46) is installed on the left end face of the partition plate (44) through a rivet, the toothed internal circulation nut (19) is installed between the rear cover (46) and the partition plate (44) through a first thrust bearing (21) and a second thrust bearing (20), the left end face and the right end face of the first thrust bearing (21) are respectively in contact connection with the rear cover (46) and the toothed internal circulation nut (19), the left end face and the right end face of the second thrust bearing (20) are respectively in contact connection with the toothed internal circulation nut (19) and the partition plate (44), the left end raceway of the lead screw ejector rod (23) is in rolling connection by adopting a ball (24) to be installed in a spiral raceway of a center hole of the toothed internal circulation nut (19), the right end of the lead screw ejector rod (23) is inserted into a stepped hole of the simulator cylinder body (31), and a, the left end of a third piston (35) is sleeved in a second piston (40), the right end of the third piston (35) is sleeved on the first piston (34) and is in sliding connection with the first piston (34), the first piston (34) and the second piston (40) are sequentially arranged in a first section of stepped hole and a second section of stepped hole of a simulator cylinder body (31) and are in sliding connection with each other, a first piston spring (36) is sleeved on a circular boss on the second end face on the left side of the first piston (34), a second piston spring (41) and a third piston spring (37) are respectively arranged on a left end shaft of the second piston (40) and a left end shaft of the third piston (35), a third piston spring seat (38) is sleeved on the left end of the third piston (35) in transition fit, a third piston spring seat (39) is arranged in a circular groove on the left end of the third piston (35), the left end face of the third piston spring seat (38) is in contact connection with the right end face of the third piston spring seat (39), a second piston sealing ring (30) and a third piston sealing ring (32) are respectively sleeved in annular grooves of a second piston (40) and a third piston (35), a motor (28) is installed on the right end face of a partition plate (44) below a simulator cylinder body (31), a driving gear (25) is sleeved on an output shaft of the motor (28) and is in interference fit connection, the driving gear (25) is in meshing connection with a toothed internal circulation nut (19), a motor controller (29) is installed on the right end face of a shell of the motor (28), the motor (28) is in electric wire connection with the motor controller (29), a limit switch (22) is installed at the central position of a rear cover (46), the limit switch (22) is connected with the motor controller electromagnetic valve (29) through a limit switch signal wire (26), an a port of a simulator (49) and a p port of a third liquid outlet electromagnetic valve (48) of the simulator, An a port of a simulator one-way valve (47) is connected with a hydraulic pipeline of an oil inlet and outlet hole (33) on a simulator cylinder body (31), a p port of a simulator electromagnetic valve (49) and a p port of a simulator first liquid outlet electromagnetic valve (50) are connected with a D port hydraulic pipeline of an active brake pedal stroke simulator (12), an a port of the simulator first liquid outlet electromagnetic valve (50) is connected with a G port hydraulic pipeline of the active brake pedal stroke simulator (12), a p port of a simulator second liquid outlet electromagnetic valve (51) and a brake master cylinder pressure sensor (52) are connected with an E port hydraulic pipeline of the active brake pedal stroke simulator (12), an a port of the simulator second liquid outlet electromagnetic valve (51) is connected with an H port hydraulic pipeline of the active brake pedal stroke simulator (12), an a port of a simulator third liquid outlet electromagnetic valve (48) and a p port of the simulator one-way valve (47) are connected with an F port hydraulic pipeline of the active brake pedal stroke simulator (12) .
5. The brake-by-wire system with backup function according to claim 4, wherein the simulator cylinder (31) is a cylindrical structure, the left end and the right end of the simulator cylinder are both open, a flange plate for installation is arranged on the outer cylindrical surface of the left end cylinder opening, three bolt holes are uniformly distributed on the flange plate, a three-section cylindrical stepped hole is processed along the central axis of the simulator cylinder (31), the diameter of the three-section stepped hole is gradually decreased from left to right, and is a first-section stepped hole, a second-section stepped hole and a third-section stepped hole in sequence, wherein the second piston (40) and the second piston spring (41) are installed in the first-section stepped hole, the first piston (34) and the first piston spring (36) are installed in the second-section stepped hole, the third-section stepped hole is an oil inlet/outlet hole (33) of the simulator cylinder (31) and is processed into an internal threaded hole, the cylinder wall of the first section of stepped hole is also provided with a vent hole (42), the three-section cylindrical stepped holes are mutually communicated and the rotation axes are collinear;
the third piston (35) is a two-section stepped shaft, the right end shaft diameter is larger, an annular groove for placing a sealing ring is processed on the cylindrical surface of the right end shaft, the left end shaft diameter is smaller and used for mounting a third piston spring (37), a circular groove for placing a third piston spring seat check ring (39) is processed on the cylindrical surface of the left end shaft, a circular hole is processed on the left end shaft along the rotation center line of the stepped shaft, and the diameter of the circular hole is slightly larger than that of a right end slide bar of the screw mandrel (23); the first piston (34) is a two-section stepped shaft, the shaft diameter of the right end is larger, the shaft diameter of the left end is smaller, the shaft diameter of the left end is used for mounting a third piston spring (37), a circular boss is arranged on the left end face of the shaft with the larger diameter and used for mounting the first piston spring (36), a circular stepped hole is machined along the rotation center line of the stepped shaft, the diameter of the right end of the stepped hole is larger and is equal to the shaft diameter of the right end of the third piston (35), and the diameter of the left end of the stepped hole is smaller and is equal to the shaft diameter of the left end of the third piston (35); the second piston (40) is a two-section type stepped shaft, the right end shaft diameter is large, a circular ring-shaped boss is arranged on the right end face and used for mounting a first piston spring (36), an annular groove used for placing a sealing ring is processed on the cylindrical surface of the right end shaft, the left end shaft diameter is small and used for mounting a second piston spring (41), a circular through hole is processed along the rotation center line of the stepped shaft, and the diameter of the through hole is slightly larger than that of the left end shaft diameter of the first piston (34).
6. The brake-by-wire system with a backup function according to claim 1, wherein the main energy supply device (13) comprises an electric hydraulic cylinder, an electric hydraulic cylinder pressure sensor (62), an electric hydraulic cylinder first fluid outlet solenoid valve (63), and an electric hydraulic cylinder second fluid outlet solenoid valve (64);
the electric hydraulic cylinder comprises an electric hydraulic cylinder body (65), an electric hydraulic cylinder piston spring (66), an electric hydraulic cylinder piston (67), an electric hydraulic cylinder ball screw (68) and an electric hydraulic cylinder motor (69); the cylinder body (65) of the electric hydraulic cylinder is a cylindrical structural member, the left end and the right end of the cylinder body are both provided with holes, the diameter of the left end opening is smaller and is processed into a threaded hole, the hole is an oil inlet and outlet hole a of the electric hydraulic cylinder, the diameter of the right end opening is larger, and an oil inlet and outlet hole p is formed in the outer cylindrical surface of the cylinder body (65) of the electric hydraulic cylinder; a center hole is formed in the center of the right end of the electric hydraulic cylinder piston (67), a spiral raceway for mounting balls is formed in the inner cylindrical surface of the center hole, and a spiral raceway matched with the spiral raceway of the electric hydraulic cylinder piston (67) is formed in the electric hydraulic cylinder ball screw (68); the electric hydraulic cylinder piston spring (66) and the electric hydraulic cylinder piston (67) are sequentially arranged in the electric hydraulic cylinder body (65), the electric hydraulic cylinder piston (67) is in sliding connection with the electric hydraulic cylinder body (65), the left end of the electric hydraulic cylinder ball screw (68) is arranged in a central hole at the right end of the electric hydraulic cylinder piston (67) and is in rolling connection, the right end of the electric hydraulic cylinder ball screw (68) is connected with an electric hydraulic cylinder motor (69) through a transmission mechanism, and the electric hydraulic cylinder ball screw (68) can convert the rotary motion of the electric hydraulic cylinder motor (69) into the linear motion of the electric hydraulic cylinder piston (67);
the hydraulic control system is characterized in that a p port of the first liquid outlet electromagnetic valve (63) of the electric hydraulic cylinder, a p port of the second liquid outlet electromagnetic valve (64) of the electric hydraulic cylinder, and a pressure sensor (62) of the electric hydraulic cylinder are connected with a hydraulic pipeline of an oil inlet and outlet hole a of the electric hydraulic cylinder, an a port of the first liquid outlet electromagnetic valve (63) of the electric hydraulic cylinder is connected with a hydraulic pipeline of an I port of the main energy supply device (13), an a port of the second liquid outlet electromagnetic valve (64) of the electric hydraulic cylinder is connected with a hydraulic pipeline of a J port of the main energy supply device (13), and an oil inlet and outlet hole p of the electric hydraulic cylinder is connected with a hydraulic pipeline.
7. The brake-by-wire system with backup function according to claim 1, wherein the hydraulic pressure adjusting unit (14) comprises a right rear wheel check valve (70), a right rear wheel liquid inlet solenoid valve (71), a left front wheel check valve (72), a left front wheel liquid inlet solenoid valve (73), a right front wheel check valve (74), a right front wheel liquid inlet solenoid valve (75), a left rear wheel check valve (76), a left rear wheel liquid inlet solenoid valve (77), a right rear wheel liquid outlet solenoid valve (78), a left front wheel liquid outlet solenoid valve (79), a right front wheel liquid outlet solenoid valve (80), and a left rear wheel liquid outlet solenoid valve (81);
an opening a of the right rear wheel check valve (70), an opening P of the right rear wheel liquid inlet electromagnetic valve (71), an opening a of the left front wheel check valve (72) and an opening P of the left front wheel liquid inlet electromagnetic valve (73) are all connected with an M opening hydraulic pipeline of the hydraulic adjusting unit (14), an opening a of the right front wheel check valve (74), an opening P of the right front wheel liquid inlet electromagnetic valve (75), an opening a of the left rear wheel check valve (76) and an opening P of the left rear wheel liquid inlet electromagnetic valve (77) are all connected with an L opening hydraulic pipeline of the hydraulic adjusting unit (14), an opening P of the right rear wheel check valve (70), an opening a of the right rear wheel liquid inlet electromagnetic valve (71) and an opening P of the right rear wheel liquid outlet electromagnetic valve (78) are all connected with a Q opening hydraulic pipeline of the hydraulic adjusting unit (14), an opening P of the left front wheel check valve (72), an opening a opening of the left front wheel liquid inlet electromagnetic valve (73) and an opening P of the left front wheel liquid outlet electromagnetic valve (79) are all connected with a P opening hydraulic pipeline of the hydraulic adjusting unit (14), the port p of the right front wheel check valve (74), the port a of the right front wheel liquid inlet electromagnetic valve (75) and the port p of the right front wheel liquid outlet electromagnetic valve (80) are all connected with an O port hydraulic pipeline of the hydraulic adjusting unit (14), the port p of the left rear wheel check valve (76), the port a of the left rear wheel liquid inlet electromagnetic valve (77) and the port p of the left rear wheel liquid outlet electromagnetic valve (81) are all connected with an N port hydraulic pipeline of the hydraulic adjusting unit (14), and the port a of the right rear wheel liquid outlet electromagnetic valve (78), the port a of the left front wheel liquid outlet electromagnetic valve (79), the port a of the right front wheel liquid outlet electromagnetic valve (80) and the port a of the left rear wheel liquid outlet electromagnetic valve (81) are all connected with an R port hydraulic pipeline of the hydraulic adjusting unit (14).
8. A control method of a brake-by-wire system with a backup function is characterized by comprising the following steps:
1) detecting whether the displacement of a brake pedal (6) is 0, receiving a pedal displacement signal transmitted by a pedal displacement sensor (5) by a brake controller, and if the pedal displacement is 0, entering a step 2), otherwise, entering a step 3);
2) when the pedal displacement is 0, the working state command sent by the brake controller to the simulator motor controller (29) is in an idle state, so that the active brake pedal stroke simulator (12) is in the idle state, when the screw mandrel (23) is already at an initial position, the motor (28) does not work, when the screw mandrel (23) is not at the initial position, the motor controller (29) drives the motor (28) to rotate reversely, the motor (28) converts the rotary motion of the motor (28) into the linear motion of the screw mandrel (23) through the driving gear (25), the toothed internal circulation nut (19), the ball (24) and the screw mandrel (23), so that the screw mandrel (23) moves leftwards until the left end of the sliding rod of the screw mandrel (23) is contacted with the limit switch (22), and the limit switch (22) transmits the acquired signal to the motor controller (29) through a limit switch signal wire (26), at the moment, the screw mandrel ejector rod (23) is considered to be in the initial position; meanwhile, the main energy supply device (13) is also in an idle state, when the electric hydraulic cylinder piston (67) is in an initial position, the electric hydraulic cylinder motor (69) does not work, when the electric hydraulic cylinder piston (67) is not in the initial position, the electric hydraulic cylinder motor (69) is driven to rotate reversely, the electric hydraulic cylinder motor (69) converts the rotary motion into the linear motion of the electric hydraulic cylinder piston (67) through the electric hydraulic cylinder ball screw (68), so that the electric hydraulic cylinder piston (67) moves rightwards to the initial position, whether the electric hydraulic cylinder piston (67) returns or not is judged through the rotating speed of the electric hydraulic cylinder motor (69), when the rotating speed of the electric hydraulic cylinder motor (69) is lower than a threshold value w, the electric hydraulic cylinder piston (67) is considered to return, and the threshold value w needs to be obtained through test calibration; when the pedal displacement is 0 and the screw mandrel (23) in the active brake pedal stroke simulator (12) and the electric hydraulic cylinder piston (67) in the main energy supply device (13) are both returned, the brake system does not work;
3) calculating a target master cylinder pressure P when the pedal displacement is greater than 0Master cylinder tarThe brake controller receives a pedal displacement signal transmitted by the pedal displacement sensor (5), and obtains a target main cylinder pressure P under corresponding pedal displacement according to a relation curve of the traditional automobile pedal displacement and the main cylinder pressure measured by a testMaster cylinder tar；
4) The working state command sent by the brake controller to the simulator motor controller (29) is a pedal stroke simulation state, so that the active brake pedal stroke simulator (12) is in the pedal stroke simulation state, when the screw mandrel (23) is already at the initial position, the motor (28) does not work, when the screw mandrel (23) is not at the initial position, the motor controller (29) drives the motor (28) to rotate reversely, so that the screw mandrel (23) runs to the initial position, after that, the simulator electromagnetic valve (49) is opened, the first simulator liquid outlet electromagnetic valve (50), the second simulator liquid outlet electromagnetic valve (51) and the third simulator liquid outlet electromagnetic valve (48) are all closed, the brake fluid of the front shaft completely enters the active brake pedal stroke simulator (12), and the pedal feeling is completely provided by the active brake pedal stroke simulator (12), in order to enable the pedal feeling to be consistent with the traditional brake pedal feeling, parameters of a first piston spring (36), a second piston spring (41), a first piston (34) and a second piston (40) of an active brake pedal stroke simulator (12) need to be matched, so that the brake pedal stroke simulator can accurately simulate the pressure volume characteristic of a wheel cylinder, and the pedal feeling is guaranteed; a first hydraulic valve (63) of the electric hydraulic cylinder and a second hydraulic valve (64) of the electric hydraulic cylinder are both opened, and at the moment, the wheel cylinder pressure is completely provided by the main energy supply device (13);
5) the brake controller receives a pressure signal P of a main energy supply device (13) transmitted by an electric hydraulic cylinder pressure sensor (62)Electric hydraulic cylinder actIf the pressure signal P of the main energy supply device (13)Electric hydraulic cylinder actLess than target master cylinder pressure PMaster cylinder tarThen the step 6) is carried out, if the pressure signal P of the main energy supply device (13)Electric hydraulic cylinder actEqual to target master cylinder pressure PMaster cylinder tarStep 7) is entered, otherwise step 8) is entered;
6) pressure signal P of main energy supply device (13)Electric hydraulic cylinder actLess than target master cylinder pressure PMaster cylinder tarWhen the main energy supply device (13) is in a pressurization state, the electric hydraulic cylinder motor (69) is driven to rotate in the forward direction, the electric hydraulic cylinder motor (69) converts the rotation motion into the linear motion of the electric hydraulic cylinder piston (67) through the electric hydraulic cylinder ball screw (68), the electric hydraulic cylinder piston (67) moves leftwards, and after the electric hydraulic cylinder piston (67) moves to the electric hydraulic cylinder oil inlet and outlet hole p, the main energy supply device (13) starts to build pressure and the actual pressure gradually rises;
7) pressure signal P of main energy supply device (13)Electric hydraulic cylinder actEqual to target master cylinder pressure PMaster cylinder tarWhen the main energy supply device (13) is in a pressure maintaining state, the electric hydraulic cylinder motor (69) is static, and the electric hydraulic cylinder ball screw (68) and the electric hydraulic cylinder piston (67) keep the original position unchanged, so that the actual pressure of the main energy supply device (13) is kept unchanged;
8) pressure signal of main energy supply device (13)Number PElectric hydraulic cylinder actGreater than target master cylinder pressure PMaster cylinder tarWhen the main energy supply device (13) is in a decompression state, the electric hydraulic cylinder motor (69) is driven to rotate reversely, the electric hydraulic cylinder motor (69) converts the rotation motion into the linear motion of the electric hydraulic cylinder piston (67) through the electric hydraulic cylinder ball screw (68), the electric hydraulic cylinder piston (67) moves rightwards, the actual pressure of the main energy supply device (13) is gradually reduced, after the electric hydraulic cylinder piston (67) returns to the electric hydraulic cylinder oil inlet and outlet hole p, the actual pressure of the main energy supply device (13) is reduced to 0, and after the electric hydraulic cylinder piston (67) returns to the position, the decompression process is finished;
9) the brake controller receives the pressure signal P of the main energy supply device (13) transmitted by the pressure sensor (62) of the electric hydraulic cylinder againElectric hydraulic cylinder actJudging whether the main energy supply device (13) fails, if so, entering the step 10), otherwise, returning to the step 1);
10) the first hydraulic cylinder outlet electromagnetic valve (63) and the second hydraulic cylinder outlet electromagnetic valve (64) of the electric hydraulic cylinder are closed, the simulator electromagnetic valve (49) is closed, the first simulator outlet electromagnetic valve (50), the second simulator outlet electromagnetic valve (51) and the third simulator outlet electromagnetic valve (48) are opened, and at the moment, the wheel cylinder pressure is completely provided by the brake master cylinder;
11) the brake controller receives a master cylinder pressure signal P from a master cylinder pressure sensor (52)Brake master cylinder actIf the master cylinder pressure signal PBrake master cylinder actLess than target master cylinder pressure PMaster cylinder tarThen, the routine proceeds to step 12), if the master cylinder pressure signal P is detectedBrake master cylinder actEqual to target master cylinder pressure PMaster cylinder tarStep 13) is entered, otherwise step 14) is entered;
12) pressure signal P of brake master cylinderBrake master cylinder actLess than target master cylinder pressure PMaster cylinder tarWhen the brake pedal stroke simulator is used, the working state command sent to the simulator motor controller (29) by the brake controller is in a pressurization state, so that the active brake pedal stroke simulator (12) is in the pressurization state, the motor controller (29) sends a control command to enable the motor (28) to rotate in the positive direction, and the motor (28) rotates in the positive direction through the driving gear (25), the toothed internal circulation nut (19) and the ball (24)) The rotary motion of the screw mandrel (23) is converted into the linear motion of the screw mandrel (23), when the screw mandrel (23) moves to be in contact with a third piston (35), the third piston (35) starts to move rightwards relative to the first piston (34), the boosting process starts, the third piston (35) is continuously pushed along with the screw mandrel (23), the boosting process is continuously carried out, brake fluid enters a third cavity of the brake master cylinder through the simulator oil inlet and outlet hole (33) and the simulator third liquid outlet electromagnetic valve (48), the active brake pedal stroke simulator (12) is adjusted in real time, the active boosting and pedal feeling simulation work is completed, and the actual pressure of the brake master cylinder is gradually increased;
13) pressure signal P of brake master cylinderBrake master cylinder actEqual to target master cylinder pressure PMaster cylinder tarWhen the pressure is maintained, the working state instruction sent to the simulator motor controller (29) by the brake controller is in a pressure maintaining state, so that the active brake pedal stroke simulator (12) is in the pressure maintaining state, the motor controller (29) sends a control instruction to enable the motor (28) to be static, and the screw mandrel (23) and the third piston (35) keep the original position unchanged, so that the actual pressure of the brake master cylinder is kept unchanged;
14) pressure signal P of brake master cylinderBrake master cylinder actGreater than target master cylinder pressure PMaster cylinder tarWhen in use, the working state command sent by the brake controller to the simulator motor controller (29) is a decompression state, so that the active brake pedal stroke simulator (12) is in a decompression state, the motor controller (29) sends a control command to enable the motor (28) to rotate reversely, the motor (28) converts the rotation motion into the linear motion of the screw mandrel ejector rod (23) through the driving gear (25), the toothed internal circulation nut (19), the ball (24) and the screw mandrel ejector rod (23) until the screw mandrel ejector rod (23) moves to be in contact with the limit switch (22), the screw mandrel ejector rod (23) returns to the initial position, the third piston (35) moves leftwards relative to the first piston (34) under the action of the third piston spring (37) and high-pressure brake fluid until the third piston (35) returns to the active brake pedal stroke simulator (12), and brake fluid in a third chamber of the brake master cylinder flows back to the brake pedal stroke simulator (12) through the simulator one-way valve (47) and the simulator oil inlet, the active pressure reduction and pedal feeling simulation work is finished by adjusting the active brake pedal stroke simulator (12) in real time, and the brake master cylinder actuallyThe pressure is gradually reduced until the pressure reduction process is finished;
15) return to step 1).
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