CN115027437A - Electromagnetic brake master cylinder based on automatic driving line control brake system and control method - Google Patents
Electromagnetic brake master cylinder based on automatic driving line control brake system and control method Download PDFInfo
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- CN115027437A CN115027437A CN202210720389.1A CN202210720389A CN115027437A CN 115027437 A CN115027437 A CN 115027437A CN 202210720389 A CN202210720389 A CN 202210720389A CN 115027437 A CN115027437 A CN 115027437A
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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
- B60T13/74—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
- B60T13/748—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 acting on electro-magnetic brakes
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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
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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
- 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
- B60T8/17—Using electrical or electronic regulation means to control braking
- B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
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- Regulating Braking Force (AREA)
Abstract
The invention relates to an electromagnetic brake master cylinder based on an automatic driving line-control brake system and a control method, and relates to the automatic driving line-control brake system. The invention aims to replace the original driving mode that a motor and a transmission mechanism drive a main cylinder by adopting electromagnetic force as driving force, so that the brake main cylinder has simpler structure, smaller volume and lower cost, and the light weight and high efficiency of a brake-by-wire system are improved. In the invention, the electromagnetic brake master cylinder comprises a double-cavity brake fluid cylinder and an electromagnetic force generating device which are welded together; the electromagnetic force generating device comprises an armature and a coil, and the coil is located on the periphery of the armature. When the coil is electrified, the coil generates electromagnetic driving force to push the armature to move, so that the piston in the double-cavity brake fluid cylinder moves to push out brake fluid. When the coil is de-energized, the piston is reset under the action of the return spring, so that the armature is reset.
Description
Technical Field
The present disclosure relates to an automatic driving brake-by-wire system, and more particularly, to an electromagnetic brake master cylinder based on an automatic driving brake-by-wire system and a control method thereof.
Background
With the rise of automatic driving, the traditional braking mode can not meet the driving safety requirement of the vehicle. The brake-by-wire is used as a novel brake system to make up the defects of the traditional brake system, and the safety performance of the automatic driving vehicle can be greatly improved. Brake-by-wire systems can be divided into two categories, Electro-Hydraulic Brake Systems (EHBs) and Electro-Mechanical Brake Systems (EMBs). At present, the EMB still has many key problems of poor reliability, low fault tolerance, weak anti-interference capability and the like, so that the EMB cannot be widely used.
The core of the existing EHB system is a pressure building module and a pressure regulating module, wherein the pressure building module mostly adopts a form of a motor-driven brake master cylinder. Because the motion mode of the motor is rotation and the motion mode of the brake master cylinder is translation, a transmission mechanism such as a worm gear, a gear rack or a ball screw needs to be additionally arranged between the motor and the brake master cylinder to convert the rotation motion into linear motion. The transmission mechanism increases the volume and mass of the system and increases the uncontrollable factors of the system.
Disclosure of Invention
In view of the above-mentioned prior art, an object of the present invention is to further improve the weight reduction and efficiency of a brake-by-wire system by using electromagnetic force as a power source of the hydraulic brake-by-wire system.
In order to achieve the above object, the present invention provides an electromagnetic brake master cylinder based on an automatic driving by-wire brake system, comprising a dual-chamber brake fluid cylinder and an electromagnetic force generating device welded together; the electromagnetic force generating device comprises an armature and a coil, and the coil is positioned on the periphery of the armature; two closed chambers for storing brake fluid are arranged in the double-cavity brake fluid cylinder, and each chamber is provided with an inlet and an outlet; the closed chamber is formed by dividing a first piston and a second piston; the first piston and the second piston are telescopically connected; a first push rod is arranged on the first end face of the first piston, and one end, far away from the first piston, of the first push rod is in contact with one end of the armature; when the coil is electrified, the armature moves linearly under the pushing of the electromagnetic driving force of the coil, so that the push rod pushes the piston to move linearly, the storage space of the cavity is reduced, and the brake fluid in the cavity is pushed out from the outlet; and when the coil is powered off, the first piston and the second piston are reset through the return spring, so that the armature is reset.
In the technical scheme, the electromagnetic force is used as the driving force to replace the existing driving mode that the motor and the transmission mechanism drive the main cylinder, so that the brake main cylinder is simpler in structure, smaller in size and lower in cost, and the lightweight and high efficiency of the brake-by-wire system are further improved.
In the technical scheme, a through hole is formed in a contact surface, a limiting sleeve with the same diameter is arranged on the through hole of the electromagnetic force generating device, two ends of the limiting sleeve are matched with a limiting bulge of an armature to limit the moving distance of the armature, and a coil is fixed in the middle of the limiting sleeve; after the first piston returns, one end of the push rod is positioned at the through hole; when the first piston is pushed, the armature extends into the double-chamber brake fluid cylinder through the through hole.
In the above technical solution, the electromagnetic driving force is calculated by using the following formula:
F M ＝F mmax +S p
S p ＝S p +cx max
in the formula: f M Is an electromagnetic driving force; f mmax The maximum braking force required for the master cylinder; s p Is the return spring force; p is a radical of max Is the maximum brake pressure of the master cylinder, d is the diameter of the piston of the master cylinder, η m Master cylinder mechanical efficiency; c is the return spring rate, x max Is the master cylinder maximum stroke, S' p Is the pretightening force of the return spring.
In the technical scheme, the size of the through hole between the double-cavity brake fluid cylinder and the electromagnetic force generating device is determined through the cross section area of the armature. The cross-sectional area of the armature is calculated using the following equation:
in the formula: f is an electromagnetic driving force during steady-state operation; k f The value of the magnetic flux leakage coefficient is determined by the composition of a magnetic circuit, and the value range is 1.2-5.0; n is the number of turns of the coil; i is the current intensity; delta is the air gap length; mu.s 0 Is a vacuum magnetic permeability.
In the technical scheme, under the condition that the electromagnetic driving force is obtained, the number of turns of the coil can be estimated by determining the current intensity. One way of determining the current intensity comprises the following steps:
calculating an ideal value of the yaw velocity and an ideal value of the centroid slip angle of the current state of the vehicle according to the vehicle speed and the front wheel steering angle of the vehicle;
acquiring the actual yaw velocity of the vehicle and the actual centroid slip angle of the vehicle;
calculating a yaw velocity ideal value and a centroid slip angle ideal value of the current state of the vehicle according to the vehicle speed and the front wheel steering angle of the vehicle;
acquiring the actual yaw velocity of the vehicle and the actual barycenter slip angle of the vehicle;
calculating a first difference value according to the ideal value of the yaw angular velocity and the actual yaw angular velocity, and calculating a second difference value according to the ideal value of the centroid sideslip angle and the actual centroid sideslip angle;
calculating an additional yaw moment required for stabilizing the vehicle under the current vehicle condition based on the first difference and the second difference;
distributing the required additional yaw moment to four wheels, and calculating to obtain the maximum braking moment of a single wheel so as to obtain the target braking pressure of a main braking cylinder;
and calculating the current intensity of the coil of the electromagnetic generating device in the electromagnetic brake master cylinder based on the difference value of the target brake pressure and the actual brake pressure.
In order to achieve the purpose, the invention also provides an electromagnetic brake master cylinder control method based on the automatic driving wire control brake system, which is characterized in that a coil is electrified to generate electromagnetic driving force, and an armature is driven by the electromagnetic driving force to push a push rod to linearly move so as to push a piston in the master cylinder to linearly move, reduce the storage space of a cavity and further push brake fluid in the cavity out of an outlet;
by powering off the coil, the piston in the main cylinder is reset under the action of the return spring, so that the armature is reset;
the magnitude of the electromagnetic driving force is calculated by using the following formula:
F M ＝F mmax +S p
S p ＝S p +cx max
in the formula: f M Is an electromagnetic driving force; f mmax The maximum braking force required for the master cylinder; s p Is the return spring force; p is a radical of max Is the maximum brake pressure of the master cylinder, d is the diameter of the piston of the master cylinder, η m Master cylinder mechanical efficiency; c is the stiffness of the return spring, x max Is the master cylinder maximum stroke, S' p Is the pretightening force of the return spring.
In the technical scheme, the electromagnetic driving force is adopted to replace the driving force which is pushed by a motor and a set of transmission mechanism, so that the brake master cylinder is simple in structure, small in size and low in manufacturing cost.
In the above technical solution, the armature calculates the cross-sectional area by using the following formula:
in the formula: f is electromagnetic drive in steady state operationPower; k f The value of the magnetic flux leakage coefficient is determined by the composition of a magnetic circuit, and the value range is 1.2-5.0; n is the number of turns of the coil; i is the current intensity; delta is the air gap length; mu.s 0 Is a vacuum magnetic permeability.
In the above technical solution, the current intensity determination method includes the following steps:
calculating a yaw velocity ideal value and a centroid side slip angle ideal value of the current state of the vehicle according to the vehicle speed and the front wheel steering angle of the vehicle;
acquiring the actual yaw velocity of the vehicle and the actual centroid slip angle of the vehicle;
calculating a first difference value according to the ideal value of the yaw angular velocity and the actual yaw angular velocity, and calculating a second difference value according to the ideal value of the centroid sideslip angle and the actual centroid sideslip angle;
calculating an additional yaw moment required for stabilizing the vehicle under the current vehicle condition based on the first difference and the second difference;
distributing the required additional yaw moment to four wheels, and calculating to obtain the maximum braking moment of a single wheel so as to obtain the target braking pressure of a brake master cylinder;
and calculating the current intensity of the coil of the electromagnetic generating device in the electromagnetic brake master cylinder based on the difference value of the target brake pressure and the actual brake pressure.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
FIG. 1 is a first general schematic diagram of an embodiment of an electromagnetic brake master cylinder;
FIG. 2 is a second general schematic view of an embodiment of an electromagnetic brake master cylinder;
FIG. 3 is a first schematic cross-sectional view of one embodiment of an electromagnetic brake master cylinder;
FIG. 4 is a second schematic cross-sectional view of one embodiment of an electromagnetic brake master cylinder;
FIG. 5 is a flow chart of a control method for an electromagnetic brake master cylinder in one embodiment.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application. In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a definition of "a first" or "a second" feature may explicitly or implicitly include one or more of the features. The operations of the flow diagrams may be performed out of order. Rather, the operations may be performed in reverse order or simultaneously. In addition, one or more other operations may be added to the flowchart. One or more operations may be removed from the flowchart.
In one embodiment of the present invention, an overall schematic view of an electromagnetic brake master cylinder based on an automatic drive-by-wire brake system is shown in fig. 1 and 2. As can be seen from fig. 1 and 2, the electromagnetic brake master cylinder includes two parts, a brake fluid cylinder and an electromagnetic force generating device which are connected together. The brake fluid cylinder is provided with two oil outlets and two oil inlets.
Fig. 3 and 4 are two cross-sectional views of the electromagnetic brake master cylinder. As can be seen from fig. 3 and 4, the electromagnetic brake master cylinder includes a coil, an armature, a push rod, a seal ring, a first piston return spring, a second piston return spring, a first cavity oil inlet, a first cavity oil outlet, a second cavity oil inlet, and a second cavity oil outlet. A push rod, a first piston return spring, a second piston and a second piston return spring are sequentially and axially arranged in the main cylinder body. The solenoid coil and the armature are arranged axially outside the master cylinder. The first piston return spring is fixed between the first piston end surface and the second piston end surface, and the second piston return spring is fixed between the second piston end surface and the cylinder body. The second piston divides the main cylinder body into two closed chambers which are not communicated, each closed chamber is provided with an oil inlet and an oil outlet, the oil inlet is connected with the brake oil cup, and the oil outlet is connected with the brake pipeline. Brake fluid enters the two chambers of the brake master cylinder from the oil cup through the first chamber oil inlet and the second chamber oil inlet. The push rod connected with the first piston is connected with the armature outside the cylinder shaft and is wrapped on the periphery of the armature by an electromagnetic coil connected with the armature. The connection between the armature and the push rod of the main cylinder is sealed, so that brake fluid is prevented from flowing into the electromagnetic driving element.
In the driving process, when a vehicle needs to be braked, current with proper magnitude is introduced into the coil, and the armature and the push rod are pushed to move linearly by electromagnetic force generated by the electromagnetic coil. The push rod drives the first piston and the second piston to simultaneously compress brake fluid in the first cavity and the second cavity, high-pressure brake fluid is generated and flows out of the first cavity oil outlet and the second cavity oil outlet to the brake wheel cylinder, and the hydraulic pressure of the brake wheel cylinder acts on the brake disc to generate brake force to complete braking of the vehicle. After braking is completed, the coil is powered off, and the pistons and the armatures of the two chambers are reset by the aid of the first piston return spring and the second piston return spring.
In one embodiment, the current intensity is determined by:
calculating a yaw velocity ideal value and a centroid side slip angle ideal value of the current state of the vehicle according to the vehicle speed and the front wheel steering angle of the vehicle;
acquiring the actual yaw velocity of the vehicle and the actual centroid slip angle of the vehicle;
calculating a first difference value according to the ideal value of the yaw angular velocity and the actual yaw angular velocity, and calculating a second difference value according to the ideal value of the centroid sideslip angle and the actual centroid sideslip angle;
calculating an additional yaw moment required for stabilizing the vehicle under the current vehicle condition based on the first difference and the second difference;
distributing the required additional yaw moment to four wheels, and calculating to obtain the maximum braking moment of a single wheel so as to obtain the target braking pressure of a main braking cylinder;
and calculating the current intensity of the coil of the electromagnetic generating device in the electromagnetic brake master cylinder based on the difference value of the target brake pressure and the actual brake pressure.
In one embodiment, the electromagnetic driving force is calculated using the following formula:
F M ＝F mmax +S p
S p ＝S′ p +cx max
in the formula: f M Is an electromagnetic driving force; f mmax The maximum braking force required for the master cylinder; s p Is the return spring force; p is a radical of max Is the maximum brake pressure of the master cylinder, d is the diameter of the piston of the master cylinder, η m Master cylinder mechanical efficiency; c is the return spring rate, x max Is the master cylinder maximum stroke, S' p Is the pretightening force of the return spring.
In the case where the electromagnetic driving force and the current intensity are determined, the number of coil winding turns of the electromagnetic generating device can be determined.
As can be seen from fig. 3 and 4, the contact surface of the dual-chamber brake fluid cylinder and the electromagnetic force generating device is provided with a through hole, a limiting sleeve with the same diameter is arranged on the through hole of the electromagnetic force generating device, two ends of the limiting sleeve are matched with a limiting bulge of the armature to limit the moving distance of the armature, and the middle of the limiting sleeve is used for fixing a coil; after the first piston returns, one end of the push rod is positioned at the through hole; when the first piston is pushed, the armature extends into the double-chamber brake fluid cylinder through the through hole.
The size of the through hole is determined by determining the area of the armature. In one embodiment, the cross-sectional area S of the armature is calculated using the following equation:
in the formula: f is an electromagnetic driving force during steady-state operation; k f The specific value is determined by the magnetic path composition, and the value range is 1.2-5.0; n is the number of turns of the coil; i is the current intensity; delta is the air gap length; mu.s 0 Is a vacuum magnetic permeability.
For an electromagnetic brake master cylinder based on an automatic drive-by-wire brake system, optimized control parameters can be obtained using the method flow illustrated in fig. 5. In the method, a genetic algorithm is adopted to obtain the current intensity required to be introduced into a coil in an electromagnetic brake master cylinder. The method comprises the following steps:
sensing the current speed u and the front wheel steering angle delta of the vehicle by related sensors f And the vehicle speed u and the front wheel steering angle delta f Feeding back to the vehicle reference model;
the vehicle reference model is based on the current vehicle speed u and the front wheel steering angle delta f Calculating to obtain the ideal yaw velocity gamma of the current state of the vehicle ref Ideal value beta of side deviation angle with centroid ref ；
The actual yaw velocity gamma of the vehicle is measured by a vehicle yaw velocity sensor, and the actual centroid slip angle beta of the vehicle is calculated by a centroid slip angle calculation module;
based on the ideal value gamma of the yaw angular velocity ref First difference value with actual yaw velocity gamma and centroid slip angle ideal value beta ref Calculating an additional yaw moment delta M required for stabilizing the vehicle under the current vehicle condition by adopting a fuzzy algorithm according to a second difference value of the actual mass center slip angle beta;
based on the yaw moment delta M, the braking moment distribution module reasonably distributes the yaw moment delta M to the four wheels, and the maximum braking moment T of the single wheel is obtained through calculation max 。
Based on maximum braking torque T max The torque-brake pressure conversion module calculates and outputs the target pressure P of the brake master cylinder Target ；
Actual pressure P of the current brake master cylinder In fact Measured by a pressure sensor of a brake master cylinder;
target brake pressure P of brake master cylinder Target With actual brake pressure P Practice of Inputting the third difference value after difference making into a PID controller module;
k for PID algorithm using genetic algorithm p 、k i 、k d Optimizing three control parameters;
and based on the third difference, the PID controller module calculates by using the optimized control parameter to obtain the current I of the coil of the electromagnetic generating device in the electromagnetic brake master cylinder.
After the current I is obtained, the power supply outputs the current I to the coil, and the coil generates electromagnetic force capable of meeting the driving size of the brake master cylinder after being electrified. When the brake master cylinder works, the armature is pushed by the electromagnetic force and the push rod moves to compress the brake fluid in the master cylinder and generate high-pressure brake fluid. The high-pressure brake fluid flows into a brake wheel cylinder through a brake pipeline, and the brake wheel cylinder presses a brake disc to generate braking force, so that the vehicle achieves the purpose of braking. The whole control system forms a closed loop, and the control process is continuously adjusted according to the feedback signal of the current vehicle state.
In summary, the invention realizes the electromagnetic driving master cylinder which takes the electromagnetic force as the driving force of the brake master cylinder, and the existing motor and transmission mechanism of the electromagnetic driving master cylinder drive the master cylinder, so that the structure of the brake master cylinder is simpler, the volume is smaller, the cost is lower, and the light weight and the high efficiency of a brake-by-wire system are further improved. The control method can obtain the specific electromagnetic force and current so as to determine the number of turns of the coil; the size of the through hole between the electromagnetic force generating device and the main cylinder is determined by determining the area of the armature.
Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications to the disclosed embodiments without departing from the scope of the invention as defined by the appended claims.
Claims (10)
1. An electromagnetic brake master cylinder based on an automatic driving wire control brake system is characterized by comprising a double-cavity brake fluid cylinder and an electromagnetic force generating device which are welded together; the electromagnetic force generating device comprises an armature and a coil, and the coil is positioned on the periphery of the armature;
two closed chambers for storing brake fluid are arranged in the double-cavity brake fluid cylinder, and each chamber is provided with an inlet and an outlet;
the closed chamber is formed by dividing a first piston and a second piston;
the first piston and the second piston are connected in a telescopic way;
a first push rod is arranged on the first end surface of the first piston, and one end of the first push rod, which is far away from the first piston, is in contact with one end of the armature;
when the coil is electrified, the armature moves linearly under the pushing of the electromagnetic driving force of the coil, so that the push rod pushes the piston to move linearly, the storage space of the cavity is compressed, and the brake fluid in the cavity is pushed out from the outlet;
and after the coil is powered off, the first piston and the second piston are reset through the return spring, so that the armature is reset.
2. The electromagnetic brake master cylinder of claim 1, wherein the contact surface of the dual-chamber brake cylinder and the electromagnetic force generating device has a through hole, a position-limiting sleeve with the same diameter is arranged on the through hole of the electromagnetic force generating device, two ends of the position-limiting sleeve are matched with position-limiting protrusions of the armature to limit the moving distance of the armature, and a coil is fixed in the middle of the position-limiting sleeve; after the first piston returns, one end of the push rod is positioned at the through hole; when the first piston is pushed, the armature extends into the double-chamber brake fluid cylinder through the through hole.
3. The electromagnetic brake master cylinder according to claim 1, characterized in that the electromagnetic driving force is calculated using the following formula:
F M ＝F m max +S p
S p ＝S′ p +cx max
in the formula: f M Is an electromagnetic driving force; f m max The maximum braking force required for the master cylinder; s p Is the return spring force; p is a radical of formula max Is the maximum brake pressure of the master cylinder, d is the diameter of the piston of the master cylinder, η m Master cylinder mechanical efficiency; c is the return spring rate, x max Is the master cylinder maximum stroke, S' p Is the pretightening force of the return spring.
4. The electromagnetic brake master cylinder of claim 1, wherein the armature calculates the cross-sectional area S using the formula:
in the formula: f is an electromagnetic driving force during steady-state operation; k is f Is the magnetic flux leakage coefficient; n is the number of turns of the coil; i is the current intensity; delta is the air gap length; mu.s 0 Is a vacuum magnetic permeability.
5. The electromagnetic brake master cylinder of claim 4, wherein the leakage coefficient ranges from 1.2 to 5.0.
6. The electromagnetic brake master cylinder of claim 4, wherein the current intensity is determined by:
calculating a yaw velocity ideal value and a centroid side slip angle ideal value of the current state of the vehicle according to the vehicle speed and the front wheel steering angle of the vehicle;
acquiring the actual yaw velocity of the vehicle and the actual centroid slip angle of the vehicle;
calculating a first difference value according to the ideal value of the yaw angular velocity and the actual yaw angular velocity, and calculating a second difference value according to the ideal value of the centroid sideslip angle and the actual centroid sideslip angle;
calculating an additional yaw moment required for stabilizing the vehicle under the current vehicle condition based on the first difference and the second difference;
distributing the required additional yaw moment to four wheels, and calculating to obtain the maximum braking moment of a single wheel so as to obtain the target braking pressure of a brake master cylinder;
and calculating the current intensity of the coil of the electromagnetic generating device in the electromagnetic brake master cylinder based on the difference value of the target brake pressure and the actual brake pressure.
7. A control method of an electromagnetic brake master cylinder based on an automatic driving line control brake system is characterized in that,
the coil is electrified to generate electromagnetic driving force, and the armature pushes the push rod to move linearly through the electromagnetic driving force so as to push the piston in the main cylinder to move linearly, reduce the storage space of the cavity and further push the brake fluid in the cavity out of the outlet;
by powering off the coil, the piston in the main cylinder is reset under the action of the return spring, so that the armature is reset;
the magnitude of the electromagnetic driving force is calculated by using the following formula:
F M ＝F m max +S p
S′ p ＝S′ p +cx max
in the formula: f M Is an electromagnetic driving force; f m max The maximum braking force required for the master cylinder; s p Is the return spring force; p is a radical of max Is the maximum brake pressure of the master cylinder, d is the master cylinder pressurePlug diameter, η m Master cylinder mechanical efficiency; c is the return spring rate, x max Is the master cylinder maximum stroke, S' p Is the pretightening force of the return spring.
8. The method of claim 7, wherein the cross-sectional area S is calculated by the armature using the following equation:
in the formula: f is an electromagnetic driving force during steady-state operation; k f The value of the magnetic flux leakage coefficient is determined by the composition of a magnetic circuit; n is the number of turns of the coil; i is the current intensity; delta is the air gap length; mu.s 0 Is a vacuum magnetic permeability.
9. The method of claim 8, wherein the leakage flux coefficient is in a range of 1.2-5.0.
10. The method of claim 8, wherein the amperage is determined by:
calculating a yaw velocity ideal value and a centroid side slip angle ideal value of the current state of the vehicle according to the vehicle speed and the front wheel steering angle of the vehicle;
acquiring the actual yaw velocity of the vehicle and the actual centroid slip angle of the vehicle;
calculating a first difference value according to the ideal value of the yaw angular velocity and the actual yaw angular velocity, and calculating a second difference value according to the ideal value of the centroid sideslip angle and the actual centroid sideslip angle;
calculating an additional yaw moment required for stabilizing the vehicle under the current vehicle condition based on the first difference and the second difference;
distributing the required additional yaw moment to four wheels, and calculating to obtain the maximum braking moment of a single wheel so as to obtain the target braking pressure of a brake master cylinder;
and calculating the current intensity of the coil of the electromagnetic generating device in the electromagnetic brake master cylinder based on the difference value of the target brake pressure and the actual brake pressure.
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| CN202210720389.1A CN115027437B (en) | 2022-06-23 | 2022-06-23 | Electromagnetic brake master cylinder based on automatic driving line control brake system and control method |
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| CN202210720389.1A CN115027437B (en) | 2022-06-23 | 2022-06-23 | Electromagnetic brake master cylinder based on automatic driving line control brake system and control method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103552557A (en) * | 2013-11-18 | 2014-02-05 | 扬州泰博汽车电子智能科技有限公司 | Electro-hydraulic composite braking system with electric braking assistant force and brake-by-wire function |
| CN104309597A (en) * | 2014-09-26 | 2015-01-28 | 同济大学 | Control method for hydraulic dual motor-driven electronic hydraulic braking system |
| CN204605541U (en) * | 2015-03-27 | 2015-09-02 | 吉林大学 | There is the electric booster braking system of friction braking and the full decoupled function of regenerative brake |
| CN105015532A (en) * | 2015-05-27 | 2015-11-04 | 南京理工大学 | Braking system for vehicles, and vehicle with braking system |
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2022
- 2022-06-23 CN CN202210720389.1A patent/CN115027437B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103552557A (en) * | 2013-11-18 | 2014-02-05 | 扬州泰博汽车电子智能科技有限公司 | Electro-hydraulic composite braking system with electric braking assistant force and brake-by-wire function |
| CN104309597A (en) * | 2014-09-26 | 2015-01-28 | 同济大学 | Control method for hydraulic dual motor-driven electronic hydraulic braking system |
| CN204605541U (en) * | 2015-03-27 | 2015-09-02 | 吉林大学 | There is the electric booster braking system of friction braking and the full decoupled function of regenerative brake |
| CN105015532A (en) * | 2015-05-27 | 2015-11-04 | 南京理工大学 | Braking system for vehicles, and vehicle with braking system |
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