CN113320591B - Four-wheel steering control system and control method for electric automobile - Google Patents
Four-wheel steering control system and control method for electric automobile Download PDFInfo
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- CN113320591B CN113320591B CN202110618449.4A CN202110618449A CN113320591B CN 113320591 B CN113320591 B CN 113320591B CN 202110618449 A CN202110618449 A CN 202110618449A CN 113320591 B CN113320591 B CN 113320591B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/046—Controlling the motor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W30/08—Active safety systems predicting or avoiding probable or impending collision or attempting to minimise its consequences
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
- B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
- B60W40/06—Road conditions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D15/00—Steering not otherwise provided for
- B62D15/02—Steering position indicators ; Steering position determination; Steering aids
- B62D15/021—Determination of steering angle
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/20—Links, e.g. track rods
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/72—Electric energy management in electromobility
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Automation & Control Theory (AREA)
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
The invention discloses a four-wheel steering control system and a four-wheel steering control method for an electric vehicle, wherein the four-wheel steering control system for the electric vehicle comprises a front wheel steering system, a road recognition sensor, a central controller, a driving computer, a speed sensor and a rear wheel steering system; through the speed sensor, the front wheel angle sensor, the rear wheel angle sensor and the central controller, various information is collected in real time, a required control signal is calculated through a preset formula, the rear wheel steering is controlled differently according to different road conditions and vehicle speeds, the turning radius of the vehicle during low-speed steering is reduced, and the high-speed running stability of the vehicle is improved.
Description
Technical Field
The invention relates to the technical field of automobile four-wheel steering control systems, in particular to an electric automobile four-wheel steering control system and a control method.
Background
The traditional automobile steering system is characterized in that the front wheels steer, and the rear wheels do not participate in steering; such a steering system is also used in most electric vehicles. The steering system causes the automobile to have larger turning radius when the automobile turns, the steering is not flexible, the steering of the automobile is greatly limited especially in downtown areas or parking lots with narrow spaces, and the automobile is easy to sideslip and cause accidents only by steering the front wheels when the automobile turns at high speed.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide a four-wheel steering control system and a four-wheel steering control method for an electric vehicle, which accurately control the matching of rear wheel steering and front wheel steering through data collection and analysis of various sensors.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a four-wheel steering control system of an electric automobile comprises a front wheel steering system, a road recognition sensor, a central controller, a traveling computer, a speed sensor and a rear wheel steering system, wherein the front wheel steering system comprises a steering wheel, a front wheel steering boosting mechanism, a front wheel steering mechanism and a front wheel angle sensor;
the rear wheel steering controller is connected with the rear wheel steering stepping motor and the rear wheel steering boosting mechanism;
the road recognition sensor is arranged on a front bumper of the automobile and transmits recognized road information to the central controller through an in-automobile signal line;
the speed sensor is arranged in the middle of the automobile chassis and transmits a measured speed signal of the automobile to the central controller through an in-automobile signal line;
the central controller is connected with the traveling crane computer through signals, the central controller feeds back and displays the analyzed and processed signals to the traveling crane computer, and the rotation angle delta of the rear wheel steering system is calculated through a vehicle motion equation arranged in the traveling crane computer y The rear wheel steering system receives and executes the control signal, and determines a rear wheel steering mode according to the speed signal to realize synchronous control on the rear wheel steering system in different modes;
furthermore, the steering wheel is in transmission connection with a front wheel steering power-assisted mechanism, the front wheel steering power-assisted mechanism is in transmission connection with a steering mechanism, a front wheel angle sensor is installed on the inner side of a left front wheel, is connected with a central controller through an in-vehicle signal line and transmits a measured steering angle signal, a road identification sensor is installed on an automobile front bar, and identified road information is transmitted to the central controller through the in-vehicle signal line.
Furthermore, the rear wheel steering controller is in signal connection with the central controller, recognizes a control signal output by the central controller and controls the rear wheel steering stepping motor to start; the rear wheel steering stepping motor is in transmission connection with a rear wheel steering power-assisted mechanism, and the rear wheel steering power-assisted mechanism is in transmission connection with a rear wheel steering mechanism; the step motor drives the rear wheel steering power-assisted mechanism, and the rear wheel steering power-assisted mechanism drives the rear wheel steering mechanism to drive the rear wheel to complete steering.
Further, the road recognition sensor is a combination of a millimeter wave radar, a laser probe and a high-definition camera; the millimeter wave radar is used for obtaining the curve and straight information of the road and whether an obstacle exists; the laser probe is used for obtaining curve and straight information of a road and comprehensively judging the curve and straight information with the millimeter wave radar; the high-definition camera is used for acquiring pavement materials, road marking lines and sign information of a road; the road information is specifically road material, road marking, roadside identification, road curvature and whether obstacles exist.
Further, front wheel steering assist drive device and rear wheel steering assist drive device structure are the same, all include the steering support pole, the connecting rod, the steering spindle, control box and transmission shaft, control box mid-mounting transmission shaft, the articulated wheel in transmission shaft both ends, the articulated steering support pole of upper portion both sides respectively in the control box, the steering support pole is A type structure, steering support pole other end fixed connection wheel, the middle fixed connection connecting rod of the steering support pole of controlling both ends, the connecting rod both ends are fixed respectively on a branch of steering support pole, the inboard welding of connecting rod has the inner rack, two inner rack symmetric distributions are at the middle meshing gear, gear fixed mounting is on the steering spindle, steering spindle and electric power steering drive are connected.
Preferably, the front wheel steering assist mechanism and the rear wheel steering assist mechanism use electric power assistance.
Preferably, the speed sensor is a Hall vehicle speed sensor.
A control method of a four-wheel steering control system of an electric automobile comprises the following steps:
s1, the road recognition sensor and the speed sensor transmit the road information and the speed signal of the vehicle to the central controller in real time and feed back the information and the speed signal to the driving computer;
s2, when the steering is needed, the steering wheel rotates through the front wheel steering assisting force, the front wheel steering mechanism and the front wheel;
s3, the front wheel angle sensor rotates the front wheel by an angle delta x Transmitted to a central controller which receives the front wheel angle signal delta x Speed signal of vehicle and road information calculation required controlSignal preparation; namely, the angle delta of the rear wheel required to rotate is calculated y The angle is the target rotation angle.
S4, the central controller determines the mode of the rear wheel steering according to the speed signal, and the mode is specifically divided into a low-speed rotation mode, a medium-speed holding mode and a high-speed rotation mode;
s5, acquiring the actual steering angle delta of the rear wheel steered by the S4 by using the rear wheel angle sensor y ' and steering the rear wheels by an actual steering angle delta y ', to a central controller;
s6, the actual steering angle delta y ' Angle of rotation from target delta y And comparing, and finely adjusting the steering angle of the rear wheels by the central controller 5 according to the angle difference between the two, so as to ensure the driving stability.
Further, when the vehicle speed is less than 20km/h, a low-speed rotation mode is executed; specifically, the rear wheel steering controller drives the rear wheel steering step motor to work according to the control signal calculated by the central controller, and the rear wheel steering step motor drives the rear wheel steering boosting mechanism and the rear wheel steering mechanism to work, so that the rear wheel rotates by an angle delta along the forward direction of the vehicle y (ii) a Namely, the rotating directions of the rear wheel and the front wheel are opposite;
when the vehicle speed is between 20km/h and 80km/h, executing a medium-speed maintaining mode; specifically, the rear wheel steering controller drives the rear wheel steering step motor to work according to the control signal calculated by the central controller, and the rear wheel steering step motor drives the rear wheel steering boosting mechanism and the rear wheel steering mechanism to work, so that the rear wheels keep consistent with the driving direction;
when the vehicle speed is more than 80km/h, executing a high-speed rotation mode; specifically, the rear wheel steering controller drives the rear wheel steering step motor to work according to the control signal calculated by the central controller, and the rear wheel steering step motor drives the rear wheel steering boosting mechanism and the rear wheel steering mechanism to work, so that the rear wheel rotates by an angle delta along the forward direction of the vehicle y (ii) a I.e. the rear wheels are turned in the same direction as the front wheels.
The invention has the beneficial effects that:
1. according to the invention, through the speed sensor, the front wheel angle sensor, the rear wheel angle sensor and the central controller, various information is collected in real time, a required control signal is calculated through a preset formula, the rear wheel steering is controlled differently according to the difference of road conditions and vehicle speed, the turning radius of the vehicle during low-speed steering is reduced, and the stability of high-speed driving of the vehicle is improved.
2. The invention can transmit the road condition and the curve camber to the central controller by arranging the road identification sensor, and the control signal calculated by the sensor can be further processed by the central controller, thereby realizing more detailed control of the rear wheel and further improving the running stability of the vehicle.
Drawings
FIG. 1 is a schematic diagram of a four-wheel steering control system according to the present invention;
FIG. 2 is a schematic view of the high speed rotation mode of the four wheel steering control system of the present invention;
FIG. 3 is a schematic view of a middle speed hold mode of the four-wheel steering control system of the present invention;
FIG. 4 is a schematic view of the four-wheel steering control system of the present invention in a low speed rotation mode;
FIG. 5 is an enlarged view of the structure at A in FIG. 1 according to the present invention;
fig. 6 is a control flow chart of the four-wheel steering control system of the present invention.
In the figure: 1. steering wheel, 2, front wheel steering assistance mechanism, 3, road recognition sensor, 4, front wheel angle sensor, 5, central controller, 6, driving computer, 7, rear wheel steering controller, 8, rear wheel steering stepper motor, 9, rear wheel steering assistance mechanism, 10, rear wheel angle sensor, 11a, front wheel steering mechanism, 11b, rear wheel steering mechanism, 1101, steering support bar, 1102, connecting rod, 1103, inner rack, 1104, gear, 1105, steering shaft, 1106, control box, 1107, transmission shaft, 12, speed sensor.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
Referring to fig. 1-6, the present invention provides a technical solution: a four-wheel steering control system of an electric automobile comprises a front wheel steering system, a road recognition sensor 3, a central controller 5, a traveling computer 6, a speed sensor 12 and a rear wheel steering system. The front wheel steering system comprises a steering wheel 1, a front wheel steering assistance mechanism 2, a front wheel steering mechanism 11a and a front wheel angle sensor 4; the steering wheel 1 is in transmission connection with a front wheel steering power-assisted mechanism 2, the front wheel steering power-assisted mechanism 2 is in transmission connection with a vehicle steering mechanism 11, a front wheel angle sensor 4 is installed on the inner side of a left front wheel, and the front wheel angle sensor 4 is connected with a central controller 5 through an in-vehicle signal line and transmits a measured front wheel steering angle signal.
The road recognition sensor 3 is mounted on the front bumper of the vehicle, and transmits recognized road information to the central controller 5 through an in-vehicle signal line.
The speed sensor 12 is installed in the middle of the chassis of the automobile and transmits a speed signal measured to the vehicle to the central controller 5 through an in-vehicle signal line.
The central controller 5 is in signal connection with the driving computer 6, the central controller 5 feeds back and displays the analyzed and processed signals to the driving computer 6, a motion equation of the vehicle is set in the driving computer 6, and a control signal of the rear wheel steering system, namely a rotation angle delta of the rear wheel steering system, is calculated according to the received front wheel steering angle signal, speed signal and road information y (ii) a The rear wheel steering system receives and executes the control signal to realize synchronous control on the rear wheel steering system; the equation of motion for the vehicle is:
F x ＝k c F y (1)
F x ＝mvK a (δ x +β x ) (2)
F y ＝mvK a (δ y +β y ) (3)
in the formula: f x 、F y Respectively front wheel lateral force and rear wheel lateral force, m is vehicle body mass, v is vehicle speed, K is a As road friction parameter, k c The lateral force transfer coefficient of the front and rear wheels, delta x 、δ y Respectively front wheel angle, rear wheel angle, beta x 、β y All are slip angle adjustment coefficients;
equation (4) can be derived, and the rear wheel steering angle is calculated:
the rear wheel steering system comprises a rear wheel steering controller 7, a rear wheel steering step motor 8, a rear wheel steering power-assisted mechanism 9, a rear wheel angle sensor 10 and a rear wheel steering mechanism 11 b; the rear wheel steering controller 7 is in signal connection with the central controller 5, and the rear wheel steering controller 7 identifies a control signal output by the central controller 5 and controls the rear wheel steering stepper motor 8 to start; the rear wheel steering stepping motor 8 is in transmission connection with a rear wheel steering power-assisted mechanism 9, and the rear wheel steering power-assisted mechanism 9 is in transmission connection with a rear wheel steering mechanism 11 b; the stepping motor 8 drives the rear wheel steering assist mechanism 9, and the rear wheel steering assist mechanism 9 drives the rear wheel steering mechanism 11b to drive the rear wheel to complete steering. A rear wheel angle sensor 10 is installed on the inner side of the left rear wheel of the rear wheel, the rear wheel angle sensor 10 is connected with the central controller 5 through an in-vehicle signal line, and a measured rear wheel steering angle signal is transmitted to the central controller 5 through the in-vehicle signal line.
The road recognition sensor 3 designed by the application is a combination of a millimeter wave radar, a laser probe and a high-definition camera. The millimeter wave radar is used for obtaining the curve and straight information of the road and whether an obstacle exists; the laser probe is used for obtaining curve and straight information of a road and comprehensively judging the curve and straight information with the millimeter wave radar; the high-definition camera is used for obtaining road surface materials of roads, road marking and sign information; based on the information collected by the sensors, the road information in this embodiment is specifically the road material, road markings, roadside signs, road straightness, and whether there are obstacles.
The front wheel steering mechanism 11a and the rear wheel steering mechanism 11b have the same structure and are hereinafter referred to simply as a steering mechanism, and the steering mechanism shown in fig. 5 includes a steering support rod 1101, a connecting rod 1102, a steering shaft 1105, a control box 1106 and a transmission shaft 1107; specifically, a transmission shaft 1107 is installed in the middle of the control box 1106, two ends of the transmission shaft 1107 are respectively hinged to wheels, a steering support rod 1101 is hinged to each of two sides of the control box 1106, the steering support rod 1101 is of an a-shaped structure, one end of the steering support rod 1101 is hinged to the middle-upper portion of the side wall of the control box 1106, the other end of the steering support rod 1101 is fixedly connected to the wheels on the same side, the steering support rods 1101 on the left side and the right side are fixedly connected through 2 connecting links 1102, and two ends of each connecting link 1102 are respectively fixed to one support rod of the steering support rod 1101. The inner racks 1103 are welded on the inner sides, opposite to the two connecting rods 1102, of the two inner racks 1103 are symmetrically distributed and meshed with the gear 1104 in the middle, the gear 1104 rotates to drive the inner racks 1103 meshed with the two sides to move left and right, the inner racks 1103 drive the fixed connecting rods 1102 to move left and right, the connecting rods 1102 pull the supporting rods 1101 to incline so as to drive the wheels to steer, the gear 1104 is fixedly sleeved on the steering shaft 1105, and the steering shaft 1105 is in transmission connection with the electric power steering mechanism respectively. The front wheel steering power-assisted device 2 and the rear wheel steering power-assisted device 9 respectively adopt electric power-assisted devices, and the electric power-assisted devices are quickly driven.
The speed sensor 12 is a hall-type vehicle speed sensor.
The control method of the four-wheel steering control system of the electric vehicle shown in fig. 6 comprises the following steps:
s1, the road recognition sensor 3 and the speed sensor 12 transmit the road information and the speed signal of the vehicle to the central controller 5 in real time and feed back the road information and the speed signal to the running computer 6;
s2, when steering is required, the steering wheel 1 is turned by the front wheel steering assist 2, the front wheel steering mechanism 11a, and the front wheels;
s3, the front wheel angle sensor 4 rotates the front wheel by an angle δ x Transmitted to the central controller 5, the central controller 5 depending on the received front wheel angle signal delta x Calculating a required control signal according to the speed signal of the vehicle and the road information; i.e. the angle delta of the rear wheel required to be rotated y The angle is the target rotation angle.
S4, the central controller 5 determines the mode of the rear wheel steering according to the speed signal, and the mode is specifically divided into a low-speed rotation mode, a medium-speed holding mode and a high-speed rotation mode; specifically, as follows, the following description will be given,
when the vehicle speed is less than 20km/h, executing a low-speed rotation mode; specifically, the rear wheel steering controller 7 drives the rear wheel steering step motor 8 to operate according to the control signal calculated by the central controller 5, and the rear wheel steering step motor 8 drives the rear wheel steering assist mechanism 9 and the rear wheel steering mechanism 11b to operate, so that the rear wheels rotate by an angle δ in the forward direction of the vehicle y (ii) a Namely, the rear wheel and the front wheel rotate in opposite directions to the state shown in figure 4;
when the speed is between 20km/h and 80km/h, a medium-speed maintaining mode is executed; specifically, the rear wheel steering controller 7 drives the rear wheel steering stepper motor 8 to operate according to the control signal calculated by the central controller 5, and the rear wheel steering stepper motor 8 drives the rear wheel steering boosting mechanism 9 and the rear wheel steering mechanism 11b to operate, so that the rear wheels keep the same direction as the driving direction as shown in fig. 3;
when the vehicle speed is more than 80km/h, executing a high-speed rotation mode; specifically, the rear wheel steering controller 7 drives the rear wheel steering step motor 8 to operate according to the control signal calculated by the central controller 5, and the rear wheel steering step motor 8 drives the rear wheel steering assist mechanism 9 and the rear wheel steering mechanism 11b to operate, so that the rear wheels rotate by an angle δ in the forward direction of the vehicle y (ii) a Namely, the rear wheels and the front wheels rotate in the same direction to the state shown in figure 2;
s5, the actual steering angle delta of the rear wheel steered by the S4 is collected by the rear wheel angle sensor 10 y ', and the actual steering angle delta of the rear wheels y ', to the central controller 5;
s6, the actual steering angle delta y ' comparing with the target rotation angle, according to the angle difference between the two, the central controller 5 finely adjusts the steering angle of the rear wheel, and ensures the driving stability.
The above embodiments are only used for illustrating the design idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.
Claims (6)
1. A control method of a four-wheel steering control system of an electric vehicle comprises a front-wheel steering system, a road recognition sensor, a central controller, a driving computer, a speed sensor and a rear-wheel steering system, wherein the front-wheel steering system comprises a steering wheel (1), a front-wheel steering boosting mechanism (2), a front-wheel steering mechanism (11 a) and a front-wheel angle sensor (4); the rear wheel steering system comprises a rear wheel steering controller (7), a rear wheel steering step motor (8), a rear wheel steering boosting mechanism (9), a rear wheel angle sensor (10) and a rear wheel steering mechanism (11 b); the road recognition sensor (3) is arranged on a front bumper of the automobile and transmits recognized road information to the central controller (5) through an in-automobile signal line; the speed sensor (12) is arranged in the middle of an automobile chassis, and a measured speed signal of the automobile is transmitted to the central controller (5) through an in-automobile signal line; the central controller (5) is in signal connection with the traveling crane computer (6), the central controller (5) feeds back and displays the analyzed and processed signals to the traveling crane computer (6),
s1, the road recognition sensor (3) and the speed sensor (12) transmit road information and speed signals of the vehicle to the central controller (5) in real time and feed back the road information and the speed signals to the running computer (6); the motion equation of the vehicle is set in a traveling computer (6) and is expressed as follows:
in the formula:
respectively a front wheel lateral force and a rear wheel lateral force,
in order to be the mass of the vehicle body,
as is the speed of the vehicle,
as a parameter of the friction of the road surface,
the lateral force transmission coefficient of the front wheel and the rear wheel,
respectively a front wheel rotating angle and a rear wheel rotating angle,
all are slip angle adjustment coefficients;
s2, when the steering is needed, the steering wheel (1) rotates through the front wheel steering assisting force (2), the front wheel steering mechanism (11 a) and the front wheel;
s3, the front wheel angle sensor (4) rotates the front wheel
Transmitted to a central controller (5), the central controller (5) receiving the front wheel angle signal
Calculating a required control signal according to the speed signal of the vehicle and the road information; calculating the angle of the rear wheel to be rotatedDegree of rotation
，
For the target rotation angle, it is expressed as:
；
s4, the central controller (5) determines the mode of rear wheel steering according to the speed signal, and the mode is specifically divided into a low-speed rotation mode, a medium-speed holding mode and a high-speed rotation mode;
when the vehicle speed is less than 20km/h, executing a low-speed rotation mode; specifically, the rear wheel steering controller (7) drives the rear wheel steering step motor (8) to work according to the control signal calculated by the central controller (5), and the rear wheel steering step motor (8) drives the rear wheel steering boosting mechanism (9) and the rear wheel steering mechanism (11 b) to work, so that the rear wheel rotates by an angle in the forward direction of the vehicle
(ii) a Namely, the rotating directions of the rear wheel and the front wheel are opposite;
when the speed is between 20km/h and 80km/h, a medium-speed maintaining mode is executed; specifically, the rear wheel steering controller (7) drives the rear wheel steering step motor (8) to work according to a control signal calculated by the central controller (5), and the rear wheel steering step motor (8) drives the rear wheel steering boosting mechanism (9) and the rear wheel steering mechanism (11 b) to work, so that the rear wheels are consistent with the driving direction;
when the vehicle speed is more than 80km/h, executing a high-speed rotation mode; specifically, the rear wheel steering controller (7) drives the rear wheel steering step motor (8) to work according to the control signal calculated by the central controller (5), and the rear wheel steering step motor (8) drives the rear wheel steering boosting mechanism (9) and the rear wheel steering mechanism (11 b) to work, so that the rear wheel rotates by an angle in the forward direction of the vehicle
(ii) a Namely, the rotating directions of the rear wheel and the front wheel are the same;
s5, acquiring the actual steering angle of the rear wheel steered by the S4 by using the rear wheel angle sensor (10)
And steering the rear wheels by the actual angle
To a central controller (5);
s6, actual steering angle
And comparing the steering angle with a target rotation angle, and finely adjusting the steering angle of the rear wheel by the central controller (5) according to an angle difference between the steering angle and the target rotation angle to ensure the driving stability.
2. The control method of the four-wheel steering control system of the electric automobile according to claim 1, characterized in that the steering wheel (1) is in transmission connection with a front wheel steering power-assisted mechanism (2), the front wheel steering power-assisted mechanism (2) is in transmission connection with a steering mechanism, the front wheel angle sensor (4) is installed on the inner side of the left front wheel, is connected with a central controller through an in-vehicle signal line and transmits a measured steering angle signal, and the road recognition sensor is installed on a front bar of the automobile and transmits recognized road information to the central controller through the in-vehicle signal line.
3. The control method of the four-wheel steering control system of the electric vehicle according to claim 1, wherein the road recognition sensor (3) is a combination of a millimeter wave radar, a laser probe and a high definition camera; the millimeter wave radar is used for obtaining the curve and straight information of the road and whether an obstacle exists; the laser probe is used for obtaining curve and straight information of a road and comprehensively judging the curve and straight information with the millimeter wave radar; the high-definition camera is used for obtaining road surface materials of roads, road marking and sign information; the road information is specifically road material, road marking, roadside identification, road curvature and whether obstacles exist.
4. The control method of the four-wheel steering control system for the electric vehicle according to claim 1 or 2, it is characterized in that the front wheel steering power-assisted mechanism (2) and the rear wheel steering power-assisted mechanism (9) have the same structure and respectively comprise a steering support rod, a connecting rod, a steering shaft, a control box and a transmission shaft, the utility model discloses a steering support device, including control box, steering support rod, connecting rod, gear fixed mounting, the transmission shaft mid-mounting transmission shaft, the articulated wheel in transmission shaft both ends, respectively articulated a steering support rod in upper portion both sides in the control box, steering support rod is A type structure, steering support rod other end fixed connection wheel, control the middle fixed connection connecting rod of steering support rod at both ends, the connecting rod both ends are fixed respectively on a branch of steering support rod, the inboard welding of connecting rod has interior rack, two interior rack symmetric distributions are at the middle meshing gear, gear fixed mounting is on the steering shaft, steering shaft and electronic power assisted steering transmission are connected.
5. The control method of the four-wheel steering control system of the electric vehicle according to claim 4, wherein the front wheel steering assist mechanism (2) and the rear wheel steering assist mechanism (9) adopt electric power assistance.
6. The control method of the four-wheel steering control system of the electric automobile according to claim 4, characterized in that the speed sensor is a Hall vehicle speed sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110618449.4A CN113320591B (en) | 2021-06-03 | 2021-06-03 | Four-wheel steering control system and control method for electric automobile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110618449.4A CN113320591B (en) | 2021-06-03 | 2021-06-03 | Four-wheel steering control system and control method for electric automobile |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113320591A CN113320591A (en) | 2021-08-31 |
| CN113320591B true CN113320591B (en) | 2022-09-16 |
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| CN116088520A (en) * | 2023-02-07 | 2023-05-09 | 睿羿科技(山东)有限公司 | Accurate direction control method for unmanned hinge vehicle |
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