Vehicle steering control method, device and system

Abstract

The present invention discloses a vehicle steering control method, comprising: in response to the activation operation of the vehicle's anti-lock function, determining whether the vehicle is on an open road; when the vehicle is on the open road, obtaining the actual yaw rate of the vehicle and calculating the target yaw rate; obtaining a first deviation between the actual yaw rate and the target yaw rate; when it is detected that the front wheel steering unit does not respond to the torque compensation operation, calculating the target rear wheel angle according to the first deviation; and controlling the rear wheels of the vehicle according to the target rear wheel angle. The present invention also discloses a vehicle steering control system and device. By adopting the embodiments of the present invention, the target rear wheel angle can be automatically generated to control the rear wheels when the vehicle is on an open road, assisting the driver in controlling the vehicle, so that the driver can keep the vehicle stable even when turning the steering wheel slightly.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle steering control, and in particular to a vehicle steering control method, device and system. Background Art

[0002] When the vehicle is on a split road, the brake pedal is pressed to activate the ABS (Anti-lock Braking System) or AEB (Autonomous Emergency Braking) / CDP (Controller Deceleration Parking) and other functions. The split road means that one side of the road has a high adhesion coefficient and the other side has a low adhesion coefficient. During the ABS function control and adjustment process, there will be an imbalance in the braking torque on both sides of the vehicle, which will generate a yaw torque. The vehicle will deflect toward the road with a high adhesion coefficient. The driver must immediately turn the steering wheel to generate a reverse yaw torque to stabilize the vehicle. The driver must meet the following conditions to stabilize the vehicle by turning the steering wheel: ① The vehicle deceleration cannot be too large (the deceleration is at the industry average level, generally a=3.2m / s2); ② The driver's driving level must have a sense of advance prediction, that is, the timing of turning the steering wheel must be timely and the direction of the steering wheel must be correct; ③ When the vehicle speed is greater than 80km / h, the steering wheel angle (>90°) must be large to generate sufficient yaw torque. Therefore, when the vehicle is on a double-sided road, in order to ensure the stable operation of the vehicle, the driver's driving skills are required to be high. Once the driver does not meet the above conditions when turning the steering wheel, it is easy to cause the vehicle to lose control. Summary of the invention

[0003] The purpose of the embodiments of the present invention is to provide a vehicle steering control method, device and system, which can automatically generate a target rear wheel turning angle to control the rear wheels when the vehicle is on an open road, assist the driver in controlling the vehicle, and enable the driver to keep the vehicle stable even when turning the steering wheel less.

[0004] To achieve the above object, an embodiment of the present invention provides a vehicle steering control method, comprising:

[0005] In response to an anti-lock brake function activation operation of the vehicle, determining whether the vehicle is on an off-road surface;

[0006] When the vehicle is on an open road, obtaining an actual yaw rate of the vehicle and calculating a target yaw rate;

[0007] Acquire a first deviation between the actual yaw angular velocity and the target yaw angular velocity;

[0008] when it is detected that the front wheel steering unit does not respond to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation;

[0009] The rear wheels of the vehicle are controlled according to the target rear wheel turning angle.

[0010] As an improvement of the above solution, after obtaining the first deviation between the actual yaw angular velocity and the target yaw angular velocity, the method further includes:

[0011] When it is detected that the front wheel steering unit responds to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation to control the rear wheels of the vehicle according to the target rear wheel steering angle;

[0012] After controlling the rear wheels according to the target rear wheel steering angle, obtaining a second deviation between the actual yaw angular velocity and the target yaw angular velocity;

[0013] When the second deviation is not 0, calculating a target steering wheel steering torque value according to the second deviation;

[0014] Acquiring an actual steering wheel steering torque value of the vehicle, and calculating a first steering wheel torque compensation value according to the target steering wheel steering torque value and the actual steering wheel steering torque value;

[0015] The front wheels of the vehicle are controlled according to the first steering wheel torque compensation value.

[0016] As an improvement of the above solution, the step of calculating the target rear wheel turning angle according to the first deviation includes:

[0017] Performing a first PID operation on the first deviation according to a preset first PID parameter;

[0018] The result obtained by the first PID operation is output from the steering angle interface of the vehicle stability control unit to convert the result obtained by the first PID operation into the target rear wheel steering angle.

[0019] As an improvement of the above solution, the step of calculating the target steering wheel steering torque value according to the second deviation includes:

[0020] performing a second PID operation on the second deviation according to a preset second PID parameter;

[0021] The result obtained by the second PID operation is output from the torque interface of the vehicle stability control unit to convert the result obtained by the second PID operation into the target steering wheel steering torque value.

[0022] As an improvement of the above solution, the method further includes:

[0023] In response to the torque compensation operation of the vehicle control unit, obtaining a second steering wheel torque compensation value generated by the vehicle control unit; wherein the vehicle control unit is a control unit other than the vehicle stability control unit, and the first steering wheel torque compensation value has a higher priority than the second steering wheel torque compensation value;

[0024] When the vehicle does not respond to the anti-lock brake function activation operation, the front wheels of the vehicle are controlled according to the second steering wheel torque compensation value.

[0025] As an improvement of the above solution, the calculation of the target yaw angular velocity includes:

[0026] Obtaining the steering wheel angle, current vehicle speed, wheelbase and characteristic vehicle speed of the vehicle; wherein the characteristic vehicle speed is the vehicle speed corresponding to when the yaw gain of the vehicle reaches a maximum value, and the yaw gain is the ratio of the actual yaw angular velocity to the front wheel angle of the vehicle;

[0027] A target yaw rate is calculated according to the steering wheel angle, the current vehicle speed, the wheelbase and the characteristic vehicle speed.

[0028] As an improvement to the above solution, the step of determining whether the vehicle is on an open road includes:

[0029] Obtaining a vehicle slip ratio; wherein the vehicle slip ratio is calculated based on the current vehicle speed and the current wheel speed of the vehicle;

[0030] Obtaining vehicle deceleration; wherein the vehicle deceleration is calculated based on the vehicle's braking torque and the vehicle's mass;

[0031] When the slip rate of the vehicle is greater than a preset slip rate threshold and the deceleration of the vehicle is within a preset deceleration threshold, it is determined that the vehicle is in an oncoming open road;

[0032] When the vehicle slip rate is less than or equal to a preset slip rate threshold, or the vehicle deceleration is not within a preset deceleration threshold, it is determined that the vehicle is not in an oncoming open road.

[0033] To achieve the above object, an embodiment of the present invention further provides a vehicle steering control system, comprising:

[0034] Vehicle stability control unit, used to:

[0035] In response to an anti-lock brake function activation operation of the vehicle, determining whether the vehicle is on an off-road surface;

[0036] When the vehicle is on an open road, obtaining an actual yaw rate of the vehicle and calculating a target yaw rate;

[0037] Acquire a first deviation between the actual yaw angular velocity and the target yaw angular velocity;

[0038] when it is detected that the front wheel steering unit does not respond to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation;

[0039] A central control unit, used for sending the target rear wheel steering angle to a rear wheel steering unit;

[0040] A rear wheel steering unit is used to control the rear wheels of the vehicle according to the target rear wheel steering angle.

[0041] As an improvement of the above solution, the vehicle steering control system further includes a front wheel steering unit; wherein,

[0042] The vehicle stability control unit is also used for:

[0043] When it is detected that the front wheel steering unit responds to the torque compensation operation, after the rear wheels are controlled according to the target rear wheel steering angle, a second deviation between the actual yaw rate and the target yaw rate is obtained;

[0044] When the second deviation is not 0, calculating a target steering wheel steering torque value according to the second deviation;

[0045] Acquiring an actual steering wheel steering torque value of the vehicle, and calculating a first steering wheel torque compensation value according to the target steering wheel steering torque value and the actual steering wheel steering torque value;

[0046] The central control unit is also used to send the first steering wheel torque compensation value to the front wheel steering unit;

[0047] Then, the front wheel steering unit is used to control the front wheels of the vehicle according to the first steering wheel torque compensation value.

[0048] To achieve the above objectives, an embodiment of the present invention also provides a vehicle steering control device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and when the processor executes the computer program, it implements the vehicle steering control method as described in any of the above embodiments.

[0049] Compared with the prior art, the vehicle steering control method, device and system disclosed in the embodiments of the present invention have the following beneficial effects:

[0050] When the anti-lock function of the vehicle is activated and the vehicle is on an open road, the actual yaw rate and the target yaw rate of the vehicle are obtained, and the first deviation between the actual yaw rate and the target yaw rate is calculated. When it is detected that the front wheel steering unit does not respond to the torque compensation operation, the target rear wheel angle is calculated according to the first deviation to control the rear wheels of the vehicle using the target rear wheel angle. In the embodiment of the present invention, since the influence of the open road on the vehicle steering is taken into account, the scope of application is extended to the field of automatic driving (ADAS), and the entire control process is short, which is equivalent to assisting the driver to turn the steering wheel in advance, and the driver can stabilize the vehicle by turning the steering wheel slightly, so that the vehicle becomes more controllable and the driving experience of the vehicle is improved.

[0051] Secondly, when it is detected that the front wheel steering unit responds to the torque compensation operation, the rear wheel control is performed first, and then the vehicle is judged to be stable according to the second deviation between the actual yaw rate and the target yaw rate. If the second deviation is not 0, the target steering wheel steering torque value is calculated according to the second deviation, and then the first steering wheel torque compensation value is calculated according to the target steering wheel steering torque value and the actual steering wheel steering torque value, and then the first steering wheel torque compensation value is applied to control the front wheels of the vehicle. While controlling the rear wheel steering of the vehicle, the front wheel steering control of the vehicle can also be realized, so that the whole control process is further shortened and the controllability of the vehicle is further improved.

[0052] In addition, the vehicle in the embodiment of the present invention can receive a second steering wheel torque compensation value generated by other vehicle control units, and control the front wheels of the vehicle according to the second steering wheel torque compensation value when the vehicle does not respond to the anti-lock braking function activation operation, so that the vehicle can achieve stable control on the oncoming road even when the anti-lock braking function is not activated. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a flow chart of a vehicle steering control method provided by an embodiment of the present invention;

[0054] Figure 2 is a flow chart of another vehicle steering control method provided by an embodiment of the present invention;

[0055] Figure 3 is a structural block diagram of a vehicle steering control system provided by an embodiment of the present invention;

[0056] Figure 4 It is a structural block diagram of a vehicle steering control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] See also Figure 1 , Figure 1 : is a flow chart of a vehicle steering control method provided by an embodiment of the present invention, the vehicle steering control method comprising:

[0059] S11, in response to an anti-lock braking function activation operation of the vehicle, determining whether the vehicle is on an oncoming road;

[0060] S12, when the vehicle is on an open road, obtaining an actual yaw rate of the vehicle and calculating a target yaw rate;

[0061] S13, obtaining a first deviation between the actual yaw angular velocity and the target yaw angular velocity;

[0062] S14, when it is detected that the front wheel steering unit does not respond to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation;

[0063] S15. Controlling the rear wheels of the vehicle according to the target rear wheel turning angle.

[0064] It is worth noting that the anti-lock function is realized by ABS (Anti-lock Brake System), which is a car safety control system with the advantages of anti-skid and anti-lock. ABS has the braking function of ordinary braking system and can prevent the wheels from locking, so that the vehicle can still turn under braking, ensure the braking direction stability of the vehicle, and prevent skidding and deviation.

[0065] Specifically, in step S11, when the vehicle receives a braking demand from the driver or an active deceleration demand from an ADAS (Advanced Driver Assistance System), the vehicle slip rate is generated to activate the ABS. At this time, it is necessary to determine whether the vehicle is on an oncoming road.

[0066] Optionally, the determining whether the vehicle is on an open road comprises steps S111 to S113:

[0067] S111, obtaining a vehicle slip ratio; wherein the vehicle slip ratio is calculated according to a current vehicle speed and a current wheel speed of the vehicle;

[0068] S112, obtaining vehicle deceleration; wherein the vehicle deceleration is calculated according to the braking torque of the vehicle and the vehicle mass;

[0069] S113: When the vehicle slip rate satisfies a preset slip rate threshold and the vehicle deceleration is within a preset deceleration threshold, it is determined that the vehicle is in an oncoming open road.

[0070] Exemplarily, the vehicle slip ratio λ satisfies λ=(V 车 -V 轮 ) / V 车 ; Among them, V 车 is the current vehicle speed, V 轮 is the current wheel speed. The vehicle deceleration V 减 Meet V 减 =T / m; where T is the braking torque and m is the vehicle mass. The braking torque T satisfies T=Cp*P; where P is the wheel cylinder pressure and Cp is the braking efficiency of the vehicle. When the vehicle enters a split road, under the same braking torque, the wheel speed on the side with a low adhesion coefficient is lower. At this time, if the wheel speed slip rate λ generated is greater than the slip rate threshold and the vehicle deceleration range is within the empirical value test range, it can be determined that the vehicle has entered a split road.

[0071] Specifically, in step S12, when the vehicle is on a split road, the braking force deviation of the wheels on both sides of the vehicle causes a yaw torque to be generated at the center of mass, causing the vehicle to rotate around the Z axis, and the actual yaw angular velocity of the rotation can be measured by a sensor inside the vehicle.

[0072] Optionally, the calculating the target yaw angular velocity comprises steps S121 to S122:

[0073] S121, obtaining a steering wheel angle, a current vehicle speed, a wheelbase, and a characteristic vehicle speed of the vehicle; wherein the characteristic vehicle speed is a vehicle speed corresponding to when a yaw gain of the vehicle reaches a maximum value, and the yaw gain is a ratio of the actual yaw angular velocity to a front wheel angle of the vehicle;

[0074] S122. Calculate a target yaw rate according to the steering wheel angle, the current vehicle speed, the wheelbase and the characteristic vehicle speed.

[0075] Exemplarily, the target yaw rate Satisfies the following formula:

[0076]

[0077] Wherein, δ is the steering wheel angle, v is the current vehicle speed, l is the wheelbase, and v ch is the characteristic vehicle speed.

[0078] Specifically, in step S13, the actual yaw rate is calculated and the target yaw rate The first deviation

[0079] Specifically, in step S14, in an embodiment of the present invention, the vehicle is installed with FWS (Front wheelsteering) and RWS (Rear wheel steering), then during vehicle steering control, there are at least two working modes, one is a separate rear wheel steering control process when it is detected that the front wheel steering unit does not respond to the torque compensation operation, and the other is a rear wheel + front wheel steering control process when it is detected that the front wheel steering unit responds to the torque compensation operation.

[0080] Optionally, when it is detected that the front wheel steering unit does not respond to the torque compensation operation, the calculating the target rear wheel steering angle according to the first deviation comprises steps S141 to S142:

[0081] S141, performing a first PID operation on the first deviation according to a preset first PID parameter;

[0082] S142: Outputting the result obtained by the first PID operation from the steering angle interface of the vehicle stability control unit to convert the result obtained by the first PID operation into the target rear wheel steering angle.

[0083] Exemplarily, using the first deviation The first PID calculation is performed, and the specific parameter values ​​of the P coefficient, the I coefficient and the D coefficient in the first PID calculation process can be set in real time. PID calculation is a dimensionless control process. Parameter adjustment is performed, and the result obtained by the first PID operation can be converted into the target rear wheel steering angle with the help of the steering angle interface of the vehicle stability control unit.

[0084] Specifically, in step S15, after the target rear wheel turning angle is acquired, the rear wheels of the vehicle are controlled according to the target rear wheel turning angle.

[0085] Furthermore, after obtaining the first deviation between the actual yaw rate and the target yaw rate, the vehicle steering control method according to the embodiment of the present invention further includes steps S21 to S25:

[0086] S21, when it is detected that the front wheel steering unit responds to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation, so as to control the rear wheels of the vehicle according to the target rear wheel steering angle;

[0087] S22, after controlling the rear wheels according to the target rear wheel steering angle, obtaining a second deviation between the actual yaw angular velocity and the target yaw angular velocity;

[0088] S23, when the second deviation is not 0, calculating a target steering wheel steering torque value according to the second deviation;

[0089] S24, acquiring an actual steering wheel steering torque value of the vehicle, and calculating a first steering wheel torque compensation value according to the target steering wheel steering torque value and the actual steering wheel steering torque value;

[0090] S25. Control the front wheels of the vehicle according to the first steering wheel torque compensation value.

[0091] Specifically, in step S21, when it is detected that the front wheel steering unit responds to the torque compensation operation, it is necessary to give priority to rear wheel control. At this time, the process of rear wheel control is the same as the above steps S13 to S15, which will not be repeated here.

[0092] Specifically, in step S22, after the rear wheels are controlled according to the target rear wheel steering angle, it is necessary to further determine whether the vehicle can maintain steering stability after the front wheels are controlled. At this time, a second deviation between the actual yaw rate and the target yaw rate is obtained. When the second deviation When the second deviation is 0, it indicates that the vehicle has been stably steered and no front wheel control is required. When it is not 0, it indicates that the vehicle is still unstable after rear-wheel steering control, and further front-wheel control is required.

[0093] Specifically, in step S23, calculating the target steering wheel steering torque value according to the second deviation includes steps S231-S232:

[0094] S231, performing a second PID operation on the second deviation according to a preset second PID parameter;

[0095] S232: Outputting the result obtained by the second PID operation from the torque interface of the vehicle stability control unit to convert the result obtained by the second PID operation into the target steering wheel steering torque value.

[0096] Exemplarily, using the second deviation The second PID calculation is performed, and the specific parameter values ​​of the P coefficient, the I coefficient and the D coefficient in the second PID calculation process can be set in real time. PID calculation is a dimensionless control process. Parameter adjustment is performed, and the result obtained by the second PID operation can be converted into the target steering wheel steering torque value with the help of the torque interface of the vehicle stability control unit.

[0097] Specifically, in step S24, when the driver controls the steering wheel, the actual steering wheel steering torque value of the vehicle is obtained, and the first steering wheel torque compensation value is obtained by subtracting the target steering wheel steering torque value from the actual steering wheel steering torque value.

[0098] Specifically, in step S25, the front wheels of the vehicle are controlled according to the first steering wheel torque compensation value. At this time, the first steering wheel torque compensation value will compensate the actual steering wheel steering torque value to assist the driver in controlling the vehicle, so that the driver can keep the vehicle stable even when turning the steering wheel less.

[0099] Furthermore, in the embodiment of the present invention, in addition to generating a steering wheel torque compensation value when the anti-lock function is activated, a steering wheel torque compensation value is also generated when the vehicle does not respond to the anti-lock function activation operation. In this case, the vehicle steering control method further includes steps S16 to S17:

[0100] S16, in response to the torque compensation operation of the vehicle control unit, obtaining a second steering wheel torque compensation value generated by the vehicle control unit; wherein the vehicle control unit is another control unit except the vehicle stability control unit, and the first steering wheel torque compensation value has a higher priority than the second steering wheel torque compensation value;

[0101] S17: When the vehicle does not respond to the anti-lock braking function activation operation, controlling the front wheels of the vehicle according to the second steering wheel torque compensation value.

[0102] Exemplarily, the vehicle control unit may be a lane keeping unit, which can activate a lane keeping function LKA (Lane Keeping Assist), which is used to assist the driver to keep the vehicle within the lane line. It is a lateral motion control ADAS function developed from the lane departure warning LDW (Lane Departure Warning) function. The position of the vehicle relative to the center of the lane is identified by an environmental perception sensor. If the driver accidentally deviates from the lane, a warning should be issued to the driver or the vehicle should be brought back to the lane through automatic steering intervention. A second steering wheel torque compensation value is generated when the automatic steering intervention is performed. When the vehicle does not respond to the anti-lock braking function activation operation, the first steering wheel torque compensation value is not generated at this time, so the vehicle needs to control the front wheels of the vehicle according to the second steering wheel torque compensation value. When the vehicle executes the LKA function and activates the ABS function, the first steering wheel torque compensation value and the second steering wheel torque compensation value exist at the same time, and the first steering wheel torque compensation value is executed first at this time.

[0103] It is worth noting that the second steering wheel torque compensation value can be obtained by a calculation method in the prior art, which will not be described in detail here.

[0104] Compared with the prior art, the vehicle steering control method disclosed in the embodiment of the present invention has the following beneficial effects:

[0105] Firstly, since the embodiment of the present invention takes into account the impact of the open road surface on vehicle steering, the scope of application is expanded to the field of autonomous driving (ADAS). The entire control process is shorter, which is equivalent to assisting the driver to turn the steering wheel in advance, and the driver can stabilize the vehicle by turning the steering wheel slightly, so the vehicle becomes more controllable, thereby improving the driving experience of the vehicle.

[0106] Secondly, when it is detected that the front wheel steering unit responds to the torque compensation operation, the rear wheel control is performed first, and then the vehicle is judged to be stable according to the second deviation between the actual yaw rate and the target yaw rate. If the second deviation is not 0, the target steering wheel steering torque value is calculated according to the second deviation, and then the first steering wheel torque compensation value is calculated according to the target steering wheel steering torque value and the actual steering wheel steering torque value, and then the first steering wheel torque compensation value is applied to control the front wheels of the vehicle. While controlling the rear wheel steering of the vehicle, the front wheel steering control of the vehicle can also be realized, so that the whole control process is further shortened and the controllability of the vehicle is further improved.

[0107] Since the embodiment of the present invention takes into account the impact of the open road on vehicle steering, the scope of application is extended to the field of autonomous driving (ADAS). The entire control process is short, and the entire control process takes at most 150ms (150ms less than human reaction), which is equivalent to assisting the driver to turn in advance. The deceleration can be increased from 3.2m / s2 to more than 3.5m / s2. When the vehicle speed is greater than 80km / h, the driver can stabilize the vehicle by turning the steering wheel less (<50°), making the vehicle more controllable, improving the driving experience of the vehicle, and the calculated yaw deflection torque is more accurate, and the timing and rotation angle of turning the steering wheel are more accurate. As the vehicle speed increases, the ratio of the rear wheels to the front wheels gradually decreases, but it is always greater than 50%. The vehicle also coordinates and distributes the front wheel steering wheel torque compensation value or the target rear wheel turning angle to offset the yaw torque generated by the braking force.

[0108] In addition, the vehicle in the embodiment of the present invention can receive a second steering wheel torque compensation value generated by other vehicle control units, and control the front wheels of the vehicle according to the second steering wheel torque compensation value when the vehicle does not respond to the anti-lock braking function activation operation, so that the vehicle can achieve stable control on the oncoming road even when the anti-lock braking function is not activated.

[0109] See also Figure 2 , Figure 2 : is a structural block diagram of a vehicle steering control system 10 provided by an embodiment of the present invention, wherein the vehicle steering control system 10 comprises:

[0110] The vehicle stability control unit 11 is used to:

[0111] In response to an anti-lock brake function activation operation of the vehicle, determining whether the vehicle is on an off-road surface;

[0112] When the vehicle is on an open road, obtaining an actual yaw rate of the vehicle and calculating a target yaw rate;

[0113] Acquire a first deviation between the actual yaw angular velocity and the target yaw angular velocity;

[0114] When it is detected that the front wheel steering unit 14 does not respond to the torque compensation operation, calculating the target rear wheel steering angle according to the first deviation;

[0115] A central control unit 12, used for sending the target rear wheel steering angle to a rear wheel steering unit;

[0116] The rear wheel steering unit 13 is used to control the rear wheels of the vehicle according to the target rear wheel steering angle.

[0117] Furthermore, the vehicle steering control system 10 further includes a front wheel steering unit 14; wherein,

[0118] The vehicle stability control unit 11 is also used for:

[0119] When it is detected that the front wheel steering unit 14 responds to the torque compensation operation, after the rear wheels are controlled according to the target rear wheel steering angle, a second deviation between the actual yaw rate and the target yaw rate is obtained;

[0120] When the second deviation is not 0, calculating a target steering wheel steering torque value according to the second deviation;

[0121] Acquiring an actual steering wheel steering torque value of the vehicle, and calculating a first steering wheel torque compensation value according to the target steering wheel steering torque value and the actual steering wheel steering torque value;

[0122] The central control unit 12 is further used to send the first steering wheel torque compensation value to the front wheel steering unit 14;

[0123] Then, the front wheel steering unit 14 is used to control the front wheels of the vehicle according to the first steering wheel torque compensation value.

[0124] Furthermore, the vehicle steering control system 10 further includes a vehicle control unit 15; wherein,

[0125] The vehicle control unit 15 is used to obtain a second steering wheel torque compensation value generated by the vehicle control unit 15 in response to the torque compensation operation; wherein the vehicle control unit is a control unit other than the vehicle stability control unit, and the first steering wheel torque compensation value has a higher priority than the second steering wheel torque compensation value;

[0126] The central control unit 12 is further used to send the second steering wheel torque compensation value to the front wheel steering unit 14;

[0127] The front wheel steering unit 14 is further configured to control the front wheels of the vehicle according to the second steering wheel torque compensation value when the vehicle does not respond to the anti-lock function activation operation.

[0128] Optionally, calculating a target rear wheel turning angle according to the first deviation comprises:

[0129] Performing a first PID operation on the first deviation according to a preset first PID parameter;

[0130] The result obtained by the first PID operation is output from the steering angle interface of the vehicle stability control unit to convert the result obtained by the first PID operation into the target rear wheel steering angle.

[0131] Optionally, calculating a target steering wheel steering torque value according to the second deviation includes:

[0132] performing a second PID operation on the second deviation according to a preset second PID parameter;

[0133] The result obtained by the second PID operation is output from the torque interface of the vehicle stability control unit to convert the result obtained by the second PID operation into the target steering wheel steering torque value.

[0134] Optionally, the vehicle stability control unit 11 calculates the target yaw rate, including:

[0135] Obtain the steering wheel angle, current vehicle speed, wheelbase and characteristic vehicle speed of the vehicle; wherein the characteristic vehicle speed is the vehicle speed corresponding to when the yaw gain of the vehicle reaches a maximum value, and the yaw gain is the ratio of the actual yaw angular velocity to the front wheel angle of the vehicle.

[0136] A target yaw rate is calculated according to the steering wheel angle, the current vehicle speed, the wheelbase and the characteristic vehicle speed.

[0137] Optionally, the vehicle stability control unit 11 determines whether the vehicle is on an open road, including:

[0138] Obtaining a vehicle slip ratio; wherein the vehicle slip ratio is calculated based on the current vehicle speed and the current wheel speed of the vehicle;

[0139] Obtaining vehicle deceleration; wherein the vehicle deceleration is calculated based on the vehicle's braking torque and the vehicle's mass;

[0140] When the slip rate of the vehicle is greater than a preset slip rate threshold and the deceleration of the vehicle is within a preset deceleration threshold, it is determined that the vehicle is in an oncoming open road;

[0141] When the vehicle slip rate is less than or equal to a preset slip rate threshold, or the vehicle deceleration is not within a preset deceleration threshold, it is determined that the vehicle is not in an oncoming open road.

[0142] Specifically, the vehicle stability control unit 11 is an ESC (Electronic Speed ​​Controller), which can calculate the vehicle deceleration, determine whether to activate the ABS function, control the braking torque of each wheel, and calculate the first steering wheel torque compensation value and the target rear wheel turning angle; ADAS does not need to receive the user stepping on the brake pedal, it only needs to send the deceleration to the ESC, and then the ESC determines whether to activate the ABS function. The central control unit 12 is a CCU (Central control unit). The front wheel steering unit 14 is a FWS (Front wheel steering). The rear wheel steering unit 13 is a RWS (Rear wheel steering). When both FWS and RWS are installed in the vehicle, the FWS controls the front wheels of the vehicle according to the first steering wheel torque compensation value or controls the front wheels of the vehicle according to the second steering wheel torque compensation value, and the RWS controls the rear wheels of the vehicle according to the target rear wheel turning angle. When only FWS is installed in the vehicle, the target rear wheel turning angle is not calculated.

[0143] It is worth noting that the working process of each unit in the vehicle steering control system 10 can refer to the working process of the vehicle steering control method described in the above embodiment, and will not be repeated here.

[0144] Compared with the prior art, the vehicle steering control system 10 disclosed in the embodiment of the present invention has the following beneficial effects:

[0145] Firstly, since the embodiment of the present invention takes into account the impact of the open road surface on vehicle steering, the scope of application is expanded to the field of autonomous driving (ADAS). The entire control process is shorter, which is equivalent to assisting the driver to turn the steering wheel in advance, and the driver can stabilize the vehicle by turning the steering wheel slightly, so the vehicle becomes more controllable, thereby improving the driving experience of the vehicle.

[0146] Secondly, when it is detected that the front wheel steering unit responds to the torque compensation operation, the rear wheel control is performed first, and then the vehicle is judged to be stable according to the second deviation between the actual yaw rate and the target yaw rate. If the second deviation is not 0, the target steering wheel steering torque value is calculated according to the second deviation, and then the first steering wheel torque compensation value is calculated according to the target steering wheel steering torque value and the actual steering wheel steering torque value, and then the first steering wheel torque compensation value is applied to control the front wheels of the vehicle. While controlling the rear wheel steering of the vehicle, the front wheel steering control of the vehicle can also be realized, so that the whole control process is further shortened and the controllability of the vehicle is further improved.

[0147] Since the embodiment of the present invention takes into account the impact of the open road on vehicle steering, the scope of application is extended to the field of autonomous driving (ADAS). The entire control process is short, and the entire control process takes at most 150ms (150ms less than human reaction), which is equivalent to assisting the driver to turn in advance. The deceleration can be increased from 3.2m / s2 to more than 3.5m / s2. When the vehicle speed is greater than 80km / h, the driver can stabilize the vehicle by turning the steering wheel less (<50°), making the vehicle more controllable, improving the driving experience of the vehicle, and the calculated yaw deflection torque is more accurate, and the timing and rotation angle of turning the steering wheel are more accurate. As the vehicle speed increases, the ratio of the rear wheels to the front wheels gradually decreases, but it is always greater than 50%. The vehicle also coordinates and distributes the front wheel steering wheel torque compensation value or the target rear wheel turning angle to offset the yaw torque generated by the braking force.

[0148] In addition, the vehicle in the embodiment of the present invention can receive a second steering wheel torque compensation value generated by other vehicle control units, and control the front wheels of the vehicle according to the second steering wheel torque compensation value when the vehicle does not respond to the anti-lock braking function activation operation, so that the vehicle can achieve stable control on the oncoming road even when the anti-lock braking function is not activated.

[0149] See also Figure 3 , Figure 3 1 is a structural block diagram of a vehicle steering control device 20 provided in an embodiment of the present invention, wherein the vehicle steering control device 20 comprises: a processor 21, a memory 22, and a computer program stored in the memory 22 and executable on the processor 21. When the processor 21 executes the computer program, the steps in the above-mentioned vehicle steering control method embodiments are implemented. Alternatively, when the processor 21 executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0150] Exemplarily, the computer program may be divided into one or more modules / units, which are stored in the memory 22 and executed by the processor 21 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program in the vehicle steering control device 20.

[0151] The vehicle steering control device 20 may be a computing device such as a desktop computer, a notebook, a PDA, and a cloud server. The vehicle steering control device 20 may include, but is not limited to, a processor 21 and a memory 22. Those skilled in the art may understand that the schematic diagram is only an example of the vehicle steering control device 20 and does not constitute a limitation on the vehicle steering control device 20. The vehicle steering control device 20 may include more or fewer components than shown in the figure, or may combine certain components, or different components. For example, the vehicle steering control device 20 may also include input and output devices, network access devices, buses, etc.

[0152] The processor 21 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor 21 is the control center of the vehicle steering control device 20, and uses various interfaces and lines to connect various parts of the entire vehicle steering control device 20.

[0153] The memory 22 can be used to store the computer program and / or module. The processor 21 realizes various functions of the vehicle steering control device 20 by running or executing the computer program and / or module stored in the memory 22 and calling the data stored in the memory 22. The memory 22 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory 22 can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0154] Wherein, if the module / unit integrated in the vehicle steering control device 20 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor 21, the steps of the above-mentioned method embodiments can be implemented. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media does not include electrical carrier signals and telecommunication signals.

[0155] It should be noted that the device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the accompanying drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art may understand and implement it without paying any creative effort.

[0156] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A vehicle steering control method, characterized in that: include: In response to an anti-lock brake function activation operation of the vehicle, determining whether the vehicle is on an off-road surface; When the vehicle is on an open road, obtaining an actual yaw rate of the vehicle and calculating a target yaw rate; Acquire a first deviation between the actual yaw angular velocity and the target yaw angular velocity; when it is detected that the front wheel steering unit does not respond to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation; controlling the rear wheels of the vehicle according to the target rear wheel turning angle; Wherein, after obtaining the first deviation between the actual yaw angular velocity and the target yaw angular velocity, the method further includes: When it is detected that the front wheel steering unit responds to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation to control the rear wheels of the vehicle according to the target rear wheel steering angle; After controlling the rear wheels according to the target rear wheel steering angle, obtaining a second deviation between the actual yaw angular velocity and the target yaw angular velocity; When the second deviation is not 0, calculating a target steering wheel steering torque value according to the second deviation; Acquiring an actual steering wheel steering torque value of the vehicle, and calculating a first steering wheel torque compensation value according to the target steering wheel steering torque value and the actual steering wheel steering torque value; The front wheels of the vehicle are controlled according to the first steering wheel torque compensation value.

2. The vehicle steering control method according to claim 1, characterized in that: The calculating a target rear wheel turning angle according to the first deviation comprises: Performing a first PID operation on the first deviation according to a preset first PID parameter; The result obtained by the first PID operation is output from the steering angle interface of the vehicle stability control unit to convert the result obtained by the first PID operation into the target rear wheel steering angle.

3. The vehicle steering control method according to claim 1, characterized in that: The calculating the target steering wheel steering torque value according to the second deviation comprises: performing a second PID operation on the second deviation according to a preset second PID parameter; The result obtained by the second PID operation is output from the torque interface of the vehicle stability control unit to convert the result obtained by the second PID operation into the target steering wheel steering torque value.

4. The vehicle steering control method according to claim 1, characterized in that: The method further comprises: In response to the torque compensation operation of the vehicle control unit, obtaining a second steering wheel torque compensation value generated by the vehicle control unit; wherein the vehicle control unit is a control unit other than the vehicle stability control unit, and the first steering wheel torque compensation value has a higher priority than the second steering wheel torque compensation value; When the vehicle does not respond to the anti-lock brake function activation operation, the front wheels of the vehicle are controlled according to the second steering wheel torque compensation value.

5. The vehicle steering control method according to claim 1, characterized in that: The calculating the target yaw angular velocity comprises: Obtaining the steering wheel angle, current vehicle speed, wheelbase and characteristic vehicle speed of the vehicle; wherein the characteristic vehicle speed is the vehicle speed corresponding to when the yaw gain of the vehicle reaches a maximum value, and the yaw gain is the ratio of the actual yaw angular velocity to the front wheel angle of the vehicle; A target yaw rate is calculated according to the steering wheel angle, the current vehicle speed, the wheelbase and the characteristic vehicle speed.

6. The vehicle steering control method according to any one of claims 1 to 5, characterized in that: The determining whether the vehicle is on an on-road road comprises: Obtaining a vehicle slip ratio; wherein the vehicle slip ratio is calculated based on the current vehicle speed and the current wheel speed of the vehicle; Obtaining vehicle deceleration; wherein the vehicle deceleration is calculated based on the vehicle's braking torque and the vehicle's mass; When the slip rate of the vehicle is greater than a preset slip rate threshold and the deceleration of the vehicle is within a preset deceleration threshold, it is determined that the vehicle is in an oncoming open road; When the vehicle slip rate is less than or equal to a preset slip rate threshold, or the vehicle deceleration is not within a preset deceleration threshold, it is determined that the vehicle is not in an oncoming open road.

7. A vehicle steering control system, characterized in that: include: Vehicle stability control unit, used to: In response to an anti-lock brake function activation operation of the vehicle, determining whether the vehicle is on an off-road surface; When the vehicle is on an open road, obtaining an actual yaw rate of the vehicle and calculating a target yaw rate; Acquire a first deviation between the actual yaw angular velocity and the target yaw angular velocity; when it is detected that the front wheel steering unit does not respond to the torque compensation operation, calculating a target rear wheel steering angle according to the first deviation; A central control unit, used for sending the target rear wheel steering angle to a rear wheel steering unit; a rear wheel steering unit, used for controlling the rear wheels of the vehicle according to the target rear wheel steering angle; The vehicle stability control unit is also used for: When it is detected that the front wheel steering unit responds to the torque compensation operation, after the rear wheels are controlled according to the target rear wheel steering angle, a second deviation between the actual yaw rate and the target yaw rate is obtained; When the second deviation is not 0, calculating a target steering wheel steering torque value according to the second deviation; Acquiring an actual steering wheel steering torque value of the vehicle, and calculating a first steering wheel torque compensation value according to the target steering wheel steering torque value and the actual steering wheel steering torque value; The central control unit is also used to send the first steering wheel torque compensation value to the front wheel steering unit; A front wheel steering unit is used to control the front wheels of the vehicle according to the first steering wheel torque compensation value.

8. A vehicle steering control device, characterized in that: The invention comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the vehicle steering control method according to any one of claims 1 to 6 when executing the computer program.

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