Rear wheel steering control method, system and equipment and computer readable storage medium

Abstract

The invention discloses a rear wheel steering control method, system and device and a computer readable storage medium, and relates to the technical field of vehicle control. If it is detected that the real-time vehicle speed is smaller than a preset first vehicle speed threshold value, a target rear wheel turning angle is determined based on the real-time front wheel turning angle; if it is detected that the real-time vehicle speed is larger than a preset second vehicle speed threshold value, the target rear wheel turning angle is determined based on the real-time vehicle speed, the real-time front wheel turning angle, the real-time transverse acceleration and the real-time yaw velocity, and the second vehicle speed threshold value is larger than the first vehicle speed threshold value; if it is detected that the real-time vehicle speed is not smaller than the first vehicle speed threshold value and not larger than the second vehicle speed threshold value, a target rear wheel rotation angle is determined based on a preset rotation angle distribution coefficient, the real-time vehicle speed, the real-time front wheel rotation angle, the real-time transverse acceleration and the real-time yaw velocity; and controlling rear wheel steering through the target rear wheel steering angle. The steering performance of the rear wheel is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a rear-wheel steering control method, system, device, and computer-readable storage medium. Background Art

[0002] As a key chassis feature, rear-wheel steering is increasingly being incorporated into new vehicle models by OEMs, leading to the development of numerous rear-wheel steering control algorithms. The simplest and most effective way to control rear wheel angle has long been a research focus for OEMs and suppliers.

[0003] Existing technologies usually adopt a single feedforward control or feedback control strategy, but it is difficult to achieve ideal steering performance based on a single control logic alone; therefore, how to improve rear-wheel steering performance is an issue that needs to be urgently addressed. Summary of the Invention

[0004] The present application provides a rear-wheel steering control method, system, device and computer-readable storage medium, which can improve rear-wheel steering performance.

[0005] In a first aspect, an embodiment of the present application provides a rear-wheel steering control method, the rear-wheel steering control method comprising:

[0006] Get real-time vehicle speed;

[0007] If it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold, determining a target rear wheel steering angle based on the real-time front wheel steering angle;

[0008] If it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, determining a target rear wheel steering angle based on the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate, and the second vehicle speed threshold is greater than the first vehicle speed threshold;

[0009] If it is detected that the real-time vehicle speed is not less than a first vehicle speed threshold and not greater than a second vehicle speed threshold, determining a target rear wheel steering angle based on a preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate;

[0010] The rear wheel steering is controlled according to the target rear wheel turning angle.

[0011] In conjunction with the first aspect, in one embodiment, determining the target rear wheel angle based on the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration, and the real-time yaw angular velocity includes:

[0012] Determine a vehicle speed weight distribution coefficient based on the real-time vehicle speed and a preset vehicle speed initial value;

[0013] Determining a desired yaw rate based on a real-time vehicle speed, a real-time front wheel angle, a preset wheelbase, and a preset understeer coefficient;

[0014] Determining a desired sideslip angle based on the real-time vehicle speed, the real-time lateral acceleration, and the real-time yaw rate;

[0015] The target rear wheel turning angle is determined according to the vehicle speed weight distribution coefficient, the expected yaw rate, the expected center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate.

[0016] In combination with the first aspect, in one embodiment, determining the vehicle speed weight distribution coefficient based on the real-time vehicle speed and the preset vehicle speed initial value includes:

[0017] Substitute the real-time vehicle speed and the preset initial speed value into the second calculation formula to obtain the vehicle speed weight distribution coefficient. The second calculation formula is:

[0018]

[0019] Where λ(v) is the vehicle speed weight distribution coefficient; v is the real-time vehicle speed; and v0 is the preset initial value of the vehicle speed.

[0020] In conjunction with the first aspect, in one embodiment, determining the target rear wheel turning angle based on the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate includes:

[0021] Substitute the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate into a third calculation formula to obtain the target rear wheel turning angle. The third calculation formula is:

[0022] δ r =λ(v)*K r (γ des -γ)+(1-λ(v))*K β β

[0023] Where λ(v) is the vehicle speed weight distribution coefficient; γ des is the desired yaw rate; β is the desired sideslip angle of the center of mass; K r is the preset yaw angle influence factor; K β is the preset center of mass sideslip angle influence factor; γ is the real-time yaw rate; δ r is the target rear wheel turning angle.

[0024] In conjunction with the first aspect, in one embodiment, determining the target rear wheel steering angle based on the preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate includes:

[0025] determining a first rear wheel steering angle based on the real-time front wheel steering angle;

[0026] determining a second rear wheel steering angle according to the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate;

[0027] A target rear wheel turning angle is determined based on a preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle.

[0028] In combination with the first aspect, in one embodiment, determining the target rear wheel turning angle based on the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle includes:

[0029] Substituting the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle into the fourth calculation formula to obtain the target rear wheel turning angle, the fourth calculation formula is:

[0030] δ r =(1-K)δ1+Kδ2

[0031] Where K is the preset steering angle distribution coefficient; δ1 is the first rear wheel steering angle; δ2 is the second rear wheel steering angle; δ r is the target rear wheel turning angle.

[0032] In conjunction with the first aspect, in one embodiment, determining the target rear wheel steering angle based on the real-time front wheel steering angle includes:

[0033] Substituting the preset vehicle speed gain coefficient and the real-time front wheel steering angle into the first calculation formula to obtain the target rear wheel steering angle, the first calculation formula is:

[0034] δ r =K v ×δ f

[0035] Where K v is the preset vehicle speed gain coefficient; δ f is the real-time front wheel angle; δ r is the target rear wheel turning angle.

[0036] In a second aspect, an embodiment of the present application provides a rear-wheel steering control system, the rear-wheel steering control system comprising:

[0037] A first processing module, which is used to obtain real-time vehicle speed;

[0038] a second processing module configured to determine a target rear wheel steering angle based on the real-time front wheel steering angle if it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold;

[0039] a third processing module configured to determine a target rear wheel steering angle based on the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate if it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, the second vehicle speed threshold being greater than the first vehicle speed threshold;

[0040] a fourth processing module configured to determine a target rear wheel steering angle based on a preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate if it is detected that the real-time vehicle speed is not less than the first vehicle speed threshold and not greater than the second vehicle speed threshold;

[0041] A fifth processing module is configured to control rear wheel steering according to the target rear wheel steering angle.

[0042] In a third aspect, an embodiment of the present application provides a rear-wheel steering control device, which includes a processor, a memory, and a rear-wheel steering control program stored on the memory and executable by the processor, wherein when the rear-wheel steering control program is executed by the processor, the steps of the rear-wheel steering control method described in any one of the above items are implemented.

[0043] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a rear-wheel steering control program is stored, wherein when the rear-wheel steering control program is executed by a processor, the steps of the rear-wheel steering control method as described in any of the foregoing items are implemented.

[0044] The beneficial effects of the technical solutions provided in the embodiments of the present application include:

[0045] By acquiring the real-time vehicle speed, if it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold, the target rear wheel angle is determined based on the real-time front wheel angle, so as to provide higher flexibility and accuracy at low speeds and meet the demand for rapid response to steering at low speeds; if it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, the target rear wheel angle is determined based on the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw angular velocity, so as to better stabilize the vehicle and prevent unnecessary oversteering when driving at high speeds; if it is detected that the real-time vehicle speed is between the first vehicle speed threshold and the second vehicle speed threshold, the target rear wheel angle is determined based on the preset angle distribution coefficient, the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw angular velocity, and the rear wheel steering is controlled by the target rear wheel angle, so that the sensitivity and accuracy of the steering response can be improved while ensuring the stability of the vehicle. To sum up, the present application automatically switches the control mode according to the real-time vehicle speed, and adopts different control strategies under three different working conditions: low speed, medium speed and high speed, so as to better adapt to the steering requirements under different vehicle speed conditions, thereby improving the rear-wheel steering performance of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of an embodiment of the rear wheel steering control method of the present application;

[0047] Figure 2 For this application Figure 1 Detailed flow chart of step S30;

[0048] Figure 3 For this application Figure 1 Detailed flow chart of step S40;

[0049] Figure 4 This is a functional module diagram of an embodiment of a rear-wheel steering control system of the present application;

[0050] Figure 5 This is a schematic diagram of the hardware structure of the rear-wheel steering control device involved in the embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 this application.

[0052] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0053] In a first aspect, an embodiment of the present application provides a rear-wheel steering control method.

[0054] In one embodiment, referring to Figure 1 , Figure 1 This is a flow chart of an embodiment of the rear wheel steering control method of this application. Figure 1 As shown, the rear wheel steering control method includes:

[0055] Step S10: Obtain real-time vehicle speed.

[0056] For example, in this embodiment of the present application, real-time vehicle speed refers to the actual speed of the target vehicle at the current moment, which can be measured in real time by onboard sensors and fed back to the control system. Specifically, the rear-wheel steering control strategy can be automatically adjusted based on changes in the target vehicle's speed. For example, at low speeds, a more sensitive steering strategy may be required, while at high speeds, a more stable and gentle steering strategy may be required to ensure driving safety.

[0057] Step S20: If it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold, a target rear wheel steering angle is determined based on the real-time front wheel steering angle.

[0058] For example, in the embodiment of the present application, the specific value of the preset first vehicle speed threshold can be determined according to actual needs and is not limited here. For example, the first vehicle speed threshold can preferably be 40 km / h; the real-time front wheel angle refers to the rotation angle of the front wheels of the target vehicle relative to the vehicle body, which directly affects the steering path and driving direction of the target vehicle; the target rear wheel angle refers to the rotation angle of the rear wheels of the target vehicle relative to the vehicle body, and the vehicle driving stability and controllability can be optimized by controlling the rotation angle of the rear wheels relative to the longitudinal centerline of the vehicle.

[0059] Specifically, since the vehicle's steering response is relatively slow at low speeds, relying solely on the front wheel angle may cause the vehicle's turning radius to be too large, understeer, or oversteer; therefore, the target rear wheel angle (i.e., feedforward rear wheel angle) can be calculated based on the front wheel angle, and the rear wheel steering can be controlled based on the target rear wheel angle, which can effectively improve the vehicle's turning flexibility and thus improve the target vehicle's handling performance when driving at low speeds.

[0060] Step S30: If it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, the target rear wheel angle is determined based on the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw angular velocity, and the second vehicle speed threshold is greater than the first vehicle speed threshold.

[0061] For example, in an embodiment of the present application, the specific value of the preset second vehicle speed threshold can be determined according to actual needs and is not limited here. For example, the preset second vehicle speed threshold can preferably be 80 km / h, wherein the second vehicle speed threshold is greater than the first vehicle speed threshold; the real-time lateral acceleration refers to the acceleration of the target vehicle in the lateral direction, that is, the speed change of the target vehicle due to steering or lateral force during driving, which reflects the lateral dynamic response of the vehicle; the real-time yaw angular velocity refers to the angular velocity of the target vehicle rotating around the vertical axis, which is used to describe the yaw behavior of the vehicle during turning or changing lanes.

[0062] Specifically, the real-time vehicle speed affects the motion state of the target vehicle. The higher the speed, the more sensitive the vehicle is to steering, and the adjustment of the rear wheel angle needs to be more precise to avoid oversteering or loss of control; the front wheel angle determines the steering direction and steering angle of the vehicle, but the influence of the front wheels on the vehicle's driving trajectory may generate a large lateral force at high speeds, which needs to be compensated by the rear wheel angle to avoid vehicle instability; the lateral acceleration reflects the acceleration or deceleration of the vehicle in the lateral direction. The greater the lateral force of the vehicle, the more important the adjustment of the rear wheel angle is to ensure the lateral stability of the vehicle; the yaw angular velocity describes the rotation rate of the vehicle around the vertical axis. When the yaw angular velocity increases when the vehicle is turning, the steering of the rear wheels needs to be appropriately adjusted to reduce the yaw angle of the vehicle, thereby enhancing steering accuracy and stability.

[0063] It is understandable that if the real-time vehicle speed is detected to be greater than the preset second vehicle speed threshold, it means that the vehicle is in a higher speed state. At this time, in order to ensure the stability and precise control of the vehicle when driving at high speed, it is necessary to combine the real-time vehicle speed, front wheel angle, lateral acceleration and yaw angular velocity to calculate the target rear wheel angle (i.e., feedback rear wheel angle); by measuring these parameters in real time, the system can calculate a target rear wheel angle that adapts to the current driving state to achieve precise dynamic adjustment, thereby maintaining the stability and flexibility of the vehicle when driving at high speed.

[0064] Step S40: If it is detected that the real-time vehicle speed is not less than the first speed threshold and not greater than the second speed threshold, the target rear wheel angle is determined based on the preset angle distribution coefficient, the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw angular velocity.

[0065] For example, in the embodiment of the present application, the specific value of the preset rear wheel steering angle distribution coefficient K can be determined according to actual needs and is not limited here. For example, in the medium speed range, if the demand is biased towards vehicle flexibility, the K value can preferably be below 0.4; if the demand is biased towards vehicle stability, the K value can preferably be above 0.7; if the demand is a balance between vehicle flexibility and stability, the K value can preferably be 0.5.

[0066] Specifically, if it is detected that the real-time vehicle speed is not less than the first vehicle speed threshold and not greater than the second vehicle speed threshold, it means that the target vehicle is in a medium-speed state. At this time, in order to ensure vehicle stability while improving the sensitivity and accuracy of steering response, the two control strategies in low-speed and high-speed states can be combined through the preset rear wheel angle distribution coefficient. The feedforward rear wheel angle is determined according to the real-time front wheel angle, and the feedback rear wheel angle is determined according to the real-time vehicle speed, real-time front wheel angle, real-time lateral acceleration and real-time yaw angular velocity; the feedforward rear wheel angle and the feedback rear wheel angle are weightedly calculated according to the preset rear wheel angle distribution coefficient to obtain the target rear wheel angle, so as to achieve optimized control of the dynamic state of the target vehicle and ensure stability and controllability during medium-speed driving.

[0067] Step S50: Controlling rear wheel steering according to the target rear wheel steering angle.

[0068] For example, in an embodiment of the present application, after determining the target rear wheel angle, the system converts it into a control signal and transmits the control signal to the rear wheel steering actuator; the rear wheel steering actuator adjusts the actual rear wheel angle according to the received control signal to achieve real-time optimization of the vehicle's dynamic state, thereby ensuring that the vehicle has optimal handling and stability under different driving conditions.

[0069] The present application obtains the real-time vehicle speed. If it is detected that the real-time vehicle speed is less than a preset first speed threshold, the target rear wheel angle is determined based on the real-time front wheel angle, so as to provide higher flexibility and accuracy at low speeds and meet the demand for rapid steering response at low speeds; if it is detected that the real-time vehicle speed is greater than a preset second speed threshold, the target rear wheel angle is determined based on the real-time vehicle speed, real-time front wheel angle, real-time lateral acceleration and real-time yaw angular velocity, so as to better stabilize the vehicle and prevent unnecessary oversteering when driving at high speeds; if it is detected that the real-time vehicle speed is between the first speed threshold and the second speed threshold, the target rear wheel angle is determined based on the preset angle distribution coefficient, the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw angular velocity, and the rear wheel steering is controlled by the target rear wheel angle, so that the sensitivity and accuracy of the steering response can be improved while ensuring the stability of the vehicle. To sum up, the present application automatically switches the control mode according to the real-time vehicle speed, and adopts different control strategies under three different working conditions: low speed, medium speed and high speed, so as to better adapt to the steering requirements under different vehicle speed conditions, thereby improving the rear-wheel steering performance of the vehicle.

[0070] Furthermore, in one embodiment, referring to Figure 2 As shown, the target rear wheel angle is determined based on the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw rate, including:

[0071] Step S301: Determine a vehicle speed weight distribution coefficient based on the real-time vehicle speed and a preset vehicle speed initial value;

[0072] Step S302: determining a desired yaw rate based on the real-time vehicle speed, the real-time front wheel angle, the preset wheelbase, and the preset understeer coefficient;

[0073] Step S303: determining a desired sideslip angle based on the real-time vehicle speed, the real-time lateral acceleration, and the real-time yaw rate;

[0074] Step S304: Determine the target rear wheel turning angle based on the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass slip angle, the preset yaw angle influence factor, the preset center of mass slip angle influence factor, and the real-time yaw rate.

[0075] For example, in an embodiment of the present application, the preset initial vehicle speed value provides a starting point for the system, based on which the influence of the vehicle speed on the rear-wheel steering control can be calculated; the vehicle speed weight distribution coefficient is used to ensure that the vehicle has optimal handling and stability at different speeds; the preset understeer coefficient is used to compensate for the understeer situation that may occur in the vehicle under different working conditions; the preset wheelbase is the designed distance between the front and rear axles of the target vehicle, which determines the steering characteristics and stability of the vehicle.

[0076] It can be understood that the yaw angle refers to the rotation angle of the vehicle around the vertical axis, and the preset yaw angle influence factor is used to set the response characteristics of the yaw angle under specific driving conditions; the center of mass sideslip angle refers to the offset angle between the center of mass of the vehicle and the driving direction, and the preset center of mass sideslip angle influence factor is used to describe the relationship between the change in the center of mass sideslip angle and vehicle control; among them, the specific values of the preset wheelbase, the preset understeer coefficient, the preset yaw angle influence factor and the preset center of mass sideslip angle influence factor can be determined according to actual needs and are not limited here; the specific value of the preset vehicle speed initial value can be determined according to actual needs and is not limited here. For example, the preset vehicle speed initial value can preferably be 60km / h.

[0077] Specifically, the real-time vehicle speed v and the preset initial speed value v0 can be substituted into the following calculation formula to obtain the vehicle speed weight distribution coefficient. The calculation formula is:

[0078]

[0079] The expected yaw rate can be determined by using the real-time vehicle speed, the real-time front wheel angle, the preset wheelbase, and the preset understeer coefficient and substituted into the following calculation formula to obtain the expected yaw rate. The calculation formula is:

[0080]

[0081] Where v is the real-time vehicle speed; L is the preset wheelbase; K usis the preset understeer coefficient; γ des is the desired yaw rate; δ f is the real-time front wheel angle.

[0082] The real-time vehicle speed, real-time lateral acceleration, and real-time yaw rate can be substituted into the following calculation formula to obtain the expected center of mass sideslip angle. The calculation formula is:

[0083]

[0084] Where, v is the real-time vehicle speed; a y is the real-time lateral acceleration; γ is the real-time yaw rate; β is the desired sideslip angle of the center of mass.

[0085] It can be understood that the vehicle speed weight distribution coefficient reflects the handling characteristics of the target vehicle at different speeds, the expected yaw rate and the expected center of mass sideslip angle represent the expected dynamic behavior of the target vehicle, the preset yaw angle and center of mass sideslip angle influencing factors are used to correct the target vehicle response, and the real-time yaw rate reflects the actual dynamic state of the current vehicle; by comprehensively considering these factors, the system can calculate the target rear wheel angle, and then adjust the vehicle's handling response according to the target rear wheel angle, thereby achieving stable and precise driving control.

[0086] Furthermore, in one embodiment, determining the target rear wheel turning angle based on the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate includes:

[0087] Substitute the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate into a third calculation formula to obtain the target rear wheel turning angle. The third calculation formula is:

[0088] δ r =λ(v)*K r (γ des -γ)+(1-λ(v))*K β β

[0089] Where λ(v) is the vehicle speed weight distribution coefficient; γ des is the desired yaw rate; β is the desired sideslip angle of the center of mass; K r is the preset yaw angle influence factor; K β is the preset center of mass sideslip angle influence factor; γ is the real-time yaw rate; δ r is the target rear wheel turning angle.

[0090] For example, in the embodiment of the present application, the vehicle speed weight distribution coefficient λ(v), the expected yaw rate γdes , expected center of mass sideslip angle β, preset yaw angle influence factor K r , preset center of mass sideslip angle influence factor K β , the real-time yaw angular velocity γ is substituted into the following calculation formula to obtain the target rear wheel angle, which is:

[0091] δ r =λ(v)*K r (γ des -γ)+(1-λ(v))*K β β.

[0092] Furthermore, in one embodiment, referring to Figure 3 As shown, the target rear wheel steering angle is determined based on the preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration and the real-time yaw rate, including:

[0093] Step S401: determining a first rear wheel steering angle based on the real-time front wheel steering angle;

[0094] Step S402: determining a second rear wheel angle based on the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration, and the real-time yaw rate;

[0095] Step S403: Determine a target rear wheel turning angle based on a preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle.

[0096] For example, in the embodiment of the present application, the first rear wheel angle refers to the rear wheel angle calculated by the feedforward control strategy, that is, the first rear wheel angle is obtained by the real-time front wheel angle and a preset vehicle speed gain coefficient; the second rear wheel angle refers to the rear wheel angle calculated by the feedback control strategy, and the second rear wheel angle is obtained by substituting the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration, and the real-time yaw rate into the following calculation formula:

[0097] δ2=λ(v)*K r (γ des -γ)+(1-λ(v))*K β β

[0098] Where λ(v) is the vehicle speed weight distribution coefficient; γ des is the desired yaw rate; β is the desired sideslip angle of the center of mass; K r is the preset yaw angle influence factor; K β is the preset center of mass sideslip angle influencing factor; γ is the real-time yaw rate; δ2 is the second rear wheel turning angle.

[0099] It should be noted that after determining the first rear wheel angle and the second rear wheel angle, a weighted calculation is performed on the first rear wheel angle and the second rear wheel angle according to a preset rear wheel angle distribution coefficient to obtain a target rear wheel angle, so as to achieve optimized control of the dynamic state of the target vehicle and ensure stability and controllability during medium-speed driving.

[0100] Furthermore, in one embodiment, determining the target rear wheel turning angle based on the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle includes:

[0101] Substituting the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle into the fourth calculation formula to obtain the target rear wheel turning angle, the fourth calculation formula is:

[0102] δ r =(1-K)δ1+Kδ2

[0103] Where K is the preset steering angle distribution coefficient; δ1 is the first rear wheel steering angle; δ2 is the second rear wheel steering angle; δ r is the target rear wheel turning angle.

[0104] For example, in the embodiment of the present application, the specific value of the preset steering angle distribution coefficient can be determined according to actual needs and is not limited here; the preset steering angle distribution coefficient K, the first rear wheel steering angle δ1 and the second rear wheel steering angle δ2 are substituted into the following calculation formula to obtain the target rear wheel steering angle δ r , the calculation formula is:

[0105] δ r =(1-K)δ1+Kδ2.

[0106] Furthermore, in one embodiment, determining the target rear wheel steering angle based on the real-time front wheel steering angle includes:

[0107] Substituting the preset vehicle speed gain coefficient and the real-time front wheel steering angle into the first calculation formula to obtain the target rear wheel steering angle, the first calculation formula is:

[0108] δ r =K v ×δ f

[0109] Where K v is the preset vehicle speed gain coefficient; δ f is the real-time front wheel angle; δ r is the target rear wheel turning angle.

[0110] For example, in the embodiment of the present application, the specific value of the preset vehicle speed gain coefficient can be determined according to actual needs and is not limited here; the preset vehicle speed gain coefficient K v and real-time front wheel steering angle δ fSubstitute the following calculation formula to obtain the target rear wheel turning angle δ r , the calculation formula is:

[0111] δ r =K v ×δ f .

[0112] In a second aspect, an embodiment of the present application also provides a rear-wheel steering control system.

[0113] In one embodiment, referring to Figure 4 , Figure 4 This is a functional module diagram of the rear wheel steering control system embodiment of the present application. Figure 4 As shown, the rear wheel steering control system includes:

[0114] A first processing module, which is used to obtain real-time vehicle speed;

[0115] a second processing module configured to determine a target rear wheel steering angle based on the real-time front wheel steering angle if it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold;

[0116] a third processing module configured to determine a target rear wheel steering angle based on the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate if it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, the second vehicle speed threshold being greater than the first vehicle speed threshold;

[0117] a fourth processing module configured to determine a target rear wheel steering angle based on a preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate if it is detected that the real-time vehicle speed is not less than the first vehicle speed threshold and not greater than the second vehicle speed threshold;

[0118] A fifth processing module is configured to control rear wheel steering according to the target rear wheel steering angle.

[0119] Furthermore, in one embodiment, the third processing module is specifically configured to:

[0120] Determine a vehicle speed weight distribution coefficient based on the real-time vehicle speed and a preset vehicle speed initial value;

[0121] Determining a desired yaw rate based on a real-time vehicle speed, a real-time front wheel angle, a preset wheelbase, and a preset understeer coefficient;

[0122] Determining a desired sideslip angle based on the real-time vehicle speed, the real-time lateral acceleration, and the real-time yaw rate;

[0123] The target rear wheel turning angle is determined according to the vehicle speed weight distribution coefficient, the expected yaw rate, the expected center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate.

[0124] Furthermore, in one embodiment, the third processing module is further configured to:

[0125] Substitute the real-time vehicle speed and the preset initial speed value into the second calculation formula to obtain the vehicle speed weight distribution coefficient. The second calculation formula is:

[0126]

[0127] Where λ(v) is the vehicle speed weight distribution coefficient; v is the real-time vehicle speed; and v0 is the preset initial value of the vehicle speed.

[0128] Furthermore, in one embodiment, the third processing module is further configured to:

[0129] Substitute the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate into a third calculation formula to obtain the target rear wheel turning angle. The third calculation formula is:

[0130] δ r =λ(v)*K r (γ des -γ)+(1-λ(v))*K β β

[0131] Where λ(v) is the vehicle speed weight distribution coefficient; γ des is the desired yaw rate; β is the desired sideslip angle of the center of mass; K r is the preset yaw angle influence factor; K β is the preset center of mass sideslip angle influence factor; γ is the real-time yaw rate; δ r is the target rear wheel turning angle.

[0132] Furthermore, in one embodiment, the fourth processing module is specifically configured to:

[0133] determining a first rear wheel steering angle based on the real-time front wheel steering angle;

[0134] determining a second rear wheel steering angle according to the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate;

[0135] A target rear wheel turning angle is determined based on a preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle.

[0136] Furthermore, in one embodiment, the fourth processing module is further configured to:

[0137] Substituting the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle into the fourth calculation formula to obtain the target rear wheel turning angle, the fourth calculation formula is:

[0138] δ r =(1-K)δ1+Kδ2

[0139] Where K is the preset steering angle distribution coefficient; δ1 is the first rear wheel steering angle; δ2 is the second rear wheel steering angle; δ r is the target rear wheel turning angle.

[0140] Furthermore, in one embodiment, the second processing module is specifically configured to:

[0141] Substituting the preset vehicle speed gain coefficient and the real-time front wheel steering angle into the first calculation formula to obtain the target rear wheel steering angle, the first calculation formula is:

[0142] δ r =K v ×δ f

[0143] Where K v is the preset vehicle speed gain coefficient; δ f is the real-time front wheel angle; δ r is the target rear wheel turning angle.

[0144] The present application obtains the real-time vehicle speed. If it is detected that the real-time vehicle speed is less than a preset first speed threshold, the target rear wheel angle is determined based on the real-time front wheel angle, so as to provide higher flexibility and accuracy at low speeds and meet the demand for rapid steering response at low speeds; if it is detected that the real-time vehicle speed is greater than a preset second speed threshold, the target rear wheel angle is determined based on the real-time vehicle speed, real-time front wheel angle, real-time lateral acceleration and real-time yaw angular velocity, so as to better stabilize the vehicle and prevent unnecessary oversteering when driving at high speeds; if it is detected that the real-time vehicle speed is between the first speed threshold and the second speed threshold, the target rear wheel angle is determined based on the preset angle distribution coefficient, the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration and the real-time yaw angular velocity, and the rear wheel steering is controlled by the target rear wheel angle, so that the sensitivity and accuracy of the steering response can be improved while ensuring the stability of the vehicle. To sum up, the present application automatically switches the control mode according to the real-time vehicle speed, and adopts different control strategies under three different working conditions: low speed, medium speed and high speed, so as to better adapt to the steering requirements under different vehicle speed conditions, thereby improving the rear-wheel steering performance of the vehicle.

[0145] Among them, the functional implementation of each module in the above-mentioned rear-wheel steering control system corresponds to the various steps in the above-mentioned rear-wheel steering control method embodiment, and their functions and implementation processes will not be repeated here one by one.

[0146] In a third aspect, an embodiment of the present application provides a rear-wheel steering control device, which may be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0147] Reference Figure 5 , Figure 5 FIG2 is a schematic diagram of the hardware structure of the rear-wheel steering control device involved in the embodiment of the present application. In the embodiment of the present application, the rear-wheel steering control device may include a processor, a memory, a communication interface, and a communication bus.

[0148] The communication bus may be of any type and is used to interconnect the processor, memory, and communication interface.

[0149] Communication interfaces include input / output (I / O) interfaces, physical interfaces, and logical interfaces, used to interconnect components within the rear-wheel steering control device, as well as interfaces used to interconnect the rear-wheel steering control device with other devices (such as other computing devices or user devices). Physical interfaces can be Ethernet, fiber, or ATM interfaces; user devices can be displays or keyboards.

[0150] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0151] The processor may be a general-purpose processor that can call a rear-wheel steering control program stored in a memory and execute the rear-wheel steering control method provided by the embodiments of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the rear-wheel steering control program is called can be referenced to the various embodiments of the rear-wheel steering control method of the present application and will not be further described here.

[0152] Those skilled in the art will understand that Figure 5 The hardware structure shown in the figure does not constitute a limitation to the present application and may include more or fewer components than shown in the figure, or a combination of certain components, or a different arrangement of components.

[0153] In a fourth aspect, an embodiment of the present application also provides a readable storage medium.

[0154] The readable storage medium of the present application stores a rear-wheel steering control program, wherein when the rear-wheel steering control program is executed by the processor, the steps of the rear-wheel steering control method as described above are implemented.

[0155] Among them, the method implemented when the rear-wheel steering control program is executed can refer to the various embodiments of the rear-wheel steering control method of the present application, and will not be repeated here.

[0156] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0157] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0158] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0159] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0160] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0161] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of the present application.

[0162] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A rear wheel steering control method, characterized in that: The rear wheel steering control method comprises: Get real-time vehicle speed; If it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold, determining a target rear wheel steering angle based on the real-time front wheel steering angle; If it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, determining a target rear wheel steering angle based on the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate, and the second vehicle speed threshold is greater than the first vehicle speed threshold; If it is detected that the real-time vehicle speed is not less than a first vehicle speed threshold and not greater than a second vehicle speed threshold, determining a target rear wheel steering angle based on a preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate; The rear wheel steering is controlled according to the target rear wheel turning angle.

2. The rear wheel steering control method according to claim 1, wherein: The determining of the target rear wheel angle based on the real-time vehicle speed, the real-time front wheel angle, the real-time lateral acceleration, and the real-time yaw rate includes: Determine a vehicle speed weight distribution coefficient based on the real-time vehicle speed and a preset vehicle speed initial value; Determining a desired yaw rate based on a real-time vehicle speed, a real-time front wheel angle, a preset wheelbase, and a preset understeer coefficient; Determining a desired sideslip angle based on the real-time vehicle speed, the real-time lateral acceleration, and the real-time yaw rate; The target rear wheel turning angle is determined according to the vehicle speed weight distribution coefficient, the expected yaw rate, the expected center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate.

3. The rear wheel steering control method according to claim 2, wherein: The method of determining the vehicle speed weight distribution coefficient based on the real-time vehicle speed and the preset vehicle speed initial value includes: Substitute the real-time vehicle speed and the preset initial speed value into the second calculation formula to obtain the vehicle speed weight distribution coefficient. The second calculation formula is: Where λ(v) is the vehicle speed weight distribution coefficient; v is the real-time vehicle speed; and v0 is the preset initial value of the vehicle speed.

4. The rear wheel steering control method according to claim 2, wherein: The target rear wheel turning angle is determined according to the vehicle speed weight distribution coefficient, the expected yaw rate, the expected center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate, including: Substitute the vehicle speed weight distribution coefficient, the desired yaw rate, the desired center of mass sideslip angle, the preset yaw angle influence factor, the preset center of mass sideslip angle influence factor, and the real-time yaw rate into a third calculation formula to obtain the target rear wheel turning angle. The third calculation formula is: d r =λ(v)*K r (c des -γ)+(1-λ(v))*K β b Where λ(v) is the vehicle speed weight distribution coefficient; γ des is the desired yaw rate; β is the desired sideslip angle of the center of mass; K r is the preset yaw angle influence factor; K β is the preset center of mass sideslip angle influence factor; γ is the real-time yaw rate; δ r is the target rear wheel turning angle.

5. The rear wheel steering control method according to claim 1, wherein: The determining of the target rear wheel steering angle based on the preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate includes: determining a first rear wheel steering angle based on the real-time front wheel steering angle; determining a second rear wheel steering angle according to the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate; A target rear wheel turning angle is determined based on a preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle.

6. The rear wheel steering control method according to claim 5, characterized in that: The determining of the target rear wheel turning angle based on the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle includes: Substituting the preset turning angle distribution coefficient, the first rear wheel turning angle, and the second rear wheel turning angle into the fourth calculation formula to obtain the target rear wheel turning angle, the fourth calculation formula is: d r =(1-K)δ1+Kδ2 Where K is the preset steering angle distribution coefficient; δ1 is the first rear wheel steering angle; δ2 is the second rear wheel steering angle; δ r is the target rear wheel turning angle.

7. The rear wheel steering control method according to claim 1, wherein: The determining of the target rear wheel steering angle based on the real-time front wheel steering angle includes: Substituting the preset vehicle speed gain coefficient and the real-time front wheel steering angle into the first calculation formula to obtain the target rear wheel steering angle, the first calculation formula is: d r =K v ×d f Where K v is the preset vehicle speed gain coefficient; δ f is the real-time front wheel angle; δ r is the target rear wheel turning angle.

8. A rear wheel steering control system, characterized in that: The rear wheel steering control system comprises: A first processing module, which is used to obtain real-time vehicle speed; a second processing module configured to determine a target rear wheel steering angle based on the real-time front wheel steering angle if it is detected that the real-time vehicle speed is less than a preset first vehicle speed threshold; a third processing module configured to determine a target rear wheel steering angle based on the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate if it is detected that the real-time vehicle speed is greater than a preset second vehicle speed threshold, the second vehicle speed threshold being greater than the first vehicle speed threshold; a fourth processing module configured to determine a target rear wheel steering angle based on a preset steering angle distribution coefficient, the real-time vehicle speed, the real-time front wheel steering angle, the real-time lateral acceleration, and the real-time yaw rate if it is detected that the real-time vehicle speed is not less than the first vehicle speed threshold and not greater than the second vehicle speed threshold; A fifth processing module is configured to control rear wheel steering according to the target rear wheel steering angle.

9. A rear wheel steering control device, characterized in that: The rear-wheel steering control device includes a processor, a memory, and a rear-wheel steering control program stored in the memory and executable by the processor, wherein when the rear-wheel steering control program is executed by the processor, the steps of the rear-wheel steering control method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a rear-wheel steering control program, wherein when the rear-wheel steering control program is executed by the processor, the steps of the rear-wheel steering control method according to any one of claims 1 to 7 are implemented.

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