Vehicle control method, electronic device, collision stability control system and vehicle

Abstract

The present invention discloses a vehicle control method, an electronic device, a collision stability control system and a vehicle. The vehicle control method comprises: determining that the vehicle meets an unstable state; controlling the rotation angle of the rear wheels of the vehicle according to a target rear wheel steering angle value, and controlling the vehicle's four-wheel motors to drive and / or brake respectively according to a target torque value. When the vehicle is in an unstable state, the method can adjust the rear wheel steering angle and drive and / or brake the four-wheel motors of the vehicle respectively, generate an additional yaw compensation torque to maintain vehicle stability, help the driver correct the vehicle body posture in the early stage of the unstable state, and avoid secondary collisions after the vehicle is unstable and cause losses.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to a vehicle control method, an electronic device, a computer-readable storage medium, a collision stability control system and a vehicle. Background Art

[0002] In the related technology, when the vehicle is in dangerous conditions such as rear-end collision where it is easy to lose control, a warning message is issued. The collision stabilization system achieves collision stability only by controlling the torque of the four wheels. There is no rear-wheel steering and four-motor joint control strategy. Since the four-motor drive strategy will have a greater impact on the yaw movement of the car, when the rear-wheel steering and the four motors are not jointly controlled, the rear-wheel steering cannot share part of the yaw torque, resulting in the vehicle failing to correct the body posture in time when a rear-end collision occurs, and the vehicle stability cannot be guaranteed. A secondary collision may occur after the vehicle is rear-ended, causing losses. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide a vehicle control method, which can adjust the rear wheel steering angle and drive and / or brake the four-wheel motors of the vehicle respectively when the vehicle is in an unstable condition, generate additional yaw compensation torque to maintain vehicle stability, help the driver correct the vehicle body posture in the early stage of instability, and avoid secondary collision after the vehicle is instability and cause losses.

[0004] The second objective of the present invention is to provide an electronic device.

[0005] A third object of the present invention is to provide a computer-readable storage medium.

[0006] A fourth objective of the present invention is to provide a collision stability control system.

[0007] A fifth object of the present invention is to provide a vehicle.

[0008] In order to solve the above problems, an embodiment of the first aspect of the present invention provides a vehicle control method, including: determining that the vehicle meets an unstable state; controlling the rotation angle of the vehicle's rear wheels according to a target rear wheel steering angle value, and controlling the vehicle's four-wheel motors to drive and / or brake respectively according to a target torque value.

[0009] According to the vehicle control method of an embodiment of the present invention, if it is determined that the vehicle meets the instability state, the rear wheel steering angle is adjusted and the four-wheel motors of the vehicle are driven and / or braked respectively to generate additional yaw compensation torque to maintain vehicle stability, thereby helping the driver to correct the vehicle body posture in the early stage of instability and avoiding secondary collision after the vehicle becomes unstable and causing losses.

[0010] In some embodiments, the vehicle satisfies an unstable state, including: the vehicle is in an unstable area of ​​a target phase plane and the tires of the vehicle are in a non-linear area of ​​a tire working area, and the target phase plane is a phase plane of the vehicle's center of mass sideslip angle and center of mass sideslip angular velocity.

[0011] In some embodiments, the vehicle being in an unstable region of a target phase plane includes the vehicle's center of mass sideslip angle and center of mass sideslip angular velocity not satisfying a stable region boundary condition in the target phase plane.

[0012] In some embodiments, the target rear wheel steering angle value is obtained according to the rear wheel steering feedback control value, the rear wheel steering angle value of the previous control cycle, the rear wheel steering feedforward control value and the front wheel steering angle value of the vehicle.

[0013] In some embodiments, the rear wheel steering feedforward control value and the rear wheel steering feedback control value are obtained by solving the rear wheel steering control performance index according to the actual value of the center of mass sideslip angle and the actual value of the yaw rate of the vehicle.

[0014] In some embodiments, the rear wheel steering control performance index is expressed as an integral function of a first term and a second term, wherein the first term is expressed as the deviation of the actual value of the center of mass sideslip angle from the expected value of the center of mass sideslip angle and the deviation of the actual value of the yaw rate from the expected value of the yaw rate, and the second term is used to limit the size of the rear wheel turning angle.

[0015] In some embodiments, the expected value of the center of mass sideslip angle is obtained based on vehicle state information and the corresponding relationship between the center of mass sideslip angle and the front wheel turning angle of the vehicle, and the corresponding relationship between the center of mass sideslip angle and the front wheel turning angle is obtained based on the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation.

[0016] In some embodiments, the expected value of the yaw rate is obtained based on the vehicle state information and the corresponding relationship between the yaw rate and the front wheel turning angle, and the corresponding relationship between the yaw rate and the front wheel turning angle is obtained based on the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation.

[0017] In some embodiments, the vehicle control method further includes: determining a maximum limit of the target rear wheel steering angle value according to the vehicle speed.

[0018] In some embodiments, the maximum limit of the target rear-wheel steering angle value is determined according to the vehicle speed, including: when the vehicle speed is less than a first vehicle speed threshold, the target rear-wheel steering angle value is less than a first steering angle value; when the vehicle speed is greater than or equal to a second vehicle speed threshold, the target rear-wheel steering angle value is less than a second steering angle value; wherein, the first vehicle speed threshold is less than the second vehicle speed threshold, and the first steering angle value is greater than the second steering angle value.

[0019] In some embodiments, the target torque value is obtained according to the driving braking feedback control value, the torque value of the previous control cycle, the driving braking feedforward control value and the front wheel steering angle value of the vehicle.

[0020] In some embodiments, the driving braking feedback control value and the driving braking feedforward control value are obtained by solving a driving braking control performance index according to an actual value of the wheel torque of the vehicle.

[0021] In some embodiments, the driving braking control performance index is represented by the sum of a third item and a fourth item, wherein the third item expresses the magnitude of the deviation of the actual wheel torque value from the expected wheel torque value, and the fourth item is used to limit the magnitude of the yaw moment.

[0022] In some embodiments, the wheel torque expected value is calculated based on vehicle state information, a driving and braking dynamics model of the vehicle, and a driving and braking linear two-degree-of-freedom equation.

[0023] In some embodiments, the vehicle control method further includes: controlling the rotation direction of the rear wheels according to the direction of the yaw force causing the vehicle to become unstable, and controlling the driving and braking state of the four-wheel motors of the vehicle according to the direction of the yaw force.

[0024] In some embodiments, the vehicle control method further includes: when the tire is in a linear region of the tire working area, controlling the rotation angle of the vehicle's rear wheels according to a target rear wheel steering angle; or, when the tire is in a saturation region of the tire working area, controlling the vehicle's four-wheel motor to drive and / or brake according to the target torque.

[0025] In some embodiments, the vehicle control method further includes: when the deviation between the actual value of the center of mass sideslip angle and the expected value of the center of mass sideslip angle is less than a center of mass sideslip angle deviation threshold and the deviation between the actual value of the yaw angular velocity and the expected value of the yaw angular velocity is less than a yaw angular velocity deviation threshold, determining that the vehicle has exited an unstable condition and giving a prompt.

[0026] A second aspect of the present invention provides an electronic device, comprising: at least one processor; a memory communicatively connected to the at least one processor; the memory storing a computer program executable by the at least one processor, wherein the at least one processor implements the vehicle control method described in the above embodiment when executing the computer program.

[0027] According to the electronic device of the embodiment of the present invention, the corresponding vehicle control program can be stored in the memory. When implementing the vehicle control method, the processor runs the program in the memory to determine whether the vehicle meets the instability state. After determining that the vehicle meets the instability state, the rear wheel steering angle is adjusted and the four-wheel motors of the vehicle are driven and / or braked respectively to generate additional yaw compensation torque to maintain vehicle stability, and help the driver correct the vehicle body posture in the early stage of the instability state to avoid secondary collision after the vehicle is rear-ended and cause losses.

[0028] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the vehicle control method described in the above embodiment.

[0029] A fourth aspect of the present invention provides a collision stability control system, comprising: a perception system for acquiring vehicle status information; a decision system connected to the perception system and used to execute the vehicle control method described in the above embodiment; an execution system, comprising a four-wheel independent drive control motor and a rear-wheel steering controller, the four-wheel independent drive control motor being connected to the decision system and used to control the four wheels to drive and / or drive, and the rear-wheel steering controller being used to control the steering of the rear wheels.

[0030] According to the collision stability control system of the embodiment of the present invention, the perception system obtains vehicle status information in real time and determines whether the vehicle meets the instability state. When the vehicle meets the instability state, the decision system runs the vehicle control method, and controls the execution system to adjust the rear wheel steering angle and drive and / or brake the four-wheel motors of the vehicle respectively, to generate additional yaw compensation torque to maintain vehicle stability, and help the driver correct the vehicle body posture in the early stage of instability to avoid secondary collision after the vehicle is rear-ended and cause losses.

[0031] A fifth aspect of the present invention provides a vehicle, the vehicle includes the electronic device described in the above embodiment, or the vehicle includes the collision stability control system described in the above embodiment.

[0032] The vehicle according to the embodiment of the present invention detects the vehicle status in real time during driving. If the vehicle meets the instability state, the rear wheel steering angle is adjusted and the four-wheel motors of the vehicle are driven and / or braked respectively to generate additional yaw compensation torque to maintain vehicle stability, thereby helping the driver to correct the vehicle body posture in the early stage of instability and avoiding secondary collision after the vehicle is rear-ended and causing losses.

[0033] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0035] Figure 1 is a flow chart of a vehicle control method according to an embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of a phase plane stability region according to an embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of the division of the tire working area according to one embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of rear wheel steering control according to one embodiment of the present invention;

[0039] Figure 5 is a schematic diagram of driving braking and rear wheel steering combined control according to an embodiment of the present invention;

[0040] Figure 6 is a schematic diagram of a collision stability control system according to an embodiment of the present invention;

[0041] Figure 7 is a flow chart of a collision stability control system strategy according to one embodiment of the present invention;

[0042] Figure 8 is a schematic diagram of a rear-wheel steering linear two-degree-of-freedom vehicle model according to one embodiment of the present invention;

[0043] Fig. 9 is a structural block diagram of an electronic device according to an embodiment of the present invention;

[0044] Fig.10 is a structural block diagram of a collision stability control system according to an embodiment of the present invention;

[0045] Fig.11 is a structural block diagram of a vehicle according to an embodiment of the present invention;

[0046] Fig.12 is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0047] Reference numerals:

[0048] Vehicles 300;

[0049] Electronic device 100; collision stability control system 200;

[0050] Processor 101; memory 102; perception system 210; decision system 220; execution system 230; four-wheel independent drive control motor 231; rear wheel steering controller 232. DETAILED DESCRIPTION

[0051] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0052] In the prior art, the collision stability control system of a vehicle driven by four motors is used in dangerous conditions such as rear-end collisions where the vehicle is prone to loss of control. Collision stability is achieved only by controlling the torque of the four wheels. There is no rear-wheel steering and four-motor combined control strategy. The rear-wheel steering cannot share part of the yaw torque, resulting in failure to correct the vehicle body posture in time when a rear-end collision occurs, and the vehicle stability cannot be guaranteed. A secondary collision may occur after the vehicle is rear-ended, causing losses.

[0053] In order to solve the above problems, an embodiment of the first aspect of the present invention provides a vehicle control method. When the vehicle is in an unstable state, the method can adjust the rear wheel steering angle and drive and / or brake the four-wheel motors of the vehicle respectively, so as to generate additional yaw compensation torque to maintain vehicle stability, help the driver correct the vehicle body posture in the early stage of instability, and avoid secondary collision after the vehicle becomes unstable and cause losses.

[0054] Reference below Figure 1 A vehicle control method according to an embodiment of the first aspect of the present invention is described as follows: Figure 1 As shown, the method at least includes step S1 to step S2.

[0055] Step S1, determining that the vehicle meets an unstable state.

[0056] Specifically, when a vehicle loses stability, the driver's control difficulty will increase significantly. In an emergency, the driver may not be able to respond accurately and in time, causing the vehicle to lose control or deviate from the normal driving route. This out-of-control state will seriously threaten road traffic safety. After the vehicle loses stability, it is easy to collide with other vehicles or obstacles. Such collisions may cause serious personal injury and property damage. For vehicles with a higher center of gravity, such as off-road vehicles and trucks, rollover accidents are more likely to occur after instability. On highways or busy urban roads, the instability of a vehicle may cause a chain accident, resulting in damage to multiple vehicles and casualties. Vehicle instability can be caused by rear-end collisions with the rear vehicle. Parameters such as yaw angular velocity and center of mass sideslip angle can be used to determine whether the vehicle meets the instability state. For example, when the vehicle collides, the yaw force generated causes the vehicle to become unstable.

[0057] Step S2, specifically, controls the rotation angle of the rear wheels of the vehicle according to the target rear wheel steering angle value, and controls the four-wheel motors of the vehicle to drive and / or brake respectively according to the target torque value.

[0058] Specifically, when the vehicle meets the instability state, the vehicle control method of the present invention adjusts the steering angle of the rear wheels of the vehicle and drives and brakes the four wheels of the whole vehicle. The yaw torque generated by the collision will cause the vehicle to be extremely unstable. At this time, an additional yaw compensation torque is generated by adjusting the rear wheel steering angle and driving and braking the four wheels of the whole vehicle for comprehensive control to maintain the stability of the vehicle; under the vehicle instability condition, when the lateral acceleration of the vehicle is relatively small, the angle of rotation of the rear wheels of the vehicle is controlled according to the target rear wheel steering angle value to ensure the handling stability of the vehicle. When the lateral acceleration of the vehicle is relatively large, the rear wheel steering system is limited by the saturated tire lateral force and the upper limit of the rear wheel steering angle, and its control effect cannot meet the requirements of the handling stability of the vehicle. At this time, a method of controlling the rear wheel steering angle and controlling the vehicle's four-wheel motors to drive and / or brake respectively is required to ensure the stability of the vehicle. The angle of rotation of the rear wheels of the vehicle and controlling the vehicle's four-wheel motors to drive and / or brake together improve the vehicle's controllability and stability, providing safety for vehicle driving.

[0059] According to the vehicle control method of the embodiment of the present invention, the vehicle status can be detected in real time. If it is determined that the vehicle meets the instability state, the rear wheel steering angle is adjusted and the four-wheel motors of the vehicle are driven and / or braked respectively to generate additional yaw compensation torque to maintain vehicle stability, thereby helping the driver to correct the vehicle body posture in the early stage of instability and avoiding secondary collision after the vehicle becomes unstable and causing losses.

[0060] In some embodiments, the vehicle satisfies an unstable state, including: the vehicle is in an unstable area of ​​a target phase plane and the tires of the vehicle are in a non-linear area of ​​a tire working area, and the target phase plane is a phase plane of the vehicle's center of mass sideslip angle and the center of mass sideslip angular velocity.

[0061] Specifically, whether the vehicle is unstable is determined based on the target phase plane of the vehicle and the tire working area. Phase plane analysis is a graphical system dynamic behavior analysis method. By plotting the trajectory of system state variables changing over time, the complexity and dynamic characteristics of the system can be intuitively understood. Since whether the vehicle meets the unstable state is determined based on parameters such as yaw angular velocity and center of mass sideslip angle, the target phase plane can be the phase plane of the vehicle's center of mass sideslip angle and center of mass sideslip angular velocity.

[0062] like Figure 2 As shown, the phase plane of the vehicle is divided into a stable area and an unstable area. The stable area and the unstable area are determined by the two lines. The stable area and the unstable area of ​​the vehicle phase plane are pre-determined in the test stage before the vehicle leaves the factory. That is to say, Figure 2 The horizontal line dividing the middle area into stable and unstable areas is known in advance; Figure 3As shown, the tire working area is divided into a linear area, a nonlinear area and a saturated area. The three working areas of the tire are also measured in advance and determined during the tire inspection period.

[0063] For example, when judging the stability of a vehicle, The phase plane divides the vehicle stability region by two straight lines symmetrical about the origin. These two straight lines are the boundary lines between the stable region and the unstable region, such as Figure 2 The boundary of the stable region can be expressed as:

[0064] ;

[0065] In the formula, is the sideslip angle of the center of mass, is the angular velocity of the sideslip angle at the center of mass, and is the stable region boundary coefficient, is the slope of the stable region boundary, To stabilize the regional boundaries and When the vehicle's center of mass sideslip angle and the center of mass sideslip angle angular velocity satisfy the above formula, that is, the vehicle is in the stable area A between the two straight lines, at this time the vehicle is considered to be in a stable state; otherwise, the vehicle is in the unstable area C outside the two straight lines, at this time the vehicle loses stability.

[0066] The rear-wheel steering strategy control is greatly affected by the lateral force of the tire. The rear-wheel steering strategy control can only play a good effect when the tire is in the linear area. In the nonlinear area of ​​the tire, the lateral force of the tire gradually tends to saturation. At this time, the driving braking control strategy needs to intervene and coordinate the control with the rear-wheel steering strategy.

[0067] In some embodiments, the vehicle being in an unstable region of the target phase plane includes the vehicle's center of mass sideslip angle and center of mass sideslip angular velocity not satisfying a stable region boundary condition in the target phase plane.

[0068] Specifically, the target phase plane is a two-dimensional plane used to analyze the dynamic stability of the vehicle, in which the horizontal axis and the vertical axis represent different dynamic parameters, such as the center of mass slip angle and the center of mass slip angular velocity; the center of mass slip angle is the angle between the center of mass velocity direction of the vehicle and the longitudinal axis of the vehicle, which reflects the degree of deviation of the vehicle from the desired driving direction during actual driving, and the center of mass slip angular velocity is the rate of change of this angle over time, that is, the speed of change of the center of mass slip angle. When the vehicle is in the unstable area of ​​the target phase plane, the center of mass slip angle and the center of mass slip angular velocity of the vehicle do not meet the boundary conditions of the stable area in the target phase plane.

[0069] In some embodiments, the target rear wheel steering angle value is obtained according to the rear wheel steering feedback control value, the rear wheel steering angle value of the previous control cycle, the rear wheel steering feedforward control value and the front wheel steering angle value of the vehicle.

[0070] Specifically, when the vehicle needs to control the rear wheel steering to reach the target rear wheel steering angle value in an unstable state, the rear wheel steering feedback control value, the rear wheel steering angle value of the previous control cycle, the rear wheel steering feedforward control value and the front wheel steering angle value of the vehicle are first obtained. According to the obtained rear wheel steering feedback control value, the rear wheel steering angle value of the previous control cycle, the rear wheel steering feedforward control value and the front wheel steering angle value of the vehicle, the vehicle control system will calculate a target rear wheel steering angle value and achieve the target rear wheel steering angle value through an actuator (such as a rear wheel steering motor). The whole process is carried out in real time to ensure the stability of the vehicle.

[0071] In some embodiments, the rear wheel steering feedforward control value and the rear wheel steering feedback control value are obtained by solving the rear wheel steering control performance index according to the actual value of the vehicle's center of mass sideslip angle and the actual value of the yaw rate.

[0072] Specifically, feedforward control is a control strategy based on prediction and compensation. It predicts the future state according to the current state of the vehicle and the input of the driver, and adjusts the control parameters accordingly to improve the system performance. Feedback control is a control strategy based on the deviation between the actual state and the expected state. It monitors the actual output of the system and compares it with the expected output, and then adjusts the control parameters according to the deviation to eliminate the deviation. The rear-wheel steering feedforward control value and rear-wheel steering feedback control value are obtained by solving the rear-wheel steering control performance index according to the actual value of the vehicle's center of mass slip angle and the actual value of the yaw rate. The center of mass slip angle reflects the state of the vehicle's lateral movement. When the center of mass slip angle is small, the vehicle is in a stable state, and when the center of mass slip angle is large, the vehicle may face the risk of instability. The yaw rate reflects the rotation speed of the vehicle around the vertical axis.

[0073] In some embodiments, the rear wheel steering control performance index is expressed as an integral function of a first term and a second term, wherein the first term is expressed as the deviation of an actual value of the center of mass sideslip angle from an expected value of the center of mass sideslip angle and the deviation of an actual value of the yaw rate from an expected value of the yaw rate, and the second term is used to limit the magnitude of the rear wheel steering angle.

[0074] Specifically, the rear-wheel steering control performance index is usually used to evaluate the contribution of the rear-wheel steering system to vehicle stability. The rear-wheel steering control performance index can be expressed as an integral function of one or more parameters, each of which reflects a certain aspect of performance.

[0075] The first term is expressed as the deviation of the actual value of the center of mass slip angle from the expected value of the center of mass slip angle and the deviation of the actual value of the yaw rate from the expected value of the yaw rate. The integral function of this term can be used to measure the degree of deviation of the vehicle from the expected driving state during the actual driving process; the center of mass slip angle is the angle between the center of mass velocity direction of the vehicle and the longitudinal axis of the vehicle. When the actual value of the center of mass slip angle deviates from the expected value, it means that the actual driving direction of the vehicle deviates from the expected direction, which will affect the stability of the vehicle; the yaw rate is the rotation speed of the vehicle around the vertical axis. When the actual value of the yaw rate deviates from the expected value, it means that the steering performance of the vehicle may be affected, making it difficult for the vehicle to drive along the expected trajectory; the integration of the center of mass slip angle and the yaw rate can obtain an indicator reflecting the degree of deviation of the vehicle from the expected state during the entire driving process. The second term is used to limit the size of the rear wheel steering angle. The rear wheel steering angle is an important parameter of the rear wheel steering system. It determines the steering angle of the rear wheel during the steering process. Excessive rear wheel steering angle may cause the vehicle to oversteer and cause instability. Therefore, the second term is used to limit the rear wheel steering angle to change within a certain range.

[0076] For example, a linear quadratic controller is used to track the ideal state of the vehicle and obtain the rear wheel steering control law. Select the performance index J. The first term is used to measure the deviation of the actual values ​​of the center of mass slip angle and yaw rate from the expected value, and the second term is used to limit the size of the rear wheel steering angle. It is expected that the expected value of the state variable can be achieved by outputting a smaller rear wheel steering angle. In a certain optimal sense, obtaining the optimal control performance index is to obtain a compromise between the two.

[0077] ;

[0078] Wherein, T represents transposition, X represents the actual value of the rear wheel steering angle, and Xa represents the expected value of the rear wheel steering angle.

[0079] The variational method is used to solve the quadratic optimal control problem and the Hamiltonian function H is constructed as:

[0080] (Ax+Bu+Cw);

[0081] The governing equation is: =0, that is, the governing equation when p approaches infinity;

[0082] Arranged ;

[0083] Canonical equation:

[0084] ;

[0085] Adjoint equation:

[0086] ;

[0087] Where: , P and ξ are intermediate calculation variables, P is obtained by calculating the Riccati equation, A, B, Q, R are constant matrices (steady-state system), , , , the Riccati algebraic equation is:

[0088] ;

[0089] The optimal control law is solved as:

[0090] ;

[0091] ;

[0092] in, is the target rear wheel steering angle value, is the rear wheel steering angle value of the previous control cycle, from which we can get: rear wheel steering feedforward controller and rear wheel steering feedback controller .

[0093] Although the rear-wheel steering system and the differential braking system are different control systems, they can both select the yaw rate and the sideslip angle of the center of mass as the control targets of vehicle stability to improve the handling stability of the vehicle. The driving torque controller achieves the control target according to the constraints. The constraints are the target driving torque and the additional yaw torque. The control target is the four-wheel drive torque directly provided by the four-wheel drive motor.

[0094] In some embodiments, the expected value of the center of mass sideslip angle is obtained based on vehicle state information and the corresponding relationship between the center of mass sideslip angle and the front wheel turning angle of the vehicle, and the corresponding relationship between the center of mass sideslip angle and the front wheel turning angle is obtained based on the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation.

[0095] Specifically, in the two-degree-of-freedom vehicle model, the vehicle is regarded as having two key degrees of freedom: the center of mass sideslip angle and the yaw rate. The state variables usually include the center of mass sideslip angle and the yaw rate. The input variable is the front wheel turning angle, and the output variables are the center of mass sideslip angle and the yaw rate. Through this model, the dynamic relationship between the front wheel turning angle and the center of mass sideslip angle can be analyzed; the corresponding relationship of the center of mass sideslip angle to the front wheel turning angle is obtained based on the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation. After obtaining the corresponding relationship of the center of mass sideslip angle to the front wheel turning angle, the expected value of the center of mass sideslip angle is obtained according to the vehicle state information and the corresponding relationship of the center of mass sideslip angle to the front wheel turning angle of the vehicle.

[0096] In some embodiments, the expected yaw rate is obtained based on vehicle state information and the corresponding relationship between the yaw rate and the front wheel turning angle, and the corresponding relationship between the yaw rate and the front wheel turning angle is obtained based on the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation.

[0097] Specifically, the expected value of the yaw rate is obtained based on the vehicle state information and the corresponding relationship between the yaw rate and the front wheel angle. The vehicle state information includes vehicle speed, front wheel angle, current yaw rate, etc. This information is acquired through real-time monitoring by sensors. Based on the acquired vehicle state information, the expected value of the yaw rate is calculated in combination with the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation. There is a corresponding relationship between the yaw rate and the front wheel angle, which can be described by the rear-wheel steering vehicle dynamics model. When the vehicle turns, the change in the front wheel angle will cause the vehicle to generate lateral force, which in turn causes the change in the yaw rate. This change relationship can be quantified by the rear-wheel steering linear two-degree-of-freedom equation; the dynamics model of the rear-wheel steering vehicle takes into account the influence of the front and rear wheel angles on the dynamic response of the vehicle, and can simulate various dynamic behaviors of the vehicle during driving, including the change in yaw rate.

[0098] For example, the dynamics model of a rear-wheel steering vehicle is:

[0099] ;

[0100] Linear two-degree-of-freedom equation:

[0101] ;

[0102] Written in standard state space form:

[0103] ;

[0104] in, is a state variable, is the control input.

[0105] A= ,B= ,C= ,D= ;

[0106] The state space equation of the lateral dynamics model of the rear-wheel steering vehicle can be expressed as follows:

[0107] ;

[0108] in, is the state variable, u= ,w= .

[0109] A= , , ;

[0110] Assume that the rear wheel angle is proportional to the front wheel angle and assume that the transmission ratio from the steering wheel angle to the front wheel angle is n:

[0111] ;

[0112] The correspondence between the yaw rate and the sideslip angle of the center of mass and the front wheel turning angle can be obtained:

[0113] ;

[0114] ;

[0115] In the formula, is the yaw angular velocity, is the sideslip angle of the center of mass, l is the wheelbase of the car; r represents the equivalent cornering stiffness of the front and rear axles, is the vehicle longitudinal velocity, is the front wheel turning angle, is the rear wheel turning angle, m is the vehicle mass, a and b are the distances from the vehicle mass center to the front and rear axles, respectively. is the yaw moment of inertia of the car about its center of mass, is the lateral force on the front wheels of the car, The lateral force on the rear axle of the vehicle.

[0116] In some embodiments, the vehicle control method further includes: determining a maximum limit of the target rear wheel steering angle value according to the vehicle speed.

[0117] Specifically, when the vehicle is driving, the maximum limit of the target rear wheel steering angle value is determined by the vehicle speed. For example, there are generally certain restrictions on the rear wheel steering angle, requiring the rear wheel steering angle value to be within 5 degrees at low speeds and the maximum rear wheel steering angle to be around 1 degree at medium and high speeds.

[0118] In some embodiments, the maximum limit of the target rear-wheel steering angle value is determined based on the vehicle speed, including: when the vehicle speed is less than a first vehicle speed threshold, the target rear-wheel steering angle value is less than the first steering angle value; when the vehicle speed is greater than or equal to a second vehicle speed threshold, the target rear-wheel steering angle value is less than the second steering angle value; wherein the first vehicle speed threshold is less than the second vehicle speed threshold, and the first steering angle value is greater than the second steering angle value.

[0119] Specifically, the first vehicle speed threshold can be understood as the vehicle traveling at a lower speed, for example, the first vehicle speed threshold can be 40km / h, and the first steering angle value is the target rear-wheel steering angle value when the vehicle speed is less than the first vehicle speed threshold, and the first steering angle value can be 5 degrees; the second vehicle speed threshold can be understood as the vehicle traveling at a higher speed, for example, the second vehicle speed threshold can be 60km / h, and the second steering angle value is the target rear-wheel steering angle value when the vehicle speed is greater than or equal to the second vehicle speed threshold, and the second steering angle value can be 1 degree. When the vehicle speed is high, the target rear-wheel steering angle value is avoided to be too large, which may cause the vehicle to be unable to drive stably and cause a safety accident.

[0120] In some embodiments, the target torque value is obtained according to the driving braking feedback control value, the torque value of the previous control cycle, the driving braking feedforward control value and the front wheel steering angle value of the vehicle.

[0121] Specifically, feedback control is adjusted based on the difference between the actual operating state and the expected state of the system. The actual torque output of the vehicle is monitored in real time by sensors and other equipment, and compared with the expected torque output to obtain a feedback control value. Torque control is a continuous process. By considering the torque value of the previous control cycle, the continuity and stability of the torque output can be ensured, and the sudden change of the torque value can be avoided to avoid adverse effects on vehicle performance. In torque control, the drive braking feedforward control value reflects the prediction of torque output based on the current vehicle state and expected driving conditions. By considering parameters such as the vehicle's driving speed, acceleration, and front wheel angle, the feedforward control value can be calculated, and the torque output can be adjusted in advance to make the vehicle better adapt to the expected driving conditions. The front wheel angle value is one of the input parameters and can be used to calculate and adjust the torque output. Through real-time monitoring and feedback control, considering the torque value of the previous control cycle, feedforward control based on predictions, and the front wheel angle value of the vehicle, a more accurate and stable target torque value can be calculated, thereby improving vehicle safety.

[0122] In some embodiments, the driving brake feedback control value and the driving brake feedforward control value are obtained by solving the driving brake control performance index according to the actual value of the wheel torque of the vehicle.

[0123] Specifically, the driving braking feedback control value is obtained by solving the driving braking control performance index by the actual value of the wheel torque, and the driving braking feedforward control value is also obtained by solving the driving braking control performance index by the actual value of the wheel torque; when obtaining the driving braking control performance index, it is necessary to comprehensively consider multiple factors, including the actual value of the wheel torque, the expected torque value, etc.

[0124] In some embodiments, the driving braking control performance index is represented by the sum of a third term and a fourth term, wherein the third term expresses the magnitude of the deviation of the actual wheel torque value from the expected wheel torque value, and the fourth term is used to limit the magnitude of the yaw moment.

[0125] Specifically, the actual wheel torque is the torque actually generated by the wheel during driving, and the expected wheel torque is the target torque value set according to the vehicle's driving state and expected performance; the yaw moment is the torque generated when the vehicle rotates around its vertical axis. Excessive yaw moment may cause the vehicle to lose control, roll over, and other dangerous situations; when evaluating the drive and braking control performance indicators, it is necessary to comprehensively consider the deviation of the actual wheel torque value from the expected wheel torque value and the size of the yaw moment limit, comprehensively evaluate the performance of the drive and braking system, and make corresponding adjustments and optimizations based on the evaluation results.

[0126] In some embodiments, the wheel torque expected value is calculated based on vehicle state information, a driving and braking dynamics model of the vehicle, and a driving and braking linear two-degree-of-freedom equation.

[0127] Specifically, vehicle status information includes vehicle speed, acceleration, steering angle, etc., which are collected in real time by sensors and transmitted to the control system. The control system calculates the expected value of the wheel torque based on the status information, and calculates the dynamic response characteristics of the vehicle under different driving conditions based on the vehicle's driving and braking dynamics model. The expected value of the wheel torque is calculated based on the vehicle status information, the vehicle's driving and braking dynamics model and the driving and braking linear two-degree-of-freedom equation.

[0128] For example, the two-degree-of-freedom driving and braking dynamics model required for designing a quadratic additional yaw moment controller for linear combined rear-wheel steering is established:

[0129] ;

[0130] The linear two-degree-of-freedom equation is:

[0131] ;

[0132] Let the state variable of the system be , control variable u=[T 矩 ], input variable , the driving and braking dynamics model can be obtained as:

[0133] ;

[0134] , D is a constant matrix;

[0135] A= , , ;

[0136] Define the error vector e as:

[0137] ;

[0138] In the formula, represents the ideal output variable.

[0139] The expected value of torque is calculated from T in the above linear quadratic degree of freedom equation 矩 Obtain, use the optimal quadratic control to solve the optimal control problem, so that the performance index Minimum, limits the yaw moment.

[0140] ;

[0141] Indicates the terminal time, represents a symmetric positive semidefinite constant matrix, Symmetric semidefinite matrices, represents a symmetric positive definite matrix.

[0142] The solution is the same as above, and the optimal control solution is:

[0143] ;

[0144] ;

[0145] The feedforward controller , feedback controller .

[0146] In some embodiments, the vehicle control method further includes: controlling the rotation direction of the rear wheels according to the direction of the yaw force causing the vehicle to become unstable, and controlling the driving and braking state of the vehicle's four-wheel motors according to the direction of the yaw force.

[0147] Specifically, the rear wheel steering principle is as follows Figure 4 As shown, the driving braking principle is as follows Figure 5 As shown in the figure, the black straight arrow represents the force exerted by the ground on the wheels, the length of the arrow represents the magnitude of the force, the direction of the arrow represents whether the force exerted by the ground on the wheels is a driving force or a braking force, the black dotted arrow represents the direction of vehicle travel, among which the one consistent with the travel direction represents the driving force, and the one in the opposite direction represents the braking force; the gray straight arrow represents the collision force exerted on the vehicle from the outside, and the gray dotted arrow represents the additional stabilizing yaw moment of the vehicle.

[0148] like Figure 4 As shown in the figure, when the vehicle collides with the left and right rear sides, the collision will generate a clockwise yaw moment on the vehicle, causing the vehicle to become unstable. At this time, the front wheel rotates to the left ( Figure 4The front wheels are not shown in the figure), the rear wheels rotate to the right, generating an additional counterclockwise stabilizing yaw moment to maintain the stability of the vehicle and improve the dynamic response of the vehicle; when the vehicle collides with the right side and the left rear, the collision will generate a counterclockwise yaw moment on the vehicle, causing the vehicle to be unstable. At this time, the front wheels rotate to the right ( Figure 4 The front wheels are not shown in the figure), and the rear wheels rotate to the left, generating an additional clockwise yaw moment to maintain the stability of the vehicle.

[0149] Stability control is performed by using a combined drive and brake control method, such as Figure 5 As shown, when the vehicle collides from the left side and the right rear, braking force is applied to the left wheel and driving force is applied to the right wheel, generating an additional counterclockwise stabilizing yaw moment to maintain the stability of the vehicle; when the vehicle collides from the right side and the left rear, braking force is applied to the right wheel and driving force is applied to the left wheel to generate an additional clockwise yawing moment to maintain the stability of the vehicle.

[0150] In some embodiments, the vehicle control method further includes: when the tire is in a linear area of ​​the tire working area, controlling the rotation angle of the vehicle's rear wheels according to a target rear wheel steering angle; or, when the tire is in a saturated area of ​​the tire working area, controlling the vehicle's four-wheel motors to drive and / or brake according to a target torque.

[0151] Specifically, the working area of ​​the tire can be divided into: linear area, nonlinear area and saturation area, such as Figure 3 As shown in Figure 1, the working conditions of each controller in each area of ​​the tire can be clearly described. Figure 3 It can be seen that the solid line area in the figure is the linear area of ​​the tire, in which the rear-wheel steering strategy controller can work alone, the dotted line area in the figure is the nonlinear area of ​​the tire, in which the rear-wheel steering strategy and the drive braking control strategy need to work in coordination, and the dotted line area with larger intervals in the figure is the saturation area of ​​the tire, at this time the tire will not be able to provide enough lateral force, and the drive braking control strategy controller works alone.

[0152] In some embodiments, the vehicle control method further includes: when the deviation between the actual value of the center of mass sideslip angle and the expected value of the center of mass sideslip angle is less than the center of mass sideslip angle deviation threshold and the deviation between the actual value of the yaw angular velocity and the expected value of the yaw angular velocity is less than the yaw angular velocity deviation threshold, determining that the vehicle exits an unstable condition and giving a prompt.

[0153] Specifically, when the deviation between the actual value of the center of mass sideslip angle and the expected value is less than the center of mass sideslip angle deviation threshold, and the deviation between the actual value of the yaw rate and the expected value is also less than the yaw rate deviation threshold, it can be determined that the vehicle is in a stable state and can exit the instability condition. At this time, corresponding prompts should be given, such as lighting up the stability indicator light, making a sound, etc., to inform the driver that the vehicle has returned to a stable state.

[0154] For example, the execution layer mainly includes four-wheel independent drive motors and electronically controlled hydraulic brake units. The execution layer receives the four-wheel drive force and braking force control signals output by the decision layer and responds quickly. When the actual yaw rate and sideslip angle of the center of mass of the vehicle reach the expected values, the control ends, the vehicle collision stability control system exits, and reminds the driver to take over vehicle control through the human-computer interaction interface to avoid secondary accidents caused by the driver's failure to control the vehicle in time; if the actual yaw rate and sideslip angle of the center of mass still deviate from the control targets in the two-degree-of-freedom reference model, the collision stability control system continues to intervene, continues to calculate the additional stabilizing yaw torque and allocates it to the execution layer for stability control until the yaw rate and sideslip angle of the center of mass reach the expected values ​​and the vehicle returns to stability.

[0155] For example, the present invention relates to a collision stability control system for a vehicle driven by four motors and with rear-wheel steering. The system is used in dangerous working conditions such as rear-end collisions where the vehicle is prone to losing control. The system can respond in a timely manner to issue warning information and help the driver correct the vehicle body posture in the early stage of vehicle instability, thereby ensuring the stability of the rear-end vehicle and reducing and avoiding the losses caused by secondary collisions after the vehicle is rear-ended. The system is implemented by adjusting the steering angle of the rear wheels of the vehicle and performing comprehensive control of the driving and braking of the four wheels of the vehicle. When a collision accident occurs, the yaw moment generated by the collision will cause the vehicle to be extremely unstable. The collision stability control system will generate additional yaw compensation torque to maintain vehicle stability by adjusting the rear wheel steering angle and performing comprehensive control of the driving and braking of the four wheels of the vehicle. The entire system consists of a perception layer (sensor module), a decision layer (computing unit) and an execution layer (four-motor torque vector control unit and electronically controlled hydraulic brake unit). Compared with the existing technology, the advantages and differences are as follows: Based on the linear two-degree-of-freedom model theory, the actual vehicle is converted into a simple two-degree-of-freedom model. The relationship between the steering wheel angle and the vehicle's yaw angular velocity and the sideslip angle of the center of mass is obtained through the two-degree-of-freedom vehicle model, thereby obtaining the desired target of the control variable; the vehicle status information is monitored in real time. When it is recognized that the vehicle status is inconsistent with the driver's input, a warning message is issued, and the rear-wheel steering function is quickly turned on. The rear wheel angle is opposite to the lateral displacement direction after the vehicle collision. When the rear wheel turns, the 4TV torque vector control function intervenes quickly, and through the reasonable control of the rear wheel steering angle, an additional yaw moment is generated to resist the yaw caused by the collision, the body state is corrected to avoid more serious accidents; the sideslip angle and yaw angular velocity of the center of mass are integrated to ensure the stability of the vehicle after the collision and to maintain the original trajectory; the four wheels can steer independently, which can provide a larger additional yaw moment to maintain the stability of the vehicle; when the body posture is stable, the collision stability control system exits in time, and reminds the driver to take over the vehicle control in time through the human-computer interaction system, to avoid secondary accidents due to the driver's failure to control the vehicle in time.

[0156] The present invention designs a vehicle collision stability control system, aiming to improve the stability of an electric vehicle after a collision.

[0157] like Figure 6As shown in the figure, the whole system consists of three modules: perception layer, decision layer and execution layer. The perception layer module includes vehicle speed sensor, wheel speed sensor, yaw rate sensor, lateral acceleration sensor, steering wheel angle sensor, camera, etc., which are used to collect and calculate vehicle speed, center of mass sideslip angle, yaw rate, lateral acceleration, longitudinal acceleration, steering wheel angle and other information in real time. The perception layer transmits the collected vehicle real-time status information to the decision layer. The decision layer contains a pre-set control algorithm, and determines whether the vehicle collides by receiving the vehicle information transmitted by the perception layer. When a collision occurs, the decision layer calculates the rear wheel steering degree required to maintain vehicle stability through the built-in control algorithm and distributes it to the four wheels. The function of the execution layer is to receive the control signal from the decision layer and respond quickly, mainly including the four-wheel independent drive control motor and the rear wheel steering controller.

[0158] refer to Figure 7 When the perception layer transmits the vehicle status information, road environment information and driver behavior information to the decision layer, the decision layer first determines whether a collision occurs based on this information. If it is determined that a collision does not occur, the decision layer ends and the collision stability control system does not start. If a collision occurs, the yaw moment calculation unit determines the stability of the vehicle at this time based on the driver's input to the vehicle and the actual state of the vehicle, as well as the linear two-degree-of-freedom reference vehicle model. The linear two-degree-of-freedom model is as follows: Figure 8 As shown, where a r 、a f is the slip angle, lr, l f is the distance from the center of mass to the front and rear axles of the car, L is the wheelbase, is the yaw angular velocity, is the sideslip angle of the center of mass, is the vehicle longitudinal velocity, is the front wheel turning angle, is the rear wheel turning angle, is the lateral force on the front wheels of the car, is the lateral force on the rear axle of the vehicle; the steady-state steering characteristics of the linear two-degree-of-freedom vehicle are taken as the ideal state of vehicle stability, and the yaw angular velocity and the sideslip angle of the center of mass of the linear two-degree-of-freedom vehicle are taken as the nominal yaw angular velocity and the nominal sideslip angle of the center of mass of the vehicle.

[0159] When the lateral acceleration is relatively small, the rear-wheel steering can ensure the handling stability of the vehicle: when the lateral acceleration is relatively large, the rear-wheel steering system is limited by the saturated tire lateral force and the upper limit of the rear wheel steering angle, and its control effect cannot meet the requirements of the vehicle's handling stability. The method of combining rear-wheel steering and drive braking control can improve the vehicle's handling stability. Since drive braking will cause a greater impact on the vehicle's yaw motion, when the rear-wheel steering and drive braking are combined, the rear-wheel steering shares part of the yaw torque, reducing the impact of drive braking on the vehicle's yaw motion, and also making up for the defect of poor rear-wheel steering control effect when the lateral acceleration is large. The combined control of rear-wheel steering and drive braking makes up for their respective shortcomings. The control idea is: based on Phase plane method to determine vehicle stability, the center of mass sideslip angle deviation and yaw rate deviation The stability threshold of the vehicle is calculated by combining the linear quadratic design controller to calculate the yaw moment M and rear wheel steering angle required to maintain vehicle stability. , where the yaw moment is converted into the front wheel angle and vehicle speed after distribution, and acts on the actual vehicle model together with the rear wheel angle. When the vehicle becomes unstable, the four-motor drive braking and rear wheel active steering are used to jointly adjust the vehicle's state to stabilize it.

[0160] A second aspect of the present invention provides an electronic device, such as Fig. 9 As shown, the electronic device 100 includes: at least one processor 101 and a memory 102 .

[0161] Among them, at least one processor 101 is communicatively connected with the memory 102, and the memory 102 stores a computer program that can be executed by the at least one processor 101. When the at least one processor 101 executes the computer program, the vehicle control method is implemented.

[0162] According to the electronic device of the embodiment of the present invention, the corresponding vehicle control program can be stored in the memory. When implementing the vehicle control method, the processor runs the program in the memory to determine whether the vehicle meets the instability state. After determining that the vehicle meets the instability state, the rear wheel steering angle is adjusted and the four-wheel motors of the vehicle are driven and / or braked respectively to generate additional yaw compensation torque to maintain vehicle stability, and help the driver correct the vehicle body posture in the early stage of the instability state to avoid secondary collision after the vehicle is rear-ended and cause losses.

[0163] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements a vehicle control method when the computer program is executed.

[0164] A fourth aspect of the present invention provides a collision stability control system, such as Fig.10 As shown, the collision stability control system 200 includes: a perception system 210 , a decision system 220 and an execution system 230 .

[0165] Among them, the perception system 210 is used to obtain vehicle status information; the decision system 220 is connected to the perception system 210 and is used to execute the vehicle control method; the execution system 230 includes a four-wheel independent drive control motor 231 and a rear-wheel steering controller 232, the four-wheel independent drive control motor 231 is connected to the decision system 220, and is used to control the four wheels to drive and / or drive, and the rear-wheel steering controller 232 is used to control the rear wheel steering.

[0166] According to the collision stability control system of the embodiment of the present invention, the perception system obtains vehicle status information in real time and determines whether the vehicle meets the instability state. When the vehicle meets the instability state, the decision system runs the vehicle control method, and controls the execution system to adjust the rear wheel steering angle and drive and / or brake the four-wheel motors of the vehicle respectively, to generate additional yaw compensation torque to maintain vehicle stability, and help the driver correct the vehicle body posture in the early stage of instability to avoid secondary collision after the vehicle is rear-ended and cause losses.

[0167] A fifth aspect of the present invention provides a vehicle, such as Fig.11 As shown, the vehicle 300 includes: an electronic device 100, or, as Fig.12 As shown, the vehicle 300 includes a collision stability control system 200 .

[0168] The vehicle according to the embodiment of the present invention detects the vehicle status in real time during driving. If the vehicle meets the instability state, the rear wheel steering angle is adjusted and the four-wheel motors of the vehicle are driven and / or braked respectively to generate additional yaw compensation torque to maintain vehicle stability, thereby helping the driver to correct the vehicle body posture in the early stage of instability and avoiding secondary collision after the vehicle is rear-ended and causing losses.

[0169] In the description of this specification, any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code including one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0170] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0171] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0172] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0173] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0174] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0175] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, substrates, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0176] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A vehicle control method, characterized in that: include: Determining that the vehicle meets the instability state; Controlling the rotation angle of the rear wheels of the vehicle according to the target rear wheel steering angle value, and controlling the four-wheel motors of the vehicle to drive and / or brake respectively according to the target torque value; Wherein, the target rear wheel steering angle value is obtained according to the rear wheel steering feedback control value, the rear wheel steering angle value of the previous control cycle, the rear wheel steering feedforward control value and the front wheel steering angle value of the vehicle; The rear wheel steering feedforward control value and the rear wheel steering feedback control value are obtained by solving the rear wheel steering control performance index according to the actual value of the center of mass sideslip angle and the actual value of the yaw angular velocity of the vehicle; The rear-wheel steering control performance index is expressed as an integral function of a first term and a second term, wherein the first term is expressed as the deviation of the actual value of the center of mass sideslip angle from the expected value of the center of mass sideslip angle and the deviation of the actual value of the yaw angular velocity from the expected value of the yaw angular velocity, and the second term is used to limit the size of the rear wheel turning angle.

2. The vehicle control method according to claim 1, characterized in that: The vehicle meets an unstable state, including: the vehicle is in an unstable area of ​​a target phase plane and the tires of the vehicle are in a non-linear area of ​​a tire working area, and the target phase plane is a phase plane of the center of mass sideslip angle and the center of mass sideslip angular velocity of the vehicle.

3. The vehicle control method according to claim 2, characterized in that: The vehicle is in an unstable region of a target phase plane, which includes a side slip angle of the center of mass and a side slip angular velocity of the center of mass of the vehicle not satisfying a boundary condition of a stable region in the target phase plane.

4. The vehicle control method according to claim 1, characterized in that: The expected value of the center of mass sideslip angle is obtained based on vehicle state information and the corresponding relationship between the center of mass sideslip angle and the front wheel turning angle of the vehicle, and the corresponding relationship between the center of mass sideslip angle and the front wheel turning angle is obtained based on the rear-wheel steering vehicle dynamics model and the rear-wheel steering linear two-degree-of-freedom equation.

5. The vehicle control method according to claim 1, characterized in that: The expected yaw rate value is obtained based on vehicle state information and the corresponding relationship between the yaw rate and the front wheel turning angle, and the corresponding relationship between the yaw rate and the front wheel turning angle is obtained based on a rear-wheel steering vehicle dynamics model and a rear-wheel steering linear two-degree-of-freedom equation.

6. The vehicle control method according to any one of claims 1 to 5, characterized in that: The vehicle control method further includes: determining a maximum limit of the target rear wheel steering angle value according to the vehicle speed.

7. The vehicle control method according to claim 6, characterized in that: The step of determining the maximum limit of the target rear wheel steering angle value according to the vehicle speed includes: When the vehicle speed is less than a first vehicle speed threshold, the target rear wheel steering angle value is less than a first steering angle value; When the vehicle speed is greater than or equal to a second vehicle speed threshold, the target rear wheel steering angle value is less than a second steering angle value; Among them, the first vehicle speed threshold is smaller than the second vehicle speed threshold, and the first steering angle value is larger than the second steering angle value.

8. The vehicle control method according to claim 1, characterized in that: The target torque value is obtained according to the driving braking feedback control value, the torque value of the previous control cycle, the driving braking feedforward control value and the front wheel steering angle value of the vehicle.

9. The vehicle control method according to claim 8, characterized in that: The driving brake feedback control value and the driving brake feedforward control value are obtained by solving the driving brake control performance index according to the actual value of the wheel torque of the vehicle.

10. The vehicle control method according to claim 9, characterized in that: The driving braking control performance index is expressed as the sum of the third item and the fourth item, wherein the third item expresses the magnitude of the deviation of the actual wheel torque value from the expected wheel torque value, and the fourth item is used to limit the magnitude of the yaw moment.

11. The vehicle control method according to claim 10, characterized in that: The wheel torque expected value is calculated based on vehicle state information, a driving and braking dynamics model of the vehicle, and a driving and braking linear two-degree-of-freedom equation.

12. The vehicle control method according to any one of claims 1 to 5 and 8 to 11, characterized in that: The vehicle control method further includes: The rear wheel rotation direction is controlled according to the direction of the yaw force causing the vehicle to become unstable, and the driving and braking state of the four-wheel motor of the vehicle is controlled according to the direction of the yaw force.

13. The vehicle control method according to claim 2, characterized in that: The vehicle control method further includes: When the tire is in the linear region of the tire working region, controlling the rotation angle of the rear wheels of the vehicle according to the target rear wheel steering angle; Alternatively, when the tire is in a saturated area of ​​the tire working area, the vehicle's four-wheel motors are controlled to drive and / or brake according to the target torque.

14. The vehicle control method according to claim 1, characterized in that: The vehicle control method further includes: When the deviation between the actual value of the center of mass sideslip angle and the expected value of the center of mass sideslip angle is less than a center of mass sideslip angle deviation threshold and the deviation between the actual value of the yaw angular velocity and the expected value of the yaw angular velocity is less than a yaw angular velocity deviation threshold, it is determined that the vehicle exits the unstable condition and a prompt is given.

15. An electronic device, characterized in that: include: at least one processor; a memory communicatively coupled to the at least one processor; The memory stores a computer program that can be executed by the at least one processor, and when the at least one processor executes the computer program, the vehicle control method according to any one of claims 1 to 14 is implemented.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the vehicle control method according to any one of claims 1 to 14 is implemented.

17. A collision stability control system, characterized in that: include: A perception system, used to obtain vehicle status information; A decision system, connected to the perception system, for executing the vehicle control method according to any one of claims 1 to 14; The execution system includes a four-wheel independent drive control motor and a rear wheel steering controller. The four-wheel independent drive control motor is connected to the decision system and is used to control the driving and / or braking of the four wheels. The rear wheel steering controller is used to control the steering of the rear wheels.

18. A vehicle, characterized in that: The vehicle includes the electronic device according to claim 15, or the vehicle includes the collision stability control system according to claim 17.

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