DYC-AFS cooperative control method under EMB single-wheel braking failure working condition

Abstract

The invention discloses a DYC-AFS cooperative control method under the working condition of EMB single-wheel braking failure, and provides a cooperative control strategy based on tire attachment utilization rate and yaw velocity deviation threshold triggering in order to solve the problem of conflict between transverse stability and braking efficiency caused by braking failure. According to the method, the yawing moment is obtained by dynamically distributing the additional braking moment, if the threshold triggering condition is met, the AFS intervenes in cooperative control, the transverse stability of the vehicle can still be kept after EMB single-wheel braking failure is finally achieved, meanwhile, the yawing moment is obtained by dynamically distributing the additional braking moment, the AFS additional rotating angle is reduced, and the stability of the vehicle is improved. And the lateral offset of the vehicle is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle chassis integrated control, and in particular to a vehicle stability active control method under a single-wheel brake failure condition of an EMB system. In particular, the longitudinal-lateral dynamic coupling instability problem caused by the single-wheel brake failure is achieved by actively maintaining the lateral stability of the vehicle after the single-wheel brake failure through the coordinated mechanism of dynamic yaw control (DYC) and active front steering (AFS). Background Art

[0002] With the popularization and application of the electronic mechanical brake system (EMB) in smart electric vehicles, its high dynamic response characteristics have significantly improved the braking performance under normal working conditions. However, under extreme working conditions such as single-wheel brake failure, the sudden change in yaw moment caused by the sudden loss of unilateral braking force leads to unexpected yaw motion and trajectory deviation of the vehicle, which has become a core problem restricting the reliability of the EMB system.

[0003] In the prior art, stability control for such failure conditions mainly revolves around two types of methods: one is the braking force redistribution strategy based on dynamic yaw moment control (DYC), which compensates the target yaw moment by adjusting the hydraulic pressure or motor torque of the remaining effective brake wheel; the other is the AFS intervention strategy, which corrects the vehicle's driving direction by adding the front wheel steering angle. However, there are inherent limitations in a single control mode: the DYC strategy may cause compensation failure due to insufficient residual braking force when it fails seriously, while the AFS strategy is prone to secondary instability due to oversteering under high-speed conditions. Although the DYC-AFS collaborative control method proposed in recent years improves control redundancy through actuator coupling, its collaborative triggering mechanism mostly uses fixed threshold switching, which fails to fully consider the constraints of the dynamic change of tire force on the control potential boundary, resulting in a control magnitude conflict between the two actuators, which is specifically manifested as: premature intervention in AFS will aggravate tire side slip and increase trajectory tracking error; excessive reliance on DYC may lose the yaw moment adjustment ability due to saturation of braking force distribution. In addition, traditional methods generally adopt the principle of equalization or empirical weight distribution when distributing yaw moment, and fail to establish a dynamic mapping relationship with real-time road adhesion conditions, resulting in insufficient utilization of tire adhesion potential, especially on low-adhesion roads, which can easily cause wheel locking or skidding.

[0004] Therefore, how to build a DYC-AFS collaborative decision-making mechanism based on real-time tire force monitoring to achieve a dynamic balance between braking performance and stability has become a technical bottleneck that needs to be broken through in this field. Summary of the invention

[0005] Aiming at the technical problem that it is difficult to coordinate the control of vehicle lateral stability and braking performance under the condition of single-wheel braking failure in the electro-mechanical braking system (EMB), a DYC-AFS coordinated control method under the condition of single-wheel braking failure in the EMB is proposed. The stable control of the vehicle after single-wheel braking failure is realized through a hierarchical and progressive control logic. The core lies in the deep integration of vehicle dynamics state perception, tire adhesion potential evaluation and actuator dynamic coordination mechanism.

[0006] The specific technical solutions adopted in the present invention are as follows:

[0007] A DYC-AFS coordinated control method under the condition of single-wheel braking failure in the EMB, comprising the following steps:

[0008] Step 1: Detect whether there is a single-wheel braking failure in the EMB system. If there is a single-wheel braking failure, select one of the balanced distribution mode, compensation distribution mode or AFS coordination mode for the initial distribution of braking torque;

[0009] When the initial distribution of braking torque is carried out in the balanced distribution mode, the torque distribution of the three normally working wheels is: T fr = 0; T avg The theoretical average torque of the rear wheels, T rl , T rr are the torques of the left rear wheel and the right rear wheel respectively; T fr is the torque of the right front wheel, and T req is the required braking torque;

[0010] When the initial distribution of braking torque is carried out in the compensation distribution mode, the torque distribution of the three normally working wheels is: T rl = T rr = min(T avg , T rl max , T rr max ), T fr = T req -(T rl + T rr ); T rl max , T rr max are the maximum torques of the left rear wheel and the right rear wheel respectively, and T req is the required braking torque;

[0011] When the initial distribution of braking torque is carried out in the AFS coordination mode, the torque distribution of the three normally working wheels is: T rl = T rl max , T rr = Trr max , T fr = T fr max , T fr max is the maximum value of the right front wheel torque;

[0012] Step 2: After the initial distribution of the braking torque, an additional yaw moment adaptive compensation control strategy is formulated according to the rear wheel tire utilization rate, and the target yaw moment is achieved through additional braking force redistribution and active front wheel steering technology to achieve the purpose of stability control;

[0013] After the initial distribution of the braking torque in the balanced distribution mode, the yaw moment distribution coefficient K is calculated based on the remaining tire adhesion utilization rate of the rear wheels, and the additional yaw moment is achieved by applying additional braking force to the rear wheels; during this process, if the threshold is triggered, the AFS is intervened to compensate for the remaining required yaw moment;

[0014] After the initial distribution of the braking torque in the compensation distribution mode, the yaw moment distribution coefficient K is calculated based on the remaining tire adhesion utilization rate of the rear wheels, and the AFS is intervened while applying additional braking force to the rear wheels to jointly achieve the additional yaw moment;

[0015] After the initial distribution of the braking torque in the AFS cooperation mode, the AFS is directly activated to achieve the additional yaw moment.

[0016] Furthermore, the threshold triggering conditions include:

[0017] (1) The yaw rate deviation exceeds the set threshold.

[0018] (2) The adhesion utilization rate of a single rear wheel exceeds the safety threshold.

[0019] Furthermore, the selection basis for the balanced distribution mode, compensation distribution mode or AFS cooperation mode is:

[0020] (4) When the theoretical equal distribution torque of the rear wheels does not exceed the single-wheel saturation limit, the balanced distribution mode is adopted;

[0021] (5) If the torque of a certain rear wheel exceeds the limit, the compensation distribution mode is adopted, that is, it is preferentially distributed to the unsaturated wheels, and the remaining braking torque demand is compensated by the right front wheel;

[0022] (6) When the sum of the braking forces of the rear wheels and the front wheels is insufficient, the AFS cooperation mode is adopted, and the AFS steering compensation is directly activated.

[0023] Furthermore, the EMB system calculates the additional yaw moment required to maintain lateral stability based on the real-time collected yaw rate, center of mass side slip angle, and longitudinal acceleration parameters, using a nonlinear vehicle dynamics model and a sliding mode control algorithm.

[0024] Furthermore, the additional yaw moment is denoted as:

[0025]

[0026] In the formula, ΔM z is the additional yaw moment, I z is the moment of inertia, δ f is the steering wheel angle, ω is the current yaw angular velocity, ω ref is the ideal yaw angular velocity, β is the center of mass sideslip angle, a 11 , a 12 , b1 are vehicle state parameters.

[0027] Furthermore, the tire adhesion utilization rate evaluation model:

[0028]

[0029] In the formula: η r is the rear axle tire load rate; F xr is the longitudinal force on the rear wheels; F zr is the vertical load on the rear wheels; μ is the road adhesion coefficient.

[0030] Furthermore, the yaw moment distribution coefficient K:

[0031]

[0032] In the formula: (1 - η rl ) and (1 - η rr ) are the remaining tire load rates of the two rear axle wheels respectively.

[0033] Furthermore, the additional braking torque for distributing the yaw moment using the yaw moment distribution coefficient K is denoted as:

[0034]

[0035] In the formula, M ri is the yaw moment compensation amount for the left and right rear wheels.

[0036] Furthermore, the additional front wheel angle required to compensate for the yaw moment through AFS control:

[0037]

[0038] Among them, c > 0 represents the relative weight coefficient between the deviation and the deviation, η is the approaching rate, which is a positive constant, and controls the speed of approaching the sliding mode surface s = 0.

[0039] Furthermore, the total braking torque can be dynamically adjusted to:

[0040] T req = T frmax +T rl max +T rr max

[0041] Among them, T req is the required braking torque; T fr max , T rl max , T rr max are the maximum torques of the right front wheel, the left rear wheel, and the right rear wheel respectively.

[0042] Advantages of the present invention:

[0043] (1) Precise yaw control: For the emergency braking condition at high vehicle speeds, a control strategy combining a sliding mode control algorithm and tire surplus potential evaluation is proposed, strictly suppressing the yaw rate deviation after the failure of a single-wheel EMB braking within ±3 deg / s. At the same time, by optimizing the additional front wheel angle, the lateral trajectory offset is effectively reduced, significantly enhancing the lateral stability and controllability of the vehicle in emergency situations.

[0044] (2) Braking efficiency optimization: Based on the principle of maximizing tire adhesion utilization, this control strategy can maintain the braking efficiency during failure, making the braking distance close to the level before failure. By reasonably distributing the additional braking torque, the tire wear is balanced, the tire service life is extended, and the usage cost is reduced.

[0045] (3) Actuator synergy and efficiency improvement: Adopting a threshold-triggered DYC-AFS collaborative strategy, the AFS intervention frequency is reduced, and the energy consumption is reduced while ensuring vehicle stability, improving the energy utilization efficiency.

[0046] (4) Adaptability to multiple failure conditions: This control strategy is applicable to single-wheel, multi-wheel failures, and different trajectory conditions. Especially during straight-line emergency braking, due to maintaining the stability of the vehicle driving direction, it can effectively improve the driving safety of the vehicle and meet the safety requirements in different failure scenarios.

[0047] (5) Low cost and high reliability: The control is realized based on existing sensors, without the need to add additional expensive hardware, reducing costs. By optimizing the algorithm and strategy, the reliability and fault tolerance of the EMB system are improved. Description of the drawings

[0048] Figure 1 is the structure diagram of the steer-by-wire system according to the embodiment of the present invention

[0049] Figure 2 is the structure diagram of the EMB system according to the embodiment of the present invention

[0050] Figure 3 Schematic diagram of the vehicle EMB system according to an embodiment of the present invention

[0051] Figure 4 Schematic diagram of the method according to an embodiment of the present invention Specific implementation manners

[0052] Aiming at the technical problem that it is difficult to coordinate the control of vehicle lateral stability and braking performance under the condition of single-wheel braking failure of the electro-mechanical braking system (EMB), the present invention proposes a DYC-AFS cooperative control method under the condition of single-wheel braking failure of EMB, and realizes the stable control of the vehicle after failure through a hierarchical and progressive control logic. The core lies in deeply integrating the perception of vehicle dynamic state, the evaluation of tire adhesion potential and the dynamic cooperation mechanism of actuators. The specific technical solutions are as follows.

[0053] Combined with the attached Figures 1-4 , the present invention proposes a DYC-AFS cooperative control method under the condition of single-wheel braking failure of EMB, including the following steps:

[0054] Step 1: Detect whether there is a single-wheel braking failure in the EMB system. If there is a single-wheel braking failure, select one of the balanced distribution mode, compensation distribution mode or AFS cooperative mode for the initial distribution of braking torque;

[0055] When the initial distribution of braking torque is carried out in the balanced distribution mode, the torque distribution of the three normally working wheels is: T fr =0; T avg The theoretical average torque of the rear wheels, T rl , T rr are the torques of the left rear wheel and the right rear wheel respectively; T fr is the torque of the right front wheel, and T req is the required braking torque;

[0056] When the initial distribution of braking torque is carried out in the compensation distribution mode, the torque distribution of the three normally working wheels is: T rl =T rr =min(T avg , T rl max , T rr max ), T fr =T req -(T rl +T rr ); T rl max , T rr max are the maximum torques of the left rear wheel and the right rear wheel respectively, and T req is the required braking torque;

[0057] When initially distributing the braking torque in the AFS collaborative mode, the torque distribution of the three normally operating wheels is: T rl = T rl max , T rr = T rr max , T fr = T fr max , where T fr max is the maximum value of the right front wheel torque;

[0058] Step 2: After the initial distribution of the braking torque, formulate an additional yaw moment adaptive compensation control strategy according to the rear wheel tire utilization rate, and achieve the target yaw moment through additional braking force redistribution and active front wheel steering technology to achieve the purpose of stability control;

[0059] After the initial distribution of the braking torque in the balanced distribution mode, calculate the yaw moment distribution coefficient K based on the remaining tire adhesion utilization rate of the rear wheels, and achieve the additional yaw moment by applying additional braking force to the rear wheels; during this process, if the threshold is triggered, intervene in the AFS to compensate for the remaining required yaw moment;

[0060] After the initial distribution of the braking torque in the compensation distribution mode, calculate the yaw moment distribution coefficient K based on the remaining tire adhesion utilization rate of the rear wheels, and intervene in the AFS while applying additional braking force to the rear wheels to jointly achieve the additional yaw moment;

[0061] After the initial distribution of the braking torque in the AFS collaborative mode, directly activate the AFS to achieve the additional yaw moment.

[0062] More specifically, the selection basis for the balanced distribution mode, compensation distribution mode, or AFS collaborative mode is:

[0063] (1) When the theoretical average torque of the rear wheels does not exceed the single-wheel saturation limit, adopt the balanced distribution mode, symmetrically distribute the braking forces of the left and right rear wheels, and minimize the yaw disturbance.

[0064] First, calculate the theoretical average torque T avg = T req / 2. If T avg ≤ min(T rl max , T rr max ), then enter the balanced distribution mode. In this mode, the left and right braking torques of the rear wheels are symmetrically distributed to minimize the yaw disturbance. At this time, the torque distribution of the three normally operating wheels is:

[0065] T rl = T rr= T avg , T fr = 0

[0066] This mode can effectively avoid vehicle instability caused by asymmetric front wheel braking force. T req Is the required braking torque; T rl max , T rr max Are the maximum values of the left rear wheel torque and the right rear wheel torque respectively.

[0067] (2) When the torque of a certain rear wheel exceeds the limit, the compensation distribution mode is adopted, that is, it is preferentially distributed to the unsaturated wheels, and the remaining braking torque demand is compensated by the right front wheel. When the average torque of the left and right rear wheels exceeds the saturation limit of a certain wheel (T avg > min(T rl max , T rr max )), the system switches to the compensation distribution mode. In this mode, the rear wheels are first distributed to the maximum allowable torque:

[0068] T rl = T rr = min(T avg , T rl max , T rr max )

[0069] The remaining torque demand is dynamically compensated by the right front wheel:

[0070] T fr = T req -(T rl + T rr )

[0071] (3) When the sum of the rear wheel and front wheel braking forces is insufficient, the AFS collaborative mode is adopted, that is, the AFS steering compensation is directly activated.

[0072] Based on the dynamic deviation between the actual yaw rate of the vehicle obtained in real time and the ideal reference value, a sliding mode switching function is constructed to calculate the additional front wheel angle required to compensate the yaw moment through AFS control:

[0073]

[0074] Among them, c > 0 represents the relative weight coefficient between the deviation and the deviation, η is the approaching rate, which is a positive constant, and controls the speed of approaching the sliding mode surface s = 0.

[0075] If the required yaw moment demand still cannot be achieved by compensating through the right front wheel (that is, T fr > T frmax ) Then, the downgrade control strategy is triggered, and while reducing the total braking torque request, the AFS compensating yaw moment is triggered to ensure vehicle stability. At this time, the total braking torque can be dynamically adjusted to:

[0076] T req = T fr max + T rl max + T rr max

[0077] More specifically, the method for calculating the additional yaw moment is as follows:

[0078] When a single-wheel braking failure of the EMB system is detected, the EMB system, based on parameters such as the yaw angular velocity, center-of-mass sideslip angle, and longitudinal acceleration collected in real time, uses the established non-linear vehicle dynamics model and calculates the additional yaw moment required to maintain lateral stability through a sliding mode control algorithm. Based on the dynamic deviation between the actual yaw angular velocity of the vehicle obtained in real time and the ideal reference value, a sliding mode switching function is constructed to calculate the additional yaw moment for maintaining the lateral motion stability of the vehicle:

[0079]

[0080] In the formula, ΔM z is the additional yaw moment, I z is the moment of inertia, δ f is the steering wheel angle, ω is the current yaw angular velocity, ω ref is the ideal yaw angular velocity, β is the center-of-mass sideslip angle, a 11 、a 12 、b1 are vehicle state parameters.

[0081] Specifically, based on the dynamic deviation between the actual yaw angular velocity of the vehicle and the ideal reference value, a sliding mode switching function with finite-time convergence characteristics is constructed, and the robust control law is derived using Lyapunov stability theory to calculate the dynamic compensation yaw moment value in real time. This process transforms the vehicle lateral stability control problem under the single-wheel braking failure condition into a yaw moment dynamic distribution optimization problem, providing a target benchmark for the subsequent actuator cooperative control.

[0082] More specifically, the method for calculating the yaw moment distribution coefficient K is: To achieve precise distribution of the yaw moment, the EMB system calculates the longitudinal force and vertical load of each wheel in real time through the Magic Formula tire model and constructs a tire adhesion utilization evaluation model.

[0083] The Magic Formula tire model is used to calculate various vehicle parameters required in the control strategy and intelligent algorithm in real time:

[0084]

[0085] Among them, a x , a y is the longitudinal / lateral acceleration, h is the height of the center of mass, and B, C, D, and E are tire parameters; λ i is the tire slip ratio; α i is the tire sideslip angle, which reflects the influence of load transfer on the tire force during braking. The dynamic distribution of the longitudinal force of each wheel and the dynamic change of the vertical load are calculated in real time through the non-linear mapping relationship of the magic formula tire model.

[0086] Tire adhesion utilization rate evaluation model:

[0087]

[0088] In the formula: η r is the rear axle tire load rate; F xr is the longitudinal force received by the rear wheels; F zr is the vertical load of the rear wheels; μ is the road surface adhesion coefficient.

[0089] After obtaining the current adhesion utilization rates of the left and right rear wheels, the remaining torque distribution space of the two rear axle wheels can be obtained. The remaining tire load rates of the two rear axle wheels are (1 - η rl ) and (1 - η rr ), and further the yaw moment distribution coefficient K can be obtained, which is used to determine the ratio of the two rear axle wheels in the yaw moment distribution::

[0090]

[0091] Based on this coefficient, the target yaw moment is distributed proportionally to the left and right rear wheels to generate an additional braking torque command.

[0092] After obtaining the yaw moment distribution coefficient K, the yaw moment is achieved by means of an additional braking torque. At this time, the specific distribution of the left and right rear wheels is as follows:

[0093]

[0094] In the formula, M ri is the yaw moment compensation amount of the left and right rear wheels.

[0095] More specifically, the threshold trigger conditions are:

[0096] (1) The yaw rate deviation exceeds the set threshold (Δω ≥ 3 deg / s).

[0097] (2) The adhesion utilization rate of a single rear wheel exceeds the safety threshold (η r ≥ 0.9).

[0098] In summary, in view of the technical bottleneck of vehicle stability control under the single-wheel braking failure condition of the EMB system, the present invention proposes a cooperative control method based on DYC and AFS. The core innovation lies in: through the coupled calculation of the vehicle dynamics-tire model, the lateral stability control problem is transformed into the dynamic distribution optimization problem of the yaw moment; based on the Magic Formula tire model, the adhesion potential is evaluated in real time, and a threshold-triggered DYC-AFS cooperative decision-making mechanism is constructed to realize the dynamic balance of braking force redistribution and steering compensation. This method breaks through the limitation of the conflict between braking efficiency and stability in traditional control strategies, can accurately suppress the yaw rate deviation (within ±3 deg / s) under the failure condition, make the braking distance close to the level before failure, and at the same time reduce the frequency of steering intervention. The present invention does not require additional hardware devices, and the algorithm calculation efficiency is adapted to the real-time deployment of in-vehicle ECUs, providing a highly robust and low-cost solution for the active safety functions of intelligent electric vehicles, and significantly improving vehicle safety and stability.

[0099] The above embodiments are only used to illustrate the design concept and characteristics of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made according to the principles and design concepts disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A DYC-AFS collaborative control method under the condition of single-wheel brake failure of EMB, characterized in that It includes the following steps: Step 1: Detect whether there is a single-wheel braking failure in the EMB system. If there is a single-wheel braking failure, select one of the balanced distribution mode, compensation distribution mode, or AFS cooperation mode for the initial distribution of braking torque; When the braking torque is initially distributed in the balanced distribution mode, the torque distribution of the three normally operating wheels is as follows: T fr = 0; T avg The theoretical average torque of the rear wheels, T rl , T rr are the torques of the left rear wheel and the right rear wheel respectively; T fr is the torque of the right front wheel, and T req is the required braking torque; When the initial distribution of braking torque is carried out in the compensation distribution mode, the torque distribution of the three normally working wheels is: T rl = T rr = min(T avg , T rl max , T rr max ), T fr = T req -(T rl + T rr ); T rl max , T rr max are the maximum torque of the left rear wheel and the maximum torque of the right rear wheel respectively; When performing the initial distribution of braking torque in the AFS cooperative mode, the torque distribution of the three normally operating wheels is: T rl = T rl max , T rr = T rr max , T fr = T fr max , T fr max is the maximum value of the right front wheel torque; Step 2: After the initial distribution of braking torque, formulate an additional yaw moment adaptive compensation control strategy according to the rear-wheel tire utilization rate, and achieve the target yaw moment through additional braking force redistribution and active front-wheel steering technology to achieve the purpose of stability control; After the initial distribution of braking torque in the balanced distribution mode, calculate the yaw moment distribution coefficient K according to the remaining tire adhesion utilization rate of the rear wheels, and achieve the additional yaw moment by applying additional braking force to the rear wheels; during this process, if the threshold is triggered, intervene in the AFS to compensate for the remaining required yaw moment; After the initial distribution of braking torque in the compensation distribution mode, calculate the yaw moment distribution coefficient K according to the remaining tire adhesion utilization rate of the rear wheels, and intervene in the AFS while applying additional braking force to the rear wheels to jointly achieve the additional yaw moment; After the initial distribution of braking torque in the AFS cooperation mode, directly activate the AFS to achieve the additional yaw moment.

2. The DYC-AFS collaborative control method under the condition of single-wheel braking failure of EMB according to claim 1, characterized in that The threshold trigger conditions include: (1) The yaw rate deviation exceeds the set threshold. (2) The adhesion utilization rate of a single rear wheel exceeds the safety threshold.

3. The DYC-AFS collaborative control method under the condition of single-wheel braking failure of EMB according to claim 1, wherein, The selection basis for the balanced distribution mode, compensation distribution mode, or AFS cooperation mode is: (1) When the theoretical equal torque of the rear wheels does not exceed the single-wheel saturation limit, the balanced distribution mode is adopted; (2) If the torque of a certain rear wheel exceeds the limit, the compensation distribution mode is adopted, that is, it is preferentially distributed to the unsaturated wheels, and the remaining braking torque demand is compensated by the right front wheel; (3) When the sum of the braking forces of the rear wheels and the front wheels is insufficient, the AFS cooperation mode is adopted to directly activate the AFS steering compensation.

4. A DYC-AFS cooperative control method under the condition of single-wheel braking failure of EMB according to claim 1, characterized in that The EMB system is based on the yaw rate, center-of-mass side slip angle, and longitudinal acceleration parameters collected in real time, uses a nonlinear vehicle dynamics model, and calculates the additional yaw moment required to maintain lateral stability through a sliding mode control algorithm.

5. The DYC-AFS collaborative control method under the single-wheel braking failure condition of EMB according to claim 4, characterized in that, The additional yaw moment is denoted as: where, ΔM z is the additional yaw moment, I z is the moment of inertia, δ f is the steering wheel angle, ω is the current yaw rate, ω ref is the ideal yaw rate, β is the sideslip angle of the center of mass, a 11 , a 12 , b1 are vehicle state parameters.

6. The DYC-AFS collaborative control method under the EMB single-wheel braking failure condition according to claim 1, wherein Tire adhesion utilization rate evaluation model: Where: η r is the rear axle tire load ratio; F xr is the longitudinal force on the rear wheels; F zr is the vertical load on the rear wheels; μ is the road surface adhesion coefficient.

7. The DYC-AFS collaborative control method under the EMB single-wheel braking failure condition according to claim 1, wherein, Yaw moment distribution coefficient K: where: (1 - η rl ) and (1 - η rr ) are the remaining tire load ratios of the two wheels on the rear axle respectively.

8. A DYC-AFS cooperative control method under the condition of single-wheel braking failure of EMB according to claim 7, characterized in that, The additional braking torque allocated using the yaw moment distribution coefficient K is denoted as: where M ri is the yaw moment compensation amount for the left and right rear wheels.

9. The DYC-AFS cooperative control method under the condition of single-wheel braking failure of EMB according to claim 1, wherein The additional front-wheel steering angle required to compensate for the yaw moment through AFS control: Among them, c represents the relative weight coefficient between the deviation and the deviation, and η is the approaching rate, which is a positive constant that controls the speed of approaching the sliding mode surface s = 0.

10. A DYC-AFS collaborative control method under the condition of single-wheel braking failure of EMB according to claim 1, characterized in that, The maximum total braking torque of the vehicle after failure can be dynamically adjusted to: T req = T fr max + T rl max + T rr max Among them, T req is the required braking torque; T fr max , T rl max , T rr max are the maximum torques of the right front wheel, the left rear wheel, and the right rear wheel, respectively.

Images