Vehicle blowout cooperative stability control method based on closed-loop regulation of yaw angular velocity

Abstract

The application discloses a kind of vehicle tire burst collaborative stability control method based on yaw angular velocity closed-loop regulation and control, based on tire burst wheel position monitoring, determine vehicle for single wheel or same side double wheel tire burst simultaneously;Identify driving condition (straight line / curve), and on the basis of determining road surface state in combination with road surface friction coefficient, determine feedforward yaw moment compensation value and initial setting value of feedback torque in PID control, real-time output optimal correction yaw moment.Subsequently, with the optimal correction yaw moment as benchmark, the ability of actuator is considered comprehensively, and the optimal correction yaw moment is implemented coordinated distribution.The vehicle tire burst collaborative stability control method based on yaw angular velocity closed-loop regulation and control of the application solves the problem of vehicle force imbalance caused by tire burst effectively through vehicle multi-actuator collaborative control, quickly suppresses yaw disturbance, corrects driving trajectory, converges vehicle posture, and comprehensively improves vehicle driving stability and safety under tire burst condition.

Description

Technical Field

[0001] This invention relates to the field of active safety control for vehicles, and more particularly to a method for coordinated stability control of vehicle tire blowout based on closed-loop regulation of yaw rate. Background Technology

[0002] Tire blowouts during high-speed driving are high-risk conditions that can easily lead to serious traffic accidents such as loss of control, rollovers, and rear-end collisions. After a tire blowout, the vertical stiffness, contact area, and rolling resistance of the blown-out wheel change instantaneously, causing an imbalance of forces on the left and right axles and the front and rear axles. This results in rapid and severe yaw disturbances, causing the vehicle's posture to shift and its trajectory to deviate, significantly reducing vehicle handling stability and driving safety. With the popularization of new energy vehicles and drive-by-wire chassis technology, precise and controllable independent torque for four wheels has become possible, providing the hardware foundation for active stability control after a tire blowout. Current mainstream tire blowout stability control solutions rely on braking intervention, single posture correction, and fixed torque compensation to achieve emergency vehicle control. However, under extreme conditions such as sudden tire blowouts at high speeds or in complex road conditions, the control response accuracy, dynamic adaptability, and overall vehicle stability still have significant shortcomings. These solutions struggle to address the core issue of vehicle yaw and loss of control after a tire blowout and cannot meet the control requirements of advanced active safety features.

[0003] Therefore, it is necessary to propose an improvement to overcome the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art. By combining existing steer-by-wire technology, distributed drive four-wheel torque control technology and rear-wheel actuator, a collaborative stability control method for vehicle tire blowout based on closed-loop control of yaw rate and integrating multiple actuators is proposed.

[0005] The technical solution of this invention is: a vehicle tire blowout collaborative stability control method based on closed-loop control of yaw rate, comprising the following steps: S1, tire blowout wheel position identification: tire blowout identification is performed based on motor speed signal, suspension height signal and tire pressure information from tire sensors to determine whether the blowout is a single-wheel blowout or a double-wheel blowout on the same side; and the blowout identification result is transmitted to the blowout control module to execute subsequent control strategies; S2, driving condition identification: when the blowout control module identifies a tire blowout, it acquires the vehicle's current driving state signal to determine whether the vehicle is driving in a straight line or a curve; S3, road surface condition identification: the road surface condition identification includes road surface adhesion coefficient confirmation and split road surface identification; the road surface adhesion coefficient estimation value is output in real time through the front-end road surface adhesion coefficient estimation module; when the blowout control module identifies a tire blowout, it reads the road surface adhesion coefficient corresponding to the time of the blowout; and acquires the relevant signals of the vehicle's distributed four motors to determine whether it is a split road surface; S4, target desired yaw rate calculation: the target desired yaw rate is determined based on the driving condition identified in step S2; S5, optimal correction yaw moment calculation: based on The results of steps S1, S2, S3, and S4 are used to calculate the optimal yaw moment. When the vehicle is on a split-plane road or when both tires on the same side burst, the feedforward yaw moment compensation value is activated. The initial setpoint of the feedback torque in the PID control is confirmed based on the outputs of steps S1, S2, and S3, and the optimal PID parameter settings at different times are confirmed based on the vehicle's driving information. Based on the deviation between the actual yaw rate and the target desired yaw rate, a PID closed-loop control algorithm is used to dynamically adjust the yaw rate deviation and output the corrected yaw moment value in real time. S6. Yaw moment: The feedforward yaw moment compensation value, the initial setting value of the feedback torque, and the corrected yaw moment are superimposed, and the optimal corrected yaw moment is obtained by constraining the road surface adhesion coefficient; S7. Actuator capacity calculation: Perform back-turn capacity calculation, distributed motor capacity calculation, and forward-turn capacity calculation; S8. Multi-actuator capacity allocation: Combine the optimal corrected yaw moment in step S5 and the back-turn capacity, distributed motor capacity, and forward-turn capacity in step S6 to determine the forward-turn actuator angle output, the back-turn actuator angle output, and the distributed motor torque output.

[0006] As a preferred technical solution, the tire blowout detection in step S1 specifically includes the following steps: S1a, acquiring tire pressure sensor signals at each tire position, distinguishing between the four tire positions: left front wheel, right front wheel, left rear wheel, and right rear wheel; if the tire pressure signal at any tire position is lower than a preset tire pressure threshold, the tire blowout detection flag at the corresponding position is triggered; when the tire pressure signal recovers to above the threshold, the tire blowout detection flag at the corresponding position is automatically reset; S1b, acquiring the rotational speed signals of each drive motor, and multiplying the wheel speed signal by the corresponding transmission ratio to obtain the motor speed calculated based on the wheel speed signal, and distinguishing between each tire position: for straight driving conditions, distinguishing between left and right motor speeds on the same axle; for cornering conditions, distinguishing between front and rear axle motor speeds; S1c, acquiring height sensor signals at each suspension position of the vehicle, and calculating the average height at each suspension position; S1d, when step S1a triggers tire blowout detection or when the motor speed signal in step S2 and the suspension height signal in step S3 simultaneously activate the tire blowout flag signal, determining that a tire blowout has occurred, and outputting the tire blowout detection result and the corresponding blowout wheel position information.

[0007] As a preferred technical solution, the vehicle current driving status signal in step S2 includes steering wheel angle signal, yaw rate signal and lateral acceleration signal.

[0008] As a further preferred technical solution, the method for determining whether the vehicle is driving in a straight line or a curve in step S2 is as follows: S2a, determine the steering input amplitude based on the steering wheel angle signal: if the absolute value of the steering wheel angle is less than or equal to a first angle threshold, record the steering input judgment result as straight-line driving; if the absolute value of the steering wheel angle is greater than the first angle threshold, record the steering input judgment result as curve driving; S2b, determine the vehicle body rotation state based on the yaw rate signal: if the absolute value of the yaw rate is less than or equal to a first yaw rate threshold, record the yaw rate judgment result as straight-line driving; if the absolute value of the yaw rate is greater than the first angle ... If the value is greater than the first yaw rate threshold, the yaw judgment result is recorded as cornering; S2c, determine the lateral force state of the vehicle based on the lateral acceleration signal: if the absolute value of the lateral acceleration is less than or equal to the lateral acceleration threshold, the lateral acceleration judgment result is recorded as straight driving; if the absolute value of the lateral acceleration is greater than the lateral acceleration threshold, the lateral acceleration judgment result is recorded as cornering; S2d, combining the judgment results of steps S2a, S2b, and S2c, if any result is judged as cornering, the current driving condition is determined to be cornering; if all judgment results are straight driving, the current driving condition is determined to be straight driving.

[0009] As a preferred technical solution, the real-time output of the road surface adhesion coefficient estimate by the pre-mounted road surface adhesion coefficient estimation module in step S3 specifically involves: estimating the road surface adhesion coefficient online using an extended Kalman filter algorithm based on the road surface friction coefficient, wheel slip ratio, braking / driving torque, and wheel speed signals; comparing the road surface adhesion coefficient with preset high adhesion thresholds and low adhesion thresholds, and outputting a road surface grade flag according to the following rules: if the road surface adhesion coefficient is greater than or equal to the high adhesion threshold, it is determined to be a high adhesion road surface; if the road surface adhesion coefficient is less than the high adhesion threshold but greater than or equal to the low adhesion threshold, it is determined to be a medium adhesion road surface; if the road surface adhesion coefficient is less than the low adhesion threshold, it is determined to be a low adhesion road surface.

[0010] As a further preferred technical solution, step S7 specifically involves: in the event of a tire blowout on a low-friction surface under split-wheel conditions, the optimal corrective yaw torque is preferentially allocated to the rear wheel steering. If the rear steering capability reaches its upper limit, the remaining yaw torque is allocated to the front wheel steering. In the event of a tire blowout under medium / high-friction conditions, the available margin of the three actuators is calculated based on the front steering capability, rear steering capability, and motor capability. The optimal corrective yaw torque is allocated based on the margin ratio of each margin divided by the total margin. If a certain capability exceeds its limit, the priority relationship of the release of the three capabilities is: rear steering capability > motor capability > front steering capability. The yaw moment allocated to the rear or front wheel steering is first obtained from the lateral force based on the geometric relationship between the center of gravity and wheelbase. The lateral force is then converted into the tire slip angle through an inverse tire model. Finally, combined with the vehicle dynamics model, it is converted into the target control angle of the rear or front wheel steering actuator. This inverse conversion process is coupled with tire nonlinear saturation boundary constraints throughout to ensure that the output steering angle command matches the tire adhesion limit and the actuator physical stroke. The yaw moment allocated to the motor is calculated to obtain the motor torque based on the geometric relationship between the center of gravity and wheelbase, the transmission ratio, the tire radius, the front wheel steering angle, and the rear wheel steering angle.

[0011] As a preferred technical solution, step S3, "obtaining relevant signals from the vehicle's four distributed motors to determine whether it is a split-road surface," specifically involves: obtaining the real-time speed signals and corresponding actual output torque signals of the vehicle's four distributed motors; activating the torque reduction flag signal obtained from the front-end module; calculating the actual output torque difference between the left and right coaxial motors; and determining whether the torque deviation between the two coaxial wheels is greater than a threshold; based on the real-time speed signals, determining whether the angular acceleration of the coaxial speed is greater than a threshold; and confirming that it is a split-road surface when both conditions are met.

[0012] As a preferred technical solution, step S4, the calculation of the target expected yaw rate, specifically includes the following steps: S4a, when the driving condition identified in step S2 is straight-line driving, the target expected yaw rate a is set to 0; S4b, when the driving condition identified in step S2 is cornering driving, and the tires are in the linear zone, the target expected yaw rate b is calculated using the following formula: Among them, Yawrate des It is the target expected yaw rate in rad / s; v x δ is the vehicle speed in m / s; δ is the front wheel steering angle in degrees; δ1 is the rear wheel steering angle in degrees; L is the wheelbase in m; K is the understeer coefficient. S4c. When the driving condition of cornering is identified in step S2 and the tires are in the nonlinear region, the target expected yaw rate c is obtained by dividing the lateral acceleration by the actual vehicle speed.

[0013] As a preferred technical solution, in step S5: the feedforward yaw moment compensation value is determined based on the torque difference of the coaxial motor; the "simultaneously determining the optimal PID parameter setting value at different times based on vehicle driving information" specifically refers to: different initial values ​​of feedback torque corresponding to different tire blowout wheel positions, different driving conditions, and different road surface adhesion; determining the optimal PID parameter setting value at different times based on vehicle speed, lateral acceleration, road surface condition, and accelerator / brake pedal opening; the calculation formula for the corrected yaw moment is: in, It is the deviation between the actual yaw rate and the target desired yaw rate calculated. It is proportional gain; It is integral gain; It is the differential gain; It is a time constant; It corrects the yaw moment; This is the upper limit of the yaw moment; It is the lower limit of the yaw moment.

[0014] As a preferred technical solution, the calculations of rear steering capability, distributed motor capability, and front steering capability in step S6 are as follows: Rear steering capability calculation: By combining the sideslip angles of the front and rear axle centers of gravity with the response rate of the rear wheel active steering actuator, the dynamic variation range of the rear wheel steering angle is solved; then, by superimposing the dual boundary constraints of the rear wheel steering mechanical physical limit and the tire model nonlinear saturation critical sideslip angle, the safe variation range of the rear axle center of gravity sideslip angle is determined; this sideslip angle range is substituted into the tire formula to map and obtain the rear axle lateral force limit range; finally, by... The geometric relationship between lateral force and center of gravity / wheelbase is used to calculate the upper and lower limits of the yaw moment that the rear-wheel active steering system can output, i.e., the rear steering capability. Distributed motor capability calculation: Based on the wheel position at the time of the tire blowout, the motor capability at the blown wheel position is reduced to 0. If it is a single-wheel blowout, to maintain driving capability, the driving torque value of the blown wheel position is transferred to the other wheel positions, obtaining the driving torque of each motor after the blowout. Based on the motor's external characteristic curve and power limitations, the upper and lower limits of the capability values ​​of the motors at the non-blowout wheel positions are obtained, and the driving torque of each motor after the blowout is subtracted from these limits. The remaining capacity of each motor in the event of a single-wheel tire blowout is obtained. This capacity is then converted into upper and lower limits of the yaw torque that the motor can provide, based on information such as the front and rear wheel angles and the distance from the tire to the center of gravity. If both tires on the same side blow out, the capacity of the motors on both tires is reduced to zero. Based on the motor's external characteristic curve and power limitations, the upper and lower limits of the capacity of the motors on the non-blowout tires are obtained. Subtracting the driving torque of each motor after the blowout yields the remaining capacity of the motors in the event of a double-wheel tire blowout on the same side. This remaining capacity is then converted into the yaw torque that the motor can provide, based on information such as the front and rear wheel angles and the distance from the tire to the center of gravity. Upper and lower limits of yaw moment; calculation of forward turning capability: the front axle center of gravity sideslip angle is solved in real time based on a two-degree-of-freedom vehicle dynamics model; the dynamic adjustment range of the front wheel steering angle is determined by combining the response rate of the front wheel active steering actuator, and the dual constraints of front wheel steering mechanical limit and tire lateral force saturation critical sideslip angle are coupled to obtain the safe working range of the front axle center of gravity sideslip angle; the sideslip angle boundary is substituted into the tire formula to map the front axle lateral force limit range, and then the upper and lower limits of the additional yaw moment that the front wheel active steering can output are calculated through the geometric relationship of the wheelbase from the front axle to the center of gravity.

[0015] This application relates to a vehicle tire blowout collaborative stability control method based on closed-loop control of yaw rate. The core control objective of this method is to improve the vehicle's driving stability after a tire blowout. It collects the vehicle's actual yaw rate in real time, calculates the target expected yaw rate under the current operating conditions using a vehicle dynamics model, and accurately solves for the real-time deviation between the two. Based on tire blowout wheel position monitoring, it determines whether the vehicle has experienced a single tire blowout or simultaneous blowouts of both tires on the same side. Simultaneously, based on the current vehicle speed, pedal opening, and steering wheel angle, it identifies the driving condition (straight line / curve) and determines the road surface condition by considering the road friction coefficient. Based on the above information, it determines the feedforward yaw moment compensation value and the initial setpoint of the feedback torque in PID control. A PID closed-loop control algorithm is used to dynamically adjust the yaw rate deviation, outputting the optimal corrected yaw moment in real time. Subsequently, using this optimal corrected yaw moment as a benchmark, it comprehensively considers the four-wheel driving state, road conditions, and actuator capability constraints (including rear wheel steering capability, motor response capability, and front wheel steering capability) to implement the coordinated distribution of the optimal corrected yaw moment. By using multi-actuator collaborative control of the vehicle (including rear wheel steering angle compensation, four-wheel differentiated precise torque distribution and front wheel steering angle compensation), the problem of vehicle force imbalance caused by tire blowout is effectively solved, yaw disturbance is quickly suppressed, driving trajectory is corrected, and vehicle body posture is converged, thus comprehensively improving the vehicle driving stability and safety under tire blowout conditions. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a specific implementation method of the vehicle tire blowout collaborative stability control method based on closed-loop control of yaw rate according to the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0019] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0020] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0021] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0022] like Figure 1 The diagram illustrates a specific embodiment of a vehicle tire blowout collaborative stability control method based on closed-loop yaw rate control according to the present invention. This embodiment of the vehicle tire blowout collaborative stability control method based on closed-loop yaw rate control includes the following steps: S1. Tire Blowout Wheel Position Recognition: Based on the motor speed signal, suspension height signal, and tire pressure information from the tire sensor, tire blowout is identified to determine whether it is a single tire blowout or a double tire blowout on the same side; and the tire blowout recognition result is transmitted to the tire blowout control module to execute subsequent control strategies. S2. Driving condition recognition: When the tire blowout control module recognizes a tire blowout, it obtains the vehicle's current driving status signal to determine whether the vehicle is driving in a straight line or on a curve. S3. Road surface condition recognition: The road surface condition recognition includes road surface adhesion coefficient confirmation and split road surface recognition; the road surface adhesion coefficient estimation value is output in real time through the front-end road surface adhesion coefficient estimation module; when the tire blowout control module detects a tire blowout, it reads the road surface adhesion coefficient corresponding to the time of the blowout; and it obtains the relevant signals of the vehicle's distributed four motors to determine whether it is a split road surface. S4. Calculation of target expected yaw rate: Determine the target expected yaw rate based on the driving conditions identified in step S2; S5. Calculation of Optimal Corrected Yaw Moment: The optimal corrected yaw moment is calculated based on the results of steps S1, S2, S3, and S4. When the vehicle is on a split road or when both tires on the same side burst, the feedforward yaw moment compensation value is activated. The initial set value of the feedback torque in the PID control is confirmed based on the output of steps S1, S2, and S3, and the optimal PID parameter setting value at different times is confirmed based on the vehicle driving information. Based on the deviation between the actual yaw rate and the target desired yaw rate, the PID closed-loop control algorithm is used to dynamically adjust the yaw rate deviation and output the corrected yaw moment in real time. The feedforward yaw moment compensation value, the initial set value of the feedback torque, and the corrected yaw moment are superimposed, and the optimal corrected yaw moment is obtained by constraining the road adhesion coefficient. S6. Actuator capacity calculation: Perform back-rotation capacity calculation, distributed motor capacity calculation and forward-rotation capacity calculation; S7. Multi-actuator capacity allocation: Combine the optimal corrected yaw moment in step S5 with the rearward rotation capacity, distributed motor capacity and forward rotation capacity in step S6 to determine the angle output of the forward rotation actuator, the angle output of the rearward rotation actuator and the torque output of the distributed motor.

[0023] In this embodiment, step S1, tire blowout wheel location identification, determines the blowout wheel location based on the motor speed signal, suspension height signal, and tire pressure information from the tire sensor, distinguishing whether the blowout is a single-wheel blowout or a double-wheel blowout on the same side, so as to adopt different control strategies subsequently. Step S1 tire blowout identification specifically includes the following steps: S1a. Obtain tire pressure sensor signals at each tire position and distinguish between the four tire positions: left front tire, right front tire, left rear tire, and right rear tire. If the tire pressure signal at any tire position is lower than the preset tire pressure threshold, trigger the tire blowout identification flag at the corresponding position. When the tire pressure signal recovers to above the threshold, the tire blowout identification flag at the corresponding position is automatically reset.

[0024] S1b: Obtain the speed signals of each drive motor, and multiply the wheel speed signals by their respective transmission ratios to obtain the motor speeds calculated based on the wheel speed signals, and distinguish the positions of each tire: in straight-line conditions, distinguish the speeds of the left and right motors on the same axle; in curve conditions, distinguish the speeds of the front and rear axle motors.

[0025] S1c: Acquire height sensor signals at various suspension positions and calculate the average suspension height at each position. Since a tire blowout at any position on the vehicle will change the corresponding suspension height, suspension height detection does not distinguish between individual tire positions.

[0026] S1d: When step S1a triggers tire blowout recognition or step S2 (motor speed signal) and step S3 (suspension height) simultaneously activate the tire blowout indicator signal, it is determined that the vehicle has experienced a tire blowout, and the tire blowout recognition result and the corresponding tire blowout wheel position information are output.

[0027] In this embodiment, when a tire blowout is detected, step S2 is simultaneously performed to identify the vehicle's driving condition at the moment preceding the blowout. The vehicle's current driving state signal in step S2 includes the steering wheel angle signal, yaw rate signal, and lateral acceleration signal. The method for determining whether the vehicle is traveling in a straight line or on a curve in step S2 is as follows: S2a. Determine the steering input amplitude based on the steering wheel angle signal: if the absolute value of the steering wheel angle is less than or equal to the first angle threshold, record the steering input judgment result as straight driving; if the absolute value of the steering wheel angle is greater than the first angle threshold, record the steering input judgment result as cornering. S2b. Determine the vehicle rotation state based on the yaw rate signal: if the absolute value of the yaw rate is less than or equal to the first yaw rate threshold, record the yaw judgment result as straight-line driving; if the absolute value of the yaw rate is greater than the first yaw rate threshold, record the yaw judgment result as cornering. S2c. Determine the lateral force state of the vehicle based on the lateral acceleration signal: if the absolute value of the lateral acceleration is less than or equal to the lateral acceleration threshold, record the lateral acceleration determination result as straight-line driving; if the absolute value of the lateral acceleration is greater than the lateral acceleration threshold, record the lateral acceleration determination result as cornering. S2d. Combining the judgment results of steps S2a, S2b, and S2c, if any result indicates driving on a curve, then the current driving condition is determined to be driving on a curve; if all judgment results indicate driving in a straight line, then the current driving condition is determined to be driving in a straight line.

[0028] In this embodiment, the real-time output of the road surface adhesion coefficient estimate by the pre-mounted road surface adhesion coefficient estimation module in step S3 specifically involves: estimating the road surface adhesion coefficient online using an extended Kalman filter algorithm based on the road surface friction coefficient, wheel slip ratio, braking / driving torque, and wheel speed signals; comparing the road surface adhesion coefficient with preset high adhesion thresholds and low adhesion thresholds, and outputting a road surface grade flag according to the following rules: if the road surface adhesion coefficient is greater than or equal to the high adhesion threshold, it is determined to be a high adhesion road surface; if the low adhesion threshold is less than or equal to the road surface adhesion coefficient and the road surface adhesion coefficient is less than the high adhesion threshold, it is determined to be a medium adhesion road surface; if the road surface adhesion coefficient is less than the low adhesion threshold, it is determined to be a low adhesion road surface. In step S3, "obtaining relevant signals from the vehicle's four distributed motors to determine whether it is a split-road surface" specifically involves: obtaining the real-time speed signals and corresponding actual output torque signals of the vehicle's four distributed motors; activating the torque reduction flag signal obtained from the front-end module; calculating the actual output torque difference between the left and right coaxial motors; and determining whether the torque deviation between the two coaxial wheels is greater than a threshold; and determining whether the angular acceleration of the coaxial speed is greater than a threshold based on the real-time speed signal; and confirming that it is a split-road surface when both conditions are met.

[0029] It should be understood that in practical applications, steps S2 and S3 are not sequential in time and can be performed simultaneously or one can be selected for priority calculation.

[0030] In this embodiment, step S4, the calculation of the target desired yaw rate, specifically includes the following steps: S4a. When the driving condition is identified as straight driving in step S2, the target expected yaw rate a is set to 0. S4b. When the driving condition identified in step S2 is cornering and the tires are in the linear zone, the target desired yaw rate b is calculated using the following formula: Among them, Yawrate des It is the target expected yaw rate in rad / s; v x δ is the vehicle speed in m / s; δ is the front wheel steering angle in degrees; δ1 is the rear wheel steering angle in degrees; L is the wheelbase in m; K is the understeer coefficient. S4c. When the driving condition of cornering is identified in step S2 and the tires are in the nonlinear region, the target expected yaw rate c is obtained by dividing the lateral acceleration by the actual vehicle speed.

[0031] In this embodiment, in step S5: The feedforward yaw moment compensation value is confirmed based on the output of steps S1, S2, and S3. The feedforward yaw moment compensation value is only activated when the vehicle is on a split road or when both wheels have a tire blowout on the same side. The feedforward yaw moment compensation value is determined based on the torque difference of the coaxial motor.

[0032] Based on the outputs of steps S1, S2, and S3, confirm the initial setpoint of the feedback torque in the PID control. Different tire blowout locations, different driving conditions, and different road surface adhesions will result in different initial feedback torque settings. Simultaneously, based on vehicle speed, lateral acceleration, road surface condition, and accelerator / brake pedal opening, confirm the optimal PID parameter settings for different times. Specifically, "confirming the optimal PID parameter settings for different times based on vehicle driving information" means: different tire blowout locations, different driving conditions, and different road surface adhesions correspond to different initial feedback torque settings; based on vehicle speed, lateral acceleration, road surface condition, and accelerator / brake pedal opening, confirm the optimal PID parameter settings for different times.

[0033] Based on the deviation between the actual yaw rate and the target desired yaw rate, a PID closed-loop control algorithm is used to dynamically adjust the yaw rate deviation and output a corrective yaw torque in real time. in, It is the deviation between the actual yaw rate and the target desired yaw rate calculated. It is proportional gain; It is integral gain; It is the differential gain; It is a time constant; It corrects the yaw moment; This is the upper limit of the yaw moment; It is the lower limit of the yaw moment.

[0034] In this embodiment, the calculations of backward rotation capability, distributed motor capability, and forward rotation capability in step S6 are as follows: Rear wheel steering capability calculation: By combining the sideslip angles of the front and rear axle centers of gravity with the response rate of the rear wheel active steering actuator, the dynamic range of rear wheel steering angle is solved. Then, by superimposing the dual boundary constraints of the rear wheel steering mechanical physical limit and the tire model's nonlinear saturation critical sideslip angle, the safe range of rear axle center of gravity sideslip angle is determined. Substituting this sideslip angle range into the tire formula, the rear axle lateral force limit range is obtained. Finally, based on the geometric relationship between lateral force and center of gravity wheelbase, the upper and lower limits of the yaw moment that the rear wheel active steering system can output, i.e., the rear wheel steering capability, are calculated. When a front tire blows out, the rear wheel steering capability can be fully released, and its value does not need to decay. When a rear tire blows out, the rear wheel steering capability needs to decay, and the degree of decay is determined by lateral acceleration, road adhesion coefficient, and other conditions.

[0035] Distributed motor capacity calculation: Based on the wheel position at the time of the tire blowout, the motor capacity of the blown wheel position is reduced to 0. If it is a single-wheel blowout, to maintain driving capacity, the driving torque value of the blown wheel position is transferred to the other wheel positions to obtain the driving torque of each motor after the blowout. Based on the motor external characteristic curve and power limit, the upper and lower limits of the capacity value of the motors in the non-blowout wheel positions are obtained. Subtracting the driving torque of each motor after the blowout, the remaining capacity value of each motor in the case of a single-wheel blowout is obtained. Then, based on the front and rear wheel angles, the distance from the tire to the center of gravity, and other information, it is converted into the upper and lower limits of the yaw torque that the motor can provide. If it is a double-wheel blowout on the same side, the motor capacity of the two wheels on the same side is reduced to 0. Based on the motor external characteristic curve and power limit, the upper and lower limits of the capacity value of the motors in the non-blowout wheel positions are obtained. Subtracting the driving torque of each motor after the blowout, the remaining capacity value of the motors in the case of a double-wheel blowout on the same side is obtained. Then, based on the front and rear wheel angles, the distance from the tire to the center of gravity, and other information, it is converted into the upper and lower limits of the yaw torque that the motor can provide.

[0036] Forward turning capability calculation: The front axle center-of-gravity sideslip angle is solved in real time based on a two-degree-of-freedom vehicle dynamics model. The dynamic adjustment range of the front wheel steering angle is determined by combining the response rate of the front wheel active steering actuator. Simultaneously, the dual constraints of the front wheel steering mechanical limit and the tire lateral force saturation critical sideslip angle are coupled to obtain the safe working range of the front axle center-of-gravity sideslip angle. The sideslip angle boundary is substituted into the tire formula to map the front axle lateral force limit range. Then, through the geometric relationship of the wheelbase from the front axle to the center of gravity, the upper and lower limits of the additional yaw moment that the front wheel active steering can output are calculated. Since the driver will operate the forward turning mechanism, for safety reasons, the angle of the forward turning after a tire blowout is limited to ±2°. When a single rear tire blows out, the forward turning capability is fully released without attenuation; when a single front tire blows out, the attenuation coefficient is calculated based on real-time lateral acceleration and road adhesion coefficient, compressing the forward turning yaw moment output range.

[0037] It should be understood that in practical applications, step S6 has no logical relationship with steps S2 to S5 in terms of time sequence. They can be performed simultaneously or one can be selected for priority calculation.

[0038] In this embodiment, based on front-wheel steering, rear-wheel steering, and a motor, three actuators can be allocated their capabilities to match the configurations of various vehicle models. Different allocations are needed based on the location of the tire blowout, driving conditions, and actuator capabilities to quickly suppress yaw disturbances and reduce vehicle body posture. Correspondingly, step S7 specifically involves: In the event of a tire blowout on a low-friction surface or in a split-wheel environment, the optimal yaw torque is preferentially allocated to the rear wheel steering. If the rear steering capability reaches its maximum value, the remaining yaw torque will be allocated to the front wheel steering. In the event of a tire blowout under medium / high-adjustment conditions, the available margins of the three actuators are calculated based on the forward rotation capability, rearward rotation capability, and motor capability. The optimal correction yaw moment is allocated based on the margin ratio of each margin divided by the total margin. If a certain capability exceeds the limit, the priority relationship of the release of the three capabilities is: rearward rotation capability > motor capability > forward rotation capability. The yaw moment distributed to the rear or front wheels is first obtained from the lateral force based on the geometric relationship between the center of gravity and wheelbase. The inverse solution from the lateral force to the tire slip angle is achieved through the inverse tire model. Then, combined with the vehicle dynamics model, it is finally converted into the target control angle of the rear or front wheel steering actuator. This inverse conversion process is coupled with tire nonlinear saturation boundary constraints throughout to ensure that the output steering angle command matches the tire adhesion limit and the actuator physical stroke. The yaw torque distributed to the motor is calculated based on the geometric relationship between the center of gravity and wheelbase, the transmission ratio, the tire radius, the front wheel angle, and the rear wheel angle.

[0039] This embodiment relates to a vehicle tire blowout collaborative stability control method based on closed-loop control of yaw rate. The core control objective is to improve vehicle stability after a tire blowout. It involves real-time acquisition of the vehicle's actual yaw rate, combined with a vehicle dynamics model to calculate the target desired yaw rate under the current operating conditions, and accurately determining the real-time deviation between the two. Based on tire blowout wheel position monitoring, it determines whether the vehicle has experienced a single tire blowout or simultaneous blowouts of both tires on the same side. Simultaneously, based on the current vehicle speed, pedal opening, and steering wheel angle, it identifies the driving condition (straight line / curve) and determines the road surface condition (high-friction / low-friction / split road surface) based on the road friction coefficient. Based on the above information, it determines the feedforward yaw moment compensation value and the initial setpoint of the feedback torque in PID control. A PID closed-loop control algorithm is used to dynamically adjust the yaw rate deviation, outputting the optimal corrected yaw moment in real time. Subsequently, using this optimal corrected yaw moment as a benchmark, it comprehensively considers the four-wheel driving state, road conditions, and actuator capability constraints (including rear wheel steering capability, motor response capability, and front wheel steering capability) to implement the coordinated distribution of the optimal corrected yaw moment. By using multi-actuator collaborative control of the vehicle (including rear wheel steering angle compensation, four-wheel differentiated precise torque distribution and front wheel steering angle compensation), the problem of vehicle force imbalance caused by tire blowout is effectively solved, yaw disturbance is quickly suppressed, driving trajectory is corrected, and vehicle body posture is converged, thus comprehensively improving the vehicle driving stability and safety under tire blowout conditions.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the claims of this invention should fall within the technical scope of this invention.

Claims

1. A vehicle tire blowout cooperative stability control method based on closed-loop control of yaw rate, characterized in that: Includes the following steps: S1. Tire Blowout Wheel Position Recognition: Based on the motor speed signal, suspension height signal, and tire pressure information from the tire sensor, tire blowout is identified to determine whether it is a single tire blowout or a double tire blowout on the same side; and the tire blowout recognition result is transmitted to the tire blowout control module to execute subsequent control strategies. S2. Driving condition recognition: When the tire blowout control module recognizes a tire blowout, it obtains the vehicle's current driving status signal to determine whether the vehicle is driving in a straight line or on a curve. S3. Road surface condition recognition: The road surface condition recognition includes road surface adhesion coefficient confirmation and split road surface recognition; the road surface adhesion coefficient estimation value is output in real time through the front-end road surface adhesion coefficient estimation module; when the tire blowout control module detects a tire blowout, it reads the road surface adhesion coefficient corresponding to the time of the blowout; and it obtains the relevant signals of the vehicle's distributed four motors to determine whether it is a split road surface. S4. Calculation of target expected yaw rate: Determine the target expected yaw rate based on the driving conditions identified in step S2; S5. Calculation of Optimal Corrected Yaw Moment: The optimal corrected yaw moment is calculated based on the results of steps S1, S2, S3, and S4. When the vehicle is on a split road or when both tires on the same side burst, the feedforward yaw moment compensation value is activated. The initial set value of the feedback torque in the PID control is confirmed based on the output of steps S1, S2, and S3, and the optimal PID parameter setting value at different times is confirmed based on the vehicle driving information. Based on the deviation between the actual yaw rate and the target desired yaw rate, the PID closed-loop control algorithm is used to dynamically adjust the yaw rate deviation and output the corrected yaw moment in real time. The feedforward yaw moment compensation value, the initial set value of the feedback torque, and the corrected yaw moment are superimposed, and the optimal corrected yaw moment is obtained by constraining the road adhesion coefficient. S6. Actuator capacity calculation: Perform back-rotation capacity calculation, distributed motor capacity calculation and forward-rotation capacity calculation; S7. Multi-actuator capacity allocation: Combine the optimal corrected yaw moment in step S5 with the rearward rotation capacity, distributed motor capacity and forward rotation capacity in step S6 to determine the angle output of the forward rotation actuator, the angle output of the rearward rotation actuator and the torque output of the distributed motor.

2. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: Step S1, tire blowout detection, specifically includes the following steps: S1a. Acquire tire pressure sensor signals at each tire position and distinguish between the four tire positions: left front wheel, right front wheel, left rear wheel, and right rear wheel. If the tire pressure signal at any tire position is lower than the preset tire pressure threshold, trigger the tire blowout identification flag at the corresponding position. When the tire pressure signal recovers to above the threshold, the tire blowout identification flag at the corresponding position is automatically reset. S1b: Obtain the speed signals of each drive motor, and multiply the wheel speed signals by their corresponding transmission ratios to obtain the motor speeds calculated based on the wheel speed signals, and distinguish the positions of each tire: in straight-line conditions, distinguish the left and right motor speeds on the same axle; in curve conditions, distinguish the front and rear axle motor speeds. S1c: Acquire height sensor signals at each suspension position of the vehicle and calculate the average height of each suspension position; S1d: When step S1a triggers tire blowout recognition or step S2 (motor speed signal) and step S3 (suspension height) simultaneously activate the tire blowout indicator signal, it is determined that the vehicle has experienced a tire blowout, and the tire blowout recognition result and the corresponding tire blowout wheel position information are output.

3. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: The vehicle current driving status signal mentioned in step S2 includes steering wheel angle signal, yaw rate signal and lateral acceleration signal.

4. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 3, characterized in that: The method for determining whether the vehicle is traveling in a straight line or a curve in step S2 is as follows: S2a. Determine the steering input amplitude based on the steering wheel angle signal: if the absolute value of the steering wheel angle is less than or equal to the first angle threshold, record the steering input judgment result as straight driving; if the absolute value of the steering wheel angle is greater than the first angle threshold, record the steering input judgment result as cornering. S2b. Determine the vehicle rotation state based on the yaw rate signal: if the absolute value of the yaw rate is less than or equal to the first yaw rate threshold, record the yaw judgment result as straight-line driving; if the absolute value of the yaw rate is greater than the first yaw rate threshold, record the yaw judgment result as cornering. S2c. Determine the lateral force state of the vehicle based on the lateral acceleration signal: if the absolute value of the lateral acceleration is less than or equal to the lateral acceleration threshold, record the lateral acceleration determination result as straight-line driving; if the absolute value of the lateral acceleration is greater than the lateral acceleration threshold, record the lateral acceleration determination result as cornering. S2d. Combining the judgment results of steps S2a, S2b, and S2c, if any result indicates driving on a curve, then the current driving condition is determined to be driving on a curve; if all judgment results indicate driving in a straight line, then the current driving condition is determined to be driving in a straight line.

5. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: The real-time output of the road adhesion coefficient estimate by the pre-road adhesion coefficient estimation module in step S3 is as follows: Based on the road friction coefficient, wheel slip ratio, braking / driving torque and wheel speed signals, the extended Kalman filter algorithm is used to estimate the road adhesion coefficient online; the road adhesion coefficient is compared with the preset high adhesion threshold and low adhesion threshold, and the road level flag is output according to the following rules: if the road adhesion coefficient is greater than or equal to the high adhesion threshold, it is determined to be a high adhesion road surface; If the adhesion coefficient of the road surface is less than the high adhesion threshold and greater than or equal to the low adhesion threshold, it is judged as a medium adhesion road surface. If the adhesion coefficient of the road surface is less than the low adhesion threshold, it is judged as a low adhesion road surface.

6. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: In step S3, "obtaining relevant signals from the vehicle's four distributed motors to determine whether it is a split-road surface" specifically involves: obtaining the real-time speed signals and corresponding actual output torque signals of the vehicle's four distributed motors; activating the torque reduction flag signal obtained from the front-end module; calculating the actual output torque difference between the left and right coaxial motors; and determining whether the torque deviation between the two coaxial wheels is greater than a threshold; and determining whether the angular acceleration of the coaxial speed is greater than a threshold based on the real-time speed signal; and confirming that it is a split-road surface when both conditions are met.

7. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: Step S4, the calculation of the target yaw rate, specifically includes the following steps: S4a. When the driving condition is identified as straight driving in step S2, the target expected yaw rate a is set to 0. S4b. When the driving condition identified in step S2 is cornering and the tires are in the linear zone, the target desired yaw rate b is calculated using the following formula: Among them, Yawrate des It is the target expected yaw rate in rad / s; v x δ is the vehicle speed in m / s; δ is the front wheel steering angle in degrees; δ1 is the rear wheel steering angle in degrees; L is the wheelbase in m; K is the understeer coefficient. S4c: When the driving condition of cornering is identified in step S2 and the tires are in the nonlinear region, the target expected yaw rate c is obtained by dividing the lateral acceleration by the actual vehicle speed.

8. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: In step S5: The feedforward yaw moment compensation value is determined based on the torque difference of the coaxial motor; The phrase "simultaneously confirming the optimal PID parameter setting value at different times based on vehicle driving information" specifically refers to: different initial values ​​of feedback torque corresponding to different tire blowout wheel positions, different driving conditions, and different road surface adhesion; confirming the optimal PID parameter setting value at different times based on vehicle speed, lateral acceleration, road surface condition, and accelerator / brake pedal opening. The formula for calculating the corrected yaw moment is as follows: in, It is the deviation between the actual yaw rate and the target desired yaw rate calculated. It is proportional gain; It is integral gain; It is the differential gain; It is a time constant; It corrects the yaw moment; This is the upper limit of the yaw moment; It is the lower limit of the yaw moment.

9. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 1, characterized in that: The calculations for rearward rotation capability, distributed motor capability, and forward rotation capability in step S6 are as follows: Rear steering capability calculation: By combining the sideslip angles of the front and rear axle centers of gravity with the response rate of the rear wheel active steering actuator, the dynamic variation range of the rear wheel steering angle is solved; then, by superimposing the dual boundary constraints of the rear wheel steering mechanical physical limit and the tire model nonlinear saturation critical sideslip angle, the safe variation range of the rear axle center of gravity sideslip angle is determined; substituting this sideslip angle range into the tire formula, the rear axle lateral force limit range is obtained; finally, by using the geometric relationship between lateral force and center of gravity wheelbase, the upper and lower limits of the yaw moment that the rear wheel active steering system can output, i.e., the rear steering capability, are calculated; Distributed motor capacity calculation: Based on the wheel position at the time of the tire blowout, the capacity of the motor at the blowout wheel position is reduced to 0. If it is a single-wheel blowout, to maintain driving capacity, the driving torque value of the blowout wheel position is transferred to the other wheel positions to obtain the driving torque of each motor after the blowout. Based on the motor external characteristic curve and power limit, the upper and lower limits of the capacity value of the motors at the non-blowout wheel positions are obtained. Subtracting the driving torque of each motor after the blowout, the remaining capacity value of each motor in the case of a single-wheel blowout is obtained. Then, based on the front and rear wheel angles, the distance from the tire to the center of gravity, and other information, it is converted into the upper and lower limits of the yaw torque that the motor can provide. If it is a double-wheel blowout on the same side, the capacity of the motors at the two wheel positions on the same side is reduced to 0. Based on the motor external characteristic curve and power limit, the upper and lower limits of the capacity value of the motors at the non-blowout wheel positions are obtained. Subtracting the driving torque of each motor after the blowout, the remaining capacity value of the motors in the case of a double-wheel blowout on the same side is obtained. Then, based on the front and rear wheel angles, the distance from the tire to the center of gravity, and other information, it is converted into the upper and lower limits of the yaw torque that the motor can provide. Forward steering capability calculation: The front axle center of gravity sideslip angle is solved in real time based on a two-degree-of-freedom vehicle dynamics model; the dynamic adjustment range of the front wheel steering angle is determined by combining the response rate of the front wheel active steering actuator; at the same time, the front wheel steering mechanical limit and the tire lateral force saturation critical sideslip angle are coupled as dual constraints to obtain the safe working range of the front axle center of gravity sideslip angle; the sideslip angle boundary is substituted into the tire formula to map the front axle lateral force limit range, and then the upper and lower limits of the additional yaw moment that the front wheel active steering can output are calculated through the wheelbase geometric relationship from the front axle to the center of gravity.

10. The vehicle tire blowout cooperative stability control method based on closed-loop yaw rate regulation according to claim 5, characterized in that: Step S7 is as follows: In the event of a tire blowout on a low-friction surface or in a split-wheel environment, the optimal yaw torque is preferentially allocated to the rear wheel steering. If the rear steering capability reaches its maximum value, the remaining yaw torque will be allocated to the front wheel steering. In the event of a tire blowout under medium / high-adjustment conditions, the available margin of the three actuators is calculated based on the forward rotation capability, rearward rotation capability, and motor capability. The optimal correction yaw moment is then allocated based on the margin ratio of each margin divided by the total margin. If a certain ability exceeds its limit, the priority relationship for releasing the three abilities is: backward rotation ability > motor ability > forward rotation ability; The yaw moment allocated to the rear or front wheel steering is first obtained from the lateral force based on the geometric relationship between the center of gravity and wheelbase. The lateral force is then converted into the tire slip angle through an inverse tire model. Finally, combined with the vehicle dynamics model, it is converted into the target control angle of the rear or front wheel steering actuator. This inverse conversion process is coupled with tire nonlinear saturation boundary constraints throughout to ensure that the output steering angle command matches the tire adhesion limit and the actuator physical stroke. The yaw moment allocated to the motor is calculated to obtain the motor torque based on the geometric relationship between the center of gravity and wheelbase, the transmission ratio, the tire radius, the front wheel steering angle, and the rear wheel steering angle.

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