Electric vehicle control method, vehicle controller and electric vehicle

Abstract

The invention discloses an electric vehicle control method for tire burst stable control, a vehicle controller and an electric vehicle, relates to the field of new energy automobiles, and can be applied to pure electric vehicles and hybrid vehicles. The control method is used for controlling the electric vehicle when one wheel bursts in the running process that the speed of the electric vehicle is larger than the preset speed. The control method comprises the steps that at the first moment after tire burst of one wheel of the electric vehicle occurs, the driving torque of the wheel is controlled to be reduced, and the braking force output by the braking system of the electric vehicle to the wheel is controlled to be reduced. According to the scheme, the torque and the braking force are rapidly adjusted, the driving torque and the braking force are rapidly reset, the lateral force friction limit is fully utilized, sufficient allowance is provided for steering lateral force, direction stability control is facilitated, and the vehicle safety is improved.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicles, and more specifically, to an electric vehicle control method, a vehicle controller and an electric vehicle. Background Art

[0002] With the development of the vehicle industry, the number of vehicles has increased year by year, and traffic safety accidents have received more and more attention. Tires are the only key components on vehicles that are in direct contact with the ground. They have an important impact on the power, braking, smoothness and handling stability of the vehicle during driving. Once an electric vehicle has a tire blowout while driving at high speed, it will have a very large impact on the stability and safety of the vehicle. Once a wheel blows out, the vehicle's driving direction and trajectory will deviate significantly in a very short time. The driver is likely to make wrong operations in a panic, making it difficult to control the vehicle. When the vehicle speed is high and the driver does not apply steering wheel control, the vehicle's driving direction and trajectory will deviate unexpectedly, which will have a greater impact on the vehicle's driving stability and safety.

[0003] The current mainstream method is to diagnose the tire pressure value, identify rapid pressure release, slow pressure release, and tire blowout, and on this basis, use the electronic stability program (ESC) to generate yaw torque on the non-blowout axle to control the stability of the vehicle body and avoid safety accidents caused by loss of control of the vehicle body. However, this method has a prolonged stability control time, a low control bandwidth, and cannot quickly control the vehicle body.

[0004] Therefore, how to perform stability control when an electric vehicle has a tire blowout is a problem that needs to be solved. Summary of the invention

[0005] The present application provides an electric vehicle control method, a vehicle controller and an electric vehicle. After a tire blowout is detected in the electric vehicle, the torque is quickly adjusted to quickly clear the driving torque and braking force of the blown wheel, thereby providing sufficient margin for the steering lateral force, making it easier to achieve stable control and improving the safety and stability of the vehicle.

[0006] In a first aspect, the present application provides a control method for an electric vehicle, the control method being used to control the electric vehicle when a tire blows out on one wheel during the driving process of the electric vehicle at a speed greater than a preset speed. The control method includes, at a first moment after a tire blows out on one wheel of the electric vehicle, controlling the driving torque of the one wheel to decrease and controlling the braking force outputted to the one wheel by the braking system of the electric vehicle to decrease.

[0007] The electric vehicle can be an electric vehicle or a hybrid vehicle. The electric vehicle can be a distributed drive motor or a centralized drive motor architecture, with multiple drive motors and multiple motor controllers. The drive motor can be a wheel-side motor or a wheel hub motor, and the drive motor can independently drive one wheel of the vehicle.

[0008] When an electric vehicle is driving and a wheel has a flat tire, the flat tire will produce a flat tire braking effect, the resistance of the flat tire wheel will increase suddenly, the radius of the wheel will decrease, the forces on the left and right wheels of the drive shaft will be unequal, and a yaw torque will be generated. The direction of travel of the vehicle will deviate, and the body of the electric vehicle will yaw toward the side of the flat tire wheel. In order to control the yaw caused by a flat tire of an electric vehicle, it is necessary to ensure that the wheel can be subjected to sufficient lateral force. By reducing the torque of the flat tire wheel, sufficient margin can be provided for the steering lateral force of the electric vehicle.

[0009] The tire blowout detection and control is performed only when the speed of the electric vehicle is greater than the preset speed, so as to avoid misjudgment and miscontrol when the vehicle is accelerating or driving at low speed. The preset speed can be pre-calibrated according to actual vehicle experiments and / or model calculations, or can be pre-set by comprehensively considering the vehicle requirements and vehicle performance.

[0010] According to the solution of the present application, when an electric vehicle has a tire blowout, the torque and braking force are adjusted quickly, the driving torque and braking force are quickly reduced, the lateral force friction limit is fully utilized, sufficient margin is provided for steering lateral force, directional stability control is facilitated, and vehicle safety is improved.

[0011] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: after a first moment, controlling the driving torque of one wheel to be reduced to zero and controlling the braking force output by a braking system of the electric vehicle to one wheel to be reduced to zero.

[0012] In order to control the yaw caused by a tire blowout in an electric vehicle, it is necessary to ensure that the wheels can be subjected to sufficient lateral force. By clearing the torque of the tire blowout wheel to zero, a sufficiently large margin can be provided for the steering lateral force of the electric vehicle.

[0013] According to the solution of the present application, when an electric vehicle has a tire blowout, the torque and braking force are quickly adjusted to clear the driving torque and braking force quickly, fully utilizing the lateral force friction limit to provide sufficient margin for steering lateral force, facilitate directional stability control, and improve vehicle safety.

[0014] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: at a second moment after the first moment, the opening of the accelerator pedal of the electric vehicle is greater than a preset throttle opening, and the driving torque of a wheel on the same side of a wheel is controlled to be greater than the driving torque of a diagonal wheel of a wheel.

[0015] At the first moment, the electric vehicle detects that a wheel has a flat tire. After the driving torque and braking force of the flat tire wheel are reset to zero, an asymmetric yaw moment can be generated through the non-flat tire axle to suppress the vehicle's yaw caused by the flat tire and correct the deviation caused by the electric vehicle.

[0016] At the second moment, the opening of the accelerator pedal of the electric vehicle is greater than the preset accelerator opening. At this time, the driver steps on the accelerator pedal. At this time, the drive system of the electric vehicle is controlled to output driving torque so that the left and right wheels of the non-flat tire axle produce unequal driving torques, thereby achieving yaw suppression.

[0017] It should be understood that the second moment and the first moment can be very close, that is, in the process of controlling the driving torque of one wheel to be reduced and controlling the braking force output by the braking system of the electric vehicle to one wheel to be reduced, the driving torque of the wheel on the same side of a wheel and the driving torque of the wheel diagonally opposite to a wheel can be adjusted.

[0018] The two front wheels of the electric vehicle are coaxial wheels, and the two rear wheels of the electric vehicle are coaxial wheels. The left front wheel and the right rear wheel of the electric vehicle are diagonal wheels, and the right front wheel and the left rear wheel of the electric vehicle are diagonal wheels. The left front wheel and the left rear wheel of the electric vehicle are wheels on the same side, and the right front wheel and the right rear wheel of the electric vehicle are wheels on the same side. The wheel on the same side of a wheel and the diagonal wheel of a wheel are two coaxial wheels, these two wheels have no tire blowout, and are located on different axles from the tire blowout wheel.

[0019] The accelerator pedal in this application may also be referred to as an accelerator pedal or an acceleration pedal. The opening of the accelerator pedal can indicate the driving force required by the driver. The larger the opening of the accelerator pedal, the greater the driver's demand for driving, and the corresponding torque required to be output by the drive motor is also greater. The motor controller can control the drive motor to output the torque indicated by the accelerator pedal opening according to the accelerator pedal opening. The larger the accelerator pedal opening, the greater the torque output by the drive motor. The smaller the accelerator pedal opening, the smaller the torque output by the drive motor. The motor controller controls the torque output by the drive motor to change with the change in the opening of the accelerator pedal.

[0020] For electric vehicles with multiple drive motors driving two coaxial wheels respectively, different drive torques can be generated by controlling one or both of the two drive motors on the left and right sides to work simultaneously, thereby generating a yaw correction torque through torque vector control of the two drive motors to suppress the yaw of the entire vehicle.

[0021] In the present application, the driving torque of a wheel can be understood as the torque output by the driving motor for driving the wheel. Controlling the driving torque of the wheel on the same side of a wheel to be greater than the driving torque of the diagonal wheel of a wheel can be to control the driving torque of one wheel to increase, while the driving torque of the other wheel remains unchanged or decreases; or to control the driving torque of one wheel to increase by a magnitude greater than the increase of the driving torque of the other wheel; or to control the driving torque of one wheel to decrease, while the driving torque of the other wheel remains unchanged; or to control the driving torque of one wheel to decrease by a magnitude less than the decrease of the driving torque of the other wheel. It should be understood that when a wheel has a tire blowout, in order to ensure the safety of the driver and the vehicle, the vehicle is usually decelerated under control, so it is usually adopted to control the driving torque of one wheel to decrease, while the driving torque of the other wheel remains unchanged; or to control the driving torque of one wheel to decrease by a magnitude less than the decrease of the driving torque of the other wheel. Thus, the vehicle can reduce the vehicle speed while reducing the yaw.

[0022] It should be understood that the driving torque can also be a negative value. The drive motor includes a stator winding and a rotor. By outputting alternating current to the three-phase stator winding, the output torque of the drive motor can be controlled. By adjusting the magnitude of the stator winding current and the phase of the three-phase current through the motor controller, the stator magnetic field strength and direction can be changed, thereby changing the interaction force between the stator and the rotor, that is, the motor torque. By changing the phase of the three-phase current output to the motor, the rotor cuts the magnetic field generated by the stator winding, and the kinetic energy of the rotor is converted into electrical energy and input into the power battery. At this time, the motor outputs a negative torque. By changing the magnitude of the three-phase current output to the motor by the motor controller, the positive torque or negative torque output by the motor can be increased or decreased.

[0023] When the driving torque of a wheel is a negative value, the driving motor driving the wheel outputs a reverse torque for braking the wheel.

[0024] According to the solution of the present application, the torque output is adjusted by utilizing the two drive motors of the non-flat tire axle, thereby performing torque vector control to generate a yaw moment, reducing the yaw of the entire vehicle, quickly achieving vehicle stability control, and effectively controlling the driving posture of the electric vehicle when a tire blows, thereby improving vehicle safety.

[0025] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: when a left front wheel of the electric vehicle has a tire blowout, at a second moment, controlling the driving torque of the left rear wheel of the electric vehicle to be greater than the driving torque of the right rear wheel. When a right front wheel of the electric vehicle has a tire blowout, at the second moment, controlling the driving torque of the left rear wheel of the electric vehicle to be less than the driving torque of the right rear wheel.

[0026] When the left front wheel of an electric vehicle has a tire blowout, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the left (counterclockwise relative to the vehicle). At this time, the driving torque of the left rear wheel is controlled to be greater than the driving torque of the right rear wheel, causing the electric vehicle to generate a yaw correction moment to the right (clockwise relative to the vehicle), thereby reducing the yaw of the electric vehicle.

[0027] When the right front wheel of an electric vehicle has a tire blowout, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the driving torque of the right rear wheel is controlled to be greater than the driving torque of the left rear wheel, causing the electric vehicle to generate a yaw correction moment to the left (counterclockwise relative to the vehicle), thereby reducing the yaw of the electric vehicle.

[0028] According to the solution of the present application, when the left front wheel of the electric vehicle has a tire burst, the driving torque of the left rear wheel is controlled to be greater than the driving torque of the right rear wheel. When the right front wheel of the electric vehicle has a tire burst, the driving torque of the right rear wheel is controlled to be greater than the driving torque of the left rear wheel. The vehicle body sway can be reduced by the driving torque difference, the vehicle stability control can be quickly achieved, and the vehicle safety is improved.

[0029] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: at the second moment, controlling the difference between the driving torque of a wheel on the same side of a wheel and the driving torque of a wheel diagonal to a wheel to increase as the speed of the electric vehicle increases.

[0030] When an electric vehicle has a tire blowout while driving, the greater the speed of the electric vehicle, the greater the vehicle yaw angular velocity offset caused by the tire blowout, the greater the yaw correction torque required for tire blowout stability control, and the greater the torque differential momentum output by the left and right drive motors of the non-flattened axle.

[0031] According to the solution of the present application, the torque difference between the two drive motors of the rear axle is determined according to the change in the yaw angular velocity when the vehicle has a tire blowout, and the torque vector control is fully utilized to quickly realize the vehicle stability control, thereby improving the vehicle safety.

[0032] In combination with the first aspect, in certain implementations of the first aspect, the control method also includes: at a third moment after the first moment, the opening of the brake pedal of the electric vehicle is greater than a preset brake opening, and the braking system is controlled to output a braking force to a wheel on the same side of a wheel that is smaller than the braking force output to a diagonal wheel of a wheel.

[0033] At the third moment, the opening of the brake pedal of the electric vehicle is greater than the preset brake opening. At this time, the driver steps on the brake pedal to control the braking system of the electric vehicle to output unequal braking forces to the left and right wheels of the non-flat tire axle, generating a yaw moment, thereby suppressing the yaw caused by the tire blowout.

[0034] It should be understood that it usually takes some time from when the electric vehicle has a tire blowout to when the driver notices the blowout. During this time, the driver still maintains the previous driving state and still presses the accelerator pedal. When the driver notices the blowout and intervenes, he may still press the accelerator pedal to maintain the vehicle speed, or he may press the brake pedal to stop the vehicle. Therefore, the second moment usually occurs in the entire blowout stability control process, while the third moment may not occur in the blowout process, and the third moment also usually occurs after the second moment.

[0035] The brake pedal in this application may also be referred to as the brake or brake pedal. The opening of the brake pedal can indicate the amount of braking force required by the driver. The larger the opening of the brake pedal, the greater the driver's demand for braking, and the greater the torque required to be output by the brake system. When the vehicle is in normal driving, the brake system can output the torque indicated by the opening of the brake pedal according to the opening of the brake pedal. The larger the opening of the brake pedal, the greater the braking force output by the brake system, and the smaller the opening of the brake pedal, the smaller the braking force output by the brake system. The braking force output by the brake system changes with the change of the opening of the brake pedal.

[0036] The braking system may include multiple wheel-end brake devices, and each wheel may correspond to at least one wheel-end brake device. The wheel-end brake device is used to output braking force to the corresponding wheel to brake the electric vehicle. Thus, different magnitudes of braking force can be generated by controlling one or two wheel-end brake devices on the left and right sides to work simultaneously, thereby generating a yaw correction torque through asymmetric braking force to suppress the yaw of the entire vehicle.

[0037] According to the solution of the present application, the braking force output to the two wheels of the non-flat tire axle through the braking system is unequal, thereby generating a yaw moment, reducing the yaw of the entire vehicle, quickly achieving vehicle stability control, and effectively controlling the driving posture of the electric vehicle when a tire blows, thereby improving vehicle safety.

[0038] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: when a tire bursts on the left front wheel of the electric vehicle, at a third moment, controlling the braking system to output a braking force to the left rear wheel of the electric vehicle that is smaller than the braking force output to the right rear wheel. When a tire bursts on the right front wheel of the electric vehicle, at a third moment, controlling the braking system to output a braking force to the left rear wheel of the electric vehicle that is larger than the braking force output to the right rear wheel.

[0039] When the left front wheel of an electric vehicle has a tire blowout, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the left (counterclockwise relative to the vehicle). At this time, the braking system is controlled to output a braking force to the left rear wheel that is smaller than the braking force output to the right rear wheel, causing the electric vehicle to generate a yaw correction moment to the right (clockwise relative to the vehicle), thereby reducing the yaw of the electric vehicle.

[0040] When the right front wheel of an electric vehicle has a tire blowout, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the braking system is controlled to output a braking force greater than the braking force output to the right rear wheel, causing the electric vehicle to generate a yaw correction moment to the left (counterclockwise relative to the vehicle), thereby reducing the yaw of the electric vehicle.

[0041] According to the solution of the present application, when the left front wheel of the electric vehicle has a tire burst, the braking force applied to the left rear wheel is controlled to be smaller than the driving torque of the right rear wheel. When the right front wheel of the electric vehicle has a tire burst, the braking force applied to the left rear wheel is controlled to be larger than the driving torque of the right rear wheel. The braking force difference can be used to reduce the sway of the vehicle body, quickly realize vehicle stability control, and improve vehicle safety.

[0042] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: at a third moment, controlling the braking system to increase the difference between the braking force output to the wheel on the same side of a wheel and the braking force output to the diagonal wheel of a wheel as the speed of the electric vehicle increases.

[0043] When an electric vehicle has a tire blowout while driving, the greater the speed of the electric vehicle, the greater the vehicle yaw angular velocity deviation caused by the tire blowout, the greater the yaw correction torque required for tire blowout stability control, and the greater the difference in braking force on the left and right wheels of the non-flattened axle.

[0044] According to the solution of the present application, the braking force difference on the two wheels of the rear axle is determined according to the change in yaw angular velocity when the vehicle has a tire blowout, and the braking system control is fully utilized to quickly achieve vehicle stability control, thereby improving vehicle safety.

[0045] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes: after the first moment, controlling a suspension system of the electric vehicle to adjust a damping increase of a shock absorber of one wheel.

[0046] The suspension system is used to connect the body and wheels of the electric vehicle, and provide support, cushioning and stability during the driving of the electric vehicle. The suspension system may include shock absorbers. Each wheel can be connected to the body of the electric vehicle through a shock absorber individually. For a suspension system with adjustable damping shock absorbers, when the electric vehicle has a tire blowout, a target damping coefficient or a target damping level can be sent to the suspension system to adjust the damping of each shock absorber. For the shock absorber of the wheel with a blowout, the damping of the shock absorber can be increased, and the contact between the wheel and the road surface can be ensured by applying strong damping. For other wheels, the damping of the shock absorber can be changed or not.

[0047] According to the solution of the present application, the performance of the shock absorber can be changed by adjusting the damping force of the shock absorber. When a tire blows out on a vehicle, the damping of the shock absorber of the wheel with the blown tire is increased to ensure the contact between the wheel with the ground, thereby improving the stability of the vehicle body and the ride comfort.

[0048] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes: after the first moment, controlling the suspension system of the electric vehicle to adjust the damping of the shock absorber of one wheel to increase to a target damping, and the target damping increases with the increase of the speed of the electric vehicle.

[0049] When an electric vehicle has a tire blowout while driving, the greater the speed of the electric vehicle, the greater the force required to stabilize the electric vehicle. Therefore, adjusting the wheel to a larger target damping can provide more sufficient support force.

[0050] According to the solution of the present application, the shock absorber damping of the tire-bursting wheel is determined according to the change in yaw angular velocity when the vehicle has a tire burst, the stability control function of the suspension system is fully utilized, the vehicle stability control is quickly achieved, and the vehicle safety is improved.

[0051] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes: after the first moment, controlling the suspension system of the electric vehicle to adjust the body height of one wheel to be greater than the body heights of other wheels of the electric vehicle.

[0052] The suspension system may include an air suspension or a fully active suspension. When a tire blowout occurs in an electric vehicle, a target wheel suspension height may be sent to the suspension system so that the suspension height at the wheel of the electric vehicle may be adjusted. In one implementation, the air suspension may control the lowering of the suspension height at the non-blowout wheel, and control the suspension height at the blowout wheel to remain unchanged, so that the vehicle height of the blowout wheel is greater than the vehicle height of other wheels. In one implementation, the fully active suspension may control the raising or lowering of the suspension height at each wheel. For a blowout wheel, the fully active suspension may control the raising of the vehicle height at the blowout wheel, so that the vehicle height of the blowout wheel is greater than the vehicle height of other wheels of the electric vehicle, thereby raising the blowout wheel. For the suspension height of a non-blowout wheel, the fully active suspension may adjust the height according to the balance of the vehicle body posture of the electric vehicle.

[0053] According to the solution of the present application, when an electric vehicle has a tire blowout, adjusting the suspension height of the wheel with the blowout and other wheels can effectively prevent the vehicle from rolling over, reduce the sway caused by the tire blowout, and improve the stability and safety of the vehicle.

[0054] In combination with the first aspect, in certain implementations of the first aspect, the control method also includes: at a second moment after the first moment, the opening of the accelerator pedal of the electric vehicle is greater than a preset throttle opening, and the steering system of the electric vehicle is controlled to adjust the steering angle of the two rear wheels.

[0055] The steering system of an electric vehicle can control the steering of the rear wheels. The steering system can change the turning angle and direction of the two rear wheels, so that the electric vehicle can effectively adjust the steering and handling characteristics of the vehicle through different steering methods. At low speeds, when the steering direction of the rear wheels is opposite to that of the front wheels, the turning radius can be reduced, improving the overall handling and flexibility of the vehicle. At high speeds, when the steering direction of the rear wheels is the same as that of the front wheels, the vehicle yaw moment generated by the steering operation can be effectively reduced, enhancing the stability of the vehicle.

[0056] When an electric vehicle is driving and a front wheel has a flat tire, the flat wheel will produce a flat tire braking effect, the wheel speed will suddenly increase, the vehicle's driving direction will deviate, and the body of the electric vehicle will yaw toward the side of the flat front wheel. In order to ensure the safety of the driver and the vehicle, the rear-wheel steering system can adjust the steering of the two rear wheels to generate a yaw control torque for the vehicle, so that the yaw control torque offsets the yaw caused by the flat tire and reduces the yaw amplitude of the vehicle.

[0057] According to the solution of the present application, the swaying of the electric vehicle caused by a tire blowout is suppressed by adjusting the rear wheel steering angle, the vehicle stability control is quickly achieved, the driving posture of the electric vehicle when a tire blowout occurs is effectively controlled, and the vehicle safety is improved.

[0058] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: when a left front wheel of the electric vehicle has a tire blowout, at a second moment, controlling a steering system of the electric vehicle to adjust the two rear wheels to turn left. When a right front wheel of the electric vehicle has a tire blowout, at a second moment, controlling a steering system of the electric vehicle to adjust the two rear wheels to turn right.

[0059] When the left front wheel of an electric vehicle has a flat tire, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the left (counterclockwise relative to the vehicle). At this time, the rear wheel steering system is controlled to turn to the left, so the leftward turning of the rear wheel can cause the electric vehicle to generate a yaw control moment to the right (clockwise relative to the vehicle). The yaw moment and the yaw control moment cancel each other out, and the yaw amplitude of the electric vehicle is reduced. When the right front wheel of an electric vehicle has a flat tire, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the rear wheel steering system is controlled to turn to the right, so the rightward turning of the rear wheel can cause the electric vehicle to generate a yaw control moment to the left (counterclockwise relative to the vehicle). The yaw moment and the yaw control moment cancel each other out, and the yaw amplitude of the electric vehicle is reduced.

[0060] According to the solution of the present application, the rear wheel steering can be used to effectively reduce the lateral swing of the vehicle body when a tire bursts, quickly achieve vehicle stability control, and improve vehicle safety.

[0061] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: at the second moment, controlling the steering system of the electric vehicle to adjust the steering angles of the two rear wheels to decrease as the speed of the electric vehicle increases.

[0062] The faster the vehicle speed, the higher the risk of a tire blowout, and the greater the impact on the vehicle's posture and trajectory. At this time, the yaw control torque applied through steering will be greater, and the danger will be greater. The higher the speed, the greater the risk of loss of control. Therefore, the higher the speed, the smaller the steering angle of the rear wheels controlled by the rear-wheel steering system.

[0063] According to the solution of the present application, when a tire blows out at different vehicle speeds, the vehicle controller adjusts the steering angle of the rear wheels according to different vehicle driving conditions, thereby reducing the risk of vehicle loss of control and effectively improving the safety of the vehicle.

[0064] In combination with the first aspect, in certain implementations of the first aspect, the control method also includes: at a second moment after the first moment, the opening of the accelerator pedal of the electric vehicle is greater than a preset throttle opening and the steering wheel angle change is greater than a direction threshold, controlling the steering system of the electric vehicle to adjust the steering angle of the two front wheels to be less than the steering angle indicated by the steering wheel angle.

[0065] When an electric vehicle has a tire blowout, if the driver steps on the accelerator pedal and the electric vehicle is still moving, the driver may sense the tire blowout and make a large steering correction. This operation may increase the safety risk of the tire blowout. Therefore, when the steering wheel steering angle is greater than the direction threshold, a corresponding suppression strategy is required to control the steering system to suppress the change in the front wheel steering angle and limit the steering wheel rotation rate to prevent the risk caused by sudden steering.

[0066] According to the solution of the present application, when an electric vehicle has a tire blowout, the driver is restrained from turning the steering wheel drastically, thereby reducing the risk of the electric vehicle losing control and improving the stability and safety of the vehicle.

[0067] In combination with the first aspect, in certain implementations of the first aspect, the control method also includes: at the second moment, the opening of the accelerator pedal of the electric vehicle is greater than the preset throttle opening and the steering wheel angle change is greater than the direction threshold, controlling the steering system to adjust the two rear wheels to turn in the opposite direction of the steering angle indicated by the steering wheel angle.

[0068] When an electric vehicle has a tire blowout, the driver may sense the blowout and make drastic steering corrections, which may increase the safety risk of the tire blowout. Therefore, when the steering wheel steering angle is greater than the direction threshold, the steering system will be controlled to suppress the change in the front wheel steering angle, and the rear wheel steering will be used to assist the driver in achieving the purpose of steering. The direction of the rear wheel steering is opposite to that of the front wheel, and the direction of the rear wheel steering is opposite to that of the steering wheel.

[0069] According to the solution of the present application, when an electric vehicle has a tire blowout, the driver is restrained from turning the steering wheel drastically, and the rear-wheel steering is used to assist the steering of the electric vehicle, thereby improving the operability of the electric vehicle, reducing the risk of the electric vehicle losing control, and improving the stability and safety of the vehicle.

[0070] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes: at a third moment after the first moment, the opening of the brake pedal of the electric vehicle is greater than a preset brake opening, and the difference between the driving torque of the wheel on the same side of the one wheel and the driving torque of the diagonal wheel of the one wheel is controlled to be reduced to zero. At a fourth moment after the first moment, in response to the speed of the electric vehicle being less than a safety threshold, the difference between the braking force output by the braking system to the wheel on the same side of the one wheel and the braking force output to the diagonal wheel of the one wheel is controlled to be reduced to zero.

[0071] At the third moment, the driver steps on the brake pedal, and the driving torque difference is controlled to be reduced to zero. At the fourth moment, the speed of the electric vehicle is reduced to a safe range or has stopped, and the driving torque difference is controlled to be reduced to zero, and the difference between the left and right wheel braking forces is also controlled to be reduced to zero.

[0072] According to the solution of the present application, when the electric vehicle slows down to a safe range, the output of the yaw torque is stopped, thereby ensuring the safety of the vehicle.

[0073] In combination with the first aspect, in certain implementations of the first aspect, a wheel of the electric vehicle has a tire blowout, including a load torque of one wheel being greater than a preset value, and / or a tire pressure of one wheel being less than a pressure threshold, and / or an increase in wheel speed of one wheel being greater than an increase in wheel speed of other wheels within a preset time period.

[0074] Electric vehicles can obtain signals representing the vehicle's driving status, including vehicle speed, steering wheel angle, yaw angular velocity and tire pressure, from vehicle sensors such as vehicle speed sensors, steering wheel angle sensors, inertial sensors and tire pressure sensors, and complete tire blowout detection and tire blowout wheel positioning based on these signals.

[0075] The load torque of the wheel with a tire blowout will increase sharply, and a large step-like fluctuation will occur in a short period of time. After stabilization, the torque value will increase significantly. The resistance of the wheel with a tire blowout will increase rapidly. For example, the rolling resistance will be 20-30 times greater than that of a normal tire. This feature can be used to detect tire blowouts. The load torque can be observed through a load observer. By measuring the speed of the drive motor through the resolver signal, the load torque can be calculated, thereby realizing the observation of the load torque.

[0076] When a wheel of the vehicle has a flat tire, the corresponding drive motor speed will suddenly increase, so the wheel with a flat tire among the four wheels can be detected by the change in the drive motor speed or wheel speed. When a wheel has a flat tire, the tire pressure will decrease. When the tire pressure is less than the pressure threshold, it can be determined that the wheel has a flat tire.

[0077] According to the solution of the present application, the changing characteristics of the distributed motor speed and the load torque change are used to detect and identify wheel tire blowouts, which shortens the tire blowout detection time, intervenes in control in a timely manner, reduces the misjudgment rate and control difficulty, and improves vehicle safety.

[0078] In a second aspect, the present application provides a vehicle controller for tire blowout stability control, where the vehicle controller is used to execute the control method as described in the first aspect and its various implementations.

[0079] The vehicle controller in the present application may be a motor controller of an electric vehicle, or a whole vehicle controller, or a separately set controller with control capability. The vehicle controller is applicable to an electric vehicle or a hybrid vehicle, and the electric vehicle may be a distributed motor or a centralized motor architecture, with multiple drive motors and multiple motor controllers, and the vehicle controller may be any one of the multiple motor controllers.

[0080] In a third aspect, the present application provides an electric vehicle, which includes a vehicle controller, a braking system, an accelerator pedal, a brake pedal and a steering wheel as described in the second aspect, the accelerator pedal is used to indicate the driving torque output to the wheels of the electric vehicle, the brake pedal is used to indicate the braking force output to the wheels of the electric vehicle, and the steering wheel angle is used to indicate the steering angle of the two front wheels.

[0081] The beneficial effects of other aspects can refer to the beneficial effects described in the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 is a schematic diagram of a scenario in which a tire blowout occurs on an electric vehicle provided in an embodiment of the present application;

[0083] Figure 2 is a schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0084] Figure 3 is a schematic diagram of the architecture of an electric vehicle provided in an embodiment of the present application;

[0085] Figure 4 is a schematic diagram of a tire blowout stability control process for an electric vehicle provided in an embodiment of the present application;

[0086] Figure 5 This is a schematic diagram of a tire blowout stability control for an electric vehicle provided in an embodiment of the present application;

[0087] Figure 6 is another schematic diagram of a tire blowout stability control for an electric vehicle provided in an embodiment of the present application;

[0088] Figure 7 is another schematic diagram of a tire blowout stability control for an electric vehicle provided in an embodiment of the present application;

[0089] Figure 8 is another schematic diagram of a tire blowout stability control for an electric vehicle provided in an embodiment of the present application;

[0090] Fig. 9 is a schematic diagram of the vehicle controller architecture provided by an embodiment of the present application;

[0091] Fig.10 is a schematic diagram of signal interaction of tire blowout stability control of a vehicle controller provided in an embodiment of the present application;

[0092] Fig.11 It is a flow chart of tire blowout stability control of a vehicle controller provided in an embodiment of the present application. DETAILED DESCRIPTION

[0093] The following will describe the technical solution in the present application in conjunction with the accompanying drawings. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0094] A tire blowout at high speed is one of the main reasons for vehicle loss of control and serious traffic accidents. As the only key component of a vehicle that comes into direct contact with the ground, tires have a significant impact on the vehicle's power, braking, ride comfort, and handling stability during driving. Figure 1 As shown in the figure, when a vehicle is driving at high speed, once a tire blows out, its dynamic characteristics will change dramatically, the vehicle's own balance will be broken, and it will deviate from the original driving trajectory, which will have a great impact on the vehicle's driving stability and safety. Therefore, it is necessary to detect and stabilize the vehicle's tire blowout.

[0095] In one possible implementation, a tire pressure sensor is used to identify a tire blowout, and the tire pressure is monitored in real time via a Bluetooth signal to diagnose the tire pressure value, identify rapid pressure release, slow pressure release, and tire blowout. After a tire blowout is detected, the electronic body stability control system (ESC) is used to control the body stability to avoid a safety accident caused by a loss of control of the body.

[0096] It should be understood that tire pressure-based tire blowout detection is a second-level signal, with slow detection and long duration, usually 1-3 seconds, resulting in a "vacuum period" for vehicle stability intervention. At this time, the vehicle body deviates and shifts toward the direction of the tire blowout wheel, and as the tire pressure drops sharply, the vehicle's lateral deviation tends to worsen, causing the driver to panic. In the second-level delay of tire pressure-based tire blowout detection, the vehicle body has already deviated, and the ESC system with a 100ms closed-loop cycle cannot quickly and accurately correct the vehicle body. Using a single ESC for stability control has a long control time and a low control bandwidth, requiring the driver to quickly perceive the vehicle status and make adjustments. It is difficult for novices to correct the direction and slow down, and excessive corrections can easily lead to safety accidents.

[0097] Based on the above problems, the present application provides an electric vehicle control method, a vehicle controller and an electric vehicle with tire blowout stability control. After a tire blowout is detected in the electric vehicle, the torque is adjusted quickly to quickly clear the driving torque and braking force of the tire blown wheel, providing sufficient margin for the steering lateral force, making it easier to achieve stability control and improving the safety and stability of the vehicle.

[0098] Figure 2 and Figure 3 It is a schematic diagram of the architecture of the electric vehicle 10 provided in an embodiment of the present application.

[0099] like Figure 2As shown, the electric vehicle 10 includes a vehicle controller 20, a drive motor 30, a motor controller 40, a brake system 60, a power battery (not shown) and a plurality of wheels. The motor controller 40 is used to output current to the drive motor 30 to control the drive motor 30 to output torque to drive the electric vehicle 10.

[0100] The vehicle controller in the present application may be the motor controller 40 of the electric vehicle 10, or the vehicle controller 20, or a separately provided controller with control capabilities.

[0101] Among them, the electric vehicle 10 includes but is not limited to pure electric vehicle (pure electric vehicle / battery electric vehicle, pure EV / battery EV), hybrid electric vehicle (hybrid electric vehicle, HEV), range extended electric vehicle (range extended electric vehicle, REEV), plug-in hybrid electric vehicle (plug-in hybrid electric vehicle, PHEV), new energy vehicle (new energy vehicle, NEV), etc.

[0102] The power battery in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., which is not limited in the present application. The power battery can also power other electrical devices in the vehicle, such as the air conditioner in the vehicle, the car player, etc.

[0103] The electric vehicle 10 may be a distributed four-drive motor drive architecture, where the drive motors are arranged on the sides of the driven wheels and controlled by a separate motor controller 40. The electric vehicle may also be a centralized drive motor drive architecture, where the drive motors for driving the two front wheels or the two rear wheels are arranged together. The motor controller 40 may be one or more. The motor controller 40 may correspond one-to-one to the drive motors, and one motor controller 40 may correspond to multiple drive motors. The motor controller 40 is used to control the output torque of one or more drive motors to drive the electric vehicle 10.

[0104] In one embodiment, if Figure 3 As shown in (a) of FIG. 1 , the electric vehicle 10 may be a distributed four-drive motor drive architecture, where the drive motors are arranged on the sides of the driven wheels and controlled by separate motor controllers. The electric vehicle 10 may also be a Figure 3 In the centralized four-motor drive architecture shown in (b), two drive motors for driving two front wheels or two rear wheels are arranged together.

[0105] Exemplarily, the electric vehicle 10 includes four motor controllers, including a motor controller 41, a motor controller 42, a motor controller 43, and a motor controller 44. The four motors include a drive motor 31, a drive motor 31, a drive motor 33, and a drive motor 34. The motor controller 41 controls the drive motor 31 to drive the wheel 51, the motor controller 42 controls the drive motor 32 to drive the wheel 52, the motor controller 43 controls the drive motor 33 to drive the wheel 53, and the motor controller 44 controls the drive motor 34 to drive the wheel 54.

[0106] According to the position of the wheels, they can be divided into the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel. According to the axle, the left front wheel and the right front wheel are coaxial and connected by the front axle, and the left rear wheel and the right rear wheel are coaxial and connected by the rear axle. According to the position, the left front wheel and the left rear wheel are on the same side and located on the left side, and the right front wheel and the right rear wheel are on the same side and located on the right side. That is to say, among the four wheels of the electric vehicle 10, the left front wheel and the right front wheel are coaxial wheels, and the left rear wheel and the right rear wheel are coaxial wheels; the left front wheel and the left rear wheel are wheels on the same side, and the right front wheel and the right rear wheel are wheels on the same side; the left front wheel and the right rear wheel are diagonal wheels, and the right front wheel and the left rear wheel are diagonal wheels. For example, when the electric vehicle is driving, if the left front wheel has a tire blowout, the wheel on the same side of the wheel with the tire blowout is the left rear wheel, the wheels on the opposite side of the wheel with the tire blowout are the right front wheel and the right rear wheel, the coaxial wheel of the wheel with the tire blowout is the right front wheel, and the diagonal wheel of the wheel with the tire blowout is the right front wheel.

[0107] Similarly, the two motors used to drive the two front wheels among the four drive motors are coaxial drive motors, and the two drive motors used to drive the two front wheels are also coaxial drive motors. The two drive motors used to drive the two left wheels among the four drive motors are motors on the same side, and the two drive motors used to drive the two right wheels are also drive motors on the same side.

[0108] In one embodiment, the electric vehicle 10 may also be Figure 3 The centralized drive motor architecture shown in (c) uses one drive motor to drive the two front wheels of the electric vehicle 10, and uses two drive motors to drive the two rear wheels of the electric vehicle 10 respectively.

[0109] In one embodiment, the various architectures mentioned above may be combined, for example, the front drive adopts a distributed drive motor architecture and the rear drive adopts a centralized drive motor architecture.

[0110] In one embodiment, the brake system 60 includes a brake controller and a plurality of wheel-end brake devices, and the brake controller is connected to the brake pedal signal. The brake controller can be used to determine the braking force according to the opening of the brake pedal. During the driving process, when the electric vehicle 10 needs to brake, the driver steps on the brake pedal, the brake controller receives the brake pedal signal from the brake pedal and outputs a braking force distribution signal to the wheel-end brake device, and the wheel-end brake device is used to receive the braking force distribution signal and output a clamping force to the brake disc according to the instruction of the braking force distribution signal, thereby generating a friction braking force, so that the electric vehicle 10 is braked.

[0111] The vehicle controller provided in the present application may be any motor controller among a plurality of motor controllers.

[0112] The electric vehicle 10 further includes an accelerator pedal, a brake pedal and a steering wheel. The accelerator pedal is used to indicate the torque output to the wheels of the electric vehicle 10. The brake pedal is used to indicate the braking force output to the wheels of the electric vehicle 10, and the steering angle of the steering wheel is used to indicate the steering angle of the two front wheels.

[0113] In one embodiment, the motor controller 40 includes a signal interface, and the motor controller 40 is connected to the vehicle controller 20 and other motor controllers 40 through the signal interface. The vehicle controller 20 is connected to the accelerator pedal signal, and the vehicle controller 20 calculates the vehicle torque demand according to the opening of the accelerator pedal during the driving of the electric vehicle 10, and sends a torque signal to the motor controller 40 according to the vehicle torque demand. Each motor controller 40 controls the corresponding drive motor to output torque to drive the corresponding wheel according to the indication of the torque signal.

[0114] In one embodiment, each motor controller 40 may also be directly connected to the accelerator pedal, and control the corresponding motor output torque according to the torque signal output by the accelerator pedal.

[0115] In one embodiment, the vehicle controller 20 is connected to the brake pedal through a signal interface. The vehicle controller 20 calculates the vehicle braking demand based on the brake pedal opening of the electric vehicle 10 during driving and sends a braking signal to the brake controller based on the vehicle braking demand. The brake controller controls the corresponding wheel-end braking device to output braking force to brake the corresponding wheel according to the indication of the braking signal.

[0116] In one embodiment, the vehicle controller 20 may also be directly connected to the brake pedal, and control the wheel-end brake device to output the braking force according to the opening of the brake pedal.

[0117] In one embodiment, each motor controller 40 uses a resolver sensor through a signal interface, and the resolver sensor is used to detect the speed of the drive motor 30 controlled by the motor controller 40, and the motor controller 40 is used to receive the signal from the resolver sensor. The motor controller 40 can also generate a speed signal according to the signal from the resolver sensor and send the speed signal to the other three motor controllers 40. Similarly, each motor controller 40 will also receive the speed signal sent by the other three motor controllers 40.

[0118] The resolver sensor can accurately detect the position, direction and speed of the motor rotor, and is responsible for monitoring and extracting the rotation speed of the drive motor. It has a high sampling rate and is directly connected to the motor controller 40, with short signal transmission time and higher stability.

[0119] In one embodiment, the motor controller 40 also obtains vehicle signals from the vehicle controller 20 or other sensors of the electric vehicle 10 through a signal interface, and the vehicle signals are used to indicate the vehicle speed, yaw angular velocity, and tire pressure of each wheel of the electric vehicle 10 .

[0120] In one embodiment, the electric vehicle 10 further includes a rear-wheel steering system, which is used to control the steering angle of the rear wheels of the electric vehicle 10. The rear-wheel steering system can change the turning angle and direction of the two rear wheels, so that the steering and handling characteristics of the vehicle can be effectively adjusted through different steering methods. When the vehicle speed is low, when the steering direction of the rear wheels is opposite to the steering direction of the front wheels, the turning radius can be reduced and the overall handling and flexibility of the vehicle can be improved. When the vehicle speed is high, when the steering direction of the rear wheels is the same as the steering direction of the front wheels, the vehicle yaw torque generated by the steering operation can be effectively reduced, and the stability of the vehicle can be enhanced.

[0121] The rear-wheel steering system gives the vehicle a higher control margin, which can improve the vehicle's handling and flexibility at low speeds, while enhancing stability at high speeds and reducing the risk of vehicle loss of control.

[0122] In one embodiment, the suspension system of the electric vehicle 10 includes a variable damping shock absorber. The variable damping shock absorber can adjust the damping force of the shock absorber by electronic control according to the driving conditions of the vehicle, for example, by changing the flow resistance of the fluid inside the shock absorber to adjust the damping force, thereby achieving a change in the response characteristics of the suspension system.

[0123] In one embodiment, the suspension system of the electric vehicle 10 includes air springs, and the suspension system can adjust the vehicle height by inflating and deflating the air, thereby providing a comfortable ride and good handling performance.

[0124] In one embodiment, the motor controller 40 can be connected to the vehicle controller 20, the suspension system, and the steering system through a controller area network (CAN) bus, a local interconnect network (LIN) bus, a high-speed fault-tolerant network protocol (FlexRay), or other types of connection methods, and interact with signals.

[0125] In order to facilitate understanding of the control method and vehicle controller for reducing turning roll provided in the embodiment of the present application, the following is combined with Figure 4 The control method for tire blowout stability control and the vehicle controller provided in the embodiment of the present application are described at the first moment t1, the second moment t2, the third moment t3 and the fourth moment t4 after the electric vehicle has a tire blowout.

[0126] It should be understood that the vehicle controller provided in the present application may be a vehicle controller 20, a motor controller 40, or other separately configured controller with control capabilities.

[0127] During the driving process of the electric vehicle 10 at a speed greater than a preset speed, a tire blowout occurs on one wheel. At a first moment t1, the electric vehicle 10 detects that a tire blowout occurs on one wheel.

[0128] In one embodiment, a wheel of the electric vehicle 10 has a tire blowout, including a load torque of one wheel being greater than a preset value, and / or a tire pressure of one wheel being less than a pressure threshold, and / or a wheel speed increase value of one wheel being greater than a wheel speed increase value of other wheels within a preset time period.

[0129] The electric vehicle 10 can obtain signals including vehicle speed, steering wheel angle, yaw angular velocity and tire pressure that characterize the vehicle's driving status from vehicle sensors such as vehicle speed sensors, steering wheel angle sensors, inertial sensors and tire pressure sensors, and complete tire blowout detection and tire blowout wheel positioning based on these signals.

[0130] In the embodiments of the present application, load torque refers to the torque applied to the drive motor by the external load, which is the torque that the drive motor needs to overcome in order to move the vehicle or maintain its motion state. Load torque includes rolling resistance, air resistance, slope resistance, and additional torque required for acceleration.

[0131] The load torque of a tire with a blowout will increase sharply, produce a large step-like fluctuation in a short period of time, and the torque value will increase significantly after stabilization. This feature can be used to detect tire blowouts. The load torque can be observed through a load observer. The drive motor speed is measured by a resolver signal, and the load torque can be calculated, thereby realizing the observation of the load torque.

[0132] When a tire bursts on one of the wheels of the vehicle, the speed of the corresponding drive motor will suddenly increase, so that the wheel with a tire burst among the four wheels can be detected by the change of the drive motor speed or the wheel speed.

[0133] Based on the load observation of the resolver signal of the resolver sensor and the output torque signal of the drive motor, tire blowout detection can be achieved at the microsecond level. Therefore, the tire load change can be accurately judged based on the resolver signal of the drive motor and the drive torque, thus realizing tire blowout detection.

[0134] When a wheel has a tire blowout, the tire pressure will decrease. When the tire pressure is less than the pressure threshold, it can be determined that the wheel has a tire blowout.

[0135] The tire blowout detection and control is performed only when the speed of the electric vehicle 10 is greater than the preset speed, so as to avoid misjudgment and miscontrol when the vehicle starts to accelerate or travels at a low speed. The preset speed can be pre-calibrated according to actual vehicle experiments and / or model calculations, or can be pre-set by comprehensively considering the vehicle requirements and vehicle performance.

[0136] like Figure 4 As shown in , at the first moment t1, the wheel speed of the wheel with a flat tire suddenly changes, and if the increase in wheel speed is greater than the increase in wheel speed of other wheels within a preset time period, it can be determined that a flat tire has occurred.

[0137] At the first time t1, the driving torque of one wheel is controlled to be reduced and the braking force output to the one wheel by the brake system 60 of the electric vehicle 10 is controlled to be reduced.

[0138] In one embodiment, after the first time t1 , the driving torque of one wheel is controlled to be reduced to zero and the braking force outputted to one wheel by the braking system 60 of the electric vehicle 10 is controlled to be reduced to zero.

[0139] The tire with a blown tire will produce a blown tire braking effect, the resistance of the blown tire wheel will increase suddenly, the radius of the wheel will decrease, the left and right wheels of the drive shaft will be subjected to unequal forces, and a yaw torque will be generated. The direction of travel of the vehicle will deviate, and the body of the electric vehicle 10 will yaw toward the side of the blown tire wheel. In order to control the yaw caused by a blown tire of the electric vehicle 10, it is necessary to ensure that the wheel can be subjected to sufficient lateral force. By clearing the torque of the blown tire wheel to zero, sufficient margin can be provided for the steering lateral force of the electric vehicle 10.

[0140] According to the solution of the present application, when a tire blows out in the electric vehicle 10, the torque and braking force are adjusted quickly, the driving torque and braking force are quickly cleared, the lateral force friction limit is fully utilized, sufficient margin is provided for steering lateral force, directional stability control is facilitated, and vehicle safety is improved.

[0141] In one embodiment, the control method further includes: after the first time t1 , controlling the suspension system of the electric vehicle 10 to adjust the damping of the shock absorber of one wheel to increase.

[0142] The suspension system is used to connect the body and wheels of the electric vehicle 10, and provide support, cushioning and stability during the driving of the electric vehicle 10. The suspension system may include a shock absorber. Each wheel can be connected to the body of the electric vehicle through a shock absorber alone. For a suspension system with a damping adjustable shock absorber, when the electric vehicle 10 has a tire blowout, a target damping coefficient or a target damping level can be sent to the suspension system to adjust the damping of each shock absorber. For the shock absorber of the tire blowout wheel, the damping of the shock absorber can be increased, and the contact between the wheel and the road surface can be ensured by applying strong damping. For other wheels, the damping of the shock absorber can be changed or not.

[0143] In one embodiment, the control method specifically includes: after the first moment t1, controlling the suspension system of the electric vehicle 10 to adjust the damping of the shock absorber of one wheel to increase to the target damping, and the target damping increases with the increase of the speed of the electric vehicle 10.

[0144] When an electric vehicle has a tire blowout while driving, the greater the speed of the electric vehicle, the greater the force required to stabilize the electric vehicle. Therefore, adjusting the wheel to a larger target damping can provide more sufficient support force.

[0145] In one embodiment, the control method further includes: after the first moment t1 , controlling the suspension system of the electric vehicle 10 to adjust the vehicle height of one wheel to be greater than the vehicle heights of other wheels of the electric vehicle 10 .

[0146] The suspension system may include an air suspension or a fully active suspension. When a tire blowout occurs in an electric vehicle, a target wheel suspension height may be sent to the suspension system so that the suspension height at the wheel of the electric vehicle may be adjusted. In one implementation, the air suspension may control the lowering of the suspension height at the non-blowout wheel, and control the suspension height at the blowout wheel to remain unchanged, so that the vehicle height of the blowout wheel is greater than the vehicle height of other wheels. In another implementation, the fully active suspension may control the raising or lowering of the suspension height at each wheel, and for the blowout wheel, the fully active suspension may control the raising of the vehicle height at the blowout wheel, so that the vehicle height of the blowout wheel is greater than the vehicle height of other wheels of the electric vehicle, thereby raising the blowout wheel. For the suspension height of the non-blowout wheel, the fully active suspension may adjust the height according to the balance of the vehicle body posture of the electric vehicle.

[0147] Continue to see Figure 4 At a second time t2 after the first time t1, the opening degree of the accelerator pedal of the electric vehicle 10 is greater than the preset accelerator opening degree.

[0148] The control method specifically includes: controlling the driving torque of a wheel on the same side of a wheel to be greater than the driving torque of a wheel diagonally opposite to a wheel.

[0149] At the second time t2, the driver steps on the accelerator pedal. At this time, the drive system of the electric vehicle 10 is controlled to output a drive torque so that the left and right wheels of the non-flat tire axle generate unequal drive torques, thereby achieving yaw suppression.

[0150] It should be understood that the second moment t2 and the first moment t1 can be very close. In the process of controlling the driving torque of one wheel to be reduced to zero and controlling the braking force output by the braking system of the electric vehicle to one wheel to be zero, the driving torque of the wheel on the same side of a wheel and the driving torque of the wheel diagonally opposite to a wheel can be adjusted.

[0151] By controlling one or both of the two drive motors on the left and right sides to work simultaneously, drive torques of different sizes are generated, so that torque vector control is performed through the two drive motors to generate yaw correction torque and suppress the yaw of the entire vehicle.

[0152] In one embodiment, the control method specifically includes: when a left front wheel of the electric vehicle 10 has a tire blowout, at a second moment t2, controlling the driving torque of the left rear wheel of the electric vehicle 10 to be greater than the driving torque of the right rear wheel.

[0153] The right front wheel of the electric vehicle 10 has a tire blowout. At the second moment, the driving torque of the left rear wheel of the electric vehicle is controlled to be smaller than the driving torque of the right rear wheel.

[0154] For example, Figure 5 As shown, when the right front wheel of the electric vehicle 10 has a tire blowout, the right front wheel will produce a tire blowout braking effect. If the driver does not apply steering wheel control, the electric vehicle 10 will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the electric vehicle 10 recognizes that the driver steps on the accelerator pedal at the second moment t2, controls the driving torque of the right rear wheel to be greater than the driving torque of the left rear wheel, and makes the electric vehicle 10 generate a yaw correction torque to the left (counterclockwise relative to the vehicle), thereby reducing the yaw of the electric vehicle 10.

[0155] In one embodiment, the control method specifically includes: at the second moment t2, controlling the difference between the driving torque of a wheel on the same side of a wheel and the driving torque of a wheel diagonally opposite to a wheel to increase as the speed of the electric vehicle 10 increases.

[0156] When a tire bursts while the electric vehicle 10 is driving, the greater the speed of the electric vehicle 10, the greater the vehicle yaw angular velocity deviation caused by the tire burst, the greater the yaw correction torque required for tire burst stability control, and the greater the torque differential momentum output by the left and right drive motors of the non-flattened axle.

[0157] In one embodiment, the control method further includes: at the second moment t2, the opening of the accelerator pedal of the electric vehicle 10 is greater than a preset accelerator opening, and controlling the steering system of the electric vehicle 10 to adjust the steering angles of the two rear wheels.

[0158] The steering system of the electric vehicle 10 can control the steering of the rear wheels. The steering system can change the turning angle and direction of the two rear wheels, so that the electric vehicle 10 can effectively adjust the steering and handling characteristics of the vehicle through different steering methods. When the electric vehicle 10 is driving, a front wheel has a flat tire, and the wheel with the flat tire will produce a flat tire braking effect, the wheel speed will suddenly increase, the driving direction of the vehicle will deviate, and the body of the electric vehicle 10 will yaw toward the side of the front wheel with the flat tire. In order to ensure the safety of the driver and the vehicle, the steering of the two rear wheels can be adjusted through the rear-wheel steering system to make the vehicle generate a yaw control torque, so that the yaw control torque offsets the yaw caused by the flat tire and reduces the yaw amplitude of the vehicle.

[0159] In one embodiment, the control method specifically includes: when a left front wheel of the electric vehicle 10 has a tire blowout, at a second moment t2, controlling the steering system of the electric vehicle 10 to adjust the two rear wheels to turn left.

[0160] The right front wheel of the electric vehicle 10 has a tire blowout, and at the second time t2, the steering system of the electric vehicle 10 is controlled to adjust the two rear wheels to turn right.

[0161] For example, Figure 6 As shown, when the right front wheel of the electric vehicle 10 has a flat tire, if the driver does not apply steering wheel control, the electric vehicle will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the electric vehicle 10 recognizes that the driver steps on the accelerator pedal at the second moment t2, and controls the rear wheel steering system to turn to the right. Then, the rightward steering of the rear wheel can cause the electric vehicle 10 to generate a yaw control moment to the left (counterclockwise relative to the vehicle). The yaw moment and the yaw control torque cancel each other out, and the yaw amplitude of the electric vehicle 10 is reduced.

[0162] In one embodiment, the control method specifically includes: at the second moment t2, controlling the steering system of the electric vehicle 10 to adjust the steering angles of the two rear wheels to decrease as the speed of the electric vehicle 10 increases.

[0163] The faster the vehicle speed, the higher the risk of a tire blowout, and the greater the impact on the vehicle's posture and trajectory. At this time, the yaw control torque applied through steering will be greater, and the danger will be greater. The higher the speed, the greater the risk of loss of control. Therefore, the higher the speed, the smaller the steering angle of the rear wheels controlled by the rear-wheel steering system.

[0164] In one embodiment, the control method also includes: at the second moment t2, the opening of the accelerator pedal of the electric vehicle 10 is greater than the preset throttle opening and the steering wheel angle change is greater than the direction threshold, controlling the steering system of the electric vehicle 10 to adjust the steering angle of the two front wheels to be less than the steering angle indicated by the steering wheel angle.

[0165] In one embodiment, the control method also includes: at the second moment t2, the opening of the accelerator pedal of the electric vehicle 10 is greater than the preset throttle opening and the steering wheel angle change is greater than the direction threshold, controlling the steering system to adjust the two rear wheels to turn in the opposite direction of the steering angle indicated by the steering wheel angle.

[0166] When the electric vehicle 10 has a tire blowout, if the driver steps on the accelerator pedal and the electric vehicle 10 is still moving, the driver may sense the tire blowout and make a large steering correction. This operation may increase the safety risk of a tire blowout. Therefore, when the steering wheel steering angle is greater than the direction threshold, a corresponding suppression strategy is required to control the steering system to suppress the change in the front wheel steering angle, limit the steering wheel rotation rate, and prevent the risk caused by sudden steering. The rear wheel steering is used to assist the driver in achieving the purpose of steering. The direction of the rear wheel steering is opposite to that of the front wheel, and the direction of the rear wheel steering is opposite to that of the steering wheel.

[0167] For example, Figure 7 As shown, when the right front wheel of the electric vehicle 10 has a tire blowout, the electric vehicle will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the electric vehicle 10 recognizes that the driver has stepped on the accelerator pedal at the second moment t2, and the driver has turned the steering wheel to the left significantly. At this time, the steering system is controlled to suppress the rate of change of the steering angle of the front wheel to the left, and the two rear wheels are controlled to turn to the right. The rightward steering of the rear wheels can make the electric vehicle 10 generate a yaw control moment to the left (counterclockwise relative to the vehicle) and assist the driver to change lanes to the left.

[0168] Continue to see Figure 4 At a third time t3 after the first time t1, the opening degree of the brake pedal of the electric vehicle 10 is greater than the preset brake opening degree.

[0169] The control method further includes: controlling the braking system 60 to output a braking force to a wheel on the same side of a wheel that is smaller than a braking force output to a wheel diagonally opposite to the wheel.

[0170] At the third moment t3, the opening of the brake pedal of the electric vehicle 10 is greater than the preset brake opening. At this time, the driver steps on the brake pedal to control the braking system 60 of the electric vehicle 10 to output unequal braking forces to the left and right wheels of the non-flat tire axle, generating a yaw moment, thereby suppressing the yaw caused by the tire blowout.

[0171] It should be understood that it usually takes a while from when the electric vehicle 10 has a tire blowout to when the driver notices the blowout, during which time the driver still maintains the previous driving state and still presses the accelerator pedal. When the driver notices the blowout and intervenes, he may still press the accelerator pedal in the hope of maintaining the vehicle speed, or he may press the brake pedal in the hope of stopping the vehicle. Therefore, the second moment t2 usually occurs during the entire blowout stability control process, while the third moment t3 may not occur during the blowout process, and the third moment t3 also usually occurs after the second moment t2.

[0172] In one embodiment, the control method specifically includes: when a tire bursts on the left front wheel of the electric vehicle 10, at a third moment t3, controlling the braking system 60 to output a braking force to the left rear wheel of the electric vehicle 10 that is smaller than the braking force output to the right rear wheel.

[0173] The right front wheel of the electric vehicle 10 has a tire blowout. At the third time t3, the braking system 60 is controlled to output a braking force greater than the braking force output to the right rear wheel of the electric vehicle 10 .

[0174] For example, Figure 8 As shown, when the right front wheel of the electric vehicle 10 has a tire blowout, if the driver does not apply steering wheel control, the electric vehicle 10 will generate a yaw moment to the right (clockwise relative to the vehicle). At this time, the electric vehicle 10 recognizes that the driver steps on the brake pedal at the third moment t3, and controls the braking system 60 to output a braking force to the left rear wheel greater than the braking force output to the right rear wheel, so that the electric vehicle 10 generates a yaw correction moment to the left (counterclockwise relative to the vehicle), thereby reducing the yaw of the electric vehicle.

[0175] In one embodiment, the control method specifically includes: at the third moment t3, controlling the braking system 60 to increase the difference between the braking force output to the wheel on the same side of a wheel and the braking force output to the diagonal wheel of a wheel as the speed of the electric vehicle 10 increases.

[0176] When a tire bursts during driving of the electric vehicle 10, the greater the speed of the electric vehicle 10, the greater the vehicle yaw angular velocity deviation caused by the tire burst, the greater the yaw correction torque required for tire burst stability control, and the greater the difference in braking force on the left and right wheels of the non-flattened axle.

[0177] In one embodiment, at the third moment t3, the opening of the brake pedal of the electric vehicle 10 is greater than the preset brake opening, and the difference between the driving torque of a wheel on the same side of a wheel and the driving torque of a wheel diagonally opposite to a wheel is controlled to be reduced to zero.

[0178] Continue to see Figure 4 At a fourth time t4 after the first time t1, the speed of the electric vehicle 10 is less than the safety threshold.

[0179] The control method includes: in response to the speed of the electric vehicle 10 being less than a safety threshold, controlling the braking system 60 to reduce the difference between the braking force output to the wheel on the same side of a wheel and the braking force output to the diagonal wheel of a wheel to zero.

[0180] At the fourth moment t4, the speed of the electric vehicle 10 decreases to a safe range or has stopped, at which time the driving torque difference is controlled to decrease to zero, and the difference in the left and right wheel braking forces is also controlled to decrease to zero.

[0181] According to the solution of the present application, the motor controller 40 accurately calculates the timing of torque intervention, instantly adjusts the torque output of the drive motor 30, quickly clears the drive torque and braking force, provides sufficient margin for the steering lateral force, and facilitates directional stability control. Based on the principle of minimum delay of multi-component coordination, the vehicle yaw torque is generated, the yaw caused by the tire blowout axle is suppressed, and the vehicle body posture is stabilized.

[0182] Combine the following Fig. 9 , Fig.10 and Fig.11 The control architecture of the vehicle controller and the control signals of the tire blowout stability control provided in the embodiments of the present application are described.

[0183] The vehicle controller implements two parts: tire blowout detection and collaborative control.

[0184] like Fig. 9 and Fig.11 As shown, when a tire blowout is detected, the vehicle controller receives the resolver signal, accelerator pedal opening signal, brake pedal opening signal, and drive torque signal from the resolver sensor. By calculating the front and rear drive road adhesion conditions, the tire blowout scene is identified and the tire blowout wheel is located. When a tire blowout is identified, a tire blowout signal is sent to multiple systems and components. The tire blowout signal is used to indicate the tire blowout wheel and the location of the tire blowout wheel.

[0185] like Fig.10 and 11 As shown, after determining a tire blowout, the vehicle controller sends a tire blowout signal and a torque distribution signal to multiple motor controllers, limits the driving torque of the driving motor of the tire blowout wheel, and controls other driving motors to apply a yaw correction torque.

[0186] The vehicle controller sends a tire blowout signal and a braking force distribution signal to the brake system 60. A braking force limit is applied to the tire blowout wheel, and a yaw correction torque is applied to the non-tire blowout wheel control to keep the vehicle from yaw.

[0187] The vehicle controller sends a tire blowout signal for a shock absorber with adjustable damping, and issues a target damping coefficient or target damping level setting. For a system with an air spring, a tire blowout signal is sent, and the tire blowout wheel spring is adjusted, and a target height adjustment setting is issued to increase the height of the tire blowout wheel; for non-tire blowout wheel springs, a target height adjustment setting is issued according to the vehicle body posture balance.

[0188] The vehicle controller sends a tire blowout signal to the steering system and limits the steering wheel rotation rate to prevent the risk of sudden steering. For the rear-wheel steering system, a tire blowout signal is sent and the rear-wheel steering angle is issued.

[0189] Combination Figure 4 As shown, in one embodiment, the vehicle controller calculates the front and rear drive road adhesion conditions according to the resolver signal of the resolver sensor, identifies the occurrence of a tire blowout and locates the tire blowout wheel, and sends a tire blowout signal to multiple systems and components. The tire blowout signal is used to indicate the tire blowout wheel and the location of the tire blowout wheel. At the first moment t1, the vehicle controller sends a torque signal to the drive system and a braking force distribution signal to the brake system. The torque signal is used to control the driving torque of the tire blowout wheel to be reduced to zero, and the braking force distribution signal is used to control the braking force output by the brake system 60 to one wheel to be zero, thereby providing a margin for vehicle control. At the second moment t2, the opening of the accelerator pedal is greater than the preset throttle opening, and the torque signal is used to control the driving torque of the wheel on the same side of the tire blowout wheel to be greater than the driving torque of the diagonal wheel of the tire blowout wheel. The difference in the driving torque on the left and right sides suppresses the yaw caused by the tire blowout. When the steering wheel angle changes greater than the direction threshold, the vehicle controller also sends a steering signal to the steering system to control the steering system of the electric vehicle to adjust the steering angle of the two front wheels to be less than the steering angle indicated by the steering wheel angle, and control the steering system to adjust the steering angle of the two rear wheels. Thereby, the driver is restrained from turning the steering wheel greatly, and the rear wheel steering is used to assist the steering of the electric vehicle, thereby improving the operability of the electric vehicle and reducing the risk of the electric vehicle losing control. At the third moment t3, the opening of the brake pedal is greater than the preset brake opening, and the braking force distribution signal is used to control the braking force output by the braking system 60 to the wheel on the same side of the tire burst wheel to be less than the braking force output to the diagonal wheel of the tire burst wheel. The torque signal is used to control the difference between the driving torque of the wheel on the same side of the tire burst wheel and the driving torque of the diagonal wheel of the tire burst wheel to be reduced to zero. After the first moment t1, the vehicle controller sends a target damping coefficient or a target height adjustment signal to the suspension system, which is used to control the suspension system to adjust the damping of the shock absorber of the tire burst wheel to increase or adjust the body height of the tire burst wheel to be greater than the body height of other wheels of the electric vehicle. At the fourth moment t4, the speed of the electric vehicle is less than the safety threshold, and the braking force distribution signal is used to control the difference between the braking force output by the braking system 60 to the wheel on the same side of the tire burst wheel and the braking force output to the diagonal wheel of the tire burst wheel to be reduced to zero.

[0190] According to the solution of the present application, tire blowout detection is achieved based on load observation of the drive motor, without relying on tire pressure sensors, and the detection cycle is greatly accelerated, from seconds to milliseconds. After a tire blowout is identified, the torque is actively reduced to achieve rapid torque adjustment, increasing the safety threshold. The system controls the multi-motor distributed drive architecture, braking system, rear-wheel steering system, and suspension system to achieve multi-system correction and joint control to ensure vehicle stability. It can suppress safety risks caused by driver misoperation while safely achieving the driver's driving goals through the intervention of other systems.

[0191] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for an electric vehicle, characterized in that: The control method is used to control the electric vehicle when a tire bursts on one wheel during the driving process of the electric vehicle at a speed greater than a preset speed, and the control method includes: At a first moment after a tire puncture occurs on one wheel of the electric vehicle, the driving torque of the one wheel is controlled to be reduced and the braking force output to the one wheel by the braking system of the electric vehicle is controlled to be reduced.

2. The control method according to claim 1, characterized in that: The control method specifically includes: After the first moment, the driving torque of the one wheel is controlled to be reduced to zero and the braking force outputted to the one wheel by the braking system of the electric vehicle is controlled to be reduced to zero.

3. The control method according to claim 1 or 2, characterized in that: The control method specifically includes: At a second moment after the first moment, the opening of the accelerator pedal of the electric vehicle is greater than a preset accelerator opening, and the driving torque of the wheel on the same side of the one wheel is controlled to be greater than the driving torque of the diagonal wheel of the one wheel.

4. The control method according to claim 3, characterized in that: The control method specifically includes: The left front wheel of the electric vehicle has a tire blowout, and at the second moment, the driving torque of the left rear wheel of the electric vehicle is controlled to be greater than the driving torque of the right rear wheel; The right front wheel of the electric vehicle has a tire blowout, and at the second moment, the driving torque of the left rear wheel of the electric vehicle is controlled to be smaller than the driving torque of the right rear wheel.

5. The control method according to claim 3 or 4, characterized in that: The control method specifically includes: At the second moment, the difference between the driving torque of the wheel on the same side of the one wheel and the driving torque of the wheel diagonally opposite to the one wheel is controlled to increase as the vehicle speed of the electric vehicle increases.

6. The control method according to any one of claims 1 to 5, characterized in that: The control method further comprises: At a third moment after the first moment, the opening of the brake pedal of the electric vehicle is greater than a preset brake opening, and the braking system is controlled to output a braking force to the wheel on the same side of the one wheel that is smaller than the braking force output to the diagonal wheel of the one wheel.

7. The control method according to claim 6, characterized in that: The control method specifically includes: The left front wheel of the electric vehicle has a tire blowout, and at the third moment, the braking system is controlled to output a braking force to the left rear wheel of the electric vehicle that is smaller than the braking force output to the right rear wheel; The right front wheel of the electric vehicle has a tire blowout, and at the third moment, the braking system is controlled to output a braking force greater than the braking force output to the right rear wheel of the electric vehicle.

8. The control method according to claim 6 or 7, characterized in that: The control method specifically includes: At the third moment, the braking system is controlled to increase a difference between a braking force output to a wheel on the same side of the one wheel and a braking force output to a wheel diagonal to the one wheel as the speed of the electric vehicle increases.

9. The control method according to any one of claims 1 to 8, characterized in that: The control method further comprises: After the first moment, the suspension system of the electric vehicle is controlled to adjust the damping of the shock absorber of the one wheel to increase.

10. The control method according to claim 9, characterized in that: The control method further comprises: After the first moment, the suspension system of the electric vehicle is controlled to adjust the damping of the shock absorber of the one wheel to increase to a target damping, and the target damping increases with an increase in the vehicle speed of the electric vehicle.

11. The control method according to any one of claims 1 to 8, characterized in that: The control method further comprises: After the first moment, the suspension system of the electric vehicle is controlled to adjust the vehicle height of the one wheel to be greater than the vehicle heights of other wheels of the electric vehicle.

12. The control method according to any one of claims 1 to 11, characterized in that: The control method further comprises: At a second moment after the first moment, the opening of the accelerator pedal of the electric vehicle is greater than a preset accelerator opening, and the steering system of the electric vehicle is controlled to adjust the steering angles of the two rear wheels.

13. The control method according to claim 12, characterized in that: The control method specifically includes: The left front wheel of the electric vehicle has a tire blowout, and at the second moment, the steering system of the electric vehicle is controlled to adjust the two rear wheels to turn left; The right front wheel of the electric vehicle has a tire blowout, and at the second moment, the steering system of the electric vehicle is controlled to adjust the two rear wheels to turn right.

14. The control method according to claim 12 or 13, characterized in that: The control method specifically includes: At the second moment, the steering system of the electric vehicle is controlled to adjust the steering angles of the two rear wheels to decrease as the speed of the electric vehicle increases.

15. The control method according to any one of claims 1 to 11, characterized in that: The control method further comprises: At a second moment after the first moment, the opening of the accelerator pedal of the electric vehicle is greater than a preset accelerator opening and the steering wheel angle change is greater than a direction threshold, and the steering system of the electric vehicle is controlled to adjust the steering angle of the two front wheels to be less than the steering angle indicated by the steering wheel angle.

16. The control method according to claim 15, characterized in that: The control method further comprises: At the second moment, the opening of the accelerator pedal of the electric vehicle is greater than the preset accelerator opening and the steering wheel angle change is greater than the direction threshold, and the steering system is controlled to adjust the two rear wheels to turn in the opposite direction of the steering angle indicated by the steering wheel angle.

17. The control method according to any one of claims 6 to 8, characterized in that: The control method further comprises: At a third moment after the first moment, the opening of the brake pedal of the electric vehicle is greater than a preset brake opening, and the difference between the driving torque of the wheel on the same side of the one wheel and the driving torque of the wheel diagonal to the one wheel is controlled to be reduced to zero; At a fourth moment after the first moment, in response to the vehicle speed of the electric vehicle being less than a safety threshold, the braking system is controlled to reduce the difference between the braking force output to the wheel on the same side of the one wheel and the braking force output to the diagonal wheel of the one wheel to zero.

18. The control method according to claim 1, characterized in that: A tire blowout occurs on one wheel of the electric vehicle, comprising: The load torque of the one wheel is greater than a preset value, and / or the tire pressure of the one wheel is less than a pressure threshold, and / or the wheel speed increase value of the one wheel is greater than the wheel speed increase values ​​of other wheels within a preset time period.

19. A vehicle controller, characterized in that: The vehicle controller is configured to execute the control method according to any one of claims 1 to 18.

20. An electric vehicle, characterized in that: The electric vehicle includes a vehicle controller as described in claim 19, a braking system, an accelerator pedal, a brake pedal and a steering wheel, the accelerator pedal is used to indicate the driving torque output to the wheels of the electric vehicle, the brake pedal is used to indicate the braking force output to the wheels of the electric vehicle, and the steering wheel angle is used to indicate the steering angle of the two front wheels.

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