A pure electric vehicle safety control method and system

Abstract

The present invention relates to a pure electric vehicle safety control method and system, the method comprising: collecting the fault states of four electronic mechanical brakes and four drive motors corresponding to the four tires of the vehicle; and adopting different emergency control modes for control according to the different fault states of the four electronic mechanical brakes and the four drive motors. In the control, the electronic mechanical brake provides braking force by controlling the brake pads to fit; the drive motor provides braking force through negative torque; the steering motor provides auxiliary braking force by controlling the longitudinal friction force obtained by rotating the two front wheels in opposite directions at the same angle at the same time; the steering motor provides auxiliary braking force by controlling the longitudinal friction force obtained by rotating the two rear wheels in opposite directions at the maximum angle at the same time. The present invention uses the steering motor to control the wheel rotation as an auxiliary emergency braking function, combines various fault conditions, and realizes active safety control of the vehicle through different control methods. It has a variety of emergency braking measures and is safer and more reliable.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control, and in particular to a pure electric vehicle safety control method and system. Background Art

[0002] The steering system and braking system are both key components of a vehicle. The steering system ensures that the car can steer and drive according to the driver's will, and is also closely related to the vehicle's operational stability; the braking system ensures that the car is forced to slow down or stop according to the driver's requirements, and is also an important component for the vehicle to enter a safe stationary state.

[0003] A car with four wheels that cannot steer independently can only decelerate by motor braking and friction braking, while a car with four-wheel independent steering can achieve emergency braking by changing the wheel angle. The existing braking system is not combined with four-wheel independent steering, cannot use the longitudinal friction of the wheels as auxiliary braking force to provide emergency braking, and cannot provide an effective safety control method when an abnormality occurs in the device that can provide braking force. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a pure electric vehicle safety control method and system.

[0005] The specific plan is as follows:

[0006] A pure electric vehicle safety control method comprises the following steps:

[0007] S1: Collect the fault status of four electronic mechanical brakes and four drive motors corresponding to the four tires of the vehicle;

[0008] S2: Different emergency control modes are adopted for control according to the different fault states of the four electronic mechanical brakes and the four drive motors.

[0009] Furthermore, during control, the electronic mechanical brake provides braking force by controlling the contact of the brake pads; the drive motor provides braking force through negative torque; the steering motor provides auxiliary braking force by controlling the longitudinal friction force obtained by simultaneously rotating the two front wheels in opposite directions at the same angle; the steering motor provides auxiliary braking force by controlling the longitudinal friction force obtained by simultaneously rotating the two rear wheels in opposite directions at the same angle.

[0010] Further, when there is a fault in the electronic mechanical brake of any of the two front wheels and the four drive motors are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking is performed through the electronic mechanical brakes of the two rear wheels and the four drive motors in the emergency control mode; otherwise, braking force is provided through the electronic mechanical brakes of the two rear wheels in the emergency control mode, and auxiliary braking force is provided through the steering motors of the two front wheels;

[0011] When there is a fault in the electronic mechanical brake of any of the two front wheels and a fault in the driving motor of any of the two front wheels, it is determined whether the battery power of the vehicle is less than the power threshold, if so, in the emergency control mode, the electronic mechanical brakes of the two rear wheels and the driving motors of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force; otherwise, in the emergency control mode, the electronic mechanical brakes of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force;

[0012] When there is a fault in the electronic mechanical brake of any of the two front wheels and a fault in the driving motor of any of the two rear wheels, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the electronic mechanical brakes of the two rear wheels and the driving motors of the two front wheels provide braking force in the emergency control mode; otherwise, the electronic mechanical brakes of the two rear wheels provide braking force in the emergency control mode, and the steering motors of the two front wheels provide auxiliary braking force;

[0013] When there is a fault in the electronic mechanical brake of any of the two front wheels and all four drive motors fail, in the emergency control mode, the electronic mechanical brakes of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force.

[0014] Further, when there is a fault in the electronic mechanical brake of any of the two rear wheels and the four drive motors are normal, it is determined whether the battery power of the vehicle is less than the power threshold, and if so, the electronic mechanical brakes of the two front wheels and the four drive motors are used to provide braking force in the emergency control mode; otherwise, the electronic mechanical brakes of the two front wheels are used to provide braking force in the emergency control mode, and the steering motors of the two rear wheels are used to provide auxiliary braking force;

[0015] When there is a fault in the electronic mechanical brake of any of the two rear wheels and a fault in the driving motor of any of the two front wheels, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the electronic mechanical brakes of the two front wheels and the driving motors of the two rear wheels provide braking force in the emergency control mode; otherwise, the electronic mechanical brakes of the two front wheels provide braking force in the emergency control mode, and the steering motors of the two rear wheels provide auxiliary braking force;

[0016] When there is a fault in the electronic mechanical brake of any one of the two rear wheels and a fault in the driving motor of any one of the two rear wheels, it is determined whether the battery power of the vehicle is less than the power threshold, if so, in the emergency control mode, the electronic mechanical brakes of the two front wheels and the driving motors of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force; otherwise, in the emergency control mode, the electronic mechanical brakes of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force;

[0017] When there is a fault in the electronic mechanical brake of any of the two rear wheels and all four drive motors fail, in the emergency control mode, the electronic mechanical brakes of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force.

[0018] Further, when the driving motor of any one of the two front wheels fails and the four electronic mechanical brakes are normal, it is determined whether the battery power of the vehicle is less than the power threshold, and if so, the braking force is provided by the four electronic mechanical brakes and the driving motors of the two rear wheels in the emergency control mode; otherwise, the braking force is provided by the four electronic mechanical brakes in the emergency control mode;

[0019] When there is a fault in the driving motor of any of the two rear wheels and the four electronic mechanical brakes are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking force is provided by the four electronic mechanical brakes and the driving motors of the two front wheels in the emergency control mode; otherwise, braking force is provided by the four electronic mechanical brakes in the emergency control mode.

[0020] Further, when all four drive motors are faulty and all four electromechanical brakes are normal, braking force is provided by the four electromechanical brakes in the emergency control mode;

[0021] When all four electronic mechanical brakes are faulty and all four drive motors are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking force is provided by the four drive motors in the emergency control mode; otherwise, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels in the emergency control mode.

[0022] Further, when the driving motor of any of the two front wheels fails and the four electronic mechanical brakes all fail, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the driving motors of the two rear wheels provide braking force in the emergency control mode, and the steering motors of the two front wheels provide auxiliary braking force; otherwise, the four steering motors of the two front wheels and the two rear wheels provide auxiliary braking force in the emergency control mode;

[0023] When there is a fault in the driving motor of any of the two rear wheels and there are faults in all four electronic mechanical brakes, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking force is provided by the driving motors of the two front wheels in the emergency control mode, and auxiliary braking force is provided by the steering motors of the two rear wheels; otherwise, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels in the emergency control mode.

[0024] Furthermore, when the four electromechanical brakes and the four drive motors all fail, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels in the emergency control mode.

[0025] A pure electric vehicle safety control system includes four steering motors corresponding to the four tires of the vehicle, four electronic mechanical brakes, four drive motors and a control terminal, wherein the control terminal includes a processor, a memory and a computer program stored in the memory and running on the processor, and the system implements the steps of the above-mentioned method in an embodiment of the present invention.

[0026] The present invention adopts the above technical solution and has the following technical effects:

[0027] (1) Using independent steering motors on the four wheels to control wheel steering, the vehicle does not deviate without the driver's intention, and the friction resistance of the wheels assists braking;

[0028] (2) All four wheels of the vehicle are equipped with steering motors, electromechanical brakes, and drive motors, which can be independently controlled. According to different fault conditions, feedback is given to the vehicle controller to control the braking strategy. It has a variety of emergency braking measures, which is safer and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shown is a flow chart of Embodiment 1 of the present invention.

[0030] Figure 2 Shown is a schematic diagram of the emergency control mode corresponding to different fault conditions in this embodiment. DETAILED DESCRIPTION

[0031] To further illustrate various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in this field should be able to understand other possible implementations and advantages of the present invention.

[0032] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0033] Embodiment 1:

[0034] The embodiment of the present invention provides a pure electric vehicle safety control method, such as Figure 1 As shown, the method comprises the following steps:

[0035] S1: Collect the fault status of the four electronic mechanical brakes and four drive motors corresponding to the four tires of the vehicle.

[0036] The vehicle's steering system in this embodiment adopts a four-wheel steering system, that is, each wheel can independently rotate a certain angle in both directions; the braking system is an electronic mechanical braking system (EMB for short), and each wheel has a brake motor that controls the engagement and separation of the brake pads.

[0037] In this embodiment, the fault status is set to include two types: fault and normal, wherein the setting status 1 is fault and 0 is normal.

[0038] S2: Different emergency control modes are adopted for control according to the different fault states of the four electronic mechanical brakes and the four drive motors.

[0039] When fault detection finds that the vehicle is abnormal and requires emergency braking, the vehicle enters the corresponding emergency control mode according to the fault status of the four electronic mechanical brakes and the four drive motors. This embodiment defines the front wheel electronic mechanical brake state as A1, the rear wheel electronic mechanical brake state as A2, the front wheel drive motor state as B1, and the rear wheel drive motor state as B2. The corresponding emergency control modes under different fault conditions are as follows: Figure 2 Each emergency control mode is introduced below.

[0040] Mode 1: When the electronic mechanical brake of any of the two front wheels fails and the four drive motors are normal, that is, A1A2B1B2 are 1000 respectively, it is necessary to determine which braking method to use based on the relationship between the battery power of the vehicle and the power threshold. Set M as the power threshold, and the size of M is set according to different batteries, mainly to avoid overcharging the battery.

[0041] If the power is less than M, the electronic mechanical brakes of the two front wheels do not provide braking force, and the four drive motors perform negative torque braking, and the electronic mechanical brakes of the two rear wheels control the brake pads to apply braking; if the power is ≥M, in the emergency control mode, the four drive motors do not provide braking force to avoid battery overcharging, and the electronic mechanical brakes of the two rear wheels provide braking force. At the same time, the steering motors of the two front wheels respectively control the left front wheel and the right front wheel to rotate in opposite directions at the same angle, so that the left front wheel and the right front wheel form an outer eight or inner eight shape, and the longitudinal friction of the two front wheels is used as auxiliary braking force. The size of the rotation angle is adjusted according to the current vehicle speed to change the size of the longitudinal friction.

[0042] Mode 2: When there is a fault in the electronic mechanical brake of any of the two front wheels and a fault in the drive motor of any of the two front wheels, that is, A1A2B1B2 are 1010 respectively, if the power is less than M, the electronic mechanical brakes of the two rear wheels and the negative torque of the drive motors of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force. If the power is ≥M, the electronic mechanical brakes of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force.

[0043] Mode three: When there is a fault in the electronic mechanical brake of any of the two front wheels and there is a fault in the drive motor of any of the two rear wheels, that is, A1A2B1B2 are 1001 respectively, if the electric charge is <M, the braking force is provided by the electronic mechanical brakes of the two rear wheels and the negative torque of the drive motors of the two front wheels; if the electric charge is ≥M, the braking force is provided by the electronic mechanical brakes of the two rear wheels, and the auxiliary braking force is provided by the steering motors of the two front wheels.

[0044] Mode 4: When there is a fault in the electronic mechanical brake of any of the two front wheels and there are faults in all four drive motors, that is, A1A2B1B2 are 1011 respectively, braking force is provided by the electronic mechanical brakes of the two rear wheels, and auxiliary braking force is provided by the steering motors of the two front wheels.

[0045] Mode 5: When the electronic mechanical brake of any of the two rear wheels fails and the four drive motors are all normal, that is, A1A2B1B2 are 0100 respectively, if the power is less than M, the electronic mechanical brake of the rear wheel will not provide braking force; the four drive motors will perform negative torque braking, and the electronic mechanical brakes of the two front wheels will control the brake pads to fit together to generate braking force; if the power is ≥M, the drive motors will not provide braking force to avoid overcharging of the battery, and the electronic mechanical brakes of the two front wheels will provide braking force. At the same time, the steering motors of the two rear wheels will control the left rear wheel and the right rear wheel to rotate in opposite directions at the same angle, so that the left rear wheel and the right rear wheel form an outer eight or inner eight shape, and the longitudinal friction of the two rear wheels will be used as auxiliary braking force. In order to reduce the front tilt caused by the front brake, the left rear wheel and the right rear wheel rotate at the same angle at this time, reducing the demand for front brake braking force.

[0046] Mode 6: When there is a fault in the electronic mechanical brake of any of the two rear wheels and a fault in the drive motor of any of the two front wheels, that is, A1A2B1B2 are 0110 respectively, if the power is less than M, the electronic mechanical brakes of the two front wheels and the negative torque of the drive motors of the two rear wheels provide braking force. If the power is ≥M, the electronic mechanical brakes of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force.

[0047] Mode 7: When there is a fault in the electronic mechanical brake of any of the two rear wheels, and there is a fault in the drive motor of any of the two rear wheels, that is, A1A2B1B2 are 0101 respectively, if the power is less than M, the braking force is provided by the electronic mechanical brakes of the two front wheels and the negative torque of the drive motors of the two front wheels. The steering motor controls the left rear wheel and the right rear wheel to rotate into an outward eight or inward eight form to reduce the braking force demand of the front brake and thus reduce the possibility of the front of the vehicle tilting forward caused by the front brake. If the power is ≥M, the braking force is provided by the electronic mechanical brakes of the two front wheels, and the auxiliary braking force is provided by the steering motors of the two rear wheels.

[0048] Mode eight: When there is a fault in the electronic mechanical brake of any of the two rear wheels and there are faults in all four drive motors, that is, A1A2B1B2 are 0111 respectively, braking force is provided by the electronic mechanical brakes of the two front wheels, and auxiliary braking force is provided by the steering motors of the two rear wheels.

[0049] Mode nine: When there is a fault in the driving motor of any of the two front wheels and the four electronic mechanical brakes are normal, that is, A1A2B1B2 are 0010 respectively, if the power level is <M, negative torque braking force is provided by the two rear wheel driving motors, and the rest of the braking force is completed by the electronic mechanical brakes; if the power level is ≥M, the driving motors do not provide braking force to avoid battery overcharging, and the rest of the braking force is completed by the electronic mechanical brakes.

[0050] Mode 10: When the driving motor of any of the two rear wheels fails and the four electronic mechanical brakes are normal, that is, A1A2B1B2 are 0001 respectively, if the power level is <M, negative torque braking force is provided by the two front wheel driving motors, and the rest of the braking force is completed by the electronic mechanical brakes; if the power level is ≥M, the driving motors do not provide braking force to avoid battery overcharging, and the rest of the braking force is completed by the electronic mechanical brakes.

[0051] Mode 11: When all four drive motors are faulty and the four electronic mechanical brakes are normal, that is, A1A2B1B2 are 0011 respectively, and the braking force is provided by the four electronic mechanical brakes.

[0052] Mode 12: When all four electronic mechanical brakes are faulty and the four drive motors are normal, that is, A1A2B1B2 are 1100 respectively. If the power is less than M, the four drive motors provide negative torque braking force. If the power is ≥M, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels. That is, the left and right front wheels and the left and right rear wheels rotate into an outward or inward eight form at the same time.

[0053] Mode thirteen: When there is a fault in the driving motor of any of the two front wheels and there are faults in the four electronic mechanical brakes, that is, A1A2B1B2 are 1110 respectively, if the power is less than M, the rear wheel driving motor provides negative torque braking force, and the steering motors of the two front wheels provide auxiliary braking force; if the power is ≥M, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels.

[0054] Mode 14: When the driving motor of any of the two rear wheels fails and all four electronic mechanical brakes fail, that is, A1A2B1B2 are 1101 respectively, if the power is less than M, the front wheel driving motor provides negative torque braking force, and the left and right rear wheels rotate to an outward or inward eight form at the same time; if the power is ≥M, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels.

[0055] Mode 15: When the four electronic mechanical brakes and the four drive motors are faulty, that is, A1A2B1B2 are 1111 respectively, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels.

[0056] In response to situations where an abnormality occurs in the vehicle braking system, or when the vehicle drive system is restricted or abnormal, the embodiment of the present invention utilizes the steering motor of the steering system to control the angle of wheel rotation as an auxiliary emergency braking function, and combines various fault conditions to achieve active vehicle safety control through different control methods.

[0057] Embodiment 2:

[0058] The present invention also provides a pure electric vehicle safety control system, comprising four steering motors corresponding to the four tires of the vehicle, four electronic mechanical brakes, four drive motors and a control terminal, wherein the control terminal comprises a processor, a memory and a computer program stored in the memory and running on the processor, and the system implements the steps in the above-mentioned method embodiment of embodiment one of the present invention.

[0059] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A pure electric vehicle safety control method, characterized in that: The following steps are involved: S1: Collect the fault status of four electronic mechanical brakes and four drive motors corresponding to the four tires of the vehicle; S2: different emergency control modes are used for control according to the different fault states of the four electronic mechanical brakes and the four drive motors; During control, the electronic mechanical brake provides braking force by controlling the contact of the brake pads; the drive motor provides braking force through negative torque; the steering motor provides auxiliary braking force by controlling the longitudinal friction force obtained by rotating the two front wheels in opposite directions at the same angle at the same time; the steering motor provides auxiliary braking force by controlling the longitudinal friction force obtained by rotating the two rear wheels in opposite directions at the same angle at the same time; When there is a fault in the electronic mechanical brake of any of the two front wheels and the four drive motors are all normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking is performed through the electronic mechanical brakes of the two rear wheels and the four drive motors in the emergency control mode; otherwise, braking force is provided through the electronic mechanical brakes of the two rear wheels in the emergency control mode, and auxiliary braking force is provided through the steering motors of the two front wheels; When there is a fault in the electronic mechanical brake of any of the two front wheels and a fault in the driving motor of any of the two front wheels, it is determined whether the battery power of the vehicle is less than the power threshold, if so, in the emergency control mode, the electronic mechanical brakes of the two rear wheels and the driving motors of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force; otherwise, in the emergency control mode, the electronic mechanical brakes of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force; When there is a fault in the electronic mechanical brake of any of the two front wheels and a fault in the driving motor of any of the two rear wheels, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the electronic mechanical brakes of the two rear wheels and the driving motors of the two front wheels provide braking force in the emergency control mode; otherwise, the electronic mechanical brakes of the two rear wheels provide braking force in the emergency control mode, and the steering motors of the two front wheels provide auxiliary braking force; When there is a fault in the electronic mechanical brake of any of the two front wheels and all four drive motors fail, in the emergency control mode, the electronic mechanical brakes of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force; When there is a fault in the electronic mechanical brake of any of the two rear wheels and the four drive motors are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the electronic mechanical brakes of the two front wheels and the four drive motors are used to provide braking force in the emergency control mode; otherwise, the electronic mechanical brakes of the two front wheels are used to provide braking force in the emergency control mode, and the steering motors of the two rear wheels are used to provide auxiliary braking force; When there is a fault in the electronic mechanical brake of any of the two rear wheels and a fault in the driving motor of any of the two front wheels, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the electronic mechanical brakes of the two front wheels and the driving motors of the two rear wheels provide braking force in the emergency control mode; otherwise, the electronic mechanical brakes of the two front wheels provide braking force in the emergency control mode, and the steering motors of the two rear wheels provide auxiliary braking force; When there is a fault in the electronic mechanical brake of any one of the two rear wheels and a fault in the driving motor of any one of the two rear wheels, it is determined whether the battery power of the vehicle is less than the power threshold, if so, in the emergency control mode, the electronic mechanical brakes of the two front wheels and the driving motors of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force; otherwise, in the emergency control mode, the electronic mechanical brakes of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force; When there is a fault in the electronic mechanical brake of any of the two rear wheels and all four drive motors fail, in the emergency control mode, the electronic mechanical brakes of the two front wheels provide braking force, and the steering motors of the two rear wheels provide auxiliary braking force.

2. The pure electric vehicle safety control method according to claim 1, characterized in that: When the driving motor of any of the two front wheels fails and the four electronic mechanical brakes are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, the braking force is provided by the four electronic mechanical brakes and the driving motors of the two rear wheels in the emergency control mode; otherwise, the braking force is provided by the four electronic mechanical brakes in the emergency control mode; When there is a fault in the driving motor of any of the two rear wheels and the four electronic mechanical brakes are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking force is provided by the four electronic mechanical brakes and the driving motors of the two front wheels in the emergency control mode; otherwise, braking force is provided by the four electronic mechanical brakes in the emergency control mode.

3. The pure electric vehicle safety control method according to claim 1, characterized in that: When all four drive motors are faulty and all four electromechanical brakes are normal, the four electromechanical brakes provide braking force in the emergency control mode; When all four electronic mechanical brakes are faulty and all four drive motors are normal, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking force is provided by the four drive motors in the emergency control mode; otherwise, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels in the emergency control mode.

4. The pure electric vehicle safety control method according to claim 1, characterized in that: When there is a fault in the driving motor of any of the two front wheels and all four electronic mechanical brakes are faulty, it is determined whether the battery power of the vehicle is less than the power threshold. If so, in the emergency control mode, the driving motors of the two rear wheels provide braking force, and the steering motors of the two front wheels provide auxiliary braking force; otherwise, in the emergency control mode, the four steering motors of the two front wheels and the two rear wheels provide auxiliary braking force; When there is a fault in the driving motor of any of the two rear wheels and there are faults in all four electronic mechanical brakes, it is determined whether the battery power of the vehicle is less than the power threshold. If so, braking force is provided by the driving motors of the two front wheels in the emergency control mode, and auxiliary braking force is provided by the steering motors of the two rear wheels; otherwise, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels in the emergency control mode.

5. The pure electric vehicle safety control method according to claim 1, characterized in that: When all four electromechanical brakes and four drive motors fail, auxiliary braking force is provided by the four steering motors of the two front wheels and the two rear wheels in emergency control mode.

6. A pure electric vehicle safety control system, characterized in that: The system comprises four steering motors corresponding to the four tires of the vehicle, four electronic mechanical brakes, four drive motors and a control terminal, wherein the control terminal comprises a processor, a memory and a computer program stored in the memory and running on the processor, and the system implements the method as claimed in any one of claims 1 to 5.

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