Control method for non-inductive braking of electric vehicle, vehicle controller and electric vehicle

Abstract

The invention provides a control method for non-inductive braking of an electric vehicle, a vehicle controller and the electric vehicle, and is applied to the technical field of vehicles so as to reduce shaking of the electric vehicle in the braking process. Wherein at the first moment, four braking devices of the electric vehicle are controlled to brake four wheels of the electric vehicle; after the first moment, a front-drive motor is controlled to output front-drive compensation torque, and a rear-drive motor is controlled to output rear-drive compensation torque; wherein the directions of the front-drive compensation torque and the rear-drive compensation torque are the same as the rotating speed direction of wheels of the electric vehicle. On the basis, the front-drive motor and the rear-drive motor are controlled to output compensation torque so that the deceleration of the vehicle can be reduced, the shaking phenomenon caused by the fact that the speed of vehicle speed change is high in the braking process of the electric vehicle is reduced, and through cooperative control over the front-drive motor and the rear-drive motor, the braking speed of the electric vehicle is increased. And it is ensured that extra shaking caused by inaccurate torque compensation in the braking process of the electric vehicle is avoided, and the driving experience of a user is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a control method for a sensorless braking of an electric vehicle, a vehicle controller and an electric vehicle. Background Art

[0002] With the development of electric vehicles, the driving experience of electric vehicles has received more and more attention, among which the braking performance of electric vehicles is a key factor affecting the driving experience of electric vehicles. During the braking process of electric vehicles, electric vehicles are prone to shaking, especially at the end of braking, there is obvious shaking.

[0003] In order to reduce the shaking phenomenon of the whole vehicle during braking, the braking device is controlled to release a certain wheel-end braking force or the driving device is controlled to output a compensating torque to reduce the deceleration of the whole vehicle. However, it is still difficult to completely avoid the shaking phenomenon of electric vehicles during braking, which affects the user's driving experience. Summary of the invention

[0004] The present application provides a control method for the sensorless braking of an electric vehicle, a vehicle controller and an electric vehicle, which are used to control the front drive motor and the rear drive motor of the electric vehicle during the braking process of the electric vehicle to reduce the shaking of the electric vehicle during the braking process and improve the user's driving experience.

[0005] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions.

[0006] In a first aspect, the present application provides a control method for the sensorless braking of an electric vehicle, the control method being used to control the front drive motor and the rear drive motor of the electric vehicle during the braking process of the electric vehicle to reduce the shaking of the electric vehicle during the braking process, the control method comprising: at a first moment, controlling the four braking devices of the electric vehicle to brake the four wheels of the electric vehicle; after the first moment, in the process of the four braking devices braking the four wheels of the electric vehicle, controlling the front drive motor to output a front drive compensation torque, and controlling the rear drive motor to output a rear drive compensation torque; wherein the directions of the front drive compensation torque and the rear drive compensation torque are the same as the rotational speed directions of the wheels of the electric vehicle.

[0007] In the embodiment of the present application, during the braking process of the electric vehicle, the vehicle controller controls the front drive motor and the rear drive motor to output a compensation torque in the same direction as the wheel speed, thereby reducing the deceleration of the electric vehicle during braking, thereby reducing the shaking of the electric vehicle caused by the rapid rate of change of the vehicle speed during braking, and through coordinated control of the front drive motor and the rear drive motor, it is ensured that the electric vehicle will not experience additional shaking during braking due to inaccurate torque compensation, thereby further reducing the shaking of the electric vehicle during braking and improving the user's driving experience.

[0008] In one embodiment, at a second moment after the first moment, the deceleration of the electric vehicle during braking is less than a preset deceleration and the vehicle speed is less than a preset vehicle speed.

[0009] During the braking process of an electric vehicle, if the deceleration of the electric vehicle during braking is less than the preset deceleration and the vehicle speed is less than the preset vehicle speed, it can be determined that the braking mode of the electric vehicle is a non-emergency braking mode and is in the final stage of braking, so that the front drive motor and the rear drive motor can be controlled to output compensation torque.

[0010] In one embodiment, at a second moment after the first moment, a speed reduction rate of the front drive motor and / or the rear drive motor is less than a preset speed reduction rate and a speed of the front drive motor and / or the rear drive motor is less than a preset speed.

[0011] During the braking process of an electric vehicle, if the speed reduction rate of the front drive motor and / or the rear drive motor of the electric vehicle during braking is less than the preset speed reduction rate and the speed of the front drive motor and / or the rear drive motor is less than the preset speed, it can be determined that the braking mode of the electric vehicle is a non-emergency braking mode and is in the final stage of braking, so that the front drive motor and the rear drive motor can be controlled to output a compensating torque.

[0012] In one embodiment, the control method specifically includes: at a second moment after the first moment, simultaneously controlling the front drive motor to output the front drive compensation torque and the rear drive motor to output the rear drive compensation torque.

[0013] Through the above method, when the braking mode of the electric vehicle is a non-emergency braking mode and is in the final stage of braking, taking into account the external working conditions, the driving conditions of the electric vehicle (such as turning, acceleration, deceleration, etc.), and the impact of the load transfer of the electric vehicle on the electric vehicle, by controlling the time nodes for starting torque compensation for the front drive motor and the rear drive motor and the distribution of the torque compensation value between the front drive motor and the rear drive motor, precise coordinated control can be performed to ensure that the front wheels and the rear vehicle maintain synchronization of power output effects during the compensation process, ensuring that the electric vehicle will not experience abnormal shaking during braking due to inaccurate torque compensation, thereby reducing the shaking of the electric vehicle during braking and improving the user's driving experience.

[0014] In this embodiment, when the center of gravity distribution of the electric vehicle is relatively stable, or when the difference between the front axle load and the rear axle load of the electric vehicle is less than a preset difference, the vehicle controller simultaneously controls the front drive motor to output the front drive compensation torque and the rear drive motor to output the rear drive compensation torque at the end of braking under non-emergency braking, thereby reducing the deceleration of the electric vehicle and reducing the shaking of the electric vehicle caused by the rapid rate of change of vehicle speed at the end of braking. It can also ensure the synchronization of power output effects between the front drive motor and the rear drive motor, so that the braking effects of the front and rear wheels are coordinated, reducing the shaking of the electric vehicle at the end of braking, and improving the user's driving experience.

[0015] In one embodiment, the control method specifically includes: at a second moment after the first moment, controlling the front drive motor to output the front drive compensation torque; at a third moment after the second moment, controlling the rear drive motor to output the rear drive compensation torque.

[0016] In this embodiment, when there is load transfer in the electric vehicle, or when the front axle load of the electric vehicle is larger than the rear axle load, the vehicle controller first controls the front drive motor to output the front drive compensation torque at the second moment, and then controls the front drive motor and the rear drive motor to output the compensation torque at the same time, thereby reducing the deceleration of the electric vehicle and reducing the shaking phenomenon of the electric vehicle caused by the rapid rate of change of vehicle speed at the end of braking. It can also ensure the synchronization of power output effects between the front drive motor and the rear drive motor, so that the braking effects of the front and rear wheels are coordinated, reducing the shaking phenomenon of the electric vehicle at the end of braking, and improving the user's driving experience.

[0017] In one embodiment, the above control method specifically includes: at a second moment after the first moment, controlling the rear-drive motor to output a rear-drive compensation torque; at a third moment after the second moment, controlling the front-drive motor to output a front-drive compensation torque; wherein, during the process of braking the four wheels of the electric vehicle, the adhesion coefficient between the wheels of the electric vehicle and the road is less than a preset adhesion coefficient.

[0018] In this embodiment, when there is load transfer in the electric vehicle; or, when the rear axle load of the electric vehicle is larger than the front axle load; or, when the electric vehicle is traveling on a low adhesion coefficient road surface (such as snow or ice), the vehicle controller first controls the rear-drive motor to output the front-drive compensation torque at the second moment, and then controls the front-drive motor and the rear-drive motor to output the compensation torque at the same time, thereby reducing the deceleration of the electric vehicle and reducing the shaking of the electric vehicle caused by the rapid rate of change of vehicle speed at the end of braking. It can also ensure that the power output effects between the front-drive motor and the rear-drive motor are synchronized, so that the braking effects of the front and rear wheels are coordinated, reducing the shaking of the electric vehicle at the end of braking, and improving the user's driving experience.

[0019] Through the above method, the vehicle controller accurately coordinates the time nodes and torque distribution values ​​for the front and rear drive motors to start torque compensation, so that the compensation torque output by the front and rear drive motors of the electric vehicle is more reasonable, effectively avoiding the power output asynchrony caused by individual differences between the motors (such as different transmission ratios), and ensuring that the electric vehicle will not have additional shaking during braking due to inaccurate torque compensation, thereby reducing the shaking of the electric vehicle during braking and improving the user's driving experience.

[0020] In one embodiment, the above-mentioned control method specifically includes: in response to the braking force output by the four braking devices to the two front wheels being greater than the braking force output to the two rear wheels during braking, after a first moment, controlling the front drive compensation torque output by the front drive motor to be greater than the rear drive compensation torque output by the rear drive motor.

[0021] In one embodiment, the above-mentioned control method specifically includes: in response to the braking force output by the four braking devices to the two rear wheels being greater than the braking force output to the two front wheels during braking, after a first moment, controlling the rear-drive compensation torque output by the rear-drive motor to be greater than the front-drive compensation torque output by the front-drive motor.

[0022] Through the above method, the vehicle controller controls the front-drive compensation torque output by the front-drive motor to be associated with the braking force output by the braking device to the two front wheels, and controls the rear-drive compensation torque output by the rear-drive motor to be associated with the braking force output by the braking device to the two rear wheels. Therefore, through precise control of the torque compensation distribution value, the instability factors caused by the difference in braking force during the compensation process are effectively reduced, thereby reducing the shaking phenomenon of the electric vehicle during braking and improving the user's driving experience.

[0023] In one embodiment, after a first moment, during the braking process of the electric vehicle decelerating at a first deceleration, the front drive motor is controlled to output a first front drive compensation torque, and the rear drive motor is controlled to output a first rear drive compensation torque; after the first moment, during the braking process of the electric vehicle decelerating at a second deceleration, the front drive motor is controlled to output a second front drive compensation torque, and the rear drive motor is controlled to output a second rear drive compensation torque; wherein the first deceleration is less than the second deceleration, and the sum of the first front drive compensation torque and the first rear drive compensation torque is less than the sum of the second front drive compensation torque and the second rear drive compensation torque.

[0024] Through the above method, when the total compensation torque output by the front-drive motor and the rear-drive motor is controlled to increase with the increase of deceleration, the front-drive compensation torque output by the front-drive motor and the rear-drive compensation torque output by the rear-drive motor can be accurately controlled, thereby reducing the deceleration of the electric vehicle while ensuring the coordinated braking effect of the front and rear wheels, thereby reducing the shaking of the electric vehicle during braking.

[0025] In one embodiment, the control method further includes: at a second moment after the first moment, controlling the suspension to increase damping. In this embodiment, since the electric vehicle will undergo load transfer when the front drive motor and the rear drive motor in the drive system output compensation torque to reduce the deceleration of the electric vehicle, when the vehicle controller instructs the front drive motor and the rear drive motor to output compensation torque, the vehicle controller may also control the shock absorber to increase damping, so that when the drive system provides compensation torque to the electric vehicle, the suspension system may provide damping compensation to the electric vehicle, so that the suspension may better suppress the vibration of the electric vehicle, thereby further reducing the shaking of the electric vehicle during braking.

[0026] In one embodiment, the control method specifically includes: controlling the damping increase value of the suspension to increase as the sum of the front drive compensation torque and the rear drive compensation torque increases.

[0027] In the above manner, when controlling the suspension to increase damping, such a control setting of the damping increase value of the suspension is helpful for the drive system to accurately grasp the damping compensation of the suspension when providing the compensation torque for the electric vehicle.

[0028] Since load transfer will occur in the electric vehicle when the front-drive motor and the rear-drive motor in the drive system output compensating torque to reduce the deceleration of the electric vehicle, when the vehicle controller instructs the front-drive motor and the rear-drive motor to output compensating torque, the vehicle controller can also control the shock absorber to increase damping, so that when the drive system provides compensating torque to the electric vehicle, the suspension system can provide damping compensation to the electric vehicle, thereby further reducing the shaking of the electric vehicle during braking.

[0029] In one embodiment, the above control method specifically includes: after a first moment, in response to the deceleration of the electric vehicle during braking being greater than or equal to a preset deceleration, controlling the sum of the front drive compensation torque output by the front drive motor and the rear drive compensation torque output by the rear drive motor to be zero.

[0030] In the above manner, during the braking process of the electric vehicle, when the deceleration of the electric vehicle is greater than or equal to the preset deceleration, it indicates that the braking mode of the electric vehicle is emergency braking, that is, the speed of the electric vehicle needs to be reduced rapidly. When the braking mode of the electric vehicle is emergency braking, the braking response speed of the electric vehicle is prioritized rather than braking comfort. Therefore, the vehicle controller will not control the front drive motor and the rear drive motor to output compensation torque at this time, thereby ensuring the braking speed and braking safety of the electric vehicle.

[0031] In the second aspect, an embodiment of the present application provides a vehicle controller for sensorless braking control of an electric vehicle, wherein the vehicle controller is used to control the front drive motor of the electric vehicle to output torque to drive the two front wheels of the electric vehicle and to control the rear drive motor of the electric vehicle to output torque to drive the two rear wheels of the electric vehicle. The vehicle controller is specifically used to: during the braking process of the electric vehicle, in response to the deceleration of the electric vehicle being less than a preset deceleration and the speed of the electric vehicle being less than a preset speed, control the front drive motor to output a front drive compensation torque, and control the rear drive motor to output a rear drive compensation torque.

[0032] In one embodiment, the above-mentioned vehicle controller is specifically used to: during the braking process of the electric vehicle, in response to the deceleration of the electric vehicle being less than a preset deceleration and the speed of the electric vehicle being less than a preset speed, simultaneously control the front drive motor to output the front drive compensation torque and the rear drive motor to output the rear drive compensation torque.

[0033] In a third aspect, an embodiment of the present application provides an electric vehicle, which includes a front drive motor and a rear drive motor, and a vehicle controller provided in the second aspect, and the vehicle controller is used to control the front drive motor and the rear drive motor to execute the control method described in the first aspect or any possible implementation of the first aspect.

[0034] Regarding the technical principles and technical effects of the above-mentioned second and third aspects, reference may be made to the relevant description of the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of an electric vehicle 1 provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of the architecture of an electric vehicle 1 provided in an embodiment of the present application;

[0037] Figure 3 A schematic diagram of the architecture of a drive system 100 provided in an embodiment of the present application;

[0038] Figure 4 A schematic diagram of a control process of a vehicle controller 510 of an electric vehicle 1 provided in an embodiment of the present application;

[0039] Figure 5 A schematic diagram of a control process of a motor controller 110 of an electric vehicle 1 provided in an embodiment of the present application;

[0040] Figure 6 A schematic diagram of an operation of a braking control process of an electric vehicle 1 provided in an embodiment of the present application;

[0041] Figure 7 Another operating schematic diagram of the braking control process of the electric vehicle 1 provided in an embodiment of the present application;

[0042] Figure 8 Another operation schematic diagram of the braking control process of the electric vehicle 1 provided in the embodiment of the present application;

[0043] Fig. 9 A schematic diagram of the operation of the electric vehicle 1 in the emergency braking mode provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The implementation and use of each embodiment will be discussed in detail below. However, it should be understood that many applicable inventive concepts provided by this application can be implemented in a variety of specific environments. The specific embodiments discussed only illustrate the specific ways to implement and use this application and this technology, and do not limit the scope of this application.

[0045] With the development of electric vehicles, the driving experience of vehicles has received more and more attention. Among them, the braking performance of vehicles is a key factor affecting the driving experience of vehicles. During the vehicle braking process, the late braking period refers to the process in which the vehicle speed decreases from very small to zero, that is, the process in which the vehicle stops completely and there is no relative movement with the ground. During the vehicle braking process, the suspension of the vehicle is compressed under the action of deceleration. After the vehicle braking is completed, although the vehicle has actually stopped, the body of the vehicle will rebound under the action of the suspension, causing the vehicle to shake, affecting the user's driving experience.

[0046] In one possible implementation, at the end of the electric vehicle's braking, the brake device is controlled to release a certain amount of wheel-end braking force to reduce the deceleration of the electric vehicle, thereby suppressing the shaking phenomenon during the electric vehicle's braking process. However, due to the current sensorless braking algorithm, the wheel-end signal transmission path is long and the time delay is large, which will cause the braking performance of the electric vehicle to decline.

[0047] In one possible implementation, the driving motor of the electric vehicle is controlled to stop without a sense of braking at the end of the braking of the electric vehicle, and the driving motor is controlled to output a driving torque to reduce the deceleration of the whole vehicle, thereby suppressing the shaking phenomenon of the electric vehicle during braking. However, when the electric vehicle includes multiple driving motors, when each driving motor is independently driven and controlled, there is a problem of asynchrony of the driving control instructions of the multiple motors. In particular, when the transmission ratios of different motors are different, the asynchrony between the multiple motors will be more obvious, and it is difficult to achieve an ideal driving compensation effect for the whole vehicle, and it may even cause additional shaking of the whole vehicle.

[0048] In order to solve the above problems, the embodiment of the present application provides a control method for electric vehicle non-sensing braking and a vehicle controller of the electric vehicle. During the braking process of the electric vehicle, the front drive motor and the rear drive motor of the electric vehicle are controlled to reduce the shaking of the electric vehicle during the braking process.

[0049] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0050] See also Figure 1 , Figure 1 Schematic diagram of an electric vehicle 1 provided in an embodiment of the present application. Figure 1 As shown, the electric vehicle 1 includes a driving system 100 , a braking system 200 and a power battery 300 , and the power battery 300 is used to supply power to the driving system 100 and the braking system 200 .

[0051] The operating state of the electric vehicle 1 includes a driving state and a braking state. When the electric vehicle 1 is in the driving state, the driving system 100 is used to receive power from the power battery 300 and provide the four wheels of the electric vehicle 1 with a driving torque in the same direction as the wheel speed, so that the electric vehicle 1 can travel under the drive of the driving torque; when the electric vehicle 1 is in the braking state, the braking system 200 is used to receive power from the power battery 300 and provide the four wheels of the electric vehicle 1 with a braking force in the opposite direction to the wheel speed, so that the electric vehicle 1 can slow down or stop under the action of the braking force.

[0052] It can be understood that the electric vehicle 1 in the embodiment of the present application can be any one of different types of vehicles such as a car, a truck, a passenger bus, etc., and can also be a transport device for carrying people or goods such as a tricycle, a two-wheeled vehicle, a train, or other types of vehicles driven by power batteries, which are not limited here. Among them, the vehicle includes but is not limited to a pure electric vehicle (pure electric vehicle / battery electric vehicle, pure EV / batteryEV), a hybrid electric vehicle (hybrid electric vehicle, HEV), a range extended electric vehicle (range extended electric vehicle, REEV), a plug-in hybrid electric vehicle (plug-in hybrid electric vehicle, PHEV), a new energy vehicle (new energy vehicle, NEV), etc.

[0053] It is understandable that the power battery 300 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 here. In terms of scale, the power battery 300 in the embodiment of the present application can be a single cell, or a battery module or a battery pack, which is not limited here. The power battery 300 can also power other electrical devices in the electric vehicle 1, such as the air conditioner in the vehicle, the car player, etc.

[0054] The electric vehicle 1 also includes a suspension system 400, and the power battery 300 is also used to power the suspension system 400. As an important component of the electric vehicle 1, the suspension system 400 connects the body and multiple wheels of the electric vehicle 1. The suspension system 400 is specifically used to transmit the force and torque between the wheels and the body, mitigate the impact caused by road bumps, attenuate the vibration of the electric vehicle 1 during driving, suppress the shaking phenomenon of the electric vehicle 1 during braking, and ensure that the wheels can maintain good contact with the road surface under various working conditions, thereby ensuring the ride comfort, handling stability and driving safety of the vehicle.

[0055] See also Figure 2 , Figure 2 The schematic diagram of the structure of the electric vehicle 1 provided in the embodiment of the present application is as follows: the driving system 100 , the braking system 200 , the suspension system 400 are in communication connection with the vehicle controller 510 .

[0056] In one embodiment, the drive system 100 includes a motor controller 110, a front drive motor 120 and a rear drive motor 130. The motor controller 110 is used to receive direct current output by the power battery 300 and output alternating current to control the front drive motor 120 to output front drive torque and the rear drive motor 130 to output rear drive torque, so that the four wheels of the electric vehicle 1 rotate under the action of the front drive torque and the rear drive torque.

[0057] The motor controller 110 in the drive system 100 can change the stator magnetic field strength and direction by adjusting the magnitude of the stator winding current and the phase of the three-phase current, thereby changing the interaction force between the stator and the rotor (i.e., the torque output by the motor). The motor controller 110 can also increase or decrease the drive torque output by the drive motor by changing the magnitude of the three-phase current output to the drive motor. Among them, the motor controller 110 can be a microcontroller (microcontrollerunit, MCU), and the motor controller 110 can also be a device in which a microcontroller and a vehicle controller 510 (vehic le controlunit, VCU) are integrated into one, etc., which is not limited here.

[0058] The brake system 200 includes a brake controller 210, a brake pedal ( Figure 21) and four braking devices, including braking devices 221, 222, 223 and 224, the four braking devices are used to brake the four wheels of the electric vehicle 1, and each braking device is used to brake one wheel of the electric vehicle 1. The user steps on the brake pedal of the electric vehicle 1, and the brake controller 210 generates a braking signal according to the pedal stroke of the brake pedal or the opening of the brake pedal. The four braking devices output braking forces to the corresponding wheels of the electric vehicle 1 according to the braking value indicated by the braking signal to reduce the speed of the electric vehicle 1. During the braking process of the electric vehicle 1, the greater the stroke of the brake pedal (or the opening of the brake pedal), the greater the braking value indicated by the braking signal, the greater the braking force output by the four braking devices, the greater the deceleration of the electric vehicle 1, that is, the faster the speed of the electric vehicle 1 decreases. Among them, the brake controller 210 in the braking system 200 can be a microcontroller or a vehicle controller 510, and the brake controller 210 can also be integrated with the motor controller 110 in the drive system 100 to form a domain controller (domain control unit, DCU) in the electric vehicle 1, which is not limited here. The braking device may be an electronic hydraulic brake (EHB) or an electronic mechanical brake (EMB) or other types of braking devices, which are not limited herein.

[0059] The suspension system 400 includes a suspension controller 410, an elastic element ( Figure 2 The damping of the suspension system 400 is adjusted by adjusting the damping of the shock absorber 420 in the suspension system 400. The elastic element is used to support the vertical load and suppress the vibration and impact caused by the uneven road surface; the shock absorber 420 is used to convert the vibration energy into heat energy and dissipate it through the flow of oil or gas inside it, so that the vehicle body can quickly return to a stable state. The shock absorber 420 is mainly composed of a cylinder, a piston, a piston rod and damping oil. The piston divides the cylinder into two upper and lower chambers. When the suspension of the electric vehicle 1 is impacted and the piston moves up and down in the cylinder, the damping oil will flow between the two chambers through the valve on the piston. The damping of the shock absorber 420 can be adjusted by adjusting the opening of the valve. Among them, the greater the damping of the shock absorber 420, the faster the shock absorber 420 can suppress the vibration after the elastic element rebounds, allowing the vehicle body to quickly return to a stable state; the smaller the damping of the shock absorber 420, the longer the duration of the vibration generated by the rebound of the elastic element when the electric vehicle 1 passes through a bumpy road, and the vehicle body may experience continuous up and down shaking.

[0060] In one embodiment, when the electric vehicle 1 is in a braking state, the vehicle controller 510 calculates the torque demand of the electric vehicle 1 according to the speed and deceleration of the electric vehicle 1 and outputs a torque signal to the motor controller 110, and the drive system 100 receives power from the power battery 300 and provides the four wheels of the electric vehicle 1 with a compensation torque in the same direction as the rotation speed of the wheels of the electric vehicle 1, so that the deceleration of the electric vehicle 1 during the braking process is reduced under the action of the compensation torque, thereby reducing the shaking of the electric vehicle 1 during the braking process. The drive system 100 in the embodiment of the present application can be specifically used to distribute the compensation torque required during the braking process to the front drive motor 120 and the rear drive motor 130 in proportion, that is, to control the front drive motor 120 to output the front drive compensation torque and control the rear drive motor 130 to output the rear drive compensation torque, and make the sum of the front drive compensation torque and the rear drive compensation torque the total compensation torque of the drive system 100. The directions of the front-drive compensation torque and the rear-drive compensation torque are the same as the rotational speed directions of the wheels of the electric vehicle 1, so that the deceleration of the electric vehicle 1 during braking is reduced under the action of the front-drive compensation torque and the rear-drive compensation torque, thereby reducing the shaking of the electric vehicle 1 during braking.

[0061] In one embodiment, when the electric vehicle 1 is in a braking state, the motor controller 110 controls the front drive motor 120 to output the front drive compensation torque and controls the rear drive motor 130 to output the rear drive compensation torque. Since the front drive motor 120 and the rear drive motor 130 in the drive system 100 output the compensation torque to reduce the deceleration of the electric vehicle 1, the electric vehicle 1 will undergo load transfer, that is, the load of the front axle 150 and the rear axle 160 of the electric vehicle 1 changes, for example, the load is relatively transferred to the rear axle 160, resulting in the torque compensation rear suspension system 400 being difficult to effectively suppress the vibration of the electric vehicle 1. Therefore, when the vehicle controller 510 instructs the motor controller 110 to control the front drive motor 120 and the rear drive motor 130 to output the compensation torque, the vehicle controller 510 can also instruct the suspension controller 410 to control the shock absorber 420 to increase the damping, so that when the drive system 100 provides the compensation torque for the electric vehicle 1, the suspension system 400 can provide damping compensation for the electric vehicle 1, thereby further reducing the shaking of the electric vehicle 1 during braking.

[0062] In one embodiment, the electric vehicle 1 further includes a speed measuring unit 520, which is used to detect the speed of the front drive motor 120 and the speed of the rear drive motor 130. The motor controller 110 is used to adjust the front drive compensation torque output by the front drive motor 120 and the rear drive compensation torque output by the rear drive motor 130 according to the speed of the front drive motor 120 and the speed of the rear drive motor 130 detected by the speed measuring unit 520. Among them, the speed measuring unit 520 can be set on the front drive motor 120 and the rear drive motor 130 (for example, on the rotor of the motor), at this time, the motor controller 110 can receive the rotary signal and speed signal of the front drive motor 120 and the rear drive motor 130 from the speed measuring unit 520. Exemplarily, the speed measuring unit 520 can be a rotary transformer, a motor speed sensor, etc. The rotary transformer is used to detect the speed and rotor position of the front drive motor 120 and the rear drive motor 130, and the motor speed sensor is used to detect the speed of the front drive motor 120 and the rear drive motor 130. The speed signal can be obtained indirectly from the resolver signal. By processing the resolver signal and calculating the change in angle per unit time, the speed signal can be obtained. The resolver acceleration signal (angular acceleration signal) is the first-order derivative of the speed signal with respect to time. The resolver acceleration signal (angular acceleration signal) can be obtained by directly deriving the speed signal or using the differential method to approximate the derivative.

[0063] The electric vehicle 1 further includes an inertial measurement unit 530, which is used to detect the acceleration of the electric vehicle 1. The drive system 100 is used to adjust the front drive compensation torque output by the front drive motor 120 and the rear drive compensation torque output by the rear drive motor 130 according to the acceleration of the electric vehicle 1 detected by the inertial measurement unit 530.

[0064] In one embodiment, the electric vehicle 1 further includes a pressure sensor 540, which is used to detect the damping of the shock absorber 420. The pressure sensor 540 can be set in the shock absorber 420. When the suspension of the electric vehicle 1 is impacted and the shock absorber 420 is working, the piston moves up and down in the cylinder, causing the damping oil to flow through the valve on the piston, thereby generating a damping force. The pressure sensor 540 can capture the pressure change when the damping oil passes through the valve on the piston. The smaller the opening of the valve, the greater the pressure drop of the damping oil through the valve on the piston detected by the pressure sensor 540, that is, the greater the damping of the shock absorber 420.

[0065] The driving system 100, the braking system 200, the suspension system 400, and the vehicle controller 510 are connected to each other through a communication bus and exchange signals. The communication bus includes a controller area network (CAN) bus, a local interconnect network (LIN) bus, a high-speed fault-tolerant network protocol (Flexray), or other types of buses, which are not limited here.

[0066] In some embodiments, the vehicle controller 510 can obtain a driving mode signal through a communication bus, where the driving mode signal is used to indicate the current driving mode of the electric vehicle 1. For example, the driving mode may include one or more of a sports mode, a comfort mode, and an intelligent mode.

[0067] In one embodiment, the drive system 100, the brake system 200, the suspension system 400, the vehicle controller 510 and at least one sensor of the electric vehicle 1 are connected to each other through a communication bus. This method can transmit multiple signals on the same communication line, greatly improving the communication efficiency and reducing a large amount of separate wiring. For example, when the motor controller 110 is connected to the communication bus, the motor controller 110 may include a communication terminal, which can be connected to the communication bus. The motor controller 110 can obtain signals from the communication bus through the communication terminal, and the signals of many sensors such as the wheel speed sensor, temperature sensor, and brake pedal position sensor in the electric vehicle 1 can be transmitted to the motor controller 110 through the bus. The motor controller 110 can obtain one or more signals such as the vehicle speed, torque signal, and brake signal from the communication bus; the motor controller 110 can also upload signals to the communication bus, such as the torque value and torque direction of the front drive compensation torque output by the front drive motor 120, and the torque value and torque direction of the rear drive compensation torque output by the rear drive motor 130.

[0068] In one embodiment, the motor controller 110, the brake controller 210, and the suspension controller 410 are directly connected to the sensor. For some sensors that have extremely high requirements for signal stability and real-time performance, direct connection can reduce interference and delay during signal transmission. For example, the motor controller 110 can be directly connected to the above-mentioned speed measurement unit 520, and the motor controller 110 can determine the speed of the electric vehicle 1, the acceleration (or deceleration) of the electric vehicle 1, etc. based on the received rotational signal of the front drive motor 120 and the rear drive motor 130; the motor controller 110 can determine the speed of the front drive motor 120 based on the received speed signal of the front drive motor 120, and determine the speed of the rear drive motor 130 based on the received speed signal of the rear drive motor 130. Among them, since the rotational signal can accurately reflect the rotation speed of the motor, for the electric vehicle 1, the rotational motion of the motor is transmitted to the wheel through the transmission system, so that the electric vehicle 1 travels. Due to the existence of the transmission ratio, there is a fixed proportional relationship between the speed of the front drive motor 120 / rear drive motor 130 and the wheel speed. The wheel speed can be calculated based on the resolver signal of any motor and the corresponding transmission ratio of the motor. The speed of the electric vehicle 1 is directly related to the wheel speed. The speed of the entire vehicle can be calculated through the wheel speed and related parameters of the wheel (such as wheel radius).

[0069] Figure 3 Schematic diagram of the architecture of the drive system 100 provided in the embodiment of the present application. Figure 3 As shown, the electric vehicle 1 also includes four wheels 140, namely two front wheels and two rear wheels. The two front wheels corresponding to the front axle 150 of the electric vehicle 1 are the left front wheel LF and the right front wheel RF, and the two rear wheels corresponding to the rear axle 160 of the electric vehicle 1 are the left rear wheel LR and the right rear wheel RR.

[0070] The drive system 100 may be a centralized drive motor drive architecture, in which two drive motors for driving two front wheels or two rear wheels are arranged together. The drive system 100 may also be a wheel-side four-drive motor drive architecture, in which the drive motors are arranged at the wheels 140 driven by the drive motors and controlled by a separate motor controller 110. The motor controller 110 may be one or more, and the motor controller 110 and the drive motor may correspond one to one, or one motor controller 110 may correspond to multiple drive motors. The motor controller 110 is used to control the output torque of one or more drive motors to drive the electric vehicle 1.

[0071] In one embodiment, if Figure 3As shown in (a), the drive system 100 may be a centralized drive motor drive architecture, and the drive system 100 includes a front drive motor 120, a rear drive motor 130, and a motor controller 110. The front drive motor 120 is used to drive the left front wheel LF and the right front wheel RF corresponding to the front axle 150 of the electric vehicle 1, and the rear drive motor 130 is used to drive the left rear wheel LR and the right rear wheel RR corresponding to the rear axle 160 of the electric vehicle 1. The motor controller 110 is used to control the front drive motor 120 to output the front drive torque so that the two front wheels rotate under the action of the front drive torque, and the motor controller 110 is also used to control the rear drive motor 130 to output the rear drive torque so that the two rear wheels rotate under the action of the rear drive torque.

[0072] In one embodiment, the driving system 100 includes two motor controllers 110 , and the two motor controllers 110 are used to control the front drive motor 120 and the rear drive motor 130 respectively.

[0073] In one embodiment, if Figure 3 As shown in (b), the drive system 100 may also be a wheel-side four-drive motor drive architecture, and the drive system 100 includes a front drive motor 121, a front drive motor 122, a rear drive motor 131, a rear drive motor 132, and a motor controller 110. The front drive motor 121 is used to drive the left front wheel LF of the electric vehicle 1, the front drive motor 122 is used to drive the right front wheel RF of the electric vehicle 1, the rear drive motor 131 is used to drive the left rear wheel LR of the electric vehicle 1, and the rear drive motor 132 is used to drive the right rear wheel RR of the electric vehicle 1.

[0074] In one embodiment, the drive system 100 includes four motor controllers 110 and four drive motors. The motor controllers 110 correspond to the drive motors one by one. Each motor controller 110 is used to control the drive motor corresponding to each motor controller 110 to output a drive torque so that each drive motor drives the wheel 140 corresponding to each drive motor.

[0075] In one embodiment, the drive system 100 may also be as follows Figure 3 As shown in (c), a front-drive motor 120 is used to drive the left front wheel LF and the right front wheel RF of the electric vehicle 1, and two rear-drive motors are used to drive the left rear wheel LR and the right rear wheel RR of the electric vehicle 1 respectively. The rear-drive motor 131 is used to drive the left rear wheel LR of the electric vehicle 1, and the rear-drive motor 132 is used to drive the right rear wheel RR of the electric vehicle 1.

[0076] In one embodiment, the drive system 100 may also be combined with the various architectures mentioned above, such as a wheel-side drive motor architecture for the front drive and a centralized drive motor architecture for the rear drive.

[0077] The braking of the electric vehicle 1 includes emergency braking and non-emergency braking. Emergency braking is the braking process of allowing the electric vehicle 1 to quickly decelerate to a stop. During the emergency braking process, the deceleration of the electric vehicle 1 is large. Non-emergency braking is the braking process of allowing the electric vehicle 1 to slowly decelerate to a stop. During the non-emergency braking process, the deceleration of the electric vehicle 1 is small. Whether the braking mode of the electric vehicle 1 is an emergency braking mode or a non-emergency braking mode can be determined based on the deceleration of the electric vehicle 1, the brake pedal stroke, or the speed reduction rate of the drive motor.

[0078] In one embodiment, during the braking process of the electric vehicle 1, if the deceleration of the electric vehicle 1 is greater than or equal to the preset deceleration, the braking mode of the electric vehicle 1 is the emergency braking mode. During the braking process of the electric vehicle 1, if the deceleration of the electric vehicle 1 is less than the preset deceleration, the braking mode of the electric vehicle 1 is the non-emergency braking mode. For example, the preset deceleration can be 5m / s 2 .

[0079] In one embodiment, during the braking process of the electric vehicle 1, if the speed reduction rate of the front drive motor 120 and / or the rear drive motor 130 is greater than or equal to a preset rate, the braking mode of the electric vehicle 1 is an emergency braking mode. During the braking process of the electric vehicle 1, if the speed reduction rate of the front drive motor 120 and / or the rear drive motor 130 is less than a preset rate, the braking mode of the electric vehicle 1 is a non-emergency braking mode.

[0080] In one embodiment, when the brake pedal stroke of the electric vehicle 1 is greater than or equal to a preset value during the braking process of the electric vehicle 1, the braking mode of the electric vehicle 1 is an emergency braking mode. When the brake pedal stroke of the electric vehicle 1 is less than a preset value during the braking process of the electric vehicle 1, the braking mode of the electric vehicle 1 is a non-emergency braking mode.

[0081] In the emergency braking mode, it is necessary to ensure that the electric vehicle 1 stops moving within the shortest possible distance to avoid collision, loss of control and other dangerous situations of the electric vehicle 1. Therefore, in the emergency braking mode, it is necessary to ensure the braking efficiency and braking safety of the electric vehicle 1. When the braking mode of the electric vehicle 1 is a non-emergency braking mode, in addition to considering the braking efficiency and braking safety of the electric vehicle 1, the braking comfort of the electric vehicle 1 and the driving experience of the user can also be considered.

[0082] The final stage of braking during the braking process is the process of the electric vehicle 1 stopping from a low speed. When the electric vehicle 1 is at the final stage of braking, the speed of the electric vehicle 1 during the braking process is less than the preset speed, or the rotation speed of the front drive motor 120 and / or the rear drive motor 130 during the braking process is less than the preset rotation speed, which is not limited here.

[0083] In an embodiment of the present application, when the electric vehicle 1 enters the final stage of braking and the braking mode of the electric vehicle 1 is a non-emergency braking mode, the deceleration of the electric vehicle 1 at the final stage of braking is reduced by controlling the front-drive motor 120 of the electric vehicle 1 to output the front-drive compensation torque and controlling the rear-drive motor 130 to output the rear-drive compensation torque. This can reduce the shaking of the electric vehicle 1 at the final stage of braking, thereby improving the driving experience of the user.

[0084] The above describes the architecture of an embodiment of the present application. At a first moment, the brake controller 210 controls four brake devices to brake the four wheels 140 of the electric vehicle 1 in response to the braking value indicated by the brake signal. The direction of the braking force is the same as the direction of the rotation speed of the wheels 140 of the electric vehicle 1, so that the four wheels 140 of the electric vehicle 1 slow down under the action of the braking force.

[0085] After the first moment, during the process of the braking device braking the four wheels 140 of the electric vehicle 1, in response to the deceleration of the electric vehicle 1 during braking being less than the preset deceleration and the vehicle speed being less than the preset vehicle speed, that is, the electric vehicle 1 enters the final stage of braking in the non-emergency braking mode, the main controller (vehicle controller) is used to control the front-drive motor 120 to output the front-drive compensation torque, and controls the rear-drive motor 130 to output the rear-drive compensation torque. The directions of the front-drive compensation torque and the rear-drive compensation torque are the same as the rotational speed direction of the wheels 140 of the electric vehicle 1, so as to reduce the deceleration of the electric vehicle 1 and reduce the shaking phenomenon of the electric vehicle 1 at the final stage of braking, thereby improving the user's driving experience.

[0086] In this embodiment, the user can pre-select to enable the senseless braking mode, wherein the user enables the senseless braking mode in the following ways: selecting to enable the senseless braking mode in the human-vehicle interaction system; enabling by pressing the senseless braking mode button; selecting to enable the senseless braking mode in a terminal device connected to the electric vehicle 1 by wire or wirelessly, etc., without limitation here. Whether the electric vehicle 1 enters the senseless braking mode at the end of braking when it enters the non-emergency braking mode is determined by the user's choice. The electric vehicle 1 automatically enters the senseless braking mode at the end of braking when the electric vehicle 1 enters the non-emergency braking mode based on the user's pre-selection to enable the senseless braking mode. In some embodiments, after the user selects to enable the senseless braking mode, the senseless braking mode is automatically enabled after the electric vehicle 1 is subsequently started, thereby simplifying user operations and improving user experience.

[0087] The following is an exemplary description of the control process of the main controller in the braking control process of the electric vehicle 1. In the embodiment of the present application, after the senseless braking mode is started and the brake controller 210 controls four brake devices to brake the four wheels 140 of the electric vehicle 1, the main controller (vehicle controller) used to implement the braking control process of the electric vehicle 1 can be the vehicle controller 510, the motor controller 110 or the domain controller, which is not limited here.

[0088] In one embodiment, at a second moment after the first moment, the deceleration of the electric vehicle 1 during braking is less than a preset deceleration and the vehicle speed is less than a preset vehicle speed, or the speed reduction rate of the front drive motor 120 and / or the rear drive motor 130 is less than a preset reduction rate and the speed of the front drive motor 120 and / or the rear drive motor 130 is less than a preset speed, then it is determined that the electric vehicle 1 enters the terminal braking stage in the non-emergency braking mode at the second moment after continuous braking.

[0089] In one embodiment, at the second moment, the main controller is used to simultaneously control the front drive motor 120 to output the front drive compensation torque and the rear drive motor 130 to output the rear drive compensation torque.

[0090] In one embodiment, at the second moment, the main controller is used to control the front drive motor 120 to output the front drive compensation torque; at a third moment after the second moment, the main controller is used to control the rear drive motor 130 to output the rear drive compensation torque.

[0091] In one embodiment, at the second moment, the main controller is used to control the rear-drive motor 130 to output the rear-drive compensation torque; at a third moment after the second moment, the main controller is used to control the front-drive motor 120 to output the front-drive compensation torque.

[0092] In any of the above embodiments, at the second moment after the first moment, after the main controller controls at least one of the front drive motor 120 and the rear drive motor 130 to output the compensation torque, the suspension controller 410 controls the shock absorber 420 to increase the damping, and controls the damping increase value of the shock absorber 420 to increase with the increase of the sum of the front drive compensation torque and the rear drive compensation torque (total compensation torque), so as to further reduce the shaking phenomenon of the electric vehicle 1 at the end of braking and enhance the user's driving experience.

[0093] In one embodiment, when the main controller for implementing the braking control process of the electric vehicle 1 is the vehicle controller 510, Figure 4 , Figure 4 Schematic diagram of the control process of the vehicle controller 510 of the electric vehicle 1 provided in the embodiment of the present application. Figure 3 Take the two-wheel drive model shown in (a) as an example.

[0094] After the brake controller 210 controls the four brake devices to brake the four wheels 140 of the electric vehicle 1 , the inertial measurement unit 530 of the electric vehicle 1 sends the detected acceleration signal (for indicating the deceleration of the electric vehicle 1 ) to the vehicle controller 510 .

[0095] The speed measurement unit 521 of the front drive motor 120 sends the detected front drive speed signal (used to indicate the speed of the front drive motor 120) to the motor controller 110, and the speed measurement unit 522 of the rear drive motor 130 sends the detected rear drive speed signal (used to indicate the speed of the rear drive motor 130) to the motor controller 110, and the motor controller 110 forwards the front drive speed signal and the rear drive speed signal to the vehicle controller 510.

[0096] The pressure sensor 540 of the shock absorber 420 sends the detected damping signal (used to indicate the damping of the shock absorber 420 ) to the suspension controller 410 , and the suspension controller 410 forwards the damping signal to the vehicle controller 510 .

[0097] After the first moment, if the vehicle controller 510 detects that the deceleration of the electric vehicle 1 is less than the preset deceleration and the speed of the front drive motor 120 and / or the speed of the rear drive motor 130 is less than the preset speed, it is determined that the electric vehicle 1 is in a non-emergency braking state and the electric vehicle 1 is in the terminal stage of braking.

[0098] The vehicle controller 510 is used to send a front-drive torque control instruction (used to indicate the torque value of the front-drive compensation torque) and a rear-drive torque control instruction (used to indicate the torque value of the rear-drive compensation torque) to the motor controller 110, so that the motor controller 110 outputs a front-drive torque control signal according to the front-drive torque control instruction to control the front-drive motor 120 to output the front-drive compensation torque, and outputs a rear-drive torque control signal according to the rear-drive torque control instruction to control the rear-drive motor 130 to output the rear-drive compensation torque, thereby reducing the deceleration of the electric vehicle 1.

[0099] The vehicle controller 510 is also used to send a damping control instruction (used to indicate a damping value) to the suspension controller 410 at the same time, so that the suspension controller 410 outputs a damping control signal according to the damping control instruction to control the shock absorber 420 to increase the damping.

[0100] exist Figure 4In the embodiment, the vehicle controller 510 is also used to periodically receive the front drive torque signal, the front drive speed signal, the rear drive torque signal and the rear drive speed signal returned by the motor controller 110. The vehicle controller 510 adjusts the torque value of the front drive compensation torque indicated by the front drive torque control instruction output to the motor controller 110 and the torque value of the rear drive compensation torque indicated by the rear drive torque control instruction according to the front drive torque signal, the front drive speed signal, the rear drive torque signal and the rear drive speed signal. The vehicle controller 510 is also used to periodically receive the damping signal returned by the suspension controller 410 at the same time. The vehicle controller 510 adjusts the damping value indicated by the damping control instruction output to the suspension controller 410 according to the front drive torque signal, the front drive speed signal, the rear drive torque signal, the rear drive speed signal and the damping signal.

[0101] In one embodiment, when the main controller for implementing the braking control process of the electric vehicle 1 is the motor controller 110, Figure 5 , Figure 5 Schematic diagram of the control process of the motor controller 110 of the electric vehicle 1 provided in the embodiment of the present application. Figure 3 Take the two-wheel drive model shown in (a) as an example.

[0102] After the brake controller 210 controls the four brake devices to brake the four wheels 140 of the electric vehicle 1, the inertial measurement unit 530 of the electric vehicle 1 sends the detected acceleration signal (used to indicate the deceleration of the electric vehicle 1) to the vehicle controller 510, and the vehicle controller 510 forwards the acceleration signal to the motor controller 110.

[0103] The speed measurement unit 521 of the front drive motor 120 sends the detected front drive speed signal (used to indicate the speed of the front drive motor 120 ) to the motor controller 110 , and the speed measurement unit 522 of the rear drive motor 130 sends the detected rear drive speed signal (used to indicate the speed of the rear drive motor 130 ) to the motor controller 110 .

[0104] The pressure sensor 540 of the shock absorber 420 sends a detected damping signal (used to indicate the damping of the shock absorber 420 ) to the suspension controller 410 , and the suspension controller 410 forwards the damping signal to the motor controller 110 .

[0105] After the first moment, if the motor controller 110 detects that the deceleration of the electric vehicle 1 is less than the preset deceleration and the speed of the front drive motor 120 and / or the speed of the rear drive motor 130 is less than the preset speed, it is determined that the electric vehicle 1 is in a non-emergency braking state and the electric vehicle 1 is in the terminal stage of braking.

[0106] The motor controller 110 is used to send a front drive torque control signal (used to indicate the torque value of the front drive compensation torque) to the front drive motor 120 and to send a rear drive torque control signal (used to indicate the torque value of the rear drive compensation torque) to the rear drive motor 130, so that the front drive motor 120 outputs the front drive compensation torque and the rear drive motor 130 outputs the rear drive compensation torque, thereby reducing the deceleration of the electric vehicle 1.

[0107] The motor controller 110 is also used to send a damping control instruction (used to indicate a damping value) to the suspension controller 410 at the same time, so that the suspension controller 410 outputs a damping control signal according to the damping control instruction to control the shock absorber 420 to increase the damping.

[0108] exist Figure 5 In the embodiment, the motor controller 110 is also used to periodically receive the front drive torque signal and the front drive speed signal returned by the front drive motor 120 and the rear drive torque signal and the rear drive speed signal returned by the rear drive motor 130. The motor controller 110 adjusts the torque value of the front drive compensation torque indicated by the front drive torque control signal output to the front drive motor 120 and the torque value of the rear drive compensation torque indicated by the rear drive torque control signal output to the rear drive motor 130 according to the front drive torque signal, the front drive speed signal, the rear drive torque signal and the rear drive speed signal. The motor controller 110 is also used to periodically receive the damping signal returned by the suspension controller 410 at the same time. The motor controller 110 adjusts the damping value indicated by the damping control instruction output to the suspension controller 410 according to the front drive torque signal, the front drive speed signal, the rear drive torque signal, the rear drive speed signal and the damping signal. The following is combined with Figures 6 to 8 An exemplary description is given of how the motor controller 110 specifically considers various factors to control the front drive motor 120 , the rear drive motor 130 , and the suspension to achieve a senseless braking.

[0109] like Figure 6 As shown, Figure 6 An operating schematic diagram of the braking control process of the electric vehicle 1 provided in an embodiment of the present application.

[0110] During the driving process of the electric vehicle 1 , the electric vehicle 1 runs normally, the brake controller 210 controls the braking force output by the four brake devices to be 0, and the deceleration a of the electric vehicle 1 is 0.

[0111] At the first moment t1, the user steps on the brake pedal, and the electric vehicle 1 enters the braking process. The brake controller 210 controls the four brake devices to brake the four wheels 140 of the electric vehicle 1. The speed v of the electric vehicle 1 (the speed n1 of the front drive motor 120 and the speed n2 of the rear drive motor 130) decreases under the action of the braking force output by the brake system 200, and the speed n1 of the front drive motor 120 and the speed n2 of the rear drive motor 130 decrease at a rate that increases with the increase of the braking force. Among them, the brake controller 210 controls the braking force output by the four brake devices to increase with the increase of the pedal stroke of the brake pedal, and the deceleration a of the electric vehicle 1 during the braking process increases with the increase of the braking force.

[0112] The motor controller 110 can receive the resolution signal of the front drive motor 120 and / or the resolution signal of the rear drive motor 130 from the speed measurement unit 520, and obtain the vehicle speed v of the electric vehicle 1 based on the resolution signal; the motor controller 110 can also receive the acceleration signal of the electric vehicle 1 from the inertia detection unit, and obtain the acceleration (or deceleration a) of the electric vehicle 1 based on the acceleration signal.

[0113] After the first moment t1, during the process of the braking device braking the four wheels 140 of the electric vehicle 1, in response to the deceleration a of the electric vehicle 1 during the braking process being less than the preset deceleration a1 and the vehicle speed v being less than the preset vehicle speed v1, that is, the electric vehicle 1 enters the final stage of braking in the non-emergency braking mode, the motor controller 110 is used to control the front-drive motor 120 to output the front-drive compensation torque T1, and controls the rear-drive motor 130 to output the rear-drive compensation torque T2, and the directions of the front-drive compensation torque T1 and the rear-drive compensation torque T2 are the same as the rotational speed direction of the wheels 140 of the electric vehicle 1, so as to reduce the deceleration a of the electric vehicle 1.

[0114] During the continuous braking process of the electric vehicle 1, if Figure 6 As shown, Figure 6 The relationship between the vehicle speed v, deceleration a, the speed n1 of the front drive motor 120, the speed n2 of the rear drive motor 130, the front drive compensation torque T1, the rear drive compensation torque T2 and the suspension damping F of the electric vehicle 1 during braking is shown.

[0115] At the second moment t2 after the first moment t1, if the motor controller 110 determines that the deceleration a of the electric vehicle 1 during the braking process is less than the preset deceleration a1 according to the acceleration signal, it indicates that the braking mode of the electric vehicle 1 at the second moment t2 is a non-emergency braking mode. Since the vehicle speed v of the electric vehicle 1 gradually decreases during the continuous braking process, while determining that the electric vehicle 1 is in a non-emergency braking state, if the motor controller 110 determines that the vehicle speed v of the electric vehicle 1 at the second moment t2 after continuous braking is less than the preset vehicle speed v1 according to the resolver signal, it indicates that the electric vehicle 1 is in the final stage of braking at the second moment t2.

[0116] In the embodiment of the present application, the motor controller 110 can control the front drive motor 120 and the rear drive motor 130 to generate compensation torque according to a preset ratio, and the sum of the front drive compensation torque T1 and the rear drive compensation torque T2 is the total compensation torque output by the drive system 100.

[0117] The following describes how the motor controller 110 determines the total compensation torque output by the front drive motor 120 and the rear drive motor 130 .

[0118] During the braking process of the electric vehicle 1, the electric vehicle 1 controls the four brake devices of the electric vehicle 1 to output braking force according to the braking value indicated by the braking signal output by the vehicle controller 510. However, during the process of the motor controller 110 outputting the compensation torque, the motor controller 110 needs to determine the total compensation torque output by the front drive motor 120 and the rear drive motor 130 according to the vehicle speed v and / or the deceleration a of the electric vehicle 1.

[0119] In one embodiment, the motor controller 110 controls the total compensation torque output by the front drive motor 120 and the rear drive motor 130 to increase as the deceleration a of the electric vehicle 1 increases. For example, at a second moment t2 after the first moment t1, during the braking process of the electric vehicle 1 decelerating at the first deceleration, the motor controller 110 controls the front drive motor 120 to output the first front drive compensation torque, and controls the rear drive motor 130 to output the first rear drive compensation torque; at a second moment t2 after the first moment t1, during the braking process of the electric vehicle 1 decelerating at the second deceleration, the motor controller 110 controls the front drive motor 120 to output the second front drive compensation torque, and controls the rear drive motor 130 to output the second rear drive compensation torque; wherein the first deceleration is less than the second deceleration, and the sum of the first front drive compensation torque and the first rear drive compensation torque is less than the sum of the second front drive compensation torque and the second rear drive compensation torque.

[0120] In one embodiment, the motor controller 110 controls the total compensation torque output by the front drive motor 120 and the rear drive motor 130 to increase as the pedal travel or pedal opening of the brake pedal increases.

[0121] In one embodiment, the motor controller 110 can determine the total compensation torque output by the front drive motor 120 and the rear drive motor 130 based on the comfort braking curve corresponding to the electric vehicle 1 as a reference curve. The comfort braking curve is a curve that describes the ideal deceleration a of the vehicle during braking, which changes with time, so as to achieve smooth and comfortable braking of the electric vehicle 1. The motor controller 110 predetermines the comfort braking curve of the electric vehicle 1, for example, by recording the speed curve and / or deceleration curve of the electric vehicle 1 during the process of gradually releasing the brake pedal when the electric vehicle 1 is braked, so that the electric vehicle 1 stops smoothly, and through multiple tests, the ideal speed curve and / or deceleration curve of the electric vehicle 1 is drawn, which is the comfort braking curve. Taking the comfort braking curve of the electric vehicle 1 as the control basis, the electric vehicle 1 is braked as much as possible according to the comfort braking curve when braking, which can not only improve the comfort of the driver and passengers, but also enhance the safety and stability of vehicle braking.

[0122] During the braking process of the electric vehicle 1, the electric vehicle 1 may not be able to decelerate according to the desired comfortable braking curve due to the torque interference of its own transmission system or motor, and the deceleration a of the electric vehicle 1 is inconsistent with the ideal deceleration corresponding to the comfortable braking curve. For example, the deceleration a of the electric vehicle 1 is greater than the ideal deceleration corresponding to the comfortable braking curve, indicating that the braking force of the electric vehicle 1 is too large, and the motor controller 110 controls the front drive motor 120 and the rear drive motor 130 to output a compensation torque in the same direction as the rotation speed of the wheel 140 of the electric vehicle 1 to reduce the deceleration a of the electric vehicle 1, so that the electric vehicle 1 brakes according to the comfortable braking curve.

[0123] At the second moment t2, the motor controller 110 determines the total compensation torque of the electric vehicle 1 according to the deceleration a of the electric vehicle 1 at the second moment t2 and the ideal deceleration corresponding to the vehicle speed v of the electric vehicle 1 at the second moment t2 in the comfort braking curve. The greater the deceleration difference between the deceleration a of the electric vehicle 1 and the ideal deceleration corresponding to the comfort braking curve, the greater the total compensation torque output by the motor controller 110 to control the front drive motor 120 and the rear drive motor 130.

[0124] Of course, other methods can be used to calculate the total compensation torque, which is not limited in this solution. The following describes how the motor controller 110 determines the magnitude of the front drive compensation torque T1 output by the front drive motor 120 and the rear drive compensation torque T2 output by the rear drive motor 130.

[0125] In one embodiment, the motor controller 110 controls the front motor 120 and the rear motor 130 to generate the compensation torque according to a preset ratio while determining the total compensation torque output by the front motor 120 and the rear motor 130 .

[0126] In one embodiment, the preset ratio between the front drive compensation torque T1 and the rear drive compensation torque T2 is the ratio between the braking force output by the four braking devices to the two front wheels and the braking force output to the two rear wheels. For example, in response to the braking force output by the four braking devices to the two front wheels being greater than the braking force output to the two rear wheels during the braking process, the front drive compensation torque T1 output by the front drive motor 120 is controlled to be greater than the rear drive compensation torque T2 output by the rear drive motor 130 after the first moment t1. In response to the braking force output by the four braking devices to the two rear wheels being greater than the braking force output to the two front wheels during the braking process, the rear drive compensation torque T2 output by the rear drive motor 130 is controlled to be greater than the front drive compensation torque T1 output by the front drive motor 120 after the first moment t1.

[0127] Under different driving conditions, the torque compensation ratio of the front and rear drive motors will also change. For example, when the electric vehicle 1 is going uphill, the load on the rear axle 160 increases due to the rearward shift of the center of gravity of the electric vehicle 1. At this time, reducing the deceleration a during braking may require increasing the rear drive compensation torque T2 output by the rear drive motor 130 in the total compensation torque. On the contrary, when the electric vehicle 1 is going downhill, the center of gravity of the electric vehicle 1 moves forward, and the load on the front axle 150 increases. At this time, reducing the deceleration a during braking may require increasing the front drive compensation torque T1 output by the front drive motor 120 in the total compensation torque. In addition, during the turning process, the load on the outer wheel 140 of the electric vehicle 1 (such as the right wheel when turning left) increases, and the load on the inner wheel 140 decreases. If the deceleration a of the electric vehicle 1 during braking is to be reduced at this time, the torque compensation ratio of the drive motor needs to be dynamically adjusted according to the load change of the wheel 140. For example, during a left turn, the torque compensation ratio of the right front wheel RF and the right rear wheel RR may increase to better control the driving posture of the electric vehicle 1.

[0128] In one embodiment, the ratio of the front drive compensation torque T1 to the rear drive compensation torque T2 is calculated as follows:

[0129]

[0130] Wherein, α1 is the rotational acceleration of the front drive motor 120; α2 is the rotational acceleration of the rear drive motor 130; J1 is the moment of inertia of the front drive motor 120; J2 is the moment of inertia of the rear drive motor 130; T b1 is the braking torque of the front axle 150; T b2 is the braking torque of the rear axle 160 front axle 150 rear axle 160 .

[0131] For the same electric vehicle 1, the moment of inertia J1 of the front drive motor 120 and the moment of inertia J2 of the rear drive motor 130 of the electric vehicle 1 are usually fixed values, that is, the ratio of the front drive compensation torque T1 allocated to the front drive motor 120 and the rear drive compensation torque T2 allocated to the rear drive motor 130 by the motor controller 110 is mainly affected by the braking torque T applied to the front axle 150. b1 and the braking torque T applied to the rear axle 160 b2 In an ideal situation (without other external interference factors), the braking force output by the brake device is the force directly applied by the brake system 200 (such as brake calipers, brake discs, etc.) to the rotating parts of the wheel 140, and the braking torque generated by the braking force output by the brake device is the braking torque T applied to the front axle 150. b1 and the braking torque T of the rear axle 160 b2 However, due to various external factors (such as ground friction, vehicle load distribution, etc.), driving conditions (such as turning, acceleration, deceleration, etc.), etc., the actual braking torque acting on the wheel 140 to decelerate the wheel 140 is inconsistent with the braking torque of the braking device. For example, if the load of the electric vehicle 1 is uneven, such as the front load of the electric vehicle 1 is large, then the vertical load of the front axle 150 will increase, and during the braking process, the front axle 150 will be affected differently by factors such as ground friction, thereby increasing the actual braking torque T of the front axle 150. b1 , the motor controller 110 needs to increase the proportion of the front drive compensation torque T1 output by the front drive motor 120 .

[0132] In one embodiment, the preset ratio between the compensation torque output by the front drive motor 120 and the rear drive motor 130 can be set arbitrarily. For example, the front drive motor 120 and the rear drive motor 130 can evenly distribute the torque, or randomly distribute the torque, etc., and this solution does not limit this. In this way, the flexibility of motor control can be improved.

[0133] In one embodiment, the motor controller 110 can also be used to obtain a pressure signal from the pressure sensor 540 provided in the suspension system 400 to determine the load on the front axle 150 and the load on the rear axle 160 of the electric vehicle 1. During the braking process of the electric vehicle 1, when the center of gravity distribution of the electric vehicle 1 is relatively stable, such as when the motor controller 110 determines at the second moment t2 that the change in the load on the front axle 150 and the load on the rear axle 160 of the electric vehicle 1 is less than a preset change, or when the difference between the load on the front axle 150 and the load on the rear axle 160 of the electric vehicle 1 is less than a preset difference, in order to achieve smooth and comfortable braking of the electric vehicle 1, the motor controller 110 simultaneously controls the front drive motor 120 to output the front drive compensation torque T1 and the rear drive motor 130 to output the rear drive compensation torque T2 at the second moment t2, thereby reducing the deceleration a of the electric vehicle 1 while ensuring that the braking effects of the front and rear wheels are coordinated and consistent, and avoiding excessive forward or backward tilting.

[0134] like Figure 6 As shown, in one embodiment, at the second moment t2, the motor controller 110 simultaneously controls the front drive motor 120 to output the front drive compensation torque T1 and the rear drive motor 130 to output the rear drive compensation torque T2. Since the directions of the front drive compensation torque T1 and the rear drive compensation torque T2 are the same as the rotational speed direction of the wheel 140 of the electric vehicle 1, the front drive compensation torque T1 and the rear drive compensation torque T2 cause the electric vehicle 1 to generate acceleration, thereby reducing the deceleration a of the electric vehicle 1.

[0135] Specifically, at the second moment t2, the braking force output by the four braking devices remains consistent with that at the first moment t1. Since the motor controller 110 simultaneously controls the front-drive motor 120 to output the front-drive compensation torque T1 and the rear-drive motor 130 to output the rear-drive compensation torque T2 at the second moment t2: under the action of the front-drive compensation torque T1, the reduction rate of the rotational speed n1 of the front-drive motor 120 decreases, and under the action of the rear-drive compensation torque T2, the reduction rate of the rotational speed n2 of the rear-drive motor 130 decreases, that is, the reduction rate of the vehicle speed v of the electric vehicle 1 decreases, and the deceleration a of the electric vehicle 1 decreases.

[0136] In one embodiment, a rotary transformer provided on the front drive motor 120 and the rear drive motor 130 obtains a rotary transformer signal, and then determines the speed v and deceleration a of the electric vehicle 1 based on the rotary transformer signal, thereby improving the detection accuracy of the speed v and deceleration a of the electric vehicle 1. Since the rotary transformer sampling frequency is high and the motor controller 110 can directly obtain the rotary transformer signals of the front drive motor 120 and the rear drive motor 130, the time delay for the motor controller 110 to obtain the speed v and deceleration a of the electric vehicle 1 is reduced, so that the motor controller 110 can quickly determine the total compensation torque based on the speed v and deceleration a of the electric vehicle 1, thereby reducing the control delay.

[0137] In one embodiment, the resolver signal obtained by the resolver is more sensitive than the vehicle speed v signal, but the resolver signal has a large fluctuation problem. In order to obtain a more accurate vehicle speed v, the vehicle dynamics model is combined with the rotation speed n1 of the front drive motor 120, the rotation speed n2 of the rear drive motor 130 and the measured vehicle speed v of the electric vehicle 1 as input quantities, and the vehicle dynamics factors such as the mass, moment of inertia, and adhesion between the tire and the ground of the electric vehicle 1 are comprehensively considered, and the fusion algorithm (such as the Kalman filter algorithm, etc.) is used for fusion processing to obtain the vehicle speed v of the electric vehicle 1. Among them, the Kalman filter algorithm can make an optimal estimate based on the uncertainty of the system (such as measurement noise, model error, etc.), so that the calculated vehicle speed v can have good performance in terms of accuracy and stability, thereby ensuring the accuracy of determining the total compensation value of the drive system 100 using the vehicle speed v of the electric vehicle 1, and improving the suppression effect of the shaking phenomenon of the electric vehicle 1.

[0138] In one embodiment, the method of calculating the deceleration a of the electric vehicle 1 using the fusion algorithm is the same as the method of calculating the vehicle speed v of the electric vehicle 1 , which will not be described in detail herein.

[0139] Due to the existence of individual differences between motors, the driving control of the motors will be unstable. When the motors are driven and controlled independently, the power output between the motors is prone to be asynchronous. For example, when the transmission ratio between the front drive motor 120 and the rear drive motor 130 is the same, the power output between the front drive motor 120 and the rear drive motor 130 is synchronized when the speed n1 of the front drive motor 120 is synchronized with the speed n2 of the rear drive motor 130. When the front drive motor 120 and the rear drive motor 130 are torque compensated independently, the speed change curve of the front drive motor 120 and the speed change curve of the rear drive motor 130 do not overlap in most time periods. The electric vehicle 1 will shake due to the asynchronous power output between the front drive motor 120 and the rear drive motor 130.

[0140] In this embodiment, under the action of the front drive motor 120 outputting the front drive compensation torque T1 and the rear drive motor 130 outputting the rear drive compensation torque T2, the deceleration a of the electric vehicle 1 is reduced to the ideal deceleration a under the comfort braking curve, so that the vehicle speed v change curve of the electric vehicle 1 at the end of braking tends to be gentle, reducing the shaking phenomenon of the electric vehicle 1 caused by the change of the vehicle speed v at the end of braking, and by accurately coordinating the time nodes and torque distribution values ​​of the front drive motor 120 and the rear drive motor 130 starting to perform torque compensation, the synchronization of the power output between the front drive motor 120 and the rear drive motor 130 is ensured, for example: Figure 6When the transmission ratio between the front drive motor 120 and the rear drive motor 130 is the same, after the torque compensation of the front drive motor 120 and the rear drive motor 130, the speed change curve of the front drive motor 120 and the speed change curve of the rear drive motor 130 are almost overlapped, thereby reducing the shaking phenomenon caused by the asynchronous power output between the motors at the end of the braking of the electric vehicle 1, and improving the user's driving experience. By adopting this method, the tendency of the center of mass of the vehicle to move forward during braking and the shaking of the vehicle after parking can be slowed down, and the comfort of the vehicle during braking can be improved. In addition, the motor controller 110 is used to obtain signals by directly connecting to the sensor, which effectively reduces the signal transmission time, thereby reducing the control delay and reducing the braking distance of the electric vehicle 1.

[0141] In one embodiment, at the second moment t2, when the motor controller 110 simultaneously controls the front-drive motor 120 to output the front-drive compensation torque T1 and the rear-drive motor 130 to output the rear-drive compensation torque T2, in order to reduce the vibration of the electric vehicle 1 caused by load transfer, the suspension controller 410 controls the shock absorber 420 to increase the damping F, and controls the increase value of the suspension damping F to increase with the increase of the sum of the front-drive compensation torque T1 and the rear-drive compensation torque T2 (total compensation torque), so that the suspension system 400 can better suppress the vibration of the electric vehicle 1, so as to further reduce the shaking phenomenon of the electric vehicle 1 at the end of braking, and enhance the user's driving experience.

[0142] In this embodiment, when the center of gravity distribution of the electric vehicle 1 is relatively stable, or when the difference between the load of the front axle 150 and the load of the rear axle 160 of the electric vehicle 1 is less than the preset difference, the motor controller 110 controls the front drive motor 120 to output the front drive compensation torque T1 and the rear drive motor 130 to output the rear drive compensation torque T2 at the end of the braking under non-emergency braking, thereby reducing the deceleration a of the electric vehicle 1 and ensuring the synchronization of the power output effect between the front drive motor 120 and the rear drive motor 130, so that the braking effect of the front and rear wheels is coordinated and consistent, and the electric vehicle 1 is achieved. Smooth and comfortable braking. In addition, while the braking compensation is in progress, the suspension controller 410 controls the shock absorber 420 to increase the damping F, further reducing the shaking phenomenon of the electric vehicle 1 at the end of the braking, and improving the user's driving experience.

[0143] like Figure 7 As shown, Figure 7 Another operating schematic diagram of the braking control process of the electric vehicle 1 provided in an embodiment of the present application.

[0144] At the first moment t1, the user steps on the brake pedal and the electric vehicle 1 enters the braking process. The brake controller 210 controls the four braking devices to brake the four wheels 140 of the electric vehicle 1. The vehicle speed v of the electric vehicle 1 decreases under the action of the braking force output by the braking system 200. The rotation speed n1 of the front drive motor 120 and the rotation speed n2 of the rear drive motor 130 decrease as the vehicle speed v of the electric vehicle 1 decreases. The deceleration a of the electric vehicle 1 during the braking process increases as the braking force increases.

[0145] At the second moment t2 after the first moment t1, the deceleration a of the electric vehicle 1 during braking is less than the preset deceleration a1 and the speed v of the electric vehicle 1 is less than the preset speed v1, indicating that at the second moment t2 the electric vehicle 1 enters the final stage of braking in a non-emergency braking state.

[0146] In one embodiment, during the braking process of the electric vehicle 1, when there is load transfer in the electric vehicle 1, such as when the electric vehicle 1 enters a downhill section, the motor controller 110 determines at the second moment t2 that the change in the load of the front axle 150 of the electric vehicle 1 is much greater than the change in the load of the rear axle 160, or when the load of the front axle 150 of the electric vehicle 1 is larger than the load of the rear axle 160, and the difference between the load of the front axle 150 and the load of the rear axle 160 of the electric vehicle 1 is greater than or equal to a preset difference. In order to achieve smooth and comfortable braking of the electric vehicle 1, the motor controller 110 first controls the front drive motor 120 to output the front drive compensation torque T1 at the second moment t2, and then controls the front drive motor 120 and the rear drive motor 130 to output the compensation torque at the same time, so that the braking effect of the front and rear wheels can be coordinated while reducing the deceleration a of the electric vehicle 1, and avoid excessive forward or backward tilting.

[0147] like Figure 7 As shown, in this embodiment, at the second moment t2 after the first moment t1, the motor controller 110 controls the front drive motor 120 to output the front drive compensation torque T1. The direction of the front drive compensation torque T1 is the same as the rotational speed direction of the wheel 140 of the electric vehicle 1. Under the action of the front drive compensation torque T1, the reduction rate of the rotational speed n1 of the front drive motor 120 is reduced, and the front drive compensation torque T1 causes the electric vehicle 1 to generate acceleration, thereby reducing the deceleration a of the electric vehicle 1.

[0148] In one embodiment, at the second moment t2 , when the motor controller 110 controls the front-drive motor 120 to output the front-drive compensation torque T1 , the suspension controller 410 controls the shock absorber 420 to increase the damping F in order to reduce the vibration of the electric vehicle 1 caused by the load transfer.

[0149] At the third moment t3 after the second moment t2, while the motor controller 110 controls the front drive motor 120 to output the front drive compensation torque T1, the motor controller 110 is also used to control the rear drive motor 130 to output the rear drive compensation torque T2. At the third moment t3, the reduction rate of the rotation speed n1 of the front drive motor 120 decreases under the action of the front drive compensation torque T1, and the reduction rate of the rotation speed n2 of the rear drive motor 130 decreases under the action of the rear drive compensation torque T2. Moreover, at the third moment t3, the front drive motor 120 and the rear drive motor 130 are controlled to perform torque compensation at the same time, compared with the second moment t2 when only the front drive motor 120 is controlled to perform torque compensation, the reduction rate of the vehicle speed v of the electric vehicle 1 decreases faster, and the deceleration a of the electric vehicle 1 is relatively smaller.

[0150] In one embodiment, at the third moment t3, when the motor controller 110 simultaneously controls the front-drive motor 120 to output the front-drive compensation torque T1 and the rear-drive motor 130 to output the rear-drive compensation torque T2, the suspension controller 410 controls the damping F of the shock absorber 420 to be greater than the damping F at the second moment t2 at the third moment t3, and controls the damping F of the suspension to increase with the increase of the sum of the front-drive compensation torque T1 and the rear-drive compensation torque T2 (total compensation torque), so as to further reduce the shaking phenomenon of the electric vehicle 1 at the end of braking and enhance the user's driving experience.

[0151] After the first moment t1, if the motor controller 110 monitors that the deceleration a of the electric vehicle 1 during braking is less than the preset deceleration a1 and the vehicle speed v of the electric vehicle 1 is less than the preset vehicle speed v1, the motor controller 110 controls the front drive motor 120 to first output the front drive compensation torque T1. After a certain period of torque compensation of the front drive motor 120, the motor controller 110 controls the front drive motor 120 to output the front drive compensation torque T1 and the rear drive motor 130 to output the rear drive compensation torque T2 at the same time, so that the front drive motor 120 and the rear drive motor 130 perform torque compensation at the same time.

[0152] In this embodiment, when there is load transfer in the electric vehicle 1, or when the load on the front axle 150 of the electric vehicle 1 is larger than the load on the rear axle 160, the motor controller 110 first controls the front drive motor 120 to output the front drive compensation torque T1 at the second moment t2, and then controls the front drive motor 120 and the rear drive motor 130 to output the compensation torque at the same time, thereby reducing the deceleration a of the electric vehicle 1, reducing the shaking phenomenon caused by the fast change rate of the vehicle speed v at the end of the braking of the electric vehicle 1, and ensuring the coordinated braking effect of the front and rear wheels, for example: Figure 8When the transmission ratio between the front drive motor 120 and the rear drive motor 130 is the same, after the torque compensation of the front drive motor 120 and the rear drive motor 130, the speed change curve of the front drive motor 120 and the speed change curve of the rear drive motor 130 are almost overlapped, thereby reducing the shaking phenomenon caused by the asynchronous power output between the motors at the end of the braking of the electric vehicle 1, and achieving smooth and comfortable braking of the electric vehicle 1. In addition, while the braking compensation is being performed, the suspension controller 410 controls the shock absorber 420 to increase the damping F, so that the suspension system 400 can better suppress the vibration of the electric vehicle 1, thereby further reducing the shaking phenomenon of the electric vehicle 1 at the end of the braking, and improving the user's driving experience.

[0153] like Figure 8 As shown, Figure 8 Another operational schematic diagram of the braking control process of the electric vehicle 1 provided in an embodiment of the present application.

[0154] At the first moment t1, the user steps on the brake pedal and the electric vehicle 1 enters the braking process. The brake controller 210 controls the four braking devices to brake the four wheels 140 of the electric vehicle 1. The vehicle speed v of the electric vehicle 1 decreases under the action of the braking force output by the braking system 200. The rotation speed n1 of the front drive motor 120 and the rotation speed n2 of the rear drive motor 130 decrease as the vehicle speed v of the electric vehicle 1 decreases. The deceleration a of the electric vehicle 1 during the braking process increases as the braking force increases.

[0155] At the second moment t2 after the first moment t1, the deceleration a of the electric vehicle 1 during braking is less than the preset deceleration a1 and the speed v of the electric vehicle 1 is less than the preset speed v1, indicating that at the second moment t2 the electric vehicle 1 enters the final stage of braking in a non-emergency braking state.

[0156] In one embodiment, when there is load transfer in the electric vehicle 1, such as when the electric vehicle 1 enters an uphill section, the motor controller 110 determines at the second moment t2 that the change in the load on the rear axle 160 of the electric vehicle 1 is much greater than the change in the load on the front axle 150; or, when the load on the rear axle 160 of the electric vehicle 1 is larger than the load on the front axle 150, the difference between the load on the front axle 150 and the load on the rear axle 160 of the electric vehicle 1 is greater than or equal to a preset difference. In order to achieve smooth and comfortable braking of the electric vehicle 1, the motor controller 110 first controls the rear drive motor 130 to output the rear drive compensation torque T2 at the second moment t2, and then controls the front drive motor 120 and the rear drive motor 130 to output the compensation torque at the same time, so that the braking effect of the front and rear wheels can be coordinated while reducing the deceleration a of the electric vehicle 1, avoiding excessive forward or backward tilting.

[0157] In one embodiment, when the deceleration a of the electric vehicle 1 decreases when the drive system 100 outputs the total compensation torque, the load of the electric vehicle 1 will be relatively transferred to the rear axle 160. During the braking process of the electric vehicle 1, when driving on a road surface with a low adhesion coefficient (such as snow or ice), for example, when the adhesion coefficient between the wheels 140 of the electric vehicle 1 and the road surface is less than the preset adhesion coefficient during the process of the four braking devices braking the four wheels 140 of the electric vehicle 1, the motor controller 110 controls the rear-drive motor 130 to output the rear-drive compensation torque T2 first to increase the load on the rear axle 160, so that the two rear wheels can better maintain contact with the ground, thereby reducing the possibility of rear wheel slippage and reducing the risk of the electric vehicle 1 spinning out of the tail.

[0158] In this embodiment, when the adhesion coefficient between the wheels 140 of the electric vehicle 1 and the road surface is less than the preset adhesion coefficient during the process of the four braking devices braking the four wheels 140 of the electric vehicle 1, at the second moment t2 after the first moment t1, the motor controller 110 controls the motor controller 110 to control the rear-drive motor 130 to output the rear-drive compensation torque T2. The direction of the rear-drive compensation torque T2 is the same as the rotational speed direction of the wheels 140 of the electric vehicle 1. Under the action of the rear-drive compensation torque T2, the speed reduction rate n2 of the rear-drive motor 130 is reduced, and the rear-drive compensation torque T2 causes the electric vehicle 1 to generate acceleration, thereby reducing the deceleration a of the electric vehicle 1.

[0159] In one embodiment, at the second moment t2 , when the motor controller 110 controls the rear-drive motor 130 to output the front-drive compensation torque T1 , in order to reduce the vibration of the electric vehicle 1 caused by the load transfer, the suspension controller 410 controls the shock absorber 420 to increase the damping F.

[0160] At the third moment t3 after the second moment t2, while the motor controller 110 controls the rear-drive motor 130 to output the rear-drive compensation torque T2, the motor controller 110 is also used to control the front-drive motor 120 to output the front-drive compensation torque T1. At the third moment t3, the rate of reduction of the rotation speed n1 of the front-drive motor 120 decreases under the action of the front-drive compensation torque T1, and the rate of reduction of the rotation speed n2 of the rear-drive motor 130 decreases under the action of the rear-drive compensation torque T2. Moreover, when the front-drive motor 120 and the rear-drive motor 130 are controlled to perform torque compensation at the third moment t3, the rate of reduction of the vehicle speed v of the electric vehicle 1 decreases faster, and the deceleration a of the electric vehicle 1 is relatively smaller than when only the rear-drive motor 130 is controlled to perform torque compensation at the second moment t2.

[0161] In one embodiment, at the third moment t3, when the motor controller 110 simultaneously controls the front-drive motor 120 to output the front-drive compensation torque T1 and the rear-drive motor 130 to output the rear-drive compensation torque T2, the suspension controller 410 at the third moment t3 controls the damping F of the shock absorber 420 to be greater than the damping F at the second moment t2, and controls the increase value of the damping F of the suspension to increase with the increase of the sum of the front-drive compensation torque T1 and the rear-drive compensation torque T2 (total compensation torque), so as to further reduce the shaking phenomenon of the electric vehicle 1 at the end of braking and enhance the user's driving experience.

[0162] After the first moment t1, if the motor controller 110 monitors that the deceleration a of the electric vehicle 1 during braking is less than the preset deceleration a1 and the vehicle speed v of the electric vehicle 1 is less than the preset vehicle speed v1, the motor controller 110 controls the rear-drive motor 130 to first output the rear-drive compensation torque T2, and after a certain period of torque compensation of the rear-drive motor 130, the motor controller 110 controls the front-drive motor 120 to output the front-drive compensation torque T1 and the rear-drive motor 130 to output the rear-drive compensation torque T2 at the same time, so that the front-drive motor 120 and the rear-drive motor 130 perform torque compensation at the same time.

[0163] In this embodiment, when there is load transfer in the electric vehicle 1; or when the load of the rear axle 160 of the electric vehicle 1 is larger than the load of the front axle 150; or when the electric vehicle 1 is traveling on a low adhesion coefficient road surface (such as snow or ice), the motor controller 110 first controls the rear drive motor 130 to output the front drive compensation torque T1 at the second moment t2, and then controls the front drive motor 120 and the rear drive motor 130 to output the compensation torque at the same time, thereby reducing the deceleration a of the electric vehicle 1, reducing the shaking phenomenon caused by the fast change rate of the vehicle speed v at the end of braking of the electric vehicle 1, and ensuring the coordinated braking effect of the front and rear wheels, for example: Figure 8 When the transmission ratio between the front drive motor 120 and the rear drive motor 130 is the same, after the torque compensation of the front drive motor 120 and the rear drive motor 130, the speed change curve of the front drive motor 120 and the speed change curve of the rear drive motor 130 are almost overlapped, thereby reducing the shaking phenomenon caused by the asynchronous power output between the motors at the end of the braking of the electric vehicle 1, and achieving smooth and comfortable braking of the electric vehicle 1. In addition, while the braking compensation is in progress, the suspension controller 410 controls the shock absorber 420 to increase the damping F, so that the suspension system 400 can better suppress the vibration of the electric vehicle 1, thereby further reducing the shaking phenomenon of the electric vehicle 1 at the end of the braking, and improving the user's driving experience.

[0164] See also Fig. 9 , Fig. 9 A schematic diagram of the operation of the electric vehicle 1 in the emergency braking mode provided in an embodiment of the present application.

[0165] In one embodiment, after the first moment t1, in response to the deceleration a of the electric vehicle 1 during braking being greater than or equal to the preset deceleration a1, the sum of the front drive compensation torque T1 output by the front drive motor 120 and the rear drive compensation torque T2 output by the rear drive motor 130 is controlled to be zero.

[0166] In one embodiment, after the first moment t1 , in response to the pedal stroke of the brake pedal being greater than or equal to a preset stroke, the sum of the front drive compensation torque T1 output by the front drive motor 120 and the rear drive compensation torque T2 output by the rear drive motor 130 is controlled to be zero.

[0167] In one embodiment, after the first moment t1, in response to the reduction rate of the rotational speed n1 of the front drive motor 120 and / or the rotational speed n2 of the rear drive motor 130 being greater than or equal to a preset reduction rate, the sum of the front drive compensation torque T1 output by the front drive motor 120 and the rear drive compensation torque T2 output by the rear drive motor 130 is controlled to be zero.

[0168] Specifically, during the braking process of the electric vehicle 1, the motor controller 110 is used to receive a braking signal from the brake controller 210. During the braking process, the deceleration a of the electric vehicle 1 is greater than or equal to the preset deceleration a1; or, the pedal stroke of the brake pedal is greater than the preset stroke; or, the reduction rate of the rotation speed n1 of the front drive motor 120 and / or the rotation speed n2 of the rear drive motor 130 is greater than or equal to the preset reduction rate, indicating that the braking mode of the electric vehicle 1 is the emergency braking mode at this time.

[0169] When the electric vehicle 1 is in the emergency braking mode, in order to ensure the braking efficiency and braking safety of the electric vehicle 1, the motor controller 110 controls the sum of the front drive compensation torque T1 output by the front drive motor 120 and the rear drive compensation torque T2 output by the rear drive motor 130 to be zero, so that the braking force of the electric vehicle 1 during the braking process always maintains the braking value indicated by the braking controller 210, and the suspension controller 410 controls the increase value of the damping F of the shock absorber 420 to be 0, that is, in the emergency braking mode, the braking scheme provided in the present application to reduce the shaking phenomenon of the electric vehicle 1 at the end of braking will not take effect.

[0170] It should be understood that Figures 6 to 9 The numerical changes in are only for illustration and do not represent specific values, and there may be certain deviations. The change trend is only used to illustrate the method flow of the present application scheme, and does not limit the deviation in the actual control process.

[0171] In this embodiment, during the braking process of the electric vehicle 1, when the deceleration a of the electric vehicle 1 is greater than or equal to the preset deceleration a1, it indicates that the braking mode of the electric vehicle 1 is emergency braking at this time. Since the emergency braking mode requires that the electric vehicle 1 stop moving within the shortest possible distance to avoid dangerous situations such as collision and loss of control of the electric vehicle 1, the braking efficiency and braking safety of the electric vehicle 1 need to be ensured when the braking mode of the electric vehicle 1 is emergency braking. Therefore, at this time, the vehicle controller will not control the front drive motor 120 and the rear drive motor 130 to output compensation torque, thereby ensuring the braking efficiency and braking safety of the electric vehicle 1.

[0172] In the embodiments provided in the present application, each functional module may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0173] 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 electric vehicle non-sensing braking, characterized in that: The control method is used to control the front drive motor and the rear drive motor of the electric vehicle during the braking process of the electric vehicle to reduce the shaking of the electric vehicle during the braking process, and the control method includes: At a first moment, controlling four braking devices of the electric vehicle to brake four wheels of the electric vehicle; After the first moment, in the process of the four braking devices braking the four wheels of the electric vehicle, controlling the front drive motor to output the front drive compensation torque, and controlling the rear drive motor to output the rear drive compensation torque; The directions of the front drive compensation torque and the rear drive compensation torque are the same as the rotational speed direction of the wheels of the electric vehicle.

2. The control method according to claim 1, characterized in that: At a second moment after the first moment, the deceleration of the electric vehicle during braking is less than a preset deceleration and the vehicle speed is less than a preset vehicle speed.

3. The control method according to claim 1, characterized in that: At a second moment after the first moment, a speed reduction rate of the front drive motor and / or the rear drive motor is less than a preset speed reduction rate and a speed of the front drive motor and / or the rear drive motor is less than a preset speed.

4. The control method according to any one of claims 1 to 3, characterized in that: The control method specifically includes: At a second moment after the first moment, the front drive motor is controlled to output the front drive compensation torque and the rear drive motor is controlled to output the rear drive compensation torque at the same time.

5. The control method according to any one of claims 1 to 3, characterized in that: The control method specifically includes: At a second moment after the first moment, controlling the front-drive motor to output the front-drive compensation torque; At a third moment after the second moment, the rear-drive motor is controlled to output the rear-drive compensation torque.

6. The control method according to any one of claims 1 to 3, characterized in that: The control method specifically includes: At a second moment after the first moment, controlling the rear-drive motor to output the rear-drive compensation torque; At a third moment after the second moment, controlling the front drive motor to output the front drive compensation torque; Wherein, during the process of the four braking devices braking the four wheels of the electric vehicle, the adhesion coefficient between the wheels of the electric vehicle and the road surface is less than a preset adhesion coefficient.

7. The control method according to any one of claims 1 to 6, characterized in that: The control method specifically includes: In response to the braking force output by the four braking devices to the two front wheels being greater than the braking force output to the two rear wheels during the braking process, after the first moment, the front drive compensation torque output by the front drive motor is controlled to be greater than the rear drive compensation torque output by the rear drive motor.

8. The control method according to any one of claims 1 to 6, characterized in that: The control method specifically includes: In response to the braking force output by the four braking devices to the two rear wheels being greater than the braking force output to the two front wheels during the braking process, after the first moment, the rear-drive compensation torque output by the rear-drive motor is controlled to be greater than the front-drive compensation torque output by the front-drive motor.

9. The control method according to claim 1, characterized in that: After the first moment, during a braking process in which the electric vehicle is decelerating at a first deceleration rate, the front drive motor is controlled to output a first front drive compensation torque, and the rear drive motor is controlled to output a first rear drive compensation torque; After the first moment, during a braking process in which the electric vehicle is decelerating at a second deceleration rate, the front drive motor is controlled to output a second front drive compensation torque, and the rear drive motor is controlled to output a second rear drive compensation torque; The first deceleration is smaller than the second deceleration, and the sum of the first front-drive compensation torque and the first rear-drive compensation torque is smaller than the sum of the second front-drive compensation torque and the second rear-drive compensation torque.

10. The control method according to any one of claims 1 to 9, characterized in that: The control method further comprises: At a second moment after the first moment, the suspension is controlled to increase damping.

11. The control method according to claim 10, characterized in that: The control method specifically includes: The damping increase value of the suspension is controlled to increase as the sum of the front drive compensation torque and the rear drive compensation torque increases.

12. The control method according to any one of claims 1 to 11, characterized in that: The control method specifically includes: After the first moment, in response to the deceleration of the electric vehicle during braking being greater than or equal to a preset deceleration, the sum of the front drive compensation torque output by the front drive motor and the rear drive compensation torque output by the rear drive motor is controlled to be zero.

13. A vehicle controller for non-sensing brake control of electric vehicles, characterized in that: The vehicle controller is used to control the front drive motor of the electric vehicle to output torque to drive the two front wheels of the electric vehicle and to control the rear drive motor of the electric vehicle to output torque to drive the two rear wheels of the electric vehicle. The vehicle controller is specifically used to: During the braking process of the electric vehicle, in response to the deceleration of the electric vehicle being less than a preset deceleration and the vehicle speed of the electric vehicle being less than a preset vehicle speed, the front drive motor is controlled to output a front drive compensation torque, and the rear drive motor is controlled to output a rear drive compensation torque.

14. The vehicle controller according to claim 13, characterized in that: The vehicle controller is specifically used for: During the braking process of the electric vehicle, in response to the deceleration of the electric vehicle being less than a preset deceleration and the vehicle speed of the electric vehicle being less than a preset vehicle speed, the front drive motor is controlled to output the front drive compensation torque and the rear drive motor is controlled to output the rear drive compensation torque at the same time.

15. An electric vehicle, characterized in that: The electric vehicle comprises a front-drive motor, a rear-drive motor and a vehicle controller as claimed in any one of claims 13 to 14, wherein the vehicle controller is used to control the front-drive motor and the rear-drive motor to execute the control method as claimed in any one of claims 1 to 12.

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