Control method for comfortable braking of electric vehicle, vehicle controller and electric vehicle

Abstract

The invention provides a control method for comfortable 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, when the opening degree of the brake pedal is increased to be larger than the preset opening degree, the driving motor is controlled to output first brake force, and the brake device is controlled to output second brake force; when the vehicle speed is reduced to be smaller than or equal to the first preset vehicle speed, one of the first braking force and the second braking force is controlled to be reduced; and controlling the other one of the first braking force and the second braking force to be reduced at a third moment after the second moment. Thus, in the braking process, by coordinating the braking force output by the driving motor and the braking device, the energy recovery performance of the driving motor is effectively utilized, the endurance mileage of the whole vehicle is increased, the high braking precision of the driving motor is effectively utilized, the shaking phenomenon of the electric vehicle in the braking process is reduced, and the service life of the electric vehicle is prolonged. Comfortable braking of the electric vehicle is achieved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a control method for comfortable 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, especially at the end of braking, there is an obvious shaking phenomenon.

[0003] When reducing the shaking phenomenon during the braking process of the whole vehicle, the braking device is controlled to release a certain amount of wheel-end braking force, that is, the hydraulic pressure of the braking device is appropriately reduced at the end of braking to reduce the deceleration of the whole vehicle. However, due to the low control accuracy of the hydraulic control, there is a problem of insufficient control accuracy of the braking force output by the braking device during the braking process, which makes it difficult to effectively suppress the shaking phenomenon of the electric vehicle during the braking process of the electric vehicle, affecting the user's driving experience. Summary of the invention

[0004] The present application provides a control method for comfortable braking of an electric vehicle, a vehicle controller and an electric vehicle, which are used to control a drive motor and a braking device 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 comfortable braking of an electric vehicle, the control method being used to control a first braking force output by a drive motor of the electric vehicle or a second braking force output by a braking device during a braking process in which the deceleration of the electric vehicle is less than a preset deceleration so as to reduce the shaking of the electric vehicle during braking. The control method comprises: at a first moment during the braking process of the electric vehicle, the opening of the brake pedal is increased to be greater than a preset opening, the drive motor is controlled to output a first braking force and the braking device is controlled to output a second braking force; at a second moment after the first moment, the speed of the electric vehicle is reduced to less than or equal to the first preset speed, and one of the first braking force and the second braking force is controlled to be reduced; at a third moment after the second moment, the other of the first braking force and the second braking force is controlled to be reduced.

[0007] In this embodiment, during the braking process of the electric vehicle, the driving motor is controlled to output the braking force. Since part of the kinetic energy of the driving motor is recovered when the driving motor outputs the braking force, it can be used for subsequent driving of the electric vehicle or other on-board equipment, thereby improving the energy utilization efficiency of the electric vehicle. In addition, when the speed of the electric vehicle is reduced to less than or equal to the first preset speed, that is, the electric vehicle enters the final stage of braking, the first braking force output by the driving motor of the electric vehicle or the second braking force output by the braking device is reduced, and since the braking control accuracy of the driving motor is higher than the braking control accuracy of the braking device, the shaking phenomenon caused by the fast speed change rate and insufficient braking control accuracy of the electric vehicle during the braking process is reduced. In this way, by coordinating the braking force output by the driving motor and the braking device during the braking process, not only the energy recovery performance of the driving motor is effectively utilized, the cruising range of the whole vehicle is improved, but also the high braking accuracy of the driving motor is effectively utilized, the shaking phenomenon of the electric vehicle during the braking process is reduced, and the comfortable braking of the electric vehicle is achieved, thereby improving the driving experience of the user.

[0008] In one embodiment, the control method specifically includes: at a third moment after the second moment, one of the first braking force and the second braking force is reduced to less than or equal to a preset braking force, and the other of the first braking force and the second braking force is controlled to be reduced.

[0009] In this embodiment, by cooperatively controlling the first braking force output by the drive motor and the second braking force output by the brake device, the deceleration of the electric vehicle during braking can be steadily reduced, thereby reducing the shaking of the electric vehicle caused by the rapid rate of change of the vehicle speed during braking, thereby achieving comfortable braking of the electric vehicle.

[0010] In one embodiment, the control method specifically includes: at a second moment after the first moment, controlling the second braking force to decrease; and at a third moment after the second moment, controlling the first braking force to decrease.

[0011] In this embodiment, since the proportion of the first braking force in the total braking force is higher, the energy recovery efficiency of the electric vehicle during the braking process is higher. After the second braking force output by the braking device is controlled to decrease, the first braking force output by the drive motor is controlled to decrease, thereby ensuring the proportion of the first braking force output by the drive motor in the total braking force and maximizing the vehicle's cruising range. In addition, since the braking control accuracy of the drive motor is higher than the braking control accuracy of the braking device, the first braking force output by the drive motor is controlled to decrease, so that the high braking accuracy of the drive motor can be effectively utilized at the end of the braking period, reducing the shaking phenomenon of the electric vehicle during the braking process and achieving comfortable braking of the electric vehicle.

[0012] In one embodiment, the control method further includes: after the third moment, controlling the sum of the first braking force and the second braking force and the speed of the electric vehicle to decrease to zero simultaneously.

[0013] In this embodiment, as the speed of the electric vehicle gradually decreases when braking, the body of the vehicle will maintain a forward movement trend due to inertia. By controlling the sum of the first braking force and the second braking force to be reduced to zero in coordination with the vehicle speed, the deceleration of the electric vehicle during braking can be evenly reduced, reducing the jerk of the electric vehicle during braking, and avoiding shaking caused by mismatch between inertia and braking force, thereby improving the comfortable braking performance of the electric vehicle.

[0014] In one embodiment, the control method further includes: between the second moment and the third moment, the greater the speed of the electric vehicle is, the smaller the rate of decrease of one of the first braking force and the second braking force is controlled.

[0015] In this embodiment, the reduction rate of one of the first braking force and the second braking force is controlled to decrease as the speed of the electric vehicle increases, ensuring that the deceleration and speed of the electric vehicle can be slowly reduced to zero at the same time, avoiding sudden changes in deceleration and speed during braking, thereby reducing the jerk of the electric vehicle during braking, reducing the shaking of the electric vehicle during braking, and improving the user's driving experience.

[0016] In one embodiment, the above-mentioned control method specifically includes: at the first moment in the braking process of the electric vehicle, the opening of the brake pedal is less than or equal to the preset opening, and the first braking force is controlled to increase with the increase of the opening of the brake pedal; at the first moment in the braking process of the electric vehicle, the opening of the brake pedal is greater than the preset opening, and the first braking force is controlled not to increase with the increase of the opening of the brake pedal.

[0017] In this embodiment, since the total braking force indicated by the brake pedal when the opening of the brake pedal is a preset opening is the maximum allowable braking force provided for the electric vehicle when the drive motor outputs the maximum allowable negative torque, when the opening of the brake pedal is greater than the preset opening, the first braking force is controlled not to increase with the increase in the opening of the brake pedal, so that the braking force output by the drive motor is not higher than its maximum allowable braking force, while ensuring the energy utilization efficiency of the electric vehicle, it also ensures the safe and effective operation of the drive motor during braking.

[0018] In one embodiment, the control method further includes: at a fourth moment after the third moment, the speed of the electric vehicle decreases to zero, and the second braking force output by the control braking device increases.

[0019] In this embodiment, the second braking force output by the brake device is controlled to increase immediately after the electric vehicle stops, thereby avoiding the movement of the vehicle caused by the gap between the transmission system and components, thereby ensuring that the electric vehicle is in a stationary state.

[0020] In one embodiment, the control method specifically includes: at the fourth moment, controlling the second braking force output by the braking device to increase to be greater than the braking force output by the braking device at the first moment.

[0021] In this embodiment, at the fourth moment, when the second braking force output by the braking device is controlled to increase, the second braking force is controlled to be greater than the braking force output by the braking device at the first moment, which not only avoids the movement of the vehicle caused by the gap between the transmission system and components, but also avoids the slipping phenomenon caused by the difficulty in overcoming the component force of gravity along the slope when the electric vehicle is on a slope, thereby ensuring that the electric vehicle is in a stationary state.

[0022] In one embodiment, the control method further includes: at a fifth moment after the fourth moment, the opening of the brake pedal is reduced to zero, and the second braking force output by the braking device is controlled to be reduced to zero.

[0023] In this embodiment, the opening of the brake pedal is reduced to zero, and the second braking force output by the braking device is controlled to be reduced to zero, thereby increasing the braking force at the time of braking and controlling the second braking force to be reduced to zero when braking ends after braking, thereby ensuring that the electric vehicle can remain stable and stationary after braking without shaking back and forth.

[0024] In one embodiment, the control method further includes: during a braking process where the deceleration of the electric vehicle is greater than or equal to a preset deceleration, controlling the first braking force output by the drive motor to increase or remain unchanged until the speed of the electric vehicle decreases to zero.

[0025] In this embodiment, when the deceleration of the electric vehicle is greater than or equal to the preset deceleration, the electric vehicle is in emergency braking mode. Therefore, at this time, the vehicle controller no longer controls the first braking force output by the drive motor to decrease, and controls the first braking force output by the drive motor to increase or remain unchanged until the speed of the electric vehicle decreases to zero, thereby ensuring the braking efficiency and braking safety of the electric vehicle during emergency braking.

[0026] In a second aspect, the present application provides a control method for comfortable braking of an electric vehicle, which is used to control a first braking force output by a drive motor of the electric vehicle during a braking process in which the deceleration of the electric vehicle is less than a preset deceleration so as to reduce the shaking of the electric vehicle during braking. The control method comprises: at a first moment in the braking process of the electric vehicle, the opening of the brake pedal is increased to less than or equal to a preset opening, and the drive motor is controlled to output a first braking force; at a second moment after the first moment, the speed of the electric vehicle is reduced to less than or equal to a second preset speed, and the first braking force is controlled to be reduced.

[0027] In this embodiment, during the braking process of the electric vehicle, when the opening of the brake pedal increases to less than or equal to the preset opening, only the drive motor is controlled to output the first braking force and the first braking force is adjusted. This not only effectively utilizes the energy recovery performance of the drive motor and improves the vehicle's cruising range, but also effectively utilizes the high braking accuracy of the drive motor, reduces the shaking of the electric vehicle during braking, achieves comfortable braking of the electric vehicle, and thereby improves the user's driving experience.

[0028] In one embodiment, the control method specifically includes: after the second moment, controlling the first braking force and the speed of the electric vehicle to be reduced to zero simultaneously.

[0029] In this embodiment, as the speed of the electric vehicle gradually decreases when braking, the vehicle body will maintain a forward movement trend due to inertia. By controlling the first braking force and the vehicle speed to be coordinated to zero, the deceleration of the electric vehicle during braking can be evenly reduced, reducing the jerk of the electric vehicle during braking, and avoiding shaking caused by mismatch between inertia and braking force, thereby improving the comfortable braking performance of the electric vehicle.

[0030] In a third aspect, an embodiment of the present application provides a vehicle controller for comfortable braking control of an electric vehicle, wherein the vehicle controller is used to control a first braking force output by a drive motor of the electric vehicle or a second braking force output by a braking device during a braking process in which the deceleration of the electric vehicle is less than a preset deceleration. The vehicle controller is specifically used to: during the braking process of the electric vehicle, in response to the opening of the brake pedal increasing to greater than a preset opening, control the drive motor to output a first braking force and control the braking device to output a second braking force to brake the four wheels of the electric vehicle; in response to the vehicle speed of the electric vehicle decreasing to less than or equal to a first preset vehicle speed, control one of the first braking force and the second braking force to decrease, and then control the other of the first braking force to decrease.

[0031] In a fourth aspect, an embodiment of the present application provides a vehicle controller for comfortable braking control of an electric vehicle, wherein the vehicle controller is used to control a first braking force output by a drive motor of the electric vehicle during a braking process in which the deceleration of the electric vehicle is less than a preset deceleration. The vehicle controller is specifically used to: during the braking process of the electric vehicle, in response to the opening of the brake pedal increasing to less than or equal to a preset opening, control the drive motor to output a first braking force to brake the four wheels of the electric vehicle; in response to the speed of the electric vehicle decreasing to less than or equal to a second preset speed, control the first braking force to decrease.

[0032] In the fifth aspect, an embodiment of the present application provides an electric vehicle, which includes a drive motor, a braking device, and a vehicle controller provided in the third aspect and the fourth aspect, and the vehicle controller is used to control the drive motor and the braking device to perform the control method described in the first aspect, any possible implementation of the first aspect, the second aspect, or any possible implementation of the second aspect.

[0033] It can be understood that the beneficial effects that can be achieved by the vehicle controller and electric vehicle provided above can correspond to the beneficial effects of the control method for comfortable braking of the electric vehicle provided in the first and second aspects above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of an electric vehicle 1 provided in an embodiment of the present application;

[0035] Figure 2 A schematic diagram of the architecture of an electric vehicle 1 provided in an embodiment of the present application;

[0036] Figure 3 Another schematic diagram of the architecture of the electric vehicle 1 provided in the embodiment of the present application;

[0037] Figure 4 A schematic diagram of a control process of a vehicle controller 410 of an electric vehicle 1 provided in an embodiment of the present application;

[0038] 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;

[0039] Figure 6 A schematic diagram of a control process of a brake controller 210 of an electric vehicle 1 provided in an embodiment of the present application;

[0040] Figure 7 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 8 for Figure 7A schematic diagram of a braking control process of an electric vehicle 1 is provided;

[0042] Fig. 9 Another operating schematic diagram of the braking control process of the electric vehicle 1 provided in an embodiment of the present application;

[0043] Fig.10 for Fig. 9 A schematic diagram of a braking control process of an electric vehicle 1 is provided;

[0044] Fig.11 Another operation schematic diagram of the braking control process of the electric vehicle 1 provided in the embodiment of the present application;

[0045] Fig.12 for Fig.11 A schematic diagram of a braking control process of an electric vehicle 1 is provided;

[0046] Fig.13 Another operation schematic diagram of the braking control process of the electric vehicle 1 provided in the embodiment of the present application;

[0047] Fig.14 for Fig.13 A schematic diagram of a braking control process of an electric vehicle 1 is provided;

[0048] Fig.15 A schematic diagram of the operation of the electric vehicle 1 in the emergency braking mode provided by an embodiment of the present application;

[0049] Fig.16 for Fig.15 A schematic diagram of a braking control process of an electric vehicle 1 is provided;

[0050] Fig.17 A flow chart of a method for controlling comfort braking of an electric vehicle 1 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] 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.

[0052] 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 vehicles. During the braking process of electric vehicles, the braking force output by the braking device is controlled to brake the four wheels of the electric vehicle, and at the end of braking, the braking force output by the braking device is reduced to slow down the tendency of the center of mass of the electric vehicle to move forward during braking and the shaking of the vehicle after parking, thereby improving the comfort of the electric vehicle during braking. Among them, the end of braking refers to the process of the electric vehicle's speed decreasing from very small to zero, that is, the process of the electric vehicle from near stop to complete stop and no relative movement with the ground.

[0053] In one possible implementation, during the braking process of the electric vehicle, the brake device is controlled to release a certain amount of wheel-end braking force, that is, the braking force output by the brake device is reduced by reducing the hydraulic pressure of the brake device, and the hydraulic pressure of the brake device is re-established at the moment of braking to keep the vehicle stationary, so that 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 by adjusting the hydraulic pressure of the brake device. However, due to the low hydraulic control accuracy of the brake device, the brake hydraulic pressure may fluctuate during the braking process, and the fluctuation of the liquid pressure will make the braking force output by the brake device unstable, that is, the clamping force output by the brake pad to the brake disc is unstable, resulting in shaking of the vehicle during braking, affecting the user's driving experience.

[0054] In one embodiment, when the driver steps on the brake pedal, the brake device has a pressure-building delay problem, which causes the brake device to lag in response time. After the driver steps on the brake pedal, the brake system cannot provide sufficient braking force in time, which may cause the driver to increase the pedal force again, exacerbating the shaking phenomenon during the braking process, wherein the pressure-building delay is the time delay from the driver stepping on the brake pedal to the brake device establishing effective hydraulic pressure. In addition, under low-speed stop-and-go conditions, the speed of the electric vehicle changes frequently and in a small range, and it is difficult for the brake device to accurately provide appropriate braking force in time according to the vehicle speed and the driver's intention, so that the brake device is likely to continue to maintain the original large braking force, and the vehicle will shake due to excessive deceleration.

[0055] In one possible implementation, the braking force output by the brake device is kept constant during the braking process of the electric vehicle, and the drive motor of the electric vehicle is controlled to output a certain positive torque to reduce the deceleration of the entire vehicle, thereby suppressing the shaking phenomenon during the braking process of the electric vehicle. However, when the deceleration of the electric vehicle is adjusted, it will have a negative impact on the energy economy of the electric vehicle, that is, controlling the drive motor to output positive torque will additionally increase the energy consumption of the electric vehicle during the braking process, shortening the vehicle's cruising range.

[0056] In order to solve the above problems, the embodiments of the present application provide a control method for comfortable braking of an electric vehicle and a vehicle controller of the electric vehicle. During the braking process of the electric vehicle, the driving motor and the braking device of the electric vehicle are controlled to reduce the shaking of the electric vehicle during the braking process, thereby improving the driving experience of the user.

[0057] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0058] See also Figure 1 , Figure 1 A 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 .

[0059] 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 force in the same direction as the wheel speed, so that the electric vehicle 1 can travel under the drive of the driving force; 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.

[0060] In some embodiments, when the electric vehicle 1 is in a braking state, the inverter in the drive system 100 is controlled to adjust the current in the stator winding, so that the stator magnetic field interacts with the rotor permanent magnet magnetic field to generate a negative torque opposite to the rotational speed of the wheels of the electric vehicle 1, so as to provide braking force for the electric vehicle 1, thereby achieving the braking effect of the electric vehicle 1. When the drive motor generates negative torque, the kinetic energy of the drive system 100 is converted into electrical energy, which is fed back to the power battery 300 through the circuit between the drive system 100 and the power battery 300 for storage, thereby realizing the energy recovery of part of the kinetic energy of the electric vehicle 1 during the braking process, so as to be used for the subsequent driving of the electric vehicle 1 or other on-board equipment, thereby improving the energy utilization efficiency of the electric vehicle 1, and enabling the electric vehicle 1 to better utilize the energy that would otherwise be consumed in the braking process during the driving process, thereby reducing the overall energy consumption of the electric vehicle 1 and improving the cruising range of the entire vehicle.

[0061] It is understandable 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 a power battery 300, 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.

[0062] 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.

[0063] See also Figure 2 , Figure 2 A schematic diagram of the structure of an electric vehicle 1 provided in an embodiment of the present application. The driving system 100 and the braking system 200 are in communication connection with the vehicle controller 410 .

[0064] In one embodiment, the drive system 100 includes a motor controller 110 and a drive motor 120. The motor controller 110 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 of the drive motor 120. The motor controller 110 can be a microcontroller unit (MCU), or a device in which a microcontroller and a vehicle control unit 410 (VCU) are integrated, etc., which is not limited here.

[0065] In the driving state, the inverter circuit in the motor controller 110 converts the DC power output by the power battery 300 into three-phase AC power to supply the stator winding. The current generates a rotating magnetic field through the stator winding. The three-phase current flows in the stator winding in sequence according to their respective phases. The magnetic field generated by the three-phase stator winding synthesizes a rotating magnetic field. The direction of the rotating magnetic field is consistent with the phase sequence of the current. The rotor of the drive motor 120 rotates along the direction of rotation of the magnetic field, outputs a positive torque in the same direction as the wheel speed of the electric vehicle 1, and provides driving force for the electric vehicle 1. In the braking state, the motor controller 110 changes the direction and magnitude of the current supplied to the stator winding. The flow sequence of the current in the stator winding changes to achieve the reversal of the direction of rotation of the magnetic field, so that the interaction between the stator magnetic field and the rotor magnetic field becomes to hinder the rotation of the rotor of the drive motor 120, thereby generating a negative torque opposite to the wheel speed of the electric vehicle 1, and providing braking force for the electric vehicle 1. Among them, the motor controller 110 collects the magnitude of the three-phase current in the inverter circuit through the current sensor, and can determine the magnitude of the positive torque or negative torque output by the drive motor 120.

[0066] The braking system 200 includes a braking controller 210, a braking device 220 and a brake pedal 230. The braking device 220 is used to brake the four wheels of the electric vehicle 1. When the user steps on the brake pedal 230 of the electric vehicle 1, the vehicle controller 410 generates a braking signal according to the opening of the brake pedal 230, and the drive motor 120 and / or the braking device 220 output a braking force to the 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 larger the opening of the brake pedal 230, the larger the braking value indicated by the braking signal, the larger the braking force output by the drive motor 120 and / or the braking device 220, the greater the deceleration of the electric vehicle 1, that is, the faster the speed of the electric vehicle 1 decreases. Among them, the braking controller 210 in the braking system 200 can be a microcontroller or a vehicle controller 410, and the braking 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 brake device 220 may be an electronic hydraulic brake (EHB) or an electronic mechanical brake (EMB) or other types of brake devices 220 , which are not limited herein.

[0067] In an embodiment of the present application, the electric vehicle 1 further includes a battery controller 420, which is connected to the power battery 300 in communication. The battery controller 420 is used to monitor the collected state information of the power battery 300, such as the voltage, current, temperature, battery power and health status of the power battery 300. The battery controller 420 is also used to protect the power battery 300 when the state information of the power battery 300 is abnormal, such as overcharge protection, over-discharge protection and overcurrent protection. In the electric vehicle 1, the battery controller 420 can also be connected to the vehicle controller 410 in communication, and the battery controller 420 is used to transmit the state information of the power battery 300 to the vehicle controller 410 of the electric vehicle 1, and receive control instructions (such as charging power control, etc.) from the vehicle controller 410. Among them, the battery controller 420 can be a battery management system (battery management system, BMS), which is used to comprehensively manage and monitor the power battery 300 to ensure the safe, reliable and efficient operation of the power battery 300.

[0068] In one embodiment, the electric vehicle 1 further includes a brake pedal position sensor 510, which is used to detect the opening or pedal travel of the brake pedal 230. The brake pedal position sensor 510 can be a Hall type or a variable resistor type. The Hall type brake pedal position sensor 510 has a permanent magnet and a Hall element. The movement of the brake pedal 230 drives the permanent magnet to produce displacement, changing the magnetic field strength around the Hall element. The Hall element in the brake pedal position sensor 510 outputs different voltage signals according to the change of the magnetic field. For example, different pedal openings, different magnetic field changes, and different output voltages accurately reflect the pedal position, so that the opening or pedal travel of the brake pedal 230 can be determined.

[0069] In one embodiment, the electric vehicle 1 further includes a speed measurement unit 520, which is used to detect the speed of the drive motor 120. The speed measurement unit 520 may be a rotary transformer, a motor speed sensor, etc. The speed measurement unit 520 may be arranged on the drive motor 120 (for example, arranged on the rotor of the motor). At this time, the motor controller 110 may receive the rotary signal and the speed signal of the drive motor 120 from the speed measurement unit 520. The speed signal may be indirectly obtained from the rotary signal. By processing the rotary signal and calculating the change in angle per unit time, the speed signal may be obtained. Moreover, since the rotary signal may accurately reflect the 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 drive motor 120 and the wheel speed. According to the transmission ratio corresponding to the drive motor 120 and the motor, the speed of the wheel may be calculated, and the speed of the electric vehicle 1 is directly related to the wheel speed. The speed of the whole vehicle may be calculated by the wheel speed and the relevant parameters of the wheel (such as the wheel radius).

[0070] In one embodiment, the electric vehicle 1 further includes an inertial measurement unit 530, which is used to detect the acceleration (or deceleration) of the electric vehicle 1. The inertial measurement unit 530 is usually composed of an accelerometer and a gyroscope. When the inertial measurement unit 530 moves with the electric vehicle 1 and acceleration occurs, the mass block in the accelerometer will be affected by the inertial force, and this force will cause the elastic element connected to the mass block to deform. By detecting this deformation (which can be detected by capacitance, piezoelectricity, etc.), the magnitude and direction of the acceleration can be measured.

[0071] In some embodiments, the drive system 100, the brake system 200, the vehicle controller 410, and the battery controller 420 in the electric vehicle 1 can be 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.

[0072] In one embodiment, the drive system 100, the brake system 200, the vehicle controller 410, the battery controller 420 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. The signals of many sensors such as the speed measurement unit 520, the inertial measurement unit 530, and the brake pedal position sensor 510 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, the vehicle acceleration and the braking signal from the communication bus; the motor controller 110 can also upload signals to the communication bus, such as one or more signals of the torque value and torque direction output by the drive motor 120.

[0073] See also Figure 3 , Figure 3 Another schematic diagram of the structure of an electric vehicle provided in an embodiment of the present application. Figure 3 As shown, the electric vehicle 1 further includes four wheels 130 , namely a left front wheel LF and a right front wheel RF corresponding to a front axle 140 of the electric vehicle 1 , and a left rear wheel LR and a right rear wheel RR corresponding to a rear axle 150 of the electric vehicle 1 .

[0074] In one embodiment, the driving system of the electric vehicle 1 may be a centralized driving motor driving architecture, where two driving motors for driving two front wheels or two driving motors for driving two rear wheels are arranged together. Figure 3 As shown, the drive system includes a drive motor 121 for driving two front wheels and a drive motor 122 for driving two rear wheels, and the motor controller 110 is used to control one or more drive motors to output positive torque to drive the electric vehicle 1, and the motor controller 110 can also be used to control one or more drive motors to output negative torque to brake the electric vehicle 1. Among them, the motor controller 110 can be one or more, and the motor controller 110 and the drive motor can be one-to-one corresponding, and one motor controller 110 can also correspond to multiple drive motors.

[0075] In one embodiment, the drive system may also be a wheel-side four-drive motor drive architecture, that is, the drive system includes four drive motors, the four drive motors correspond to the four wheels 130 one by one, and each drive motor is arranged at the wheel 130 driven by each drive motor. In addition, 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.

[0076] In one embodiment, if Figure 3 As shown, the braking system can be a wheel-side braking architecture, and each wheel 130 is equipped with an independent braking device 220, and the braking device 220 corresponding to each wheel 130 can be directly installed near the wheel hub. During the braking process, after the driver steps on the brake pedal 230, the brake controller 210 independently controls the braking device 220 corresponding to each wheel 130 to output braking force according to the braking demand of the electric vehicle 1, that is, the brake pads in the braking device 220 corresponding to each wheel 130 output clamping force to the brake disc to brake the electric vehicle 1. The brake controller 210 can be one or more, and the brake controller 210 and the brake device 220 can correspond one to one, or one brake controller 210 can correspond to multiple brake devices 220.

[0077] In one embodiment, the braking system can also be a centralized braking architecture. After the driver steps on the brake pedal 230, the brake controller 210 controls the braking device 220 to generate hydraulic pressure according to the braking demand of the electric vehicle 1, and then transmits the hydraulic pressure to the brake wheel cylinder of each wheel 130 through the brake pipeline, pushing the brake pad corresponding to each wheel 130 to output clamping force to the brake disc to brake the electric vehicle 1.

[0078] The above describes the architecture of the embodiment of the present application. The following is an exemplary description of the vehicle controller in the braking control process of the electric vehicle 1. In the embodiment of the present application, after the comfort braking mode is started, the vehicle controller used to implement the braking control process of the electric vehicle 1 can be the vehicle controller 410, the motor controller 110 or the brake controller 210, which is not limited here.

[0079] In some embodiments, the user may pre-select to enable the comfort braking mode, wherein the user may enable the comfort braking mode in the following ways: selecting to enable the comfort braking mode in the human-vehicle interaction system; enabling by pressing the comfort braking mode button; selecting to enable the comfort braking mode in a terminal device connected to the electric vehicle 1 by wire or wirelessly, etc., without limitation. Whether the electric vehicle 1 enters the comfort braking mode during braking is determined by the user's choice. The electric vehicle 1 automatically enters the comfort braking mode when the driving state of the electric vehicle 1 meets the comfort braking conditions based on the user's pre-selection to enable the comfort braking mode. In some embodiments, after the user selects to enable the comfort braking mode, the comfort braking mode is automatically enabled after the electric vehicle 1 is subsequently started, thereby simplifying user operations and improving user experience.

[0080] In one embodiment, when the vehicle controller used to implement the braking control process of the electric vehicle 1 provided in the embodiment of the present application is a vehicle controller 410, it can be referred to Figure 4 , Figure 4A schematic diagram of the control process of the vehicle controller 410 of the electric vehicle 1 provided in an embodiment of the present application.

[0081] During the braking process of the electric vehicle 1, after the driver steps on the brake pedal, the vehicle controller 410 is used to obtain a pedal opening signal of the brake pedal from the brake pedal position sensor 510, wherein the pedal opening signal is used to indicate the opening of the brake pedal.

[0082] In one embodiment, since the maximum allowable negative torque that the drive motor 120 can output changes dynamically during the driving process of the electric vehicle 1, the maximum allowable negative torque of the drive motor 120 is limited by the state of the drive motor 120 and the state of the power battery 300, that is, when the braking force of the drive motor 120 gradually increases, it is necessary to consider whether the energy recovery power of the drive motor 120 will exceed the charging power limit of the electric battery and whether the drive motor 120 itself can withstand it. Therefore, the vehicle controller 410 is also used to obtain the motor state signal from the motor controller 110 and the battery state signal from the battery controller 420 to determine the maximum allowable negative torque of the drive motor 120, and then determine the preset opening corresponding to the current brake pedal. Among them, the maximum allowable negative torque of the drive motor 120 is the maximum negative torque that the drive motor 120 can output when it is running safely and stably, and the total braking force indicated by the brake signal generated by the vehicle controller 410 when the opening of the brake pedal increases to the preset opening is the maximum allowable braking force provided to the electric vehicle 1 when the drive motor 120 outputs the maximum allowable negative torque.

[0083] The motor status signal is used to indicate at least the motor peak torque and motor temperature of the drive motor 120, wherein the motor peak torque is the maximum torque value that the drive motor 120 can output in a short time, which reflects the power performance limit of the drive motor 120, and the maximum allowable negative torque of the drive motor 120 is less than or equal to the motor peak torque. In addition, since the drive motor 120 generates heat during operation, excessive temperature will affect the performance and life of the drive motor 120. In order to protect the drive motor 120, when determining the maximum allowable negative torque, the current temperature of the drive motor 120 needs to be considered. When the motor temperature approaches or exceeds its maximum allowable temperature, the maximum allowable negative torque should be reduced accordingly.

[0084] The battery status signal is used to indicate at least the battery power, battery temperature and maximum charge and discharge power of the power battery 300, wherein the energy recovery power when the drive motor 120 outputs negative torque cannot exceed the maximum charge power of the power battery 300, otherwise it will cause the power battery 300 to be overcharged. First, when the battery power is high, in order to ensure the service life of the power battery 300, it is necessary to limit the energy recovery power of the drive motor 120, thereby reducing the maximum allowable negative torque; when the battery power is low, the power battery 300 may allow a higher charging power, and the energy recovery power of the drive motor 120 can be appropriately increased to increase the maximum allowable negative torque of the drive motor 120. In addition, in a low temperature environment, the internal resistance of the power battery 300 will increase, resulting in a decrease in the charge and discharge capacity of the power battery 300. At this time, the maximum allowable negative torque of the drive motor 120 should be limited; in a high temperature environment, the life of the power battery 300 will be shortened. In order to protect the power battery 300, it is also necessary to appropriately reduce the maximum allowable negative torque of the drive motor 120.

[0085] In one embodiment, if the vehicle controller 410 detects that the opening of the brake pedal increases to be greater than a preset opening, the vehicle controller 410 is used to output a first braking control instruction to the motor controller 110 and a second braking control instruction to the brake controller 210, wherein the first braking control instruction is used to instruct the motor controller 110 to control the first braking force output by the drive motor 120, and the second braking control instruction is used to instruct the brake controller 210 to control the second braking force output by the braking device 220.

[0086] The vehicle controller 410 is used to determine the total braking force of the electric vehicle 1 during braking based on the detected opening of the brake pedal. The total braking force is the sum of the first braking force indicated by the first braking control instruction output by the vehicle controller 410 and the second braking force indicated by the second braking control instruction. The vehicle controller 410 controls the total braking force to increase as the opening of the brake pedal increases. The vehicle controller 410 controls the first braking force output by the drive motor 120 to be less than or equal to the maximum allowable braking force provided when the drive motor 120 outputs the maximum allowable negative torque.

[0087] In one embodiment, in a manual driving scenario, the vehicle controller 410 is used to determine the total braking force of the electric vehicle 1 when braking based on the detected opening of the brake pedal. In an intelligent driving scenario, the vehicle controller 410 is used to obtain the total braking force of the electric vehicle 1 when braking from the advanced driver assistance system (ADAS) of the electric vehicle 1.

[0088] Among them, the advanced driver assistance system determines the appropriate total braking force by integrating information from multiple sensors, combining vehicle dynamics models, and considering driving strategies and goals. The advanced driver assistance system integrates data collected by millimeter-wave radar, cameras, lidar, wheel speed sensors, etc. to understand the vehicle's surrounding environment, the state of target objects, and its own driving conditions. At the same time, based on the vehicle dynamics model, the current vehicle speed, steering angle, road adhesion coefficient, etc., the total braking force required for braking is calculated.

[0089] Since the greater the first braking force output by the drive motor 120 during braking, the higher the energy recovery efficiency of the electric vehicle 1 during braking, when the vehicle controller 410 detects that the opening of the brake pedal increases to be greater than the preset opening, it controls the first braking force output by the drive motor 120 to be the maximum allowable braking force of the drive motor 120, and controls the second braking force output by the braking device 220 to be the difference between the total braking force corresponding to the opening of the brake pedal and the maximum allowable braking force of the drive motor 120, thereby greatly improving the energy recovery rate of the drive motor 120 during braking, thereby reducing the overall energy consumption of the electric vehicle 1.

[0090] In this embodiment, the motor controller 110 is used to output a negative torque control signal to the drive motor 120 based on the first braking control instruction, and control the drive motor 120 to output a negative torque opposite to the rotational speed of the wheels of the electric vehicle 1, so that the drive motor 120 provides a first braking force for the electric vehicle 1. The motor controller 110 is also used to feed back a torque signal and a speed signal to the vehicle controller 410, wherein the torque signal is used to indicate the actual negative torque output by the drive motor 120, and the vehicle controller 410 is used to determine the actual first braking force provided by the drive motor 120 for the electric vehicle 1 based on the actual negative torque; the speed signal is used to indicate the rotational speed of the drive motor 120, and the vehicle controller 410 is used to determine the vehicle speed of the electric vehicle 1 based on the rotational speed of the drive motor 120 and the transmission ratio parameter.

[0091] The brake controller 210 is used to output a braking force control signal to the brake device 220 based on the second brake control instruction, so that the brake device 220 outputs the second braking force to brake the four wheels of the electric vehicle 1. The brake controller 210 is also used to feed back a braking force signal to the vehicle controller 410, and the braking force signal is used to indicate the actual braking force output by the brake device 220. The vehicle controller 410 is used to determine the actual second braking force provided by the brake device 220 to the electric vehicle 1 based on the actual braking force.

[0092] In one embodiment, after the driver steps on the brake pedal, when the vehicle controller 410 obtains the pedal opening signal of the brake pedal from the brake pedal position sensor 510, the vehicle controller 410 is also used to obtain an acceleration signal from the inertial measurement unit 530, and the acceleration signal is used to indicate the acceleration (or deceleration) of the electric vehicle 1. The braking of the electric vehicle 1 includes emergency braking and non-emergency braking. Emergency braking is a braking process in which the electric vehicle 1 is quickly decelerated to a stop. During the emergency braking process, the deceleration of the electric vehicle 1 is large. Non-emergency braking is a braking process in which the electric vehicle 1 is slowly decelerated 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 opening, etc.

[0093] In one embodiment, when the deceleration of the electric vehicle 1 is greater than or equal to the preset deceleration during the braking process of the electric vehicle 1, the braking mode of the electric vehicle 1 is the emergency braking mode. When the deceleration of the electric vehicle 1 is less than the preset deceleration during the braking process of the electric vehicle 1, the braking mode of the electric vehicle 1 is the non-emergency braking mode.

[0094] In one embodiment, when the opening of the brake pedal during the braking process of the electric vehicle 1 is greater than or equal to the emergency brake opening, the braking mode of the electric vehicle 1 is the emergency brake mode. When the opening of the brake pedal during the braking process of the electric vehicle 1 is less than the emergency brake opening, the braking mode of the electric vehicle 1 is the non-emergency brake mode.

[0095] Since the braking mode of the electric vehicle 1 is the emergency braking mode, it is necessary to ensure that the electric vehicle 1 stops moving within the shortest possible distance to avoid dangerous situations such as collision and loss of control of the electric vehicle 1. Therefore, the braking efficiency and braking safety of the electric vehicle 1 need to be ensured in the emergency braking mode. If the vehicle controller 410 determines that the deceleration of the electric vehicle 1 is greater than or equal to the preset deceleration based on the acquired acceleration signal, the vehicle controller 410 controls the drive motor 120 to output the first braking force and controls the braking device 220 to output the second braking force. In addition, during the braking process, the first braking force output by the drive motor 120 is controlled to increase or remain unchanged; or, the second braking force output by the braking device 220 is controlled to increase or remain unchanged; or, the first braking force output by the drive motor 120 and the second braking force output by the braking device 220 are controlled to increase or remain unchanged until the speed of the electric vehicle 1 decreases to zero, and there is no restriction here.

[0096] When the braking mode of the electric vehicle 1 is a non-emergency braking mode, while 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. If the vehicle controller 410 determines that the deceleration of the electric vehicle 1 is less than the preset deceleration based on the acquired acceleration signal, the vehicle controller 410 controls the drive motor 120 to output the first braking force and controls the braking device 220 to output the second braking force. In addition, the vehicle controller 410 determines that the speed of the electric vehicle 1 is reduced to less than or equal to the first preset speed based on the acquired speed signal, that is, when it is determined that the electric vehicle 1 enters the final stage of braking, the vehicle controller 410 is also used to control the first braking force output by the drive motor 120 and the second braking force output by the braking device 220 to decrease, and one of the first braking force and the second braking force is reduced to less than or equal to the preset braking force, and the other of the first braking force and the second braking force is controlled to decrease, so as to reduce the deceleration of the electric vehicle 1 during the braking process, thereby reducing the shaking phenomenon caused by the rapid speed change of the electric vehicle 1 during the braking process.

[0097] In one embodiment, if the speed of the electric vehicle 1 is less than a preset speed during the braking process of the electric vehicle 1, or if the rotation speed of the drive motor 120 is less than a preset rotation speed during the braking process of the electric vehicle 1, the electric vehicle 1 enters the final stage of braking.

[0098] In one embodiment, if the vehicle controller 410 detects that the opening of the brake pedal increases to less than or equal to a preset opening, the vehicle controller 410 is used to output a first braking control signal to the drive motor 120, and the motor controller 110 is used to output a negative torque control signal to the drive motor 120 based on the acquired first braking control instruction, controlling the drive motor 120 to output a negative torque in the opposite direction to the rotational speed of the wheels of the electric vehicle 1, so that the drive motor 120 provides a first braking force for the electric vehicle 1.

[0099] Since the higher the first braking force output by the drive motor 120 during braking, the higher the energy recovery efficiency of the electric vehicle 1 during braking, when the vehicle controller 410 detects that the opening of the brake pedal increases to less than or equal to the preset opening, the second braking force output by the braking device 220 is controlled to be zero, and only the drive motor 120 is controlled to output the first braking force to brake the four wheels of the electric vehicle 1, which can ensure the energy recovery efficiency of the electric vehicle 1 during braking, thereby reducing the overall energy consumption of the electric vehicle 1.

[0100] In one embodiment, when the vehicle controller for implementing the braking control process of the electric vehicle 1 is the motor controller 110, reference may be made to Figure 5 , Figure 5 A schematic diagram of the control process of the motor controller 110 of the electric vehicle 1 provided in an embodiment of the present application.

[0101] During the braking process of the electric vehicle 1, after the driver steps on the brake pedal, the motor controller 110 is used to obtain the pedal opening signal of the brake pedal from the brake pedal position sensor 510 and the acceleration signal from the inertial measurement unit 530 to determine the opening of the brake pedal and the deceleration of the electric vehicle 1.

[0102] In one embodiment, the vehicle controller 410 is used to obtain a battery status signal from the battery controller 420 and transparently transmit the battery status signal to the motor controller 110, wherein transparent transmission means that after receiving the battery status signal, the vehicle controller 410 does not perform complex signal processing (such as modifying the signal content), but directly transmits the battery status signal to the motor controller 110.

[0103] In one embodiment, the motor controller 110 is used to directly obtain the battery status signal from the battery controller 420 to reduce the signal transmission delay and improve the signal transmission rate.

[0104] The motor controller 110 determines the maximum allowable negative torque of the drive motor 120 based on the battery status signal and the status information of the drive motor 120 obtained from the drive motor 120 and the vehicle's sensors. The maximum allowable negative torque of the drive motor 120 is the maximum negative torque that the drive motor 120 can output during safe and stable operation.

[0105] In one embodiment, if the motor controller 110 determines that the deceleration of the electric vehicle 1 is less than a preset deceleration based on the acquired acceleration signal, and determines that the opening of the brake pedal is increased to be greater than the preset opening based on the acquired pedal opening signal, the motor controller 110 is used to output a negative torque control signal to the drive motor 120 and to output a second braking control instruction to the brake controller 210, wherein the negative torque control signal is used to indicate the first braking force output by the drive motor 120, and the second braking control instruction is used to indicate the brake controller 210 to control the second braking force output by the braking device 220.

[0106] In one implementation, the motor controller 110 may send the second brake control instruction to the brake controller 210 in the following manner: the motor controller 110 sends the second brake control instruction to the vehicle controller 410 , and the vehicle controller 410 transmits the second brake control instruction to the brake controller 210 .

[0107] In this embodiment, the motor controller 110 is used to control the drive motor 120 to output a negative torque opposite to the rotational speed of the wheel of the electric vehicle 1 based on the negative torque control signal, so that the drive motor 120 provides a first braking force for the electric vehicle 1. The motor controller 110 is also used to obtain the torque signal and the rotational speed signal fed back by the drive motor 120. The control method of the motor controller 110 on the drive motor 120 and the brake device 220 during the braking process can also be referred to. Figure 4 The relevant description of the vehicle controller 410 in the provided embodiment will not be repeated here.

[0108] The brake controller 210 is used to output a braking force control signal to the brake device 220 based on the second brake control instruction, so that the brake device 220 outputs the second braking force to brake the four wheels of the electric vehicle 1. The brake controller 210 is also used to feed back the braking force signal to the motor controller 110, or feed back the braking force signal to the motor controller 110 through the vehicle controller 410 transparent transmission, which is not limited here.

[0109] In one embodiment, when the vehicle controller for implementing the braking control process of the electric vehicle 1 is the braking controller 210, reference may be made to Figure 6 , Figure 6 A schematic diagram of the control process of the brake controller 210 of the electric vehicle 1 provided in an embodiment of the present application.

[0110] During the braking process of the electric vehicle 1, after the driver steps on the brake pedal, the brake controller 210 is used to obtain the pedal opening signal of the brake pedal from the brake pedal position sensor 510 and the acceleration signal from the inertial measurement unit 530 to determine the opening of the brake pedal and the deceleration of the electric vehicle 1.

[0111] In one embodiment, the vehicle controller 410 is used to obtain a battery status signal from the battery controller 420 and a motor status signal from the motor controller 110, and determine the maximum allowable negative torque of the drive motor 120 based on the battery status signal and the motor status signal, and output the maximum allowable negative torque signal to the brake controller 210, and the maximum allowable negative torque signal is used to indicate the maximum allowable negative torque of the drive motor 120.

[0112] In one embodiment, if the brake controller 210 determines that the deceleration of the electric vehicle 1 is less than a preset deceleration based on the acquired acceleration signal, and determines that the opening of the brake pedal increases to be greater than the preset opening based on the acquired pedal opening signal, the brake controller 210 is used to output a first braking control instruction to the motor controller 110 and to output a braking force control signal to the braking device 220, wherein the first braking control instruction is used to instruct the motor controller 110 to control the first braking force output by the drive motor 120, and the braking force control signal is used to indicate the second braking force output by the braking device 220.

[0113] In one implementation, the brake controller 210 may send the first brake control instruction to the motor controller 110 in the following manner: the brake controller 210 sends the first brake control instruction to the vehicle controller 410 , and the vehicle controller 410 transmits the first brake control instruction to the motor controller 110 .

[0114] In this embodiment, the motor controller 110 is used to output a negative torque control signal to the drive motor 120 based on the first brake control instruction, and control the drive motor 120 to output a negative torque opposite to the rotational speed of the wheels of the electric vehicle 1, so that the drive motor 120 provides a first braking force for the electric vehicle 1. The motor controller 110 is also used to feed back a torque signal and a speed signal to the brake controller 210, or feed back the torque signal and the speed signal to the brake controller 210 by transparent transmission through the vehicle controller 410, which is not limited here.

[0115] The brake controller 210 is used to control the brake device 220 to output a second braking force based on the braking force control signal to brake the four wheels of the electric vehicle 1. The brake controller 210 is also used to receive the braking force signal fed back by the brake device 220. The control method of the brake controller 210 on the drive motor 120 and the brake device 220 during the braking process can also be referred to Figure 4 The relevant description of the vehicle controller 410 in the provided embodiment will not be repeated here.

[0116] Combine the following Figures 7 to 14 An example is given of how to take various factors into consideration to coordinately control the drive motor 120 and the brake device 220 to achieve comfortable braking.

[0117] like Figure 7 as well as Figure 8 As shown, Figure 7 A schematic diagram of the braking control process of the electric vehicle 1 provided in an embodiment of the present application is shown in FIG. Figure 8 for Figure 7 A schematic diagram of a scenario of a braking control process of an electric vehicle 1 is provided.

[0118] At the first moment t1 during the braking process of the electric vehicle 1, after the driver steps on the brake pedal 230, the vehicle controller can obtain the pedal opening signal of the brake pedal 230 from the brake pedal position sensor 510 and the acceleration signal from the inertial measurement unit 530. When it is detected that the deceleration a of the electric vehicle 1 is less than the preset deceleration a1, or when it is detected that the opening A of the brake pedal 230 is less than the emergency braking opening, the vehicle controller is used to control the electric vehicle 1 to enter a non-emergency braking state, and during the braking process, the first braking force F1 output by the drive motor 120 or the second braking force F2 output by the brake device 220 is controlled to reduce the shaking of the electric vehicle 1 during the braking process.

[0119] The vehicle controller is also used to determine the maximum allowable negative torque of the drive motor 120 based on the motor status signal of the drive motor 120 and the battery status signal of the power battery 300, so as to determine the preset opening A1 corresponding to the brake pedal 230 during braking, that is, when the opening A of the brake pedal 230 is the preset opening A1, the total braking force F0 indicated by the brake pedal 230 is the maximum allowable braking force Fmax provided for the electric vehicle 1 when the drive motor 120 outputs the maximum allowable negative torque.

[0120] At the first moment t1 , if the vehicle controller detects that the opening A of the brake pedal 230 increases to be greater than the preset opening A1 , the vehicle controller controls the drive motor 120 to output the first braking force F1 and controls the brake device 220 to output the second braking force F2 .

[0121] In one embodiment, at the first moment t1 during the braking process of the electric vehicle 1, when the opening A of the brake pedal 230 is greater than the preset opening A1, the vehicle controller controls the first braking force F1 output by the drive motor 120 to be the maximum allowable braking force Fmax of the drive motor 120. Since the maximum allowable negative torque of the drive motor 120 is the maximum negative torque that the drive motor 120 can output when operating safely and stably, if the first braking force F1 output by the drive motor 120 is controlled to be greater than the maximum allowable braking force Fmax provided to the electric vehicle 1 when the drive motor 120 outputs the maximum allowable negative torque, it may cause the power battery 300 to be overcharged or affect the performance and life of the drive motor 120.

[0122] At the first moment t1, if the vehicle controller detects that the opening A of the brake pedal 230 is less than or equal to the preset opening A1, the vehicle controller controls the first braking force F1 output by the drive motor 120 to increase as the opening A of the brake pedal 230 increases; if the vehicle controller detects that the opening A of the brake pedal 230 is greater than the preset opening A1, and the first braking force F1 output by the drive motor 120 is the maximum allowable braking force Fmax of the drive motor 120, the vehicle controller controls the first braking force F1 output by the drive motor 120 not to increase as the opening A of the brake pedal 230 increases, and controls the second braking force F2 output by the braking device 220 to increase as the opening A of the brake pedal 230 increases.

[0123] In one embodiment, if Figure 7 As shown, at the first moment t1, the vehicle controller determines the speed v of the electric vehicle 1 based on the speed signal of the electric vehicle 1. If it is detected that the speed v of the electric vehicle 1 is greater than the first preset speed v1, it is determined that the electric vehicle 1 has not entered the final stage of braking. In order to ensure the braking efficiency of the electric vehicle 1 during the braking process, the vehicle controller controls the first braking force F1 and the second braking force F2 to remain unchanged, so that the deceleration a of the electric vehicle 1 remains unchanged for a period of time. For example, the first preset speed v1 is 8km / h.

[0124] At a second moment t2 after the first moment t1, if the vehicle controller detects that the vehicle speed v of the electric vehicle 1 decreases to less than or equal to the first preset speed v1, it is determined that the electric vehicle 1 enters the final stage of braking, and the vehicle controller controls the total braking force F0 of the electric vehicle 1 to decrease so as to reduce the deceleration a of the electric vehicle 1, thereby reducing the shaking phenomenon of the electric vehicle 1 caused by the faster rate of change of the vehicle speed v at the final stage of braking.

[0125] At the second time t2 , the vehicle controller controls one of the first braking force F1 output by the driving motor 120 and the second braking force F2 output by the brake device 220 to decrease, so as to reduce the total braking force F0 of the electric vehicle 1 .

[0126] At the third moment t3 after the second moment t2, when the vehicle controller controls one of the first braking force F1 and the second braking force F2 to be reduced to less than or equal to the preset braking force F3, the vehicle controller controls the other of the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the braking device 220 to be reduced.

[0127] In one embodiment, when the preset braking force F3 is greater than zero and one of the first braking force F1 and the second braking force F2 is reduced to less than or equal to the preset braking force F3, the vehicle controller controls the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220 to be reduced simultaneously.

[0128] In one embodiment, when one of the first braking force F1 and the second braking force F2 is reduced to zero, the vehicle controller controls the other of the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220 to be reduced.

[0129] When the drive motor 120 generates braking force, the kinetic energy of the drive system 100 is converted into electrical energy. This part of the electrical energy is fed back to the power battery 300 through the circuit between the drive motor 120 and the power battery 300 for storage, thereby realizing energy recovery of part of the kinetic energy of the electric vehicle 1 during braking. Therefore, the greater the first braking force F1 output by the drive motor 120 during braking, that is, the higher the proportion of the first braking force F1 in the total braking force F0, the higher the energy recovery efficiency of the electric vehicle 1 during braking.

[0130] like Figure 7 As shown, in one embodiment, at the first moment t1, if the opening A of the brake pedal 230 increases to be greater than the preset opening A1, the vehicle controller determines the total braking force F0 of the electric vehicle 1 based on the opening A of the brake pedal 230, controls the first braking force F1 output by the drive motor 120 to be the maximum allowable braking force Fmax of the drive motor 120, and controls the second braking force F2 output by the braking device 220 to be the difference between the total braking force F0 and the maximum allowable braking force Fmax of the drive motor 120.

[0131] At the second moment t2, the vehicle speed v of the electric vehicle 1 decreases to less than or equal to the first preset vehicle speed v1. In the process of reducing the total braking force F0 of the electric vehicle 1, in order to ensure that the first braking force F1 output by the drive motor 120 accounts for a proportion of the total braking force F0, the vehicle controller controls the second braking force F2 output by the braking device 220 to decrease first, and controls the first braking force F1 output by the drive motor 120 to remain unchanged.

[0132] At a third time t3 after the second time t2, if the second braking force F2 output by the brake device 220 decreases to zero, the vehicle controller controls the first braking force F1 output by the drive motor 120 to decrease until the first braking force F1 decreases to zero.

[0133] Between the second time t2 and the third time t3, the greater the vehicle speed v of the electric vehicle 1 is, the smaller the reduction rate k of one of the first braking force F1 and the second braking force F2 is controlled.

[0134] In one embodiment, after the third moment t3, the vehicle controller controls the sum of the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220 and the vehicle speed v of the electric vehicle 1 to be reduced to zero simultaneously. When the electric vehicle 1 brakes, the speed gradually decreases, and the vehicle body will maintain a forward movement trend due to inertia. The braking force and the vehicle speed v are reduced to zero in coordination, which can help the electric vehicle 1 to smoothly overcome inertia during the braking process and avoid shaking caused by the mismatch between inertia and braking force. In addition, the suspension system of the electric vehicle 1 plays a role of buffering and supporting during the braking process. The sudden change of braking force will cause the suspension system to bear a large impact force. The braking force and the vehicle speed v are reduced to zero in coordination, which can make the suspension system of the electric vehicle 1 always work in a relatively stable state, thereby further reducing the shaking of the electric vehicle 1 during the braking process.

[0135] After the second moment t2, the vehicle controller controls the first braking force F1 and / or the second braking force F2 to decrease until the total braking force F0 of the electric vehicle 1 and the vehicle speed v of the electric vehicle 1 simultaneously decrease to zero, and the reduction rate k of the total braking force F0 of the electric vehicle 1 remains unchanged.

[0136] In one embodiment, the reduction rate k of the total braking force F0 can be calculated as follows:

[0137] Use the acceleration formula: a = ak + kt. Among them, ak is the deceleration a of the electric vehicle 1 when the total braking force F0 starts to decrease, Fk is the total braking force F0 of the electric vehicle 1 when the total braking force F0 starts to decrease, and m is the mass of the electric vehicle 1 .

[0138] Using the speed formula: Finally get Here, vk is the vehicle speed v of the electric vehicle 1 at the moment when the total braking force F0 starts to decrease.

[0139] In one embodiment, when the moment when the total braking force F0 begins to decrease is the second moment t2, the greater the total braking force F0 of the electric vehicle 1 at the second moment t2, the greater the reduction rate k of the total braking force F0; or, the greater the vehicle speed v of the electric vehicle 1 at the second moment t2, the smaller the reduction rate k of the total braking force F0.

[0140] In one embodiment, after the second moment t2, the reduction rate k of the total braking force F0 of the electric vehicle 1 remains unchanged, so that the total braking force F0 is reduced to zero and the speed v of the electric vehicle 1 is reduced to zero. For example, after the second moment t2, the vehicle controller controls the second braking force F2 to reduce at a certain reduction rate k until it is reduced to zero at the third moment t3. After the third moment t3, the vehicle controller controls the first braking force F1 to reduce at the same reduction rate k until the first braking force F1 is reduced to zero and the speed v of the electric vehicle 1 is reduced to zero at the fourth moment t4. In this way, the deceleration a of the electric vehicle 1 during braking can be uniformly reduced, thereby reducing the jerk of the electric vehicle 1 during braking, reducing the shaking phenomenon of the electric vehicle 1 during braking, achieving comfortable braking of the electric vehicle 1, and improving the user's driving experience.

[0141] In one embodiment, the electric vehicle 1 is in a low-speed stop-and-go condition, and the vehicle speed v of the electric vehicle 1 changes frequently and with a small amplitude. Since the braking control accuracy of the drive motor 120 is higher than the braking control accuracy of the braking device 220, in the process of controlling the total braking force F0 to decrease, the second braking force F2 is controlled to decrease, and then the first braking force F1 is controlled to decrease, so that in the process of reducing the deceleration a of the electric vehicle 1 at the end of braking, the high braking accuracy of the drive motor 120 is effectively utilized, so that the braking process or the electric vehicle 1 can accurately provide appropriate braking force in a timely manner according to the vehicle speed v and the driver's intention, thereby reducing the shaking phenomenon of the electric vehicle 1 during the braking process and achieving comfortable braking of the electric vehicle 1.

[0142] At the fourth moment t4 after the third moment t3, the speed v of the electric vehicle 1 decreases to zero. The vehicle controller is also used to control the increase of the second braking force F2 output by the braking device 220 immediately after the electric vehicle 1 stops, so as to avoid vehicle movement caused by the gap between the transmission system and components, or the slipping phenomenon caused by the component force of gravity along the slope direction when on a slope, thereby ensuring that the electric vehicle 1 is in a stationary state.

[0143] In one embodiment, at the fourth moment t4, the vehicle controller controls the second braking force F2 output by the braking device 220 to increase to be greater than the braking force output by the braking device 220 at the first moment t1. Moreover, at the fifth moment t5 after the fourth moment t4, the opening A of the brake pedal 230 is reduced to zero, and the second braking force F2 output by the braking device 220 is controlled to be reduced to zero. Thus, by increasing the braking force at the moment of braking, it is ensured that the electric vehicle 1 can remain stable and stationary after braking without shaking forward and backward.

[0144] In this embodiment, during the braking process of the electric vehicle 1, when the opening A of the brake pedal 230 increases to be greater than the preset opening A1, since the total braking force F0 indicated by the brake pedal 230 when the opening A of the brake pedal 230 is the preset opening A1 is the maximum allowable braking force Fmax provided for the electric vehicle 1 when the drive motor 120 outputs the maximum allowable negative torque, by controlling the first braking force F1 output by the drive motor 120 to be the maximum allowable negative torque, and controlling the brake motor to output the second braking force F2 to be the difference between the total braking force F0 and the first braking force F1, at the same time, in the process of controlling the total braking force F0 to decrease, the second braking force F2 is controlled to decrease first and then the first braking force F1 is controlled to decrease, thereby ensuring that the first braking force F1 output by the drive motor 120 accounts for a certain proportion of the total braking force F0, thereby improving the cruising range of the whole vehicle. Furthermore, by cooperatively controlling the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the braking device 220, the deceleration a and the vehicle speed v of the electric vehicle 1 during braking can be stably reduced to zero, thereby reducing the shaking of the electric vehicle 1 caused by the rapid rate of change of the vehicle speed v during braking, achieving comfortable braking of the electric vehicle 1, and improving the user's driving experience.

[0145] like Fig. 9 as well as Fig.10 As shown, Fig. 9 Another operating schematic diagram of the braking control process of the electric vehicle 1 provided in the embodiment of the present application, Fig.10 for Fig. 9 A schematic diagram of a scenario of a braking control process of an electric vehicle 1 is provided.

[0146] During the braking process of the electric vehicle 1, the vehicle controller is used to determine the maximum allowable negative torque of the drive motor 120 according to the motor status signal of the drive motor 120 and the battery status signal of the power battery 300, so as to determine the preset opening A1 corresponding to the brake pedal 230 during the braking process.

[0147] At the first moment t1 during the braking process of the electric vehicle 1, after the driver steps on the brake pedal 230, if the vehicle controller determines that the opening A of the brake pedal 230 increases to be greater than the preset opening A1 based on the pedal opening signal of the brake pedal 230 obtained from the brake pedal position sensor 510, and determines that the deceleration a of the electric vehicle 1 is less than the preset deceleration a1 based on the acceleration signal obtained from the inertial measurement unit 530, the vehicle controller controls the drive motor 120 to output the first braking force F1 and controls the braking device 220 to output the second braking force F2.

[0148] In one embodiment, if Fig. 9As shown, at the first moment t1, if the opening A of the brake pedal 230 increases to be greater than the preset opening A1, the vehicle controller is used to determine the total braking force F0 of the electric vehicle 1 based on the opening A of the brake pedal 230, control the first braking force F1 output by the drive motor 120 to be the maximum allowable braking force Fmax of the drive motor 120, and control the second braking force F2 output by the braking device 220 to be the difference between the total braking force F0 and the maximum allowable braking force Fmax of the drive motor 120.

[0149] At the first moment t1, the vehicle controller is also used to determine the vehicle speed v of the electric vehicle 1 based on the speed signal of the electric vehicle 1. If it is detected that the vehicle speed v of the electric vehicle 1 is less than or equal to the first preset speed v1, it is determined that the electric vehicle 1 is in the final stage of braking. The vehicle controller controls the total braking force F0 of the electric vehicle 1 to decrease so as to reduce the deceleration a of the electric vehicle 1.

[0150] At the first moment t1, after the vehicle controller controls the drive motor 120 to output the first braking force F1 and controls the brake device 220 to output the second braking force F2, the vehicle controller controls one of the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220 to decrease, so as to reduce the total braking force F0 of the electric vehicle 1. At the second moment t2 after the first moment t1, when the vehicle controller controls one of the first braking force F1 and the second braking force F2 to decrease to less than or equal to the preset braking force F3, the vehicle controller controls the other of the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220 to decrease.

[0151] Since the larger the first braking force F1 output by the driving motor 120 during braking, that is, the higher the proportion of the first braking force F1 in the total braking force F0, the higher the energy recovery efficiency of the electric vehicle 1 during braking. Fig. 9 As shown, at the first moment t1, the vehicle controller controls the second braking force F2 output by the braking device 220 to decrease first, and controls the first braking force F1 output by the drive motor 120 to remain unchanged. At the second moment t2 after the first moment t1, if the second braking force F2 output by the braking device 220 decreases to zero, the vehicle controller controls the first braking force F1 output by the drive motor 120 to decrease until the first braking force F1 decreases to zero.

[0152] In one embodiment, after the second moment t2, the vehicle controller controls the sum of the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220 and the vehicle speed v of the electric vehicle 1 to be reduced to zero simultaneously. By controlling the total braking force F0 of the electric vehicle 1 to be reduced to zero in coordination with the vehicle speed v, the shaking of the electric vehicle 1 during the braking process or due to the mismatch between inertia and braking force can be avoided, and the suspension system of the electric vehicle 1 is always operated in a relatively stable state, thereby further reducing the shaking of the electric vehicle 1 during the braking process.

[0153] At the third moment t3 after the second moment t2, the first braking force F1 output by the drive motor 120 is reduced to zero, that is, the total braking force F0 of the electric vehicle 1 is reduced to zero, and the speed v of the electric vehicle 1 is reduced to zero. The vehicle controller is also used to control the second braking force F2 output by the brake device 220 to increase immediately after the electric vehicle 1 stops. And, at the fourth moment t4 after the third moment t3, the opening A of the brake pedal 230 is reduced to zero, and the second braking force F2 output by the brake device 220 is controlled to be reduced to zero. Thus, by increasing the braking force at the moment of braking, it is ensured that the electric vehicle 1 can remain stable and stationary after braking without shaking forward and backward.

[0154] like Fig.11 as well as Fig.12 As shown, Fig.11 Another operation schematic diagram of the braking control process of the electric vehicle 1 provided in the embodiment of the present application; Fig.12 for Fig.11 A schematic diagram of a scenario of a braking control process of an electric vehicle 1 is provided.

[0155] During the braking process of the electric vehicle 1, the vehicle controller is used to determine the maximum allowable negative torque of the drive motor 120 according to the motor status signal of the drive motor 120 and the battery status signal of the power battery 300, so as to determine the preset opening A1 corresponding to the brake pedal 230 during the braking process.

[0156] At the first moment t1 during the braking process of the electric vehicle 1, after the driver steps on the brake pedal 230, if the vehicle controller determines that the opening A of the brake pedal 230 increases to less than or equal to the preset opening A1 based on the pedal opening signal of the brake pedal 230 obtained from the brake pedal position sensor 510, and determines that the deceleration a of the electric vehicle 1 is less than the preset deceleration a1 based on the acceleration signal obtained from the inertial measurement unit 530, the vehicle controller controls the drive motor 120 to output the first braking force F1. The first braking force F1 output by the vehicle controller controls the drive motor 120 to increase as the opening A of the brake pedal 230 increases.

[0157] When the drive motor 120 generates braking force, the kinetic energy of the drive system 100 is converted into electrical energy for storage. When the opening A of the brake pedal 230 is less than or equal to the preset opening A1, the vehicle controller determines that the total braking force F0 of the electric vehicle 1 is less than or equal to the maximum allowable braking force Fmax of the drive motor 120 based on the opening A of the brake pedal 230. During braking, the vehicle controller controls the drive motor 120 to output the first braking force F1, and controls the second braking force F2 output by the braking device 220 to be zero, so as to ensure the energy recovery efficiency of the electric vehicle 1 during braking.

[0158] In one embodiment, if Fig.11 As shown, at the first moment t1, the vehicle controller determines the speed v of the electric vehicle 1 based on the speed signal of the electric vehicle 1. If it is detected that the speed v of the electric vehicle 1 is greater than the second preset speed v2, it is determined that the electric vehicle 1 has not entered the final stage of braking. In order to ensure the braking efficiency of the electric vehicle 1 during the braking process, the vehicle controller controls the first braking force F1 output by the drive motor 120 to remain unchanged, so that the deceleration a of the electric vehicle 1 remains unchanged for a period of time. For example, the second preset speed v2 is 4km / h.

[0159] In one embodiment, the first preset speed v1 and the second preset speed v2 are both preset speeds determined by the vehicle controller for the electric vehicle 1 to enter the final stage of braking. When the speed v of the electric vehicle 1 is lower than the preset speed, the vehicle controller controls the total braking force F0 output by the drive motor 120 to decrease, so as to reduce the shaking phenomenon of the electric vehicle 1 at the final stage of braking due to the fast rate of change of the speed v. In order to reduce the shaking phenomenon of the electric vehicle 1 during the braking process and to ensure the braking efficiency, when the total braking force F0 output by the electric vehicle 1 is different, that is, the electric vehicle 1 outputs the first braking force F1 and the second braking force F2 at the same time, and when the electric vehicle 1 only outputs the first braking force F1, the threshold of the preset speed determined by the vehicle controller for the electric vehicle 1 to enter the final stage of braking is different. The greater the total braking force F0 of the electric vehicle 1, the greater the preset speed of the electric vehicle 1 to enter the final stage of braking.

[0160] At a second moment t2 after the first moment t1, if the vehicle controller detects that the vehicle speed v of the electric vehicle 1 decreases to less than or equal to the second preset vehicle speed v2, it is determined that the electric vehicle 1 enters the final stage of braking, and the vehicle controller controls the total braking force F0 of the electric vehicle 1 to decrease, that is, controls the first braking force F1 output by the drive motor 120 to decrease, so as to reduce the deceleration a of the electric vehicle 1, thereby reducing the shaking phenomenon of the electric vehicle 1 caused by the faster rate of change of the vehicle speed v at the final stage of braking.

[0161] In one embodiment, after the second moment t2, the vehicle controller controls the first braking force F1 output by the drive motor 120 and the vehicle speed v of the electric vehicle 1 to be reduced to zero simultaneously. By controlling the total braking force F0 of the electric vehicle 1 and the vehicle speed v to be reduced to zero in coordination, the shaking of the electric vehicle 1 during the braking process or due to the mismatch between inertia and braking force can be avoided, and the suspension system of the electric vehicle 1 is always operated in a relatively stable state, thereby further reducing the shaking of the electric vehicle 1 during the braking process.

[0162] At the third moment t3 after the second moment t2, the first braking force F1 output by the drive motor 120 is reduced to zero, that is, the total braking force F0 of the electric vehicle 1 is reduced to zero, and the speed v of the electric vehicle 1 is reduced to zero. The vehicle controller is also used to control the second braking force F2 output by the brake device 220 to increase immediately after the electric vehicle 1 stops. And, at the fourth moment t4 after the third moment t3, the opening A of the brake pedal 230 is reduced to zero, and the second braking force F2 output by the brake device 220 is controlled to be reduced to zero. Thus, by increasing the braking force at the moment of braking, it is ensured that the electric vehicle 1 can remain stable and stationary after braking without shaking forward and backward.

[0163] In this embodiment, during the braking process of the electric vehicle 1, when the opening A of the brake pedal 230 increases to less than or equal to the preset opening A1, since the total braking force F0 indicated by the brake pedal 230 when the opening A of the brake pedal 230 is the preset opening A1 is the maximum allowable braking force Fmax provided to the electric vehicle 1 when the drive motor 120 outputs the maximum allowable negative torque, the vehicle controller only controls the drive motor 120 to output the first braking force F1, thereby ensuring the energy recovery efficiency of the electric vehicle 1 during the braking process and improving the vehicle's cruising range. At the same time, since the braking control accuracy of the drive motor 120 is higher than the braking control accuracy of the brake device 220, in the process of controlling the first braking force F1 to decrease in order to reduce the deceleration a of the electric vehicle 1, the high braking accuracy of the drive motor 120 is effectively utilized, the shaking phenomenon of the electric vehicle 1 during the braking process is reduced, and the comfortable braking of the electric vehicle 1 is achieved.

[0164] like Fig.13 as well as Fig.14 As shown, Fig.13 Another operation schematic diagram of the braking control process of the electric vehicle 1 provided in the embodiment of the present application, Fig.14 for Fig.13 A schematic diagram of a scenario of a braking control process of an electric vehicle 1 is provided.

[0165] During the braking process of the electric vehicle 1, the vehicle controller is used to determine the maximum allowable negative torque of the drive motor 120 according to the motor status signal of the drive motor 120 and the battery status signal of the power battery 300, so as to determine the preset opening A1 corresponding to the brake pedal 230 during the braking process.

[0166] At the first moment t1 during the braking process of the electric vehicle 1, after the driver steps on the brake pedal 230, if the vehicle controller determines that the opening A of the brake pedal 230 increases to less than or equal to the preset opening A1 based on the pedal opening signal of the brake pedal 230 obtained from the brake pedal position sensor 510, and determines that the deceleration a of the electric vehicle 1 is less than the preset deceleration a1 based on the acceleration signal obtained from the inertial measurement unit 530, the vehicle controller controls the drive motor 120 to output the first braking force F1. The first braking force F1 output by the vehicle controller controls the drive motor 120 to increase as the opening A of the brake pedal 230 increases.

[0167] In one embodiment, if Fig.13 As shown, at the first moment t1, the vehicle controller determines the speed v of the electric vehicle 1 based on the speed signal of the electric vehicle 1. If it is detected that the speed v of the electric vehicle 1 is less than the second preset speed v2, it is determined that the electric vehicle 1 enters the final stage of braking. The vehicle controller controls the total braking force F0 of the electric vehicle 1 to decrease, that is, controls the first braking force F1 output by the drive motor 120 to decrease, so as to reduce the deceleration a of the electric vehicle 1, thereby reducing the shaking phenomenon of the electric vehicle 1 caused by the rapid rate of change of the speed v at the final stage of braking.

[0168] In one embodiment, after the first moment t1, the vehicle controller controls the first braking force F1 output by the drive motor 120 and the vehicle speed v of the electric vehicle 1 to be reduced to zero simultaneously. By controlling the total braking force F0 of the electric vehicle 1 and the vehicle speed v to be reduced to zero in coordination, the shaking of the electric vehicle 1 during the braking process or due to the mismatch between inertia and braking force can be avoided, and the suspension system of the electric vehicle 1 is always operated in a relatively stable state, thereby further reducing the shaking of the electric vehicle 1 during the braking process.

[0169] At the second moment t2 after the first moment t1, the first braking force F1 output by the drive motor 120 is reduced to zero, that is, the total braking force F0 of the electric vehicle 1 is reduced to zero, and the speed v of the electric vehicle 1 is reduced to zero. The vehicle controller is also used to control the second braking force F2 output by the brake device 220 to increase immediately after the electric vehicle 1 stops. And, at the third moment t3 after the second moment t2, the opening A of the brake pedal 230 is reduced to zero, and the second braking force F2 output by the brake device 220 is controlled to be reduced to zero. Thus, by increasing the braking force at the time of braking, it is ensured that the electric vehicle 1 can remain stable and stationary after braking without shaking forward and backward.

[0170] In this embodiment, during the braking process of the electric vehicle 1, when the opening A of the brake pedal 230 increases to be less than or equal to the preset opening A1, only the drive motor 120 is controlled to output the first braking force F1 and the first braking force F1 is adjusted. This not only effectively utilizes the energy recovery performance of the drive motor 120 and improves the cruising range of the entire vehicle, but also effectively utilizes the high braking accuracy of the drive motor 120, reduces the shaking phenomenon of the electric vehicle 1 during braking, and achieves comfortable braking of the electric vehicle 1, thereby improving the user's driving experience.

[0171] like Fig.15 as well as Fig.16 As shown, Fig.15 This is a schematic diagram of the operation of the electric vehicle 1 in the emergency braking mode provided by the embodiment of the present application. Fig.16 for Fig.15 A schematic diagram of a scenario of a braking control process of an electric vehicle 1 is provided.

[0172] During the braking process of the electric vehicle 1, after the driver steps on the brake pedal 230, the vehicle controller can obtain the pedal opening signal of the brake pedal 230 from the brake pedal position sensor 510 and the acceleration signal from the inertial measurement unit 530. When it is detected that the deceleration a of the electric vehicle 1 is greater than or equal to the preset deceleration a1, or when it is detected that the opening A of the brake pedal 230 is greater than or equal to the emergency brake opening A2, the vehicle controller is used to control the electric vehicle 1 to enter the emergency braking state, and during the braking process, control the first braking force F1 output by the drive motor 120 or control the second braking force F2 output by the brake device 220 to reduce the shaking of the electric vehicle 1 during the braking process.

[0173] At the first moment t1, if the vehicle controller detects that the opening A of the brake pedal 230 increases to be greater than or equal to the emergency brake opening A2, or the deceleration a of the electric vehicle 1 is greater than or equal to the preset deceleration a1, the vehicle controller is used to control the first braking force F1 output by the drive motor 120 and the second braking force F2 output by the brake device 220.

[0174] After the first moment t1, during the emergency braking process of the electric vehicle 1, the vehicle controller is used to control the first braking force F1 output by the drive motor 120 to increase or remain unchanged, and the first braking force F1 drive motor 120 is less than or equal to the maximum allowable braking force Fmax, until the vehicle speed v of the electric vehicle 1 decreases to zero. During the braking process, the vehicle controller controls the first braking force F1 drive motor 120 output by the drive motor 120 to be less than or equal to the maximum allowable braking force Fmax.

[0175] In one embodiment, during the emergency braking process of the electric vehicle 1, the vehicle controller is used to control the first braking force F1 output by the drive motor 120 and / or the second braking force F2 output by the brake device 220 to increase or remain unchanged until the vehicle speed v of the electric vehicle 1 decreases to zero. 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 total braking force F0 output by the electric vehicle 1 is no longer controlled to decrease, so that the total braking force F0 of the electric vehicle 1 during the braking process always maintains the braking value indicated by the brake controller 210, that is, in the emergency braking mode, the braking scheme provided in the present application for reducing the shaking phenomenon of the electric vehicle 1 during the braking process will not take effect.

[0176] At the second moment t2 after the first moment t1, the total braking force F0 of the electric vehicle 1 remains unchanged, and the speed v of the electric vehicle 1 decreases to zero. The vehicle controller is also used to control the second braking force F2 output by the brake device 220 to increase immediately after the electric vehicle 1 stops. Moreover, at the third moment t3 after the second moment t2, the opening A of the brake pedal 230 decreases to zero, and the second braking force F2 output by the brake device 220 is controlled to decrease to zero. Thus, by increasing the braking force at the moment of braking, it is ensured that the electric vehicle 1 can remain stable and stationary after braking without shaking forward and backward.

[0177] In this embodiment, since it is necessary to ensure that the electric vehicle 1 stops moving within the shortest possible distance in the emergency braking mode to avoid dangerous situations such as collision and loss of control of the electric vehicle 1, the vehicle controller will not control the first braking force F1 output by the drive motor 120 and / or the second braking force F2 output by the braking device 220 to decrease, thereby ensuring the braking efficiency and braking safety of the electric vehicle 1.

[0178] It should be understood that Figures 7 to 16 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.

[0179] 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.

[0180] like Fig.17 As shown, Fig.17 A flow chart of a control method for comfortable braking of an electric vehicle provided in an embodiment of the present application. The control method is used to control a driving motor and a braking device of the electric vehicle during braking of the electric vehicle to reduce the shaking of the electric vehicle during braking, and includes the following steps:

[0181] S1. Determine whether the electric vehicle is in a comfort braking mode.

[0182] If it is determined that the electric vehicle is in the comfort braking mode, step S2 is executed, otherwise the comfort braking control is terminated.

[0183] S2. Determine whether the electric vehicle is in a forward gear.

[0184] If it is determined that the electric vehicle is in the forward gear, step S3 is executed, otherwise the comfort braking control is terminated.

[0185] S3. Determine whether the deceleration of the electric vehicle is less than a preset deceleration.

[0186] If it is determined that the electric vehicle is in a deceleration less than a preset deceleration, the electric vehicle is determined to be in a non-emergency braking mode, and step S4 is executed; otherwise, the electric vehicle is determined to be in an emergency braking mode, and the comfort braking control is terminated.

[0187] S4. Determine whether the opening of the brake pedal is greater than a preset opening.

[0188] If it is determined that the opening of the brake pedal is greater than the preset opening, it is determined that the total braking force indicated by the brake pedal is greater than the maximum allowable braking force provided for the electric vehicle when the drive motor outputs the maximum allowable negative torque, and step S5 is executed; otherwise, step S10 is executed.

[0189] S5. Control the drive motor to output a first braking force and control the brake device to output a second braking force, where the first braking force is the maximum allowable braking force of the drive motor.

[0190] S6. Determine whether the vehicle speed is less than or equal to a first preset vehicle speed.

[0191] If it is determined that the vehicle speed is less than or equal to the first preset vehicle speed, it is determined that the electric vehicle enters the final stage of braking, the total braking force is controlled to decrease, and step S7 is executed.

[0192] S7. Control the second braking force to decrease to zero.

[0193] S8. Control the first braking force and the vehicle speed to decrease to zero simultaneously.

[0194] S9. Control the brake pedal to output a second braking force until the opening of the brake pedal is reduced to zero.

[0195] S10, controlling the driving motor to output a first braking force.

[0196] If it is determined that the opening of the brake pedal is less than or equal to the preset opening, the total braking force indicated by the brake pedal is determined to be less than or equal to the maximum allowable braking force provided for the electric vehicle when the drive motor outputs the maximum allowable negative torque, and only the drive motor is controlled to output the first braking force.

[0197] S11. Determine whether the vehicle speed is less than or equal to a second preset vehicle speed.

[0198] If it is determined that the vehicle speed is less than or equal to the second preset vehicle speed, it is determined that the electric vehicle enters the final stage of braking, the total braking force is controlled to decrease, and step S12 is executed.

[0199] S12. Control the first braking force and the vehicle speed to decrease to zero simultaneously.

[0200] In another embodiment of the embodiment of the present application, a vehicle controller for an electric vehicle is also provided, and the vehicle controller is used to control the electric vehicle to realize a comfort braking function.

[0201] In another embodiment of the present application, an electric vehicle is also provided, which includes a drive motor, a braking device and a vehicle controller provided in the above embodiment, and the vehicle controller is used to control the drive motor and the braking device to realize the comfort braking function of the electric vehicle.

[0202] It can be understood that all relevant contents of each step involved in the above method embodiment can be referred to the embodiment of the above vehicle controller and the embodiment of the electric vehicle, and the embodiments of the present application will not be repeated here.

[0203] 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 comfortable braking of an electric vehicle, characterized in that: The control method is used to control the first braking force output by the driving motor of the electric vehicle or the second braking force output by the braking device during the braking process when the deceleration of the electric vehicle is less than the preset deceleration to reduce the shaking of the electric vehicle during the braking process, and the control method includes: At a first moment during the braking process of the electric vehicle, the opening of the brake pedal increases to be greater than a preset opening, the drive motor is controlled to output the first braking force and the brake device is controlled to output the second braking force; At a second moment after the first moment, the speed of the electric vehicle decreases to less than or equal to a first preset speed, and one of the first braking force and the second braking force is controlled to decrease; At a third time after the second time, the other of the first braking force and the second braking force is controlled to decrease.

2. The control method according to claim 1, characterized in that: The control method specifically includes: At a third moment after the second moment, one of the first braking force and the second braking force is reduced to be less than or equal to a preset braking force, and the other of the first braking force and the second braking force is controlled to be reduced.

3. The control method according to claim 1 or 2, characterized in that: The control method specifically includes: At a second moment after the first moment, controlling the second braking force to decrease; At a third time after the second time, the first braking force is controlled to be reduced.

4. The control method according to any one of claims 1 to 3, characterized in that: The control method further comprises: After the third moment, the sum of the first braking force and the second braking force is controlled to decrease to zero simultaneously with the vehicle speed of the electric vehicle.

5. The control method according to any one of claims 1 to 3, characterized in that: The control method further comprises: Between the second time point and the third time point, the greater the vehicle speed of the electric vehicle is, the smaller the reduction rate of one of the first braking force and the second braking force is controlled.

6. The control method according to claim 1, characterized in that: The control method specifically includes: At a first moment in the braking process of the electric vehicle, the opening of the brake pedal is less than or equal to the preset opening, and the first braking force is controlled to increase as the opening of the brake pedal increases; At a first moment in the braking process of the electric vehicle, the opening of the brake pedal is greater than the preset opening, and the first braking force is controlled not to increase with the increase of the opening of the brake pedal.

7. The control method according to any one of claims 1 to 6, characterized in that: The control method further comprises: At a fourth moment after the third moment, the speed of the electric vehicle decreases to zero, and the second braking force output by the braking device is controlled to increase.

8. The control method according to claim 7, characterized in that: The control method specifically includes: At the fourth moment, the second braking force output by the braking device is controlled to increase to be greater than the braking force output by the braking device at the first moment.

9. The control method according to claim 7 or 8, characterized in that: The control method further comprises: At a fifth moment after the fourth moment, the opening degree of the brake pedal is reduced to zero, and the second braking force output by the braking device is controlled to be reduced to zero.

10. The control method according to claim 1, characterized in that: The control method further comprises: During a braking process in which the deceleration of the electric vehicle is greater than or equal to the preset deceleration, the first braking force output by the drive motor is controlled to increase or remain unchanged until the speed of the electric vehicle decreases to zero.

11. A control method for comfortable braking of an electric vehicle, characterized in that: The control method is used to control a first braking force output by a driving motor of the electric vehicle during a braking process in which the deceleration of the electric vehicle is less than a preset deceleration so as to reduce the shaking of the electric vehicle during the braking process, and the control method includes: At a first moment during the braking process of the electric vehicle, the opening of the brake pedal increases to be less than or equal to a preset opening, and the drive motor is controlled to output the first braking force; At a second moment after the first moment, the speed of the electric vehicle decreases to less than or equal to a second preset speed, and the first braking force is controlled to decrease.

12. The control method according to claim 11, characterized in that: The control method specifically includes: After the second moment, the first braking force and the vehicle speed of the electric vehicle are controlled to decrease to zero simultaneously.

13. A vehicle controller for comfortable braking control of an electric vehicle, characterized in that: The vehicle controller is used to implement the control method according to any one of claims 1 to 10, and the vehicle controller is used to control the first braking force output by the driving motor of the electric vehicle or the second braking force output by the braking device during the braking process in which the deceleration of the electric vehicle is less than the preset deceleration, and the vehicle controller is specifically used to: During the braking process of the electric vehicle, in response to the opening of the brake pedal increasing to be greater than a preset opening, the drive motor is controlled to output the first braking force and the brake device is controlled to output the second braking force to brake the four wheels of the electric vehicle; In response to a vehicle speed of the electric vehicle decreasing to be less than or equal to a first preset vehicle speed, one of the first braking force and the second braking force is controlled to decrease and then the other of the first braking force and the second braking force is controlled to decrease.

14. A vehicle controller for comfortable braking control of an electric vehicle, characterized in that: The vehicle controller is used to implement the control method according to any one of claims 11 to 12, and the vehicle controller is used to control the first braking force output by the drive motor of the electric vehicle during a braking process in which the deceleration of the electric vehicle is less than a preset deceleration, and the vehicle controller is specifically used to: During the braking process of the electric vehicle, in response to the opening of the brake pedal increasing to be less than or equal to a preset opening, controlling the drive motor to output the first braking force to brake the four wheels of the electric vehicle; In response to the vehicle speed of the electric vehicle decreasing to be less than or equal to a second preset vehicle speed, the first braking force is controlled to decrease.

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

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