Driving control method and apparatus for electric vehicle, and electric vehicle

Abstract

A driving control method and apparatus for an electric vehicle, and an electric vehicle, which can improve the speed control stability of the vehicle. The driving control method for an electric vehicle comprises: on the basis of an actual rotational speed of a vehicle and a target rotational speed of the vehicle, acquiring a total torque required by the vehicle; acquiring a first actual torque value of a front wheel electric motor and a second actual torque value of a rear wheel electric motor during start-up control; on the basis of an actual load ratio of front wheels to rear wheels, determining a torque distribution ratio of the front wheels to the rear wheels; on the basis of a speed difference between the front wheels and the rear wheels, determining anti-slip compensation values for the front wheels and the rear wheels; on the basis of a preset torque limit value of the vehicle, determining output limit values of the front wheel electric motor and the rear wheel electric motor; and on the basis of the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio of the front wheels to the rear wheels, the anti-slip compensation values for the front wheels and the rear wheels, and the output limit values of the front wheel electric motor and the rear wheel electric motor, controlling the front wheel electric motor to output a first torque value, and controlling the rear wheel electric motor to output a second torque value.

Description

A method, device and electric vehicle for driving control

[0001] This application claims priority to Chinese Patent Application No. 202510115985.0, filed on January 23, 2025, entitled "A Method, Apparatus and Electric Vehicle for Driving Control", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of vehicle control technology, specifically to an electric vehicle driving control method, device, and electric vehicle. Background Technology

[0003] With increasing global awareness of environmental protection and the transformation of energy structures, electric vehicles, as representatives of new energy vehicles, have experienced rapid development in recent years. However, when electric vehicles are applied to road machinery, existing technologies are difficult to apply due to the different operating characteristics of the equipment compared to electric vehicles. For example, while existing dual-drive electric vehicles can achieve torque distribution between the front and rear wheels, they cannot maintain vehicle speed while simultaneously achieving torque distribution, thus reducing the vehicle's speed control stability. Summary of the Invention

[0004] To address the aforementioned technical problems, this application is proposed. Embodiments of this application provide an electric vehicle driving control method, apparatus, and electric vehicle, which can improve the speed control stability of the vehicle.

[0005] According to a first aspect of this application, an electric vehicle driving control method is provided, comprising: obtaining the total torque required by the vehicle based on the actual rotational speed of the vehicle and the target rotational speed of the vehicle; wherein the vehicle includes front wheels, rear wheels, a front wheel motor, and a rear wheel motor; obtaining a first actual torque value of the front wheel motor and a second actual torque value of the rear wheel motor during start-up control; determining the torque distribution ratio between the front and rear wheels based on the actual load ratio between the front and rear wheels; determining the anti-slip compensation value between the front and rear wheels based on the speed difference between the front and rear wheels; determining the output limit values ​​of the front wheel motor and the rear wheel motor based on a preset torque limit value of the vehicle; and controlling the front wheel motor to output the first torque value and controlling the rear wheel motor to output the second torque value based on the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value between the front and rear wheels, and the output limit values ​​of the front and rear wheel motors.

[0006] One possible implementation involves obtaining the total torque required by the vehicle based on its actual speed and target speed, including: obtaining the difference between the actual speed and target speed; finding the corresponding proportional and integral coefficients in a preset table based on the difference between the actual speed and target speed; and adjusting the difference between the actual speed and target speed using proportional and integral coefficients to obtain the total torque required by the vehicle.

[0007] As one possible implementation, obtaining the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor during start-up control includes: when entering start-up control, the motor control performs zero-speed control mode and opens the brake release valve; when the vehicle's brake release pressure is greater than the brake release opening value, the start-up control is determined to be completed; when the start-up control is completed and the start-up control is exited, the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor are read and recorded.

[0008] As one possible implementation, based on the total torque required by the vehicle, a first actual torque value, a second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors, controlling the front wheel motor to output a first torque value and controlling the rear wheel motor to output a second torque value includes: determining the vehicle's driving road state based on the first actual torque value of the front wheel motor, the second actual torque value of the rear wheel motor, and a preset torque; wherein, the driving road state includes driving on flat roads and driving on slopes; when the vehicle's driving road state is driving on a slope, controlling the front wheel motor to output a first torque value greater than or equal to the first actual torque value, and controlling the rear wheel motor to output a second torque value greater than or equal to the second actual torque value.

[0009] As one possible implementation, after determining the torque distribution ratio between the front and rear wheels based on the actual load ratio of the front and rear wheels, the electric vehicle driving control method includes: allocating a first torque proportional coefficient to the front wheels and a second torque proportional coefficient to the rear wheels based on the torque distribution ratio between the front and rear wheels; wherein, according to the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors, controlling the front wheel motor to output a first torque value and controlling the rear wheel motor to output a second torque value includes: controlling the front wheel motor to output a first torque value according to the total torque required by the vehicle, the first actual torque value, the first torque proportional coefficient, the anti-slip compensation value of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors; and controlling the rear wheel motor to output a second torque value according to the total torque required by the vehicle, the second actual torque value, the second torque proportional coefficient, the anti-slip compensation value of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors.

[0010] As one possible implementation, the anti-slip compensation value of the front and rear wheels is determined based on the speed difference between the front and rear wheels, including: when the first speed difference between the front and rear wheels is greater than a preset speed difference, the slipping wheel and the non-slipping wheel are determined based on the first real-time rotational speed value of the front wheel and the second real-time rotational speed value of the rear wheel; the anti-slip compensation value of the slipping wheel is calculated based on the minimum speed difference, maximum speed difference, maximum compensation value and the first speed difference between the front and rear wheels.

[0011] As one possible implementation, determining the anti-slip compensation value of the front and rear wheels based on the speed difference between the front and rear wheels also includes: obtaining the second speed difference between the real-time rotational speed of the non-slipping wheel and the vehicle's target rotational speed; and calculating the anti-slip compensation value of the non-slipping wheel based on the anti-slip compensation value of the slipping wheel, the minimum speed difference, the maximum speed difference, the maximum compensation value, and the second speed difference between the front and rear wheels.

[0012] As one possible implementation, the anti-slip compensation value of the non-slipping wheel is calculated based on the anti-slip compensation value of the slipping wheel, the minimum speed difference, maximum speed difference, maximum compensation value, and second speed difference between the front and rear wheels. This includes: when the real-time rotational speed of the non-slipping wheel is less than the vehicle's target rotational speed, the anti-slip compensation value of the non-slipping wheel is the negative of the anti-slip compensation value of the slipping wheel; when the real-time rotational speed of the non-slipping wheel is greater than or equal to the vehicle's target rotational speed, the anti-slip compensation value of the non-slipping wheel is related to the minimum speed difference, maximum speed difference, maximum compensation value, and second speed difference between the front and rear wheels.

[0013] According to a second aspect of this application, an electric vehicle driving control device is provided, comprising: a first acquisition module, configured to acquire the total torque required by the vehicle based on the actual rotational speed of the vehicle and the target rotational speed of the vehicle; wherein the vehicle includes front wheels, rear wheels, a front wheel motor, and a rear wheel motor; a second acquisition module, configured to acquire a first actual torque value of the front wheel motor and a second actual torque value of the rear wheel motor during start-up control; a first determination module, configured to determine the torque distribution ratio between the front and rear wheels based on the actual load ratio between the front and rear wheels; a second determination module, configured to determine the anti-slip compensation value between the front and rear wheels based on the speed difference between the front and rear wheels; a third determination module, configured to determine the output limit values ​​of the front wheel motor and the rear wheel motor based on a preset torque limit value of the vehicle; and a control module, configured to control the front wheel motor to output the first torque value and control the rear wheel motor to output the second torque value based on the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value between the front and rear wheels, and the output limit values ​​of the front and rear wheel motors.

[0014] According to a third aspect of this application, an electric vehicle is provided, comprising: a front wheel motor and a rear wheel motor; and an electric vehicle driving control device as described in the second aspect, wherein the electric vehicle driving control device is electrically connected to the front wheel motor and the electric vehicle driving control device is electrically connected to the rear wheel motor.

[0015] The electric vehicle driving control method, device, and electric vehicle provided in this application consider the actual speed and target speed of the vehicle during the control process to achieve closed-loop speed control. Based on the actual torque of the front and rear wheels during start-up control, the start-up output torque can be controlled to reduce the possibility of slippage during start-up. Anti-slip compensation is performed considering the speed difference between the front and rear wheels to further improve the stability of wheel control. After proportional distribution, start-up control, and drive anti-slip control, the front and rear wheel-side motors are controlled to output corresponding target torques, realizing front and rear wheel torque distribution and closed-loop speed control, thereby improving the speed control stability of the vehicle. Attached Figure Description

[0016] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 is a schematic diagram of the structure of a control system for an electric vehicle provided in an exemplary embodiment of this application.

[0018] Figure 2 is a flowchart illustrating an exemplary embodiment of the electric vehicle driving control method provided in this application.

[0019] Figure 3 is a schematic diagram illustrating the calculation principle of the total torque required for a vehicle according to an exemplary embodiment of this application.

[0020] Figure 4 is a schematic diagram of the start-up control process provided in an exemplary embodiment of this application.

[0021] Figure 5 is a schematic diagram of the structure of an electric vehicle driving control device provided in an exemplary embodiment of this application.

[0022] Figure 6 is a structural diagram of an electronic device provided in an exemplary embodiment of this application.

[0023] Explanation of reference numerals in the attached diagram: 11. Handle; 12. Vehicle controller; 131. Front wheel motor controller; 132. Rear wheel motor controller; 141. Front wheel motor; 142. Rear wheel motor; 151. Front wheel reducer and steel wheel; 152. Rear wheel reducer and steel wheel; 16. Battery management system; 17. Hydraulic parking system. Detailed Implementation

[0024] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0025] Application Overview

[0026] Distributed electric drive systems typically employ direct drive via motors and reducers, offering advantages such as energy efficiency, high power, and simple transmission structure, making them a hot research topic in the electric vehicle field. However, when applied to road machinery, existing technologies cannot be directly applied due to the different operating characteristics of the equipment compared to electric vehicles. For example, a dual-drive electric roller using a distributed electric drive system may encounter the following challenges in travel control: 1. Achieving torque distribution between the front and rear wheels is crucial to avoid uneven torque distribution or even wheel collisions; 2. Implementing anti-slip and anti-rollover functions during travel is essential.

[0027] To address the incompatibility of distributed electric drive solutions in the field of road machinery, this application proposes an electric vehicle driving control method, device, and electric vehicle. By obtaining the difference between the actual speed and the target speed of the vehicle, the method adjusts the difference to obtain the total torque required by the vehicle. After proportional distribution, start-up control, and drive anti-slip control, the method controls the front wheel motor and the rear wheel motor to output the corresponding target torque, thereby realizing front and rear wheel torque distribution and closed-loop speed control. This method is suitable for low-speed, forward and reverse switching work equipment that needs to maintain speed.

[0028] Exemplary vehicle

[0029] The electric vehicle driving control method provided in this application is applicable to electric vehicles, which include a front wheel motor and a rear wheel motor. The electric vehicle driving control device provided in this application is electrically connected to the front wheel motor and electrically connected to the rear wheel motor.

[0030] Electric vehicle driving control devices are used to execute electric vehicle driving control methods. The electric vehicle can be a road machinery vehicle, such as a distributed dual-drive electric road roller, a distributed dual-drive electric excavator, and a distributed dual-drive electric loader. Distributed dual-drive electric vehicles use two or more motors to drive the vehicle, and the distributed drive system can independently control the torque and speed of each wheel.

[0031] Figure 1 is a schematic diagram of the structure of the control system of an electric vehicle provided in an exemplary embodiment of this application. As shown in Figure 1, the control system of the electric vehicle includes a handle 11, a vehicle controller 12, a front wheel motor controller 131, a front wheel motor 141, a front wheel reducer and steel wheel 151, a rear wheel motor controller 132, a rear wheel motor 142, a rear wheel reducer and steel wheel 152, a battery management system 16 (BMS), and a hydraulic parking system 17.

[0032] In electric vehicles, handle 11 typically refers to the accelerator pedal and brake pedal, along with their associated operating mechanisms. The function of handle 11 is to convert the driver's acceleration and braking intentions into electrical signals, which are then input into the vehicle controller 12 to control the vehicle's acceleration, deceleration, and braking. The vehicle controller 12 (VCU) is the core control component of an electric vehicle, responsible for controlling the vehicle's critical tasks. The VCU can be used for drive torque control, controlling the motor's output torque based on the driver's input (such as the accelerator and brake pedal inputs) to achieve vehicle acceleration and deceleration. It can also be used for braking energy optimization, energy management, network management, and fault diagnosis. The front wheel motor controller 131 and rear wheel motor controller 132 are control units that control the motors driving the vehicle; they are core components of electric vehicles. The motor controllers can be used for regulating motor operation, precise control, energy recovery, and real-time monitoring. The front wheel motor 141 and rear wheel motor 142 are the power sources of the electric vehicle, responsible for converting electrical energy into mechanical energy to drive the vehicle. Distributed dual-drive electric vehicles use two or more motors to drive the vehicle together; therefore, the front wheel motor 141 and rear wheel motor 142 can be configured to control the front and rear wheels separately. The front wheel reducer and rear wheel reducer convert the high-speed, low-torque output of the motor into a low-speed, high-torque output suitable for the wheels, ensuring sufficient power for low-speed driving and starting. The steel wheels are the driving components of the electric vehicle, responsible for transmitting the driving force of the motor to the road surface, enabling the vehicle to move forward, backward, and steer. The battery management system 16 monitors the working status and efficiency of the battery pack, achieving battery balance management, heat dissipation and heating management, and safety assurance. The hydraulic parking system 17 is the parking brake device of the electric vehicle, its main function being to provide sufficient braking force when the vehicle is parked to prevent the vehicle from sliding or rolling. The hydraulic parking system 17 typically features easy operation, large braking force, and high reliability, providing a safe and reliable parking brake for the electric vehicle.

[0033] Exemplary methods

[0034] To address the incompatibility of distributed electric drive solutions in road machinery applications, Figure 2 is a flowchart illustrating an exemplary embodiment of an electric vehicle driving control method provided in this application. Taking Figure 2 as an example, the vehicle includes front wheels, rear wheels, a front wheel motor, and a rear wheel motor. First, based on the vehicle's actual rotational speed and target rotational speed, the total torque required by the vehicle is obtained (see S100 in Figure 2). Then, the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor during start-up control are obtained (see S200 in Figure 2). The actual torque value during start-up control is recorded and can be used to control the start-up output torque to reduce the possibility of rollback. Next, based on the actual load ratio of the front and rear wheels, the torque distribution ratio between the front and rear wheels is determined (see S300 in Figure 2). A distribution coefficient is calculated based on the vehicle's real-time state, such as the wheel load ratio, so that the front and rear wheel motors can output torque corresponding to the distribution coefficient. Next, based on the speed difference between the front and rear wheels, the anti-slip compensation values ​​for the front and rear wheels are determined (see S400 in Figure 2). When the front and rear wheel speeds are inconsistent, resulting in a speed difference, negative compensation can be applied to the slipping wheel to reduce torque distribution, while positive compensation can be applied to the non-slipping wheel to increase torque, thereby achieving drive anti-slip control. Then, based on the vehicle's preset torque limit value, the output limit values ​​for the front and rear wheel motors are determined (see S500 in Figure 2). Limiting the torque of the front and rear wheel motors protects the powertrain, improves driving safety, and optimizes energy use. Finally, based on the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value between the front and rear wheels, and the output limit values ​​of the front and rear wheel motors, the front wheel motor is controlled to output the first torque value, and the rear wheel motor is controlled to output the second torque value (see S600 in Figure 2). After considering the proportional distribution, start control, and drive anti-slip control, the front and rear wheel side motors are controlled to output the corresponding target torque, thereby realizing the front and rear wheel torque distribution and vehicle speed closed-loop control and improving vehicle control stability.

[0035] The electric vehicle driving control method provided in the embodiments of this application will be described in more detail below with reference to Figure 2.

[0036] In the S100, the total torque required by the vehicle is obtained based on the vehicle's actual speed and target speed. By adjusting the torque according to the vehicle's actual speed and target speed, closed-loop speed control can be achieved.

[0037] One possible implementation of S100 is as follows: obtain the difference between the actual vehicle speed and the target vehicle speed; based on the difference between the actual vehicle speed and the target vehicle speed, look up the corresponding proportional coefficient and integral coefficient in a preset table; based on the corresponding proportional coefficient and integral coefficient, perform proportional-integral adjustment on the difference between the actual vehicle speed and the target vehicle speed to obtain the total torque required by the vehicle.

[0038] Figure 3 is a schematic diagram illustrating the calculation principle of the total torque required by the vehicle according to an exemplary embodiment of this application. As shown in Figure 3, the actual speed of the vehicle is first obtained, and then the target speed of the vehicle is obtained by processing the handle opening. The difference E between the actual speed and the target speed is calculated. Based on the difference E, PI (proportional-integral) control is performed to obtain the total torque T required by the vehicle. t PI control, or proportional-integral control, is a widely used controller in industrial control systems. It combines proportional (P) and integral (I) control mechanisms, achieving precise control of the system output by adjusting these two parameters. Proportional control amplifies the deviation between the input signal (in this case, the speed difference) and the setpoint to generate a control signal. Its characteristics include fast response, allowing for rapid adjustment of the system output to reduce deviation. Integral control eliminates the steady-state error inherent in proportional control. By integrating the deviation signal, the PI controller generates a control signal proportional to the accumulated deviation. This signal accumulates over time until the deviation is completely eliminated, at which point integral control ceases. Thus, integral control improves the system's error-free performance.

[0039] Furthermore, in vehicles operating under complex conditions, different speeds and loads require different parameter adjustments. Therefore, different gears can be set according to different target speeds. For example, distributed dual-drive road rollers operate under complex conditions, and the load span is difficult to statistically distinguish. The difference between the target speed and the actual speed can be used to represent the load. The gears are set as low, medium, and high load levels based on the difference between the target and actual speeds, and different KP (proportional coefficient) and KI (integral coefficient) are set for adjustment to meet the speed response of complex load conditions. KP reflects the controller's response speed and sensitivity to deviation signals. When there is a deviation between the actual speed and the target speed, the KP parameter determines how much adjustment the controller outputs to eliminate this deviation. The larger the deviation, the larger the adjustment, thereby accelerating the system response speed and bringing the actual speed closer to the target speed as quickly as possible. The KI parameter reflects the cumulative effect of the controller on deviation signals. By accumulating deviation signals, integral adjustment can gradually eliminate the static error of the system and improve control accuracy.

[0040] In some embodiments, the preset table can be set as Table 1:

[0041] Table 1

[0042] In S200, the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor are obtained during start-up control. The torque value during start-up control helps prevent the vehicle from rolling backward during start-up.

[0043] Figure 4 is a schematic flowchart of the start-up control provided in an exemplary embodiment of this application. Taking Figure 4 as an example, one possible implementation of S200 is as follows: When entering start-up control, the motor control performs zero-speed control mode and opens the brake release valve (see S41 in Figure 4); it is determined whether the brake release pressure is greater than the brake release opening value (see S42 in Figure 4). When the vehicle's brake release pressure is greater than the brake release opening value, it is determined that the start-up control is completed; when the start-up control is completed and the start-up control is exited, the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor are read and recorded (see S43 in Figure 4). If the vehicle's brake release pressure is less than or equal to the brake release opening value, the brake release valve continues to open. A brake release pressure greater than the brake release opening value means that during the process of releasing the brake, the pressure generated inside the brake system exceeds the preset brake release opening value. This usually indicates that the brake system has completed the transition from the locked state to the released state, that is, the brake has been completely released. Zero-speed control mode refers to a mode in which the system takes specific control measures when the motor speed is maintained at a certain set value (usually close to or equal to zero).

[0044] Recording the torque during start-up control can be used to determine if the vehicle is on a slope. For example, based on the first actual torque value of the front wheel motor, the second actual torque value of the rear wheel motor, and a preset torque, the road condition is determined. The preset torque can be the torque recorded when the vehicle is on flat ground, or it can be a torque value set based on the torque recorded when the vehicle is on flat ground. By comparing the first actual torque value of the front wheel motor, the second actual torque value of the rear wheel motor, and the preset torque, it can be determined whether the vehicle is on a slope. When the vehicle is on a slope, the control ensures that the first torque value output by the front wheel motor is greater than or equal to the first actual torque value, and the control ensures that the second torque value output by the rear wheel motor is greater than or equal to the second actual torque value. The purpose is to ensure that the start-up output torque is not less than the torque output in the zero-speed control mode, ensuring that the vehicle does not roll back from a start.

[0045] In some embodiments, after the brake release pressure exceeds the brake release threshold, a delay of T1S (set as needed) can be used to determine whether the start-up control is complete. When the brake release pressure exceeds the threshold, it usually means that the driver has expressed the intention to start. To ensure the clarity of this intention, the system needs a certain amount of time to confirm. Delaying the determination helps the system more accurately determine whether the brake is fully released, avoiding triggering a jump out of start-up control (when the brake has not actually been released) due to misoperation or brief pressure changes. Furthermore, after the brake release pressure exceeds the threshold, these systems need a certain amount of time to respond and reach a stable state. Delaying the determination ensures that the vehicle system has fully responded and is ready to start, thereby improving the smoothness and stability of the start-up.

[0046] In S300, based on the actual load ratio of the front and rear wheels, determine the torque distribution ratio of the front and rear wheels. The actual load ratio of the front and rear wheels is affected by the attributes of the vehicle itself. For example, the total weight of the vehicle is the basis for determining the loads on the front and rear wheels. The position of the engine has a certain impact on the load ratio of the front and rear wheels. Vehicles with a front-mounted engine usually have a heavier load on the front axle, while vehicles with a rear-mounted engine have a heavier load on the rear axle. The driving habits of the driver, such as accelerating, braking, and turning, will also affect the load ratio of the front and rear wheels. Therefore, based on the attributes and operating conditions of each vehicle itself, obtain the actual load ratio of the front and rear wheels of the vehicle. Based on the actual load ratio, determine the torque distribution ratio of the front and rear wheels.

[0047] In some embodiments, after S300, based on the torque distribution ratio of the front and rear wheels, assign a first torque ratio coefficient to the front wheel and a second torque ratio coefficient to the rear wheel. According to the total torque required by the vehicle, the first actual torque value, the first torque ratio coefficient, the anti-slip compensation values of the front and rear wheels, and the output limit values of the front-wheel motor and the rear-wheel motor, control the front-wheel motor to output a first torque value; according to the total torque required by the vehicle, the second actual torque value, the second torque ratio coefficient, the anti-slip compensation values of the front and rear wheels, and the output limit values of the front-wheel motor and the rear-wheel motor, control the rear-wheel motor to output a second torque value.

[0048] For example, the sum of the first torque ratio coefficient of the front wheel and the second torque ratio coefficient of the rear wheel is 1, that is, a + b = 1, where a can represent the first torque ratio coefficient of the front wheel, b can represent the second torque ratio coefficient of the rear wheel, and 0 < a < 1, 0 < b < 1. In some ideal states, the loads on the front and rear wheels are close, so a:b = 1, a = 0.5, b = 0.5 can be set.

[0049] In S400, based on the speed difference between the front and rear wheels, determine the anti-slip compensation values of the front and rear wheels. After determining the torque distribution ratio, different situations of the frictional forces between the front and rear wheels may be encountered. When the driving force distributed to the wheels is greater than their frictional forces, a slipping phenomenon will occur, manifested as a speed difference due to inconsistent rotational speeds of the front and rear wheels. Calculate the anti-slip compensation torques of the front and rear wheels through anti-slip control, give negative compensation to the slipping wheel (high-speed wheel) to reduce torque distribution, and give positive compensation to the non-slipping wheel (low-speed wheel) to increase torque, so as to achieve drive anti-slip control.

[0050] In some embodiments, a possible implementation of anti-slip compensation is as follows: when the first speed difference between the front wheel and the rear wheel is greater than a preset speed difference, the slipping wheel and the non-slipping wheel are determined based on the first real-time rotational speed of the front wheel and the second real-time rotational speed of the rear wheel; the anti-slip compensation value of the slipping wheel is calculated based on the minimum speed difference, maximum speed difference, maximum compensation value, and the first speed difference between the front wheel and the rear wheel. The second speed difference between the real-time rotational speed of the non-slipping wheel and the vehicle's target rotational speed is obtained; the anti-slip compensation value of the non-slipping wheel is calculated based on the anti-slip compensation value of the slipping wheel, the minimum speed difference, maximum speed difference, maximum compensation value, and the second speed difference between the front wheel and the rear wheel.

[0051] For example, first compare the rotational speeds of the front and rear wheels, and obtain the initial speed difference SD1 between the front and rear wheels. Determine the wheel with the faster speed as the slipping wheel and the wheel with the slower speed as the non-slipping wheel. Calculate the anti-slip compensation value T for the slipping wheel. a =map(SD) min SD max ,0,T amax ,SD1), where, T a SD represents the anti-slip compensation value of the slipper wheel. min Indicates the minimum speed difference, SD max T represents the maximum speed difference. amax This represents the maximum anti-slip compensation value, and SD1 represents the first speed difference. After calculating the anti-slip compensation value for the slipping wheel, the real-time rotational speed of the non-slipping wheel is compared with the vehicle's target rotational speed to obtain the second speed difference SD2. The anti-slip compensation value for the non-slipping wheel is then calculated. When the real-time rotational speed of the non-slipping wheel is less than the vehicle's target rotational speed, the anti-slip compensation value for the non-slipping wheel is the negative of the anti-slip compensation value for the slipping wheel, such as T. n1 =-T a When the real-time speed of the non-slipping wheel is greater than or equal to the vehicle's target speed, the anti-slip compensation value of the non-slipping wheel is related to the minimum speed difference, maximum speed difference, maximum compensation value, and second speed difference between the front and rear wheels, such as T. n2 =map(SD) min SD max ,0,T amax ,SD2),T n1 and T n2 This indicates the anti-slip compensation value for the non-slipping wheel at different speeds.

[0052] In the S500, the output limits for the front and rear wheel motors are determined based on the vehicle's preset torque limit values. To limit the motor torque, the minimum value between the vehicle's rated motor torque and the fault power limit torque is taken as the maximum output torque for both the front and rear wheel motors—the minimum limit torque. Limiting the torque of the front and rear wheel motors prevents overloading of the powertrain. Furthermore, under extreme driving conditions, such as on slippery surfaces or during rapid acceleration, excessive torque could lead to vehicle skidding or loss of control. By limiting torque, vehicle stability is improved, ensuring driving safety.

[0053] In the S600, based on the vehicle's required total torque, a first actual torque value, a second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value for the front and rear wheels, and the output limits of the front and rear wheel motors, the front wheel motor outputs the first torque value, and the rear wheel motor outputs the second torque value. By considering the vehicle's required total torque, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value for the front and rear wheels, and the output limits of the front and rear wheel motors when controlling the output torque of the front and rear wheel motors, closed-loop speed control can be achieved, reducing the possibility of rollback during start-up and the possibility of wheel slippage.

[0054] In some embodiments, the method for calculating the first torque value output by the front wheel motor can be: T f =limit{-T max ,max[T sf , (T t *a±T af )], T max}, where T f T represents the first torque value output by the front wheel motor. max T represents the minimum limiting torque (i.e., the output limit value) obtained in the S500. sf T represents the first actual torque value of the front wheel motor obtained during start-up control in S200. t T represents the total torque required by the vehicle in S100, a represents the first torque proportionality coefficient of the front wheels in S300, and T represents the torque required by the vehicle in S100. af This represents the anti-slip compensation value obtained in S400, for example, when the front wheels are slipping, T af For T a T af The value is T a =map(SD) min SD max ,0,T amax ,SD1), if the front wheel is a non-slipping wheel, then T af For T n1 or Tn2 The value is determined based on the ratio of the front wheel speed to the target vehicle speed. When starting control is not on an incline, T... sf The value can be 0. When the first speed difference between the front wheel and the rear wheel is less than or equal to the preset speed difference, T af It can take the value 0.

[0055] In other embodiments, the method for calculating the second torque value output by the rear wheel motor can be: T r =limit{-T max ,max[T sr , (T t *b±T ar )], T max}, where T r T represents the second torque value output by the rear wheel motor. max T represents the minimum limiting torque (i.e., the output limit value) obtained in the S500. sr T represents the second actual torque value of the rear wheel motor obtained during start-up control in S200. t T represents the total torque required by the vehicle in S100, b represents the second torque proportionality coefficient of the rear wheels in S300, and T represents the torque required by the vehicle in S100. ar This represents the anti-slip compensation value obtained in S400, for example, when the rear wheel is slipping, T ar For T a T ar The value is T a =map(SD) min SD max ,0,T amax If the rear wheel is not slipping, then T ar For T n1 or T n2 The value is determined based on the relative speeds of the rear wheels and the target vehicle speed. When starting control is not on an incline, T... sr The value can be 0. When the first speed difference between the front wheel and the rear wheel is less than or equal to the preset speed difference, T ar It can take the value 0.

[0056] Exemplary device

[0057] Figure 5 is a schematic diagram of the structure of an electric vehicle driving control device provided in an exemplary embodiment of this application. As shown in Figure 5, the electric vehicle driving control device 5 includes: a first acquisition module 51, used to acquire the total torque required by the vehicle based on the actual rotational speed of the vehicle and the target rotational speed of the vehicle; wherein the vehicle includes front wheels, rear wheels, a front wheel motor, and a rear wheel motor; a second acquisition module 52, used to acquire the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor during start-up control; and a first determination module 53, used to determine the load ratio of the front wheels and the rear wheels based on the actual load ratio of the front wheels and the rear wheels. The system includes: a torque distribution ratio; a second determining module 54, used to determine the anti-slip compensation value of the front and rear wheels based on the speed difference between the front and rear wheels; a third determining module 55, used to determine the output limit values ​​of the front wheel motor and the rear wheel motor based on the vehicle's preset torque limit value; and a control module 56, used to control the front wheel motor to output a first torque value and the rear wheel motor to output a second torque value based on the vehicle's required total torque, a first actual torque value, a second actual torque value, the torque distribution ratio of the front and rear wheels, the anti-slip compensation value of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors.

[0058] As one possible implementation, the first acquisition module 51 can be configured to: acquire the difference between the actual vehicle speed and the target vehicle speed; based on the difference between the actual vehicle speed and the target vehicle speed, look up the corresponding proportional coefficient and integral coefficient in a preset table; based on the corresponding proportional coefficient and integral coefficient, perform proportional-integral adjustment on the difference between the actual vehicle speed and the target vehicle speed to obtain the total torque required by the vehicle.

[0059] As one possible implementation, the second acquisition module 52 can be configured to: when entering start control, the motor control performs zero-speed control mode and opens the brake release valve; when the vehicle's brake release pressure is greater than the brake release opening value, the start control is determined to be completed; when the start control is completed and the start control is exited, the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor are read and recorded.

[0060] As one possible implementation, the control module 56 can be configured to: determine the driving road state of the vehicle based on the first actual torque value of the front wheel motor, the second actual torque value of the rear wheel motor, and a preset torque; wherein the driving road state includes driving on a flat road and driving on a slope; when the driving road state of the vehicle is driving on a slope, control the front wheel motor to output a first torque value greater than or equal to the first actual torque value, and control the rear wheel motor to output a second torque value greater than or equal to the second actual torque value.

[0061] As one possible implementation, the electric vehicle driving control device 5 can be configured to: allocate a first torque proportional coefficient to the front wheels and a second torque proportional coefficient to the rear wheels based on the torque distribution ratio between the front and rear wheels; wherein, the control module 56 can be configured to: control the front wheel motor to output a first torque value based on the total torque required by the vehicle, a first actual torque value, a first torque proportional coefficient, anti-slip compensation values ​​for the front and rear wheels, and output limit values ​​for the front and rear wheel motors; and control the rear wheel motor to output a second torque value based on the total torque required by the vehicle, a second actual torque value, a second torque proportional coefficient, anti-slip compensation values ​​for the front and rear wheels, and output limit values ​​for the front and rear wheel motors.

[0062] As one possible implementation, the second determining module 54 can be configured to: when the first speed difference between the front wheel and the rear wheel is greater than a preset speed difference, determine the slipping wheel and the non-slipping wheel based on the first real-time rotational speed value of the front wheel and the second real-time rotational speed value of the rear wheel; and calculate the anti-slip compensation value of the slipping wheel based on the minimum speed difference, maximum speed difference, maximum compensation value and the first speed difference between the front wheel and the rear wheel.

[0063] As one possible implementation, the second determining module 54 can also be configured to: obtain the real-time rotational speed value of the non-slipping wheel and the second speed difference between the vehicle's target rotational speed; and calculate the anti-slip compensation value of the non-slipping wheel based on the anti-slip compensation value of the slipping wheel, the minimum speed difference between the front wheel and the rear wheel, the maximum speed difference, the maximum compensation value, and the second speed difference.

[0064] As one possible implementation, the second determining module 54 can also be configured as follows: when the real-time rotational speed of the non-slipping wheel is less than the vehicle target rotational speed, the anti-slip compensation value of the non-slipping wheel is the opposite of the anti-slip compensation value of the slipping wheel; when the real-time rotational speed of the non-slipping wheel is greater than or equal to the vehicle target rotational speed, the anti-slip compensation value of the non-slipping wheel is related to the minimum speed difference, maximum speed difference, maximum compensation value, and second speed difference between the front and rear wheels.

[0065] Exemplary electronic devices

[0066] An electronic device includes: a processor; a memory for storing processor-executable instructions; and a processor for executing the electric vehicle driving control method described in the embodiments provided in this application.

[0067] The electronic device according to an embodiment of this application will now be described with reference to FIG6. The electronic device may be either or both of a first device and a second device, or a standalone device independent of them, which may communicate with the first device and the second device to receive acquired input signals from them.

[0068] Figure 6 illustrates a block diagram of an electronic device according to an embodiment of this application.

[0069] As shown in Figure 6, the electronic device 60 includes one or more processors 61 and a memory 62.

[0070] The processor 61 may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device 60 to perform desired functions.

[0071] The memory 62 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 61 may execute the program instructions to implement the electric vehicle driving control methods of the various embodiments of this application described above, and / or other desired functions. Various contents such as input signals, signal components, and noise components may also be stored in the computer-readable storage medium.

[0072] In one example, the electronic device 60 may also include an input device 63 and an output device 64, which are interconnected via a bus system and / or other forms of connection mechanism (not shown).

[0073] When the electronic device is a standalone device, the input device 63 can be a communication network connector for receiving the acquired input signals from the first device and the second device.

[0074] In addition, the input device 63 may also include, for example, a keyboard, a mouse, etc.

[0075] The output device 64 can output various information to the outside, including determined distance information, direction information, etc. The output device 64 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0076] Of course, for simplicity, Figure 6 only shows some of the components of the electronic device 60 that are relevant to this application, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device 60 may include any other suitable components depending on the specific application.

[0077] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0078] A computer-readable storage medium stores a computer program for executing the electric vehicle driving control method described in the embodiments provided in this application.

[0079] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may, for example, include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0080] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for controlling the driving of an electric vehicle, characterized in that, include: The total torque required by the vehicle is obtained based on the vehicle's actual rotational speed and target rotational speed; the vehicle includes the front wheels, rear wheels, front wheel motor, and rear wheel motor. Obtain the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor during start-up control; Determine the torque distribution ratio between the front and rear wheels based on the actual load ratio between the front and rear wheels; Based on the speed difference between the front and rear wheels, determine the anti-slip compensation values ​​for the front and rear wheels; Based on the vehicle's preset torque limit value, determine the output limit values ​​for the front wheel motor and the rear wheel motor; Based on the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value between the front and rear wheels, and the output limit values ​​of the front and rear wheel motors, the front wheel motor is controlled to output the first torque value, and the rear wheel motor is controlled to output the second torque value.

2. The electric vehicle driving control method according to claim 1, characterized in that, Based on the vehicle's actual rotational speed and target rotational speed, the total torque required by the vehicle is obtained, including: Obtain the difference between the vehicle's actual rotational speed and the vehicle's target rotational speed; Based on the difference between the vehicle's actual speed and the vehicle's target speed, find the corresponding proportional coefficient and integral coefficient in the preset table; Based on the corresponding proportional and integral coefficients, the difference between the actual vehicle speed and the target vehicle speed is adjusted proportionally and integrally to obtain the total torque required by the vehicle.

3. The electric vehicle driving control method according to claim 1, characterized in that, Obtain the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor during start-up control, including: When entering start-up control, the motor control enters zero-speed control mode and opens the brake release valve; When the vehicle's brake release pressure is greater than the brake release opening value, the start control is confirmed to be complete. When the start control is completed and the start control is exited, the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor are read and recorded.

4. The electric vehicle driving control method according to claim 3, characterized in that, Based on the vehicle's required total torque, a first actual torque value, a second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation values ​​for the front and rear wheels, and the output limits of the front and rear wheel motors, the system controls the front wheel motor to output the first torque value and the rear wheel motor to output the second torque value, including: The driving road condition of the vehicle is determined based on the first actual torque value of the front wheel motor, the second actual torque value of the rear wheel motor, and the preset torque; wherein, the driving road condition includes driving on flat roads and driving on slopes; When the vehicle is traveling on a slope, the front wheel motor is controlled to output a first torque value that is greater than or equal to a first actual torque value, and the rear wheel motor is controlled to output a second torque value that is greater than or equal to a second actual torque value.

5. The electric vehicle driving control method according to claim 1, characterized in that, After determining the torque distribution ratio between the front and rear wheels based on the actual load ratio of the front and rear wheels, the electric vehicle driving control method includes: Based on the torque distribution ratio between the front and rear wheels, a first torque ratio coefficient is assigned to the front wheels, and a second torque ratio coefficient is assigned to the rear wheels. Specifically, based on the vehicle's required total torque, a first actual torque value, a second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation values ​​for the front and rear wheels, and the output limit values ​​for the front and rear wheel motors, the system controls the front wheel motor to output the first torque value and controls the rear wheel motor to output the second torque value, including: Based on the total torque required by the vehicle, the first actual torque value, the first torque proportional coefficient, the anti-slip compensation values ​​of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors, the output torque value of the front wheel motor is controlled to be the first torque value. Based on the total torque required by the vehicle, the second actual torque value, the second torque proportional coefficient, the anti-slip compensation values ​​of the front and rear wheels, and the output limit values ​​of the front and rear wheel motors, the rear wheel motor outputs the second torque value.

6. The electric vehicle driving control method according to claim 1, characterized in that, Based on the speed difference between the front and rear wheels, determine the anti-skid compensation values ​​for the front and rear wheels, including: When the first speed difference between the front wheel and the rear wheel is greater than the preset speed difference, the slipping wheel and the non-slipping wheel are determined based on the first real-time rotational speed of the front wheel and the second real-time rotational speed of the rear wheel. Based on the minimum speed difference, maximum speed difference, maximum compensation value, and first speed difference between the front and rear wheels, calculate the anti-slip compensation value for the slipping wheel.

7. The electric vehicle driving control method according to claim 6, characterized in that, Determining the anti-skid compensation values ​​for the front and rear wheels based on the speed difference between them also includes: Obtain the second speed difference between the real-time rotational speed of the non-slipping wheel and the target rotational speed of the vehicle; Calculate the anti-slip compensation value for the non-slipping wheel based on the anti-slip compensation value of the slipping wheel, the minimum speed difference between the front and rear wheels, the maximum speed difference, the maximum compensation value, and the second speed difference.

8. The electric vehicle driving control method according to claim 7, characterized in that, Based on the anti-slip compensation value of the slipping wheel, the minimum speed difference between the front and rear wheels, the maximum speed difference, the maximum compensation value, and the second speed difference, calculate the anti-slip compensation value of the non-slipping wheel, including: When the real-time speed of the non-slipping wheel is less than the vehicle's target speed, the anti-slip compensation value of the non-slipping wheel is the opposite of the anti-slip compensation value of the slipping wheel. When the real-time rotational speed of the non-slipping wheel is greater than or equal to the vehicle's target rotational speed, the anti-slip compensation value of the non-slipping wheel is related to the minimum speed difference, maximum speed difference, maximum compensation value, and second speed difference between the front and rear wheels.

9. An electric vehicle driving control device, characterized in that, include: The first acquisition module is used to acquire the total torque required by the vehicle based on the vehicle's actual rotational speed and the vehicle's target rotational speed; wherein the vehicle includes front wheels, rear wheels, front wheel motors and rear wheel motors; The second acquisition module is used to acquire the first actual torque value of the front wheel motor and the second actual torque value of the rear wheel motor during start-up control. The first determining module is used to determine the torque distribution ratio between the front and rear wheels based on the actual load ratio between the front and rear wheels; The second determining module is used to determine the anti-slip compensation values ​​of the front and rear wheels based on the speed difference between the front and rear wheels; The third determining module is used to determine the output limit values ​​of the front wheel motor and the rear wheel motor based on the vehicle's preset torque limit value; The control module is used to control the front wheel motor to output the first torque value and the rear wheel motor to output the second torque value based on the total torque required by the vehicle, the first actual torque value, the second actual torque value, the torque distribution ratio between the front and rear wheels, the anti-slip compensation value between the front and rear wheels, and the output limit values ​​of the front wheel motor and the rear wheel motor.

10. An electric vehicle, characterized in that, include: Front wheel motor and rear wheel motor; The electric vehicle driving control device as described in claim 9, wherein the electric vehicle driving control device is electrically connected to the front wheel motor and the electric vehicle driving control device is electrically connected to the rear wheel motor.

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