Torque control method and device
By monitoring the state changes of the front axle of the electric vehicle and pre-controlling the rear axle, the problem of unstable driving when the road friction coefficient changes is solved, and a better driving experience is achieved.
Patent Information
- Application Number
- CN202510125840.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-27
- Publication Date
- 2025-03-21
AI Technical Summary
When the road friction coefficient of electric vehicles changes, the driving torque of the front axle and rear axle of the vehicle is not controlled in time, resulting in unstable driving of the vehicle.
By monitoring the operating state of the front axle of the vehicle, it is determined whether the state changes occur, and after the change occurs, the torque pre-control of the rear axle of the vehicle is performed so that its driving torque changes in the same direction as the front axle.
It effectively improves the vehicle's driving stability on the road surface that changes in friction coefficient and improves the passenger's driving experience.
Smart Images
Figure CN119659361A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of vehicle control. More specifically, the present application relates to a torque control method for an electric vehicle, which is intended to improve the driving experience of the vehicle. The present application also relates to a torque control device, a computer system, a computer-readable storage medium, and a computer program product. Background Art
[0002] The electric vehicle may be provided with at least two drive motors, and the front axle and the rear axle of the vehicle may be driven respectively. The front axle of the vehicle may drive the two front wheels of the vehicle, and the rear axle of the vehicle may drive the two rear wheels of the vehicle. The front axle and the rear axle of the vehicle may have different driving torques respectively, and the torque of the front axle of the vehicle and the torque of the rear axle of the vehicle may be controlled respectively by independent control methods. When the friction coefficient changes significantly on the road surface on which the vehicle is traveling, the control torque of the front axle of the vehicle will change before the control torque of the rear axle of the vehicle, thereby causing the vehicle to travel unsteadily. Summary of the invention
[0003] The purpose of the present application is to provide a torque control method for an electric vehicle, which can effectively improve the driving experience of the vehicle. The purpose of the present application is to provide a torque control device, a computer system, a computer readable storage medium and a computer program product to implement the above torque control method.
[0004] The purpose of this application is achieved through the following technical solutions: A torque control method for an electric vehicle comprises the following steps: Monitor the operating status of the vehicle's front axle; Determine whether the state of the front axle of the vehicle changes; After the state of the front axle of the vehicle changes, the torque of the rear axle of the vehicle is pre-controlled; The torque pre-control includes: changing the driving torque of the rear axle of the vehicle and the driving torque of the front axle of the vehicle in the same direction and synchronously.
[0005] A torque control device executes the steps of the torque control method for an electric vehicle.
[0006] A computer system comprises a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the torque control method for an electric vehicle.
[0007] A computer-readable storage medium stores a computer program, wherein the computer program implements the steps of the torque control method for an electric vehicle when executed by a processor.
[0008] A computer program product includes a computer program, wherein the computer program implements the steps of the torque control method for an electric vehicle when the computer program is executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present application will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments. Those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present application. In addition, unless otherwise specified, the drawings are intended only to conceptually represent the composition or structure of the described objects and may contain exaggerated displays. The drawings are not necessarily drawn to scale.
[0010] Figure 1 It is a flow chart of an embodiment of the torque control method of the present application.
[0011] Figure 2 yes Figure 1 A partial flow chart of the embodiment shown in .
[0012] Figure 3 yes Figure 1 Another partial flow chart of the embodiment shown in . DETAILED DESCRIPTION
[0013] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings. It will be appreciated by those skilled in the art that these descriptions are only illustrative and exemplary and should not be construed as limiting the scope of protection of the present application.
[0014] First, it should be noted that the top, bottom, upward, downward, and other directional terms mentioned in this article are defined relative to the directions in the various drawings. These directions are relative concepts and will therefore vary depending on the position and state they are in. Therefore, these or other directional terms should not be understood as restrictive.
[0015] In addition, it should be pointed out that for any single technical feature described or implied in the embodiments of this document or any single technical feature shown or implied in the accompanying drawings, these technical features (or their equivalents) can be further combined to obtain other embodiments not directly mentioned in this document.
[0016] It should be noted that in different drawings, the same reference numerals denote the same or substantially the same components.
[0017] Figures 1 to 3 Various aspects of an embodiment of the torque control method of the present application are presented. Figure 1 The overall structure of an embodiment of the torque control method for an electric vehicle of the present application is shown, and Figure 2 and Figure 3 They were shown Figure 1 The specific details of step 300 and step 500 in FIG.
[0018] According to one embodiment of the present application, the torque control method for an electric vehicle may include the following steps: a start and monitoring step 100, a state determination step 200, a torque pre-control step 300, a predetermined time determination step 400, a correction step 500 and an end 600. Figure 1 As shown, the above steps can be performed sequentially, and different branch routes are executed according to different judgments at the state judgment step 200 and the predetermined time judgment step 400. As shown in the figure, the letter Y represents the branch route when a "yes" judgment is made, and the letter N represents the branch route when a "no" judgment is made. In one embodiment, the torque control method for an electric vehicle may include at least the following steps: a start and monitoring step 100, a state judgment step 200, a torque pre-control step 300, etc.
[0019] Specifically, at the start and monitoring component 100, the torque control method for an electric vehicle according to an embodiment of the present application is started, and one or more of the following operating parameters of the vehicle are collected: vehicle front axle speed, reference vehicle speed of the whole vehicle, vehicle front axle actual torque, vehicle rear axle actual torque, vehicle front axle target torque and vehicle rear axle target torque. In one embodiment, the vehicle control system can continuously monitor and provide the above parameters. In one embodiment, the vehicle to which the embodiment of the present application is applied can be an electric vehicle with a distributed motor control (Distributed Motor Control, abbreviated as DMC) function. In one embodiment, the embodiment of the present application can be applied in the traction control system (Traction Control System, abbreviated as TCS) of a vehicle.
[0020] At state step 200, a torque control method for an electric vehicle according to an embodiment of the present application determines whether a state change occurs in the front axle of the vehicle. Such a state change may include the wheels switching from traveling on a road surface having a first friction coefficient to traveling on a road surface having a second friction coefficient. In one embodiment, such a state change may include the wheels switching from traveling on a road surface having a relatively high friction coefficient to traveling on a road surface having a relatively low friction coefficient. In one embodiment, such a state change reflects a fundamental change in road surface conditions, such as switching from a cement road surface to a soil road surface. In one embodiment, such a state change reflects a local change in road surface conditions, such as the presence of foreign garbage, localized water accumulation or ice on the road surface.
[0021] The torque control method of the present application is intended to identify such road state changes, and the state change can be judged based on one or more of the following conditions: whether the difference between the front axle speed multiplied by the tire radius and the reference vehicle speed is greater than the first threshold, whether the rate of change of the front axle speed is greater than the second threshold, whether the reference vehicle speed is within a predetermined threshold range, and whether the integral value of the PID control is greater than the third threshold. In one embodiment, the state change is judged only in the following case: all of the above conditions are met. In one embodiment, the state change is judged only in the following case: all of the above conditions are met, and the duration of each judgment condition is greater than the fourth threshold.
[0022] In one embodiment, whether the difference between the front axle speed multiplied by the tire radius and the reference vehicle speed is greater than a first threshold value is used to determine whether the front axle of the wheel is slipping. In one embodiment, whether the rate of change of the front axle speed is greater than a second threshold value can be estimated based on the change in the front wheel speed within a smaller operation cycle, and can be used to determine whether the front axle of the vehicle is slipping. It is easy to understand that when the front axle of the wheel vehicle slips, the rotational linear velocity on the outer contour of the front axle wheel will be greater than the reference vehicle speed, and the rate of change of the front axle speed can also increase. In one embodiment, the predetermined threshold range of the reference vehicle speed can be between 3 meters per second and 15 meters per second. The purpose of this setting is to limit the vehicle speed range for executing the torque control method of the present application, thereby reducing the driver's perception of power loss and improving driving comfort. In one embodiment, PID is the abbreviation of Proportional, Integral and Derivative, and PID control refers to proportional, integral and differential control. The integral value of PID control refers to the accumulated value of I or the integral part when the traction control system of the wheel continuously performs PID control on the front axle of the wheel and the rear axle of the vehicle. The purpose of this judgment is to avoid the undesired triggering of the torque control method.
[0023] In one embodiment of the present application, starting from the state change of the front axle of the vehicle, after a predetermined time, the torque pre-control is exited. In one embodiment, the predetermined time is calculated according to the following method: the wheelbase of the vehicle is divided by the reference speed. The predetermined time actually reflects: after the state change of the front axle of the vehicle, how long will it take for the rear axle of the vehicle to also enter the state change state. Since the axle spacing or wheelbase between the front axle and the rear axle of the vehicle is known, and the reference speed of the vehicle can be considered constant in a short time. Therefore, the above-mentioned predetermined time can be calculated by dividing the wheelbase of the vehicle by the reference speed. The predetermined time can be calculated between the state judgment step 200 and the predetermined time judgment step 400. In one embodiment, the predetermined time can be calculated immediately after the state judgment step 200 ends, so as to obtain the end time of the torque pre-control. Before the end time of the torque pre-control or within the predetermined time, the torque control method of the present application will continuously or cyclically perform the torque pre-control step 300. In one embodiment, if the predetermined time determination step 400 gives a "yes" judgment, the subsequent correction step 500 is continued to be executed; if the predetermined time determination step 400 gives a "no" judgment, the torque pre-control step 300 is returned to be continued to be executed.
[0024] The torque pre-control step 300 refers to pre-controlling the torque of the rear axle of the vehicle, and pre-controlling the torque of the rear axle of the vehicle before the above-mentioned predetermined time ends. In fact, during the execution of the torque control method of the present application, the torque of the rear axle of the vehicle has been controlled by the conventional vehicle rear axle torque control method, and the torque pre-control disclosed in the present application is added on the basis of this conventional control.
[0025] like Figure 2 As shown, the torque pre-control step 300 may include: a vehicle rear axle actual torque determination step 310, a vehicle rear axle target torque determination step 320, a first error determination step 330, a first error judgment step 340, step 350: whether the vehicle rear axle actual torque is greater than the vehicle rear axle target torque, a vehicle rear axle actual torque decreasing step 360, step 370: whether the vehicle rear axle actual torque is less than the vehicle rear axle target torque, a vehicle rear axle actual torque increasing step 380, a vehicle rear axle target torque setting step 390, etc. In one embodiment, the torque pre-control may include: changing the driving torque of the vehicle rear axle in the same direction and synchronously with the driving torque of the vehicle front axle. That is, after monitoring the state change of the vehicle front axle and before the state change of the vehicle rear axle, the driving torque is adjusted on the vehicle rear axle in advance, so that the vehicle rear axle can better adapt to the subsequent state change, thereby improving the driving stability of the vehicle and improving the driving experience of the passengers.
[0026] In the vehicle rear axle actual torque determination step 310, the vehicle rear axle actual torque is determined according to the following: between the vehicle rear axle actual torque and the vehicle rear axle requested torque, the smaller one is selected as the value of the vehicle rear axle actual torque. In the vehicle rear axle target torque determination step 320, the vehicle rear axle target torque is determined according to the following: between the vehicle front axle target torque, the vehicle rear axle target torque and the vehicle rear axle actual torque, the smallest one is selected as the first intermediate value; then, between the first intermediate value and the sixth threshold, a relatively larger one is selected as the second intermediate value; finally, the second intermediate value is multiplied by the first calibration value as the vehicle rear axle target torque. The purpose of the above steps 310 and 320 is to ensure the acceleration and smoothness of the vehicle, and to take into account the load distribution of the vehicle front axle and the vehicle rear axle.
[0027] In the first error determination step 330, the first error is determined according to the following: the vehicle rear axle actual torque is subtracted from the vehicle rear axle target torque as the first error. The first error is then judged at the first error judgment step 340. When the first error is greater than the fifth threshold, the logical operation of steps 360, 370 and 380 is continued, that is, the vehicle rear axle actual torque changes toward the vehicle rear axle target torque. When the first error is less than or equal to the fifth threshold, step 390 is continued to update the vehicle rear axle target torque according to the following: between the actual vehicle rear axle target torque and the vehicle rear axle target torque recorded last time, a relatively smaller one is selected as the value of the vehicle rear axle target torque.
[0028] The execution of steps 370 to 380 will cause the actual torque of the vehicle rear axle to change toward the target torque of the vehicle rear axle. Specifically, when the actual torque of the vehicle rear axle is greater than the target torque of the vehicle rear axle, the actual torque of the vehicle rear axle is gradually reduced toward the target torque of the vehicle rear axle, and the single reduction value is the value obtained by looking up the table in the vehicle reference speed table. In this case, the vehicle is likely to experience a complete change in road conditions. In addition, the actual torque of the vehicle rear axle can be smoothly and gradually reduced.
[0029] When the vehicle rear axle actual torque is less than the vehicle rear axle target torque, the vehicle rear axle actual torque is gradually increased toward the vehicle rear axle target torque, and the single increase value may be a second calibration value. In this case, the vehicle may be facing a small accumulation of water or ice on the road surface or a short road condition change, rather than a complete road condition change. In addition, the vehicle rear axle actual torque may be smoothly and gradually increased.
[0030] When the actual torque of the vehicle rear axle is equal to the target torque of the vehicle rear axle, the process proceeds to step 390 to update the target torque of the vehicle rear axle according to the following: between the actual target torque of the vehicle rear axle and the target torque of the vehicle rear axle recorded last time, a relatively smaller one is selected as the value of the target torque of the vehicle rear axle. At this point, it can be considered that the actual torque of the vehicle rear axle has been fully adjusted.
[0031] like Figure 3 As shown, the correction step 500 may include: a second error determination step 510, a second error judgment step 520, a step 530: whether the actual torque of the vehicle rear axle is greater than the conventional control required torque of the vehicle rear axle, a step 540 of decreasing the actual torque of the vehicle rear axle, a step 550: whether the actual torque of the vehicle rear axle is less than the conventional control required torque of the vehicle rear axle, a step 560 of increasing the actual torque of the vehicle rear axle, etc. The correction step 500 represents that after the torque pre-control is ended, in the second error determination step 510, the second error is determined according to the following: the conventional control required torque of the vehicle rear axle is subtracted from the actual torque of the vehicle rear axle, as the second error. The second error is then compared with the seventh threshold value in the second error judgment step 520. When the second error is greater than the seventh threshold value, the correction operation of steps 530 to 560 is performed, that is, the actual torque of the vehicle rear axle changes toward the conventional control required torque of the vehicle rear axle. When the second error is less than or equal to the seventh threshold value, the steering ends 600 to end the torque control method according to the present application.
[0032] The execution of steps 530 to 560 will cause the actual torque of the vehicle rear axle to change toward the conventional control required torque of the vehicle rear axle. In general, when the actual torque of the vehicle rear axle is greater than the conventional control required torque of the vehicle rear axle, the actual torque of the vehicle rear axle is gradually reduced toward the target torque of the vehicle rear axle; when the actual torque of the vehicle rear axle is less than the conventional control required torque of the vehicle rear axle, the actual torque of the vehicle rear axle is gradually increased toward the target torque of the vehicle rear axle. The value of a single increase or decrease may be a second calibration value. In one embodiment, the actual torque of the vehicle rear axle may be smoothly decreased or increased. In addition, when the actual torque of the vehicle rear axle is equal to the conventional control required torque of the vehicle rear axle, turn to end 600 to end the torque control method according to the present application. At this point, it can be considered that the actual torque of the vehicle rear axle has been fully adjusted.
[0033] The values of the various thresholds, errors and calibration values disclosed above can be determined according to the actual conditions of different vehicles, and can be set and recorded in the vehicle's memory at the factory.
[0034] The present application also relates to a torque control device, which is configured to perform the steps of the above-mentioned torque control method. In one embodiment, the torque control device may include one or more control units, such as an integrated power brake (Integrated Power Brake, abbreviated as IPB) controller, a VCU (Vehicle Control Unit) or a vehicle controller and one or more power source controllers. In one embodiment, the vehicle controller receives information from an integrated power brake controller, a motor controller, etc., so as to perform at least part of the steps of the above-mentioned torque control method. In one embodiment, the power source controller may be a motor controller (Motor Control Unit, abbreviated as MCU). In one embodiment, one or more power source controllers may perform at least part of the steps of the torque control method.
[0035] In one embodiment, the integrated dynamic brake controller may belong to the chassis domain in the automotive electrical and electronic architecture, the motor controller may belong to the power domain, and the vehicle controller may belong to the power domain.
[0036] The present application also relates to a computer system, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the torque control method for an electric vehicle. In one embodiment, the processor may be a vehicle control unit. In one embodiment, the memory may be a memory disposed on a vehicle.
[0037] The present application also relates to a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of the torque control method for an electric vehicle are implemented. In one embodiment, the processor may be a vehicle control unit. In one embodiment, the computer-readable storage medium may be a computer-readable storage medium disposed on a vehicle.
[0038] The present application also relates to a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the torque control method for an electric vehicle are implemented. In one embodiment, the processor may be a vehicle control unit.
[0039] The torque control method, torque control device, computer system, readable storage medium and program product of the present application have the advantages of being simple and reliable, easy to implement and convenient to use, and can significantly improve the driving stability and user experience of electric vehicles.
[0040] This specification discloses the present application with reference to the accompanying drawings, and also enables those skilled in the art to implement the present application, including making and using any device or system, selecting suitable materials, and using any combined method. The scope of the present application is defined by the technical solution for protection, and includes other examples that occur to those skilled in the art. As long as such other examples include structural elements that are not different from the literal language of the technical solution for protection, or such other examples include equivalent structural elements that are not substantially different from the literal language of the technical solution for protection, such other examples should be deemed to be within the scope of protection determined by the technical solution for protection of the present application.
Claims
1. A torque control method for an electric vehicle, characterized in that: The steps include: Monitor the operating status of the vehicle's front axle; Determining whether a state change occurs to the front axle of the vehicle; After the state of the front axle of the vehicle changes, torque pre-control is performed on the rear axle of the vehicle; The torque pre-control includes: changing the driving torque of the rear axle of the vehicle and the driving torque of the front axle of the vehicle in the same direction and synchronously.
2. The torque control method according to claim 1, characterized in that: The state change of the front axle of the vehicle includes: the wheels switching from traveling on a road surface with a first friction coefficient to traveling on a road surface with a second friction coefficient.
3. The torque control method according to claim 2, characterized in that: The occurrence of the state change is determined based on one or more of the following judgment conditions: whether the difference between the front axle speed multiplied by the tire radius and the reference vehicle speed is greater than a first threshold, whether the rate of change of the front axle speed is greater than a second threshold, whether the reference vehicle speed is within a predetermined threshold range, and whether the integral value of the PID control is greater than a third threshold.
4. The torque control method according to claim 3, characterized in that: The occurrence of the state change needs to meet the following conditions: the duration of meeting each judgment condition is greater than the fourth threshold.
5. The torque control method according to claim 3, characterized in that: The predetermined threshold range of the reference vehicle speed is between 3 meters per second and 15 meters per second.
6. The torque control method according to claim 1, characterized in that: The torque pre-control is exited after a predetermined time has passed since the state of the front axle of the vehicle changes.
7. The torque control method according to claim 6, characterized in that: The predetermined time is calculated according to the following method: the wheelbase of the vehicle is divided by the reference vehicle speed.
8. The torque control method according to claim 1, characterized in that: The torque pre-control comprises the following steps: Determine the actual torque on the rear axle of the vehicle; Determine the target torque of the vehicle rear axle; determining a first error; and When the first error is greater than a fifth threshold, the vehicle rear axle actual torque is changed toward the vehicle rear axle target torque.
9. The torque control method according to claim 8, characterized in that: The vehicle rear axle actual torque is determined according to the following: between the vehicle rear axle actual torque and the vehicle rear axle requested torque, a smaller one is selected as the value of the vehicle rear axle actual torque; The vehicle rear axle target torque is determined according to the following: among the vehicle front axle target torque, the vehicle rear axle target torque and the vehicle rear axle actual torque, a minimum one is selected as a first intermediate value; Then, between the first intermediate value and the sixth threshold, a relatively larger one is selected as the second intermediate value; finally, the second intermediate value is multiplied by the first calibration value to obtain the target torque of the rear axle of the vehicle; and The first error is determined by subtracting the vehicle rear axle target torque from the vehicle rear axle actual torque to obtain the first error.
10. The torque control method according to claim 9, characterized in that: If the first error is less than or equal to the fifth threshold, or the actual vehicle rear axle torque is equal to the vehicle rear axle target torque, the vehicle rear axle target torque is updated according to the following: between the actual vehicle rear axle target torque and the previously recorded vehicle rear axle target torque, a relatively smaller one is selected as the value of the vehicle rear axle target torque.
11. The torque control method according to claim 8, characterized in that: If the vehicle rear axle actual torque decreases gradually toward the vehicle rear axle target torque, the single reduction value is a value obtained by looking up the vehicle reference speed table; and If the vehicle rear axle actual torque increases gradually toward the vehicle rear axle target torque, the single increased value is the second calibration value.
12. The torque control method according to any one of claims 8 to 11, characterized in that: The following steps are also included: After the torque pre-control is exited, the difference between the actual torque of the vehicle rear axle and the conventional control required torque of the vehicle rear axle is eliminated.
13. The torque control method according to claim 12, characterized in that: After exiting the torque pre-control, the following steps are performed: Calculating a second error, wherein the second error is set equal to the actual torque of the vehicle rear axle minus the conventional control demand torque of the vehicle rear axle; When the second error is greater than a seventh threshold, the actual torque of the vehicle rear axle is gradually increased or decreased toward the conventional control required torque of the vehicle rear axle, and the value of a single increase or decrease is a second calibration value; and When the second error is less than or equal to a seventh threshold, or the actual torque of the vehicle rear axle is equal to the conventional control required torque of the vehicle rear axle, the torque control method is terminated.
14. A torque control device, characterized in that: The torque control device executes the steps of the torque control method for an electric vehicle according to any one of claims 1-13.
15. The torque control device according to claim 14, characterized in that: The torque control device includes an integrated power brake controller, a vehicle controller and one or more power source controllers.
16. A computer system comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the torque control method for an electric vehicle according to any one of claims 1 to 13.
17. A computer-readable storage medium having a computer program stored thereon, characterized in that When the computer program is executed by a processor, the steps of the torque control method for an electric vehicle according to any one of claims 1 to 13 are implemented.
18. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the torque control method for an electric vehicle according to any one of claims 1 to 13 are implemented.