Controller, power assembly and steering return control method of electric vehicle

Abstract

The invention provides a controller of an electric vehicle, a power assembly and a steering return control method, and is applied to the technical field of electric vehicles. A controller of the electric vehicle is used for controlling a wheel end braking device of the electric vehicle and is used for controlling the wheel end braking device of the electric vehicle under the working condition that a left wheel of the electric vehicle fails to brake or slips in the process that the electric vehicle turns right and then returns to the right. And controlling a wheel end braking device of the electric vehicle to output braking force to brake the other left wheel of the electric vehicle. The yaw stability of the electric vehicle is controlled, and the electric vehicle is helped to return quickly after steering.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a controller, a powertrain, and a steering return control method of an electric vehicle. Background Art

[0002] In recent years, new energy vehicles have developed rapidly, and electric vehicles are the main direction of new energy vehicle research and development. Electric vehicles usually include multiple wheel-end brake devices. Among them, each wheel-end brake device is used to brake a wheel. When the electric vehicle needs to brake, the multiple wheel-end brake devices can brake the four wheels of the electric vehicle respectively through the braking force distribution, thereby reducing the speed of the electric vehicle. However, in the process of turning back to center, such as changing lanes, when the brakes of a wheel of the electric vehicle fail or slip, the vehicle will yaw, causing the electric vehicle to become unstable. Therefore, it is urgent to provide a solution to the above problems. Summary of the invention

[0003] The embodiments of the present application provide a controller, a powertrain and a steering return control method for an electric vehicle to help the vehicle return to center quickly when a single wheel brake fails or slips during the process of returning to center after the electric vehicle turns (such as returning to center after changing lanes), thereby achieving yaw stability control of the electric vehicle.

[0004] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions.

[0005] In a first aspect, the present application provides a controller for an electric vehicle, the controller being used to control a wheel-end brake device of the electric vehicle. In addition, the controller is also used to control the wheel-end brake device to output a braking force to brake another left wheel of the electric vehicle when the wheel speed of one left wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time period during the process of the electric vehicle returning to the left after turning right.

[0006] Through the above method, when the brakes of a wheel on the side of the electric vehicle's return direction fail or slip, the controller can brake the other left wheel, so that the wheel speed of the right wheel on the same axle as the above-mentioned other left wheel is greater than the wheel speed of the above-mentioned other left wheel, thereby enabling the electric vehicle to return to the center more quickly, timely realize the yaw control of the electric vehicle, and enhance the yaw stability of the electric vehicle.

[0007] In one embodiment, the controller is further used to: at a first moment after the wheel-end brake device brakes the other left wheel, control the wheel-end brake device to increase the braking force for braking the other left wheel.

[0008] In the above manner, when braking the other left wheel, if the braking force provided by the wheel end brake device is insufficient to help the electric vehicle return to the center, the electric vehicle can be further helped to return to the center by timely controlling the wheel end brake device to increase the braking force.

[0009] In one embodiment, the controller is communicatively connected to a motor controller of the electric vehicle, and at a second moment after the first moment, the controller is further used to control the motor controller corresponding to the left wheel in the electric vehicle to control the drive motor to reduce the wheel speed of the left wheel.

[0010] Through the above method, when the braking force of the other left wheel has reached the maximum but still cannot help the electric vehicle to return to the center, the controller can control the motor controller corresponding to the one left wheel to control the drive motor to reduce the wheel speed of the one left wheel, thereby further helping the electric vehicle to return to the center.

[0011] In one embodiment, during the process of the electric vehicle returning to the left after turning right on a low-adhesion road, the controller is further used to control the motor controller corresponding to the above-mentioned one left wheel in the electric vehicle to control the drive motor to output zero torque to reduce the wheel speed of the above-mentioned one left wheel at a second moment after the first moment.

[0012] Through the above method, when the electric vehicle is turning right on a low-adhesion road surface (such as an icy or snowy road) and then returning to the left, the motor controller corresponding to the above-mentioned left wheel controls the drive motor to output zero torque to reduce the wheel speed of the above-mentioned left wheel, thereby avoiding wheel locking resulting in inability to turn or skidding.

[0013] In one embodiment, before the condition that the wheel speed of a left wheel is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time period during the process of the electric vehicle turning left after turning right, the controller is further used to: receive a braking signal and control the wheel-end brake device of the electric vehicle to brake the two left wheels and the two right wheels of the electric vehicle. At a third moment after the wheel-end brake device brakes the other left wheel and before the first moment, the wheel-end brake device is controlled to brake the other left wheel and the two right wheels of the electric vehicle.

[0014] Through the above method, before the electric vehicle turns left and returns to center, the controller can also pre-brake the wheels of the electric vehicle, predict the wheel-end braking condition of the vehicle, and promptly control the wheel speed of the slipping wheel or the brake failure wheel when slipping or brake failure occurs, so that the electric vehicle is more stable during the steering and returning process.

[0015] In one embodiment, the controller is further used to: at a fourth moment after the third moment and before the first moment, control the wheel-end braking device of the electric vehicle to reduce the braking force of the two right wheels.

[0016] In the above manner, before the electric vehicle turns left and returns to center, the electric vehicle can return to center more quickly by reducing the braking force of the two right wheels.

[0017] In one embodiment, the controller is also used to control the wheel-end braking device of the electric vehicle to brake the two left wheels of the electric vehicle when the wheel speed of one right wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time.

[0018] By means of the above method, when the right wheel brake fails or slips during the process of returning to the left after turning right, the electric vehicle can be helped to return to the center by braking the two left wheels.

[0019] In one embodiment, the controller is further used to: at the fifth moment after the wheel-end braking device brakes the two left wheels, control the wheel-end braking device to increase the braking force for braking the two left wheels.

[0020] In the above manner, if the electric vehicle cannot return to the center position in time after braking the two left wheels, the controller further controls the wheel-end braking device to increase the braking force of the two left wheels to help the electric vehicle return to the center position faster.

[0021] In one embodiment, the controller is communicatively connected to a motor controller of the electric vehicle. At a sixth moment after the fifth moment, the controller can control the motor controller corresponding to another right wheel in the electric vehicle to control the drive motor to increase the wheel speed of the other right wheel.

[0022] In the above manner, when the braking force of the two left wheels is exhausted and the electric vehicle cannot be straightened in time, increasing the wheel speed of the right wheel can help the electric vehicle to straighten.

[0023] In one embodiment, the above-mentioned controller is also used to control the braking force output by the wheel-end braking device of the electric vehicle to increase as at least one of the return angle of the electric vehicle, the lateral acceleration of the electric vehicle, the yaw angular velocity of the electric vehicle and the vehicle speed of the electric vehicle increases during the process of the electric vehicle returning to the left after turning right.

[0024] Through the above method, in the process of the electric vehicle returning to the left after turning right, the braking force output by the wheel-end braking device can be dynamically adjusted according to at least one of the electric vehicle's return angle, lateral acceleration, yaw angular velocity and vehicle speed, so that the electric vehicle can return to the center more quickly.

[0025] In addition, when the electric vehicle is returning to the right after turning left, the controller can also help the electric vehicle return to the right position by referring to any one of the embodiments of the first aspect.

[0026] In a second aspect, a powertrain of an electric vehicle is provided, which powertrain includes a motor controller, a drive motor, a reducer, and a controller in any possible implementation of the first aspect above, and the controller is also used to control the motor controller to drive the drive motor to drive at least one front wheel or at least one rear wheel of the electric vehicle.

[0027] The powertrain of the second aspect integrates a motor controller, a drive motor, a reducer and the controller provided by the first aspect, realizing the integration and miniaturization of the powertrain, being able to increase the power density of the powertrain and save the installation space of the electric vehicle.

[0028] In a third aspect, a steering return control method for an electric vehicle is provided, wherein the steering return control method is used for a wheel-end braking device of the electric vehicle during a process in which the electric vehicle returns to the left after turning right, and the electric vehicle control method comprises:

[0029] Under the condition that the wheel speed of one right wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time period, the wheel end braking device of the electric vehicle is controlled to brake the two left wheels of the electric vehicle.

[0030] Through the above method, when the brakes of a wheel on the different side of the return direction of the electric vehicle fail or slip, the controller can brake the wheel on the same side of the return direction, so that the wheel speed of the wheel on the different side of the return direction is greater than the wheel speed of the wheel on the same side of the return direction, so that the electric vehicle can return to the center more quickly, the yaw control of the electric vehicle can be realized in time, and the yaw stability of the electric vehicle is enhanced.

[0031] In one embodiment, the steering return control method further includes: at a first moment after the wheel end brake device brakes the two left wheels, controlling the wheel end brake device to increase the braking force of the two left wheels. At a second moment after the first moment, controlling the drive motor corresponding to the other right wheel in the electric vehicle to increase the wheel speed of the other right wheel.

[0032] In the above manner, when the electric vehicle still cannot return to the correct direction after the wheel on the same side of the return direction is braked, the electric vehicle can be further helped to return to the correct direction by timely controlling the wheel end brake device corresponding to the wheel on the same side of the return direction to increase the braking force.

[0033] In one embodiment, the steering return control method further includes: when the wheel speed of one left wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time, controlling the wheel-end brake device to brake the other left wheel of the electric vehicle. At a third moment after the wheel-end brake device brakes the other left wheel, controlling the wheel-end brake device to increase the braking force of the other left wheel. At a fourth moment after the third moment, controlling the drive motor corresponding to the one left wheel in the electric vehicle to reduce the wheel speed of the one left wheel.

[0034] Through the above method, when a wheel on the same side of the electric vehicle's return direction fails to brake or slips, the controller can brake the other wheel on the same side of the return direction, and when the electric vehicle still cannot return to the center after the other wheel is braked, timely measures are taken to increase the braking force of the other wheel and reduce the wheel speed of the wheel that fails to brake or slips, so as to further help the electric vehicle return to the center.

[0035] In one embodiment, the steering return control method further includes: before the wheel speed of one left wheel of the electric vehicle is greater than the wheel speed of the other three wheels of the electric vehicle within a preset time, receiving a braking signal and controlling the wheel-end braking device of the electric vehicle to brake the two left wheels and the two right wheels of the electric vehicle. At a fifth moment after the wheel-end braking device brakes the other left wheel and before the third moment, controlling the wheel-end braking device to brake the other left wheel and the two right wheels of the electric vehicle. At a sixth moment after the fifth moment and before the third moment, controlling the wheel-end braking device of the electric vehicle to reduce the braking force of the two right wheels.

[0036] In the above manner, the controller can pre-brake the four wheels of the electric vehicle to determine the wheel that has failed or slipped. In addition, when a wheel on the same side of the return direction of the electric vehicle fails or slips, after braking the wheel that has failed or slipped, the controller can brake the other three wheels, and after braking the other three wheels, reduce the braking force of the two wheels on the different side of the return direction, so that the electric vehicle can travel more stably during the braking process.

[0037] Based on the technical principles and beneficial effects of the second and third aspects above, control schemes for other single wheels that always slip or brake failure during the steering return process can also be obtained, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0039] Figure 2 Another schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of a powertrain provided in an embodiment of the present application;

[0041] Figure 4 Another schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0042] Figure 5 Another schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0043] Figure 6 Another schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0044] Figure 7 Another schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0045] Figure 8 Another schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0046] Fig. 9 A schematic diagram of an electric vehicle returning to center after turning provided by an embodiment of the present application;

[0047] Fig.10 Another schematic diagram of an electric vehicle returning to center after turning provided by an embodiment of the present application;

[0048] Fig.11 A schematic diagram of a steering return control method provided in an embodiment of the present application;

[0049] Fig.12 Another schematic diagram of the steering return control method provided in an embodiment of the present application;

[0050] Fig.13 Another schematic diagram of the steering return control method provided in an embodiment of the present application;

[0051] Fig.14 Another schematic diagram of the steering return control method provided in an embodiment of the present application;

[0052] Fig.15 Another schematic diagram of the steering return control method provided in an embodiment of the present application;

[0053] Fig.16 Another schematic diagram of the steering return control method provided in an embodiment of the present application;

[0054] Fig.17 Another schematic diagram of the steering return control method provided in an embodiment of the present application;

[0055] Fig.18Another schematic diagram of the steering return control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0057] It should be noted that "in one embodiment" in this application is used to indicate an example, illustration or description. The solution described as "in one embodiment" in this application should not be interpreted as being more preferred or more advantageous than the solutions of other embodiments. Specifically, the use of "in one embodiment" is intended to present the inventive concept of this application in a specific way.

[0058] During the driving of an electric vehicle, when the driver wants to change lanes or turn, he needs to control the steering of the electric vehicle through the steering wheel to return to the center. During the process of returning to the center after the electric vehicle turns, due to the speed change in the lateral direction of the vehicle, one or more wheel-end brake devices are required to cooperate to output braking force to help the electric vehicle return to the center. However, when the wheel-end brake device of a wheel fails, the wheel-end brake device will not be able to output the expected braking force; or the wheel slips due to water accumulation or wetness on the road, resulting in poor adhesion of the wheel, which will cause the rotation speed of the wheel to be unbalanced with the other three wheels during the process of returning to the center after the electric vehicle turns. In the above two scenarios, if the electric vehicle is improperly braked, excessive yaw will occur, making it impossible for the electric vehicle to return to the center quickly, thereby causing the body of the electric vehicle to become unstable and affecting the driving stability of the electric vehicle.

[0059] If one of the wheels of the electric vehicle fails or slips during the process of returning to the center after the electric vehicle turns, the traditional hydraulic braking system has a slow braking response, so its braking method is to brake the diagonal wheels of the electric vehicle to enable the electric vehicle to keep moving straight. However, this method cannot adjust the driving direction of the electric vehicle and therefore cannot help the vehicle return to the center. At the same time, the effective control of the yaw stability of the electric vehicle is lost, so the driving stability of the electric vehicle cannot be well guaranteed.

[0060] In order to solve the above problems, the embodiments of the present application provide a controller, a powertrain and a steering return control method for an electric vehicle. When an electric vehicle equipped with an electronic mechanical braking system returns to center after turning, if one of the wheels of the electric vehicle fails to brake or slips, the electric vehicle will have an unbalanced rotation speed of the four wheels, which will cause the electric vehicle to yaw. At this time, when the wheel with brake failure or slip is located on one side of the return direction, the controller of the electric vehicle helps the vehicle to return to center quickly by braking the wheel on the same side of the wheel with brake failure or slip; when the wheel with brake failure or slip is located on different sides of the return direction, the controller of the electric vehicle helps the vehicle to return to center quickly by braking the wheel on different sides of the wheel with brake failure or slip. Through the above two braking methods, the electric vehicle can help the vehicle to return to center quickly during the process of returning to center after turning, so as to achieve yaw control of the electric vehicle and improve the driving stability of the vehicle during steering and returning to center.

[0061] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0062] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of the present application. Figure 1 As shown, the electric vehicle 10 includes a drive system 100, a brake system 200, a power battery 300 and a controller 400. The drive system 100 is used to drive the four wheels of the electric vehicle 10 to drive the electric vehicle 10. The brake system 200 is used to brake the four wheels of the electric vehicle 10 to slow down the electric vehicle 10. The power battery 300 is used to power the drive system 100 and the brake system 200. The controller 400 is used to control the brake system 200 to output braking force to brake the wheels, and is also used to communicate with the drive system 100 to control its output torque to drive the wheels to rotate.

[0063] Figure 2 Another schematic diagram of an electric vehicle provided in an embodiment of the present application. Figure 2 As shown in FIG. 1 , in one embodiment, the drive system 100 includes a motor controller 110 (MCU), a drive motor 120 and a reducer 130. Figure 2 As shown, the motor controller 110 is used to receive the direct current output by the power battery 300 and output the alternating current to control the drive motor 120 to output the driving torque. The driving torque output by the drive motor 120 drives the wheels of the electric vehicle 10 to rotate through the reducer 130. The braking system 200 includes a plurality of wheel-end braking devices 210, and the plurality of wheel-end braking devices 210 are used to brake the plurality of wheels of the electric vehicle 10 respectively.

[0064] The controller 400 is used to control the braking system 200 to output braking force to brake the wheels. The controller 400 is also used to communicate with the drive system 100 to control the drive system 100 to output appropriate torque to drive the wheels to rotate when the steering is returned to the center position to help the vehicle return to the center position in time.

[0065] In one embodiment, the brake system 200 is an electric mechanical brake (EMB).

[0066] Figure 3 A schematic diagram of a powertrain is provided for an embodiment of the present application. Figure 3 As shown, the powertrain includes a controller 400 and a drive system 100. The drive system 100 is used to control the voltage of the AC power output by the motor controller 110 in the drive system 100 according to the indication signal of the accelerator pedal to control the drive motor 120 to output the drive torque. The powertrain integrates the controller 400 with the drive system 100, realizes the integration and miniaturization of the powertrain, can provide the power density of the powertrain and save the installation space of the electric vehicle.

[0067] In the electric vehicle 10, the drive system will be arranged according to the drive mode of the electric vehicle 10. Among them, the common drive modes of the electric vehicle 10 include front single motor drive, rear single motor drive, front dual motor drive, rear dual motor drive, front single motor drive + rear single motor drive, front single motor drive + rear dual motor drive, front dual motor drive + rear single motor drive and distributed four-motor drive.

[0068] Figure 4 Another schematic diagram of an electric vehicle provided in an embodiment of the present application. In one embodiment, the two wheels corresponding to the front axle 220 of the electric vehicle 10 are the left front wheel LF and the right front wheel RF, and the two wheels corresponding to the rear axle 230 of the electric vehicle 10 are the left rear wheel LR and the right rear wheel RR. Figure 4 As shown, when the electric vehicle 10 is driven by a front single motor, the electric vehicle 10 includes a drive system 100, and the drive system 100 includes a drive motor 120 and a motor controller 110. The drive system 100 is used to drive the left front wheel LF and the right front wheel RF on the front axle 220 of the electric vehicle 10. In addition, the electric vehicle 10 includes four wheel-end brake devices 210. Among them, two wheel-end brake devices 210 are respectively used to brake the left front wheel LF and the right front wheel RF of the electric vehicle 10. The other two wheel-end brake devices 210 are respectively used to brake the left rear wheel LR and the right rear wheel RR of the electric vehicle 10.

[0069] Similarly, when the electric vehicle 10 is driven by a rear single motor, the drive system 100 is used to drive the left rear wheel LR and the right rear wheel RR of the electric vehicle 10, and the two wheel-end brake devices 210 are respectively used to brake the left front wheel LF and the right front wheel RF of the electric vehicle 10. The other two wheel-end brake devices 210 are respectively used to brake the left rear wheel LR and the right rear wheel RR of the electric vehicle 10.

[0070] Figure 5 Another schematic diagram of an electric vehicle provided in an embodiment of the present application. In one embodiment, when the electric vehicle 10 is driven by a front dual motor drive or a rear dual motor drive, the electric vehicle 10 includes two drive systems 100, and each drive system 100 includes a drive motor 120 and a motor controller 110. The two drive systems 100 are respectively used to drive two wheels on the same axle of the electric vehicle 10, for example, the two wheels are the left front wheel LF and the right front wheel RF of the electric vehicle 10, or the two wheels are the left rear wheel LR and the right rear wheel RR of the electric vehicle 10. Figure 5 As shown, when the electric vehicle 10 is driven by the front dual motor drive, the drive motors 120 of the two drive systems 100 are respectively used to drive the left front wheel LF and the right front wheel RF of the electric vehicle 10, so that the left front wheel LF and the right front wheel RF can be controlled independently. Similarly, when the electric vehicle 10 is driven by the rear dual motor drive, the drive motors 120 of the two drive systems 100 are respectively used to drive the left rear wheel LR and the right rear wheel RR of the electric vehicle 10.

[0071] Figure 6 Another schematic diagram of an electric vehicle provided in an embodiment of the present application. In one embodiment, as Figure 6 As shown, when the electric vehicle 10 is driven by the front motor + the rear motor, the electric vehicle 10 includes two drive systems 100, each of which includes a drive motor 120 and a motor controller 110. Figure 6 In addition to driving the left front wheel LF and the right front wheel RF of the electric vehicle 10 by one driving system 100 , the left rear wheel LR and the right rear wheel RR of the electric vehicle 10 are also driven by another driving system 100 .

[0072] Figure 7 Another schematic diagram of an electric vehicle provided in an embodiment of the present application. In one embodiment, as Figure 7As shown, the electric vehicle 10 includes three drive systems 100. The power architecture of this embodiment is arranged in that: on the basis of one drive system 100 being used to drive the left front wheel LF and the right front wheel RF of the electric vehicle 10, the other two drive systems 100 are respectively used to drive the left rear wheel LR and the right rear wheel RR of the electric vehicle 10, so that the left rear wheel LR and the right rear wheel RR can be independently controlled.

[0073] Figure 8 Another schematic diagram of an electric vehicle provided in an embodiment of the present application. In one embodiment, as Figure 8 As shown, when the electric vehicle 10 is driven in a distributed four-wheel drive manner, the electric vehicle 10 includes four drive systems 100. Among them, in this embodiment, the first drive system 100 is used to drive the left rear wheel LR of the electric vehicle 10, and the second drive system 100 is used to drive the right rear wheel RR of the electric vehicle 10. The third drive system 100 is used to drive the left front wheel LF of the electric vehicle 10, and the fourth drive system 100 is used to drive the right front wheel RF of the electric vehicle 10.

[0074] Fig. 9 A schematic diagram of an electric vehicle returning to center after turning provided by an embodiment of the present application. During the process of returning to center after turning, if the wheels of the electric vehicle 10 fail to brake or slip, the speed of one wheel will be greater than that of the other wheels, thereby affecting the body stability of the electric vehicle 10. Fig. 9 As shown, in the prior art, the braking system of the electric vehicle 10 usually adopts the method of braking the diagonal wheels to ensure the stability of the vehicle body, but the method of braking the diagonal wheels cannot help the electric vehicle 10 to return to the center, which is not conducive to the driving experience of the electric vehicle 10 during the process of returning to the center after turning.

[0075] The controller, powertrain and steering return control method provided in the embodiments of the present application control the wheel-end brake device 210 of the electric vehicle 10 to brake the wheels of the electric vehicle 10 when one wheel fails or slips during the steering return process, so that the average rotational speed of the wheel on one side of the return direction is less than the average rotational speed of the wheel on the other side of the return direction, thereby generating a torque in the return direction to help the electric vehicle 10 return quickly.

[0076] In one embodiment, the wheel-end braking device of the electric vehicle 10 brakes the other wheel on the same side to reduce the rotation speed of the other wheel on the same side, or brakes the two wheels on the same side to reduce the rotation speed of the two wheels on the same side, so that the average rotation speed of the wheel on one side of the return direction is less than the average rotation speed of the wheel on the other side of the return direction, thereby generating a torque in the return direction to help the electric vehicle 10 return to the center quickly.

[0077] In one embodiment, if the brakes of a wheel on the same side of the return direction fail, the controller 400 of the electric vehicle 10 brakes the other wheel on the same side to reduce the rotation speed of the other wheel on the same side, so that the average rotation speed of the wheel on one side of the return direction is less than the average rotation speed of the wheel on the other side of the return direction, thereby generating a torque in the return direction to help the electric vehicle 10 return quickly.

[0078] In one embodiment, if a wheel on the same side of the return direction slips, the controller 400 of the electric vehicle 10 brakes the other wheel on the same side to reduce the rotation speed of the other wheel on the same side, so that the average rotation speed of the wheel on one side of the return direction is less than the average rotation speed of the wheel on the other side of the return direction, thereby generating a torque in the return direction to help the electric vehicle 10 return to the center quickly.

[0079] For ease of understanding, the controller, powertrain, and steering return control method provided in the embodiment of the present application are first described in conjunction with the steering return process of the electric vehicle 10.

[0080] Fig.10 Another schematic diagram of an electric vehicle returning to the center position after turning provided in an embodiment of the present application. Fig.10 As shown, during the lane change process, the electric vehicle 10 first turns right and then returns to the left.

[0081] In one embodiment, before the electric vehicle 10 turns left after turning right or during the process of turning left after turning right, the driver operates the brake pedal of the electric vehicle 10, and the controller 400 controls the wheel-end brake devices 210 corresponding to the four wheels LF, LR, RF, and RR of the electric vehicle 10 to brake. Among them, the wheel-end brake device 210 corresponding to the left front wheel LF fails. Accordingly, the wheel speed of the left front wheel LF when the electric vehicle 10 turns right and changes lanes will be greater than the wheel speeds of the other three wheels.

[0082] In one embodiment, before the electric vehicle 10 turns left after turning right or during the process of turning left after turning right, the adhesion coefficient of the road surface passed by the left front wheel LF is smaller than the adhesion coefficients of the road surfaces passed by the other three wheels, and the left front wheel LF slips. Accordingly, the wheel speed of the left front wheel LF will be greater than the wheel speeds of the other three wheels.

[0083] like Fig.10 The wheel speed of the left front wheel LF is greater than the wheel speeds of the other three wheels. The average speed of the left wheel of the electric vehicle 10 is greater than the average speed of the left wheel, and the rightward yaw moment generated by the vehicle body will affect the rapid return of the electric vehicle 10.

[0084] In one embodiment, when the electric vehicle 10 is returning to the left after turning right, under the condition that the wheel speed of the left front wheel LF of the electric vehicle 10 is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time, the controller 400 automatically controls the wheel-end brake device 210 to output braking force to brake the left rear wheel LR of the electric vehicle 10, so that the average speed of the left wheel of the electric vehicle 10 is less than the average speed of the right wheel, thereby generating a torque in the direction of returning to the left to help the electric vehicle 10 return to the left quickly.

[0085] Fig.11 A schematic diagram of a steering return control method provided in an embodiment of the present application. Fig.12 Another schematic diagram of the steering return control method provided in the embodiment of the present application. Fig.11 As shown, the moment T1 represents that the wheel end brake device 210 increases the braking force F2 of the left rear wheel LR, and the moment T2 represents that the braking force F2 output by the wheel end brake device 210 to the left rear wheel LR has reached the maximum, and the motor controller 110 controls the left front wheel LF to reduce the speed n1, as shown in FIG. Fig.12 shown.

[0086] In one embodiment, the electric vehicle 10 changes lanes at a high speed, so that the speed of the electric vehicle 10 when turning is greater than the first preset speed threshold, or the road is a serpentine S-shaped curve, so that the steering wheel angle is greater than the first preset angle threshold. The electric vehicle 10 cannot return to the center after the wheel-end brake device 210 brakes the left rear wheel, and it is still necessary to reduce the average speed of the left wheel to obtain a larger left-centering torque to quickly return the electric vehicle 10 to the center. Fig.11 As shown, at the first moment T1 after the left rear wheel LR has been braked for a period of time, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically further increases the braking force F2 output by the wheel end brake device 210 of the left rear wheel LR at the first moment T1, thereby further reducing the average rotation speed of the left wheel and generating a larger torque in the left return direction, so that the electric vehicle 10 quickly returns to the center.

[0087] In one embodiment, the electric vehicle 10 is still unable to return to the center after time T1, and the average rotation speed of the left wheels still needs to be reduced to quickly return the electric vehicle 10 to the center. The electric vehicle 10 changes lanes at a very high speed, so that the speed of the electric vehicle 10 when turning is greater than the second preset speed threshold, or the road is a serpentine S-shaped curve, so that the steering wheel angle is greater than the second preset angle threshold, wherein the second preset speed threshold is greater than the first preset speed threshold, and the second preset angle threshold is greater than the first preset angle threshold. The electric vehicle 10 is still unable to return to the center after time T1, and the average rotation speed of the left wheels needs to be reduced to obtain a larger return torque to quickly return the electric vehicle 10 to the center. Fig.11As shown, at the second moment T2 after the wheel-end brake device 210 of the left rear wheel LR increases the braking force to the maximum at T1, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically keeps the braking force F2 output by the wheel-end brake device 210 of the left rear wheel LR unchanged at the second moment T2, and simultaneously automatically controls the motor controller 110 corresponding to the left front wheel LF to control the drive motor 120 to reduce the wheel speed n1 of the left front wheel LF, thereby further reducing the average rotation speed of the left wheel to generate a larger torque in the left return direction to allow the electric vehicle 10 to return quickly.

[0088] In one embodiment, the electric vehicle 10 is traveling on a medium-high adhesion road surface, and the electric vehicle 10 helps the electric vehicle 10 to quickly return to the normal position by dragging the left front wheel backward. Fig.11 As shown, the electric vehicle 10 is traveling on a medium-high adhesion road surface, and the right yaw angular velocity monitored by the electric vehicle 10 at T2 is greater than the first preset yaw angular velocity threshold. The controller 400 of the electric vehicle 10 automatically controls the motor controller 110 corresponding to the left front wheel LF at the second moment T2 to control the drive motor 120 to output a reverse torque to reduce the wheel speed of the left front wheel LF to below zero speed, thereby making the average wheel speed of the left side of the electric vehicle 10 less than the average wheel speed of the right side, thereby generating a larger torque in the left return direction to make the electric vehicle 10 return to the center quickly.

[0089] In one embodiment, when the vehicle is traveling on a low-adhesion road, the electric vehicle 10 reduces the speed of the left front wheel to a follow-up state to help the electric vehicle 10 quickly return to the center and prevent the left front wheel from being locked and unable to turn. Fig.11 As shown, the electric vehicle 10 is traveling on an icy or slippery road, and the right yaw angular velocity monitored by the electric vehicle 10 at T2 is greater than the first preset yaw angular velocity threshold. The controller 400 of the electric vehicle 10 automatically controls the motor controller 110 corresponding to the left front wheel LF at the second moment T2 to control the drive motor 120 to output zero torque and reduce the wheel speed of the left front wheel LF to a follow-up state, thereby preventing the left front wheel from being locked and unable to turn, and at the same time making the average wheel speed of the left side of the electric vehicle 10 smaller than the average wheel speed of the right side, generating a larger torque in the left return direction to make the electric vehicle 10 return to the center quickly.

[0090] In an embodiment of the present application, before the electric vehicle 10 returns to the left after turning right or during the process of returning to the left after turning right, the driver operates the brake pedal of the electric vehicle 10 for driving safety, and the controller 400 controls the wheel-end brake devices 210 corresponding to the four wheels LF, LR, RF, and RR of the electric vehicle 10 to brake. Among them, the wheel-end brake device 210 corresponding to the left front wheel LF fails. Accordingly, the wheel speed of the left front wheel LR will be greater than the wheel speeds of the other three wheels when the electric vehicle 10 turns right and changes lanes, and the electric vehicle 10 will yaw to the right. The motor controller 400 controls the end brake device 210 to reduce the braking force on the right wheel according to the right yaw angular velocity of the electric vehicle, so that the average wheel speed of the right side of the electric vehicle decreases slowly, thereby controlling the right yaw of the electric vehicle 10 and helping the electric vehicle 10 to maintain stable driving.

[0091] Fig.11 A schematic diagram of a steering return control method provided in an embodiment of the present application. Fig.11 As shown, T11 represents that the controller 400 controls the LR, RF, and RR output braking forces to keep the electric vehicle 10 running stably, and T12 represents that the controller 400 controls the LR output braking force while reducing the RF and RR output braking forces F3 and F4 to help the electric vehicle 10 return to the left.

[0092] In one embodiment, at a third moment T11 after the driver operates the brake pedal of the electric vehicle 10 to brake the four wheels and before the first moment T1, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 adjusts and distributes the wheel-end brake devices 210 corresponding to the three wheels LR, RF, and RR of the electric vehicle 10 for braking. The controller 400 reduces the braking forces F3 and F4 output by the wheel-end brake devices 210 of RF and RR so that the average wheel speed on the right side of the electric vehicle decreases slowly, thereby controlling the right yaw of the electric vehicle 10 and helping the electric vehicle 10 maintain stable driving.

[0093] In one embodiment, the speed of the electric vehicle 10 is relatively fast or the steering wheel turns right at a large angle. After the driver operates the brake pedal of the electric vehicle 10 for driving safety, the controller 400 controls the wheel-end brake devices 210 corresponding to the three wheels LR, RF, and RR of the electric vehicle 10 to brake after two adjustments to control the rightward yaw of the electric vehicle 10. At the fourth moment T12 after the third moment T11 and before the first moment T1, the rightward yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 reduces the braking forces F3 and F4 output by the wheel-end brake devices 210 of RF and RR to zero to maintain the average wheel speed of the right side of the electric vehicle so that it no longer decreases, thereby quickly controlling the rightward yaw of the electric vehicle 10 and helping the electric vehicle 10 to maintain stable driving.

[0094] In an embodiment of the present application, the controller 400 is also used to control the increase of the braking force output by the wheel-end braking device of the electric vehicle during the process of the electric vehicle returning to the left after turning right, according to an increase in at least one of the electric vehicle's return angle, the electric vehicle's lateral acceleration, the electric vehicle's yaw angular velocity and the electric vehicle's speed, so as to help the electric vehicle return to center quickly.

[0095] In one embodiment, when the electric vehicle 10 is returning to the left after turning right, when the angle at which the electric vehicle 10 needs to return to the center increases, or the lateral acceleration of the electric vehicle 10 increases, or the yaw angular velocity of the electric vehicle 10 increases, or the speed of the electric vehicle 10 increases, the controller 400 controls the braking force output by the wheel-end brake device 210 of the electric vehicle 10 to increase, so that the electric vehicle 10 obtains the desired difference in wheel speed between the left and right wheels, helping the electric vehicle 10 to return to the center quickly.

[0096] In one embodiment, when the electric vehicle 10 is in the process of returning to the left after turning right, when multiple of the angle at which the electric vehicle 10 needs to return to the center, the lateral acceleration of the electric vehicle 10, the yaw angular velocity of the electric vehicle 10, and the speed of the electric vehicle 10 increase, the controller 400 controls the braking force output by the wheel-end brake device 210 of the electric vehicle 10 to also increase, so that the electric vehicle 10 obtains the desired difference in wheel speeds between the left and right wheels, helping the electric vehicle 10 to return to the center quickly.

[0097] In one embodiment of the present application, if braking failure occurs on a wheel on different sides of the return direction, the controller 400 of the electric vehicle 10 quickly reduces the rotation speed of the two wheels on the same side of the return direction by braking the two wheels on the same side of the return direction, so that the average rotation speed of the wheels on one side of the return direction is quickly less than the average rotation speed of the wheels on the other side of the return direction, thereby generating a torque in the return direction to help the electric vehicle 10 return quickly.

[0098] In one embodiment, if a wheel on a different side of the return direction slips, the controller 400 of the electric vehicle 10 brakes the two wheels on the same side of the return direction to quickly reduce the rotation speed of the two wheels on the same side, so that the average rotation speed of the wheels on one side of the return direction is quickly less than the average rotation speed of the wheels on the other side of the return direction, thereby generating a torque in the return direction to help the electric vehicle 10 return to the center quickly.

[0099] In one embodiment, before the electric vehicle 10 turns left after turning right or during the process of turning left after turning right, the driver operates the brake pedal of the electric vehicle 10, and the controller 400 controls the wheel-end brake devices 210 corresponding to the four wheels LF, LR, RF, and RR of the electric vehicle 10 to brake. The braking function of the right front wheel RF fails, such as the wheel-end brake device 210 corresponding to the right front wheel RF fails. Accordingly, the wheel speed of the right front wheel RF will be greater than the wheel speeds of the other three wheels.

[0100] In one embodiment, before the electric vehicle 10 turns left after turning right or during the process of turning left after turning right, the adhesion coefficient of the road surface passed by the right front wheel RF is smaller than the adhesion coefficients of the road surfaces passed by the other three wheels, and the right front wheel RF slips. Accordingly, the wheel speed of the right front wheel RF will be greater than the wheel speeds of the other three wheels.

[0101] like Fig.10 , the wheel speed of the right front wheel RF is greater than the wheel speeds of the other three wheels. However, the average speed of the left wheels of the electric vehicle 10 needs to be quickly reduced to less than the average speed of the left wheels to prevent the vehicle body from generating a rightward yaw moment that affects the rapid return of the electric vehicle 10.

[0102] In one embodiment, when the electric vehicle 10 turns right, its left wheel is located on the outside when turning, so the average wheel speed of its left wheel is greater than the average wheel speed of the right wheel. When the electric vehicle 10 starts to return to the left after turning right, the average wheel speed of its left wheel will not decrease quickly. Under the condition that the wheel speed of the right front wheel RF of the electric vehicle 10 is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time, the controller 400 automatically controls the wheel end brake device 210 to output braking force to brake the left front wheel LF and the left rear wheel LR of the electric vehicle 10, so that the average rotation speed of the left wheel of the electric vehicle 10 is quickly reduced to less than the average rotation speed of the right wheel, thereby quickly generating a torque in the direction of returning to the left to help the electric vehicle 10 quickly return to the left.

[0103] In the embodiments provided in the present application, the wheel-end brake device of the left wheel of the electric vehicle is controlled to increase the output braking force to brake the wheel during the process of the electric vehicle returning to the left after turning right, and the wheel-end brake device of the left wheel is controlled to increase the output braking force to brake the wheel after the wheel-end brake device of the left wheel increases the output braking force to brake the wheel, so as to help the electric vehicle return to the center quickly.

[0104] Fig.13 Another schematic diagram of the steering return control method provided in an embodiment of the present application. Fig.14 Another schematic diagram of the steering return control method provided in the embodiment of the present application. Fig.13As shown, time T5 represents that the wheel-end brake device 210 increases the braking force F1 of the left front wheel LF and the braking force F2 of the left rear wheel LR, and time T6 represents that the braking force F1 of the left front wheel LF and the braking force F2 of the left rear wheel LR output by the wheel-end brake device 210 have reached the maximum, and the motor controller 110 controls the right rear wheel RR to increase the speed n4, as shown in FIG. Fig.14 shown.

[0105] In one embodiment, the electric vehicle 10 changes lanes at a high speed, so that the speed of the electric vehicle 10 when turning is greater than the first preset speed threshold, or the road curve angle is large, so that the steering wheel angle is greater than the first preset angle threshold. The electric vehicle 10 cannot quickly return to the center after the wheel end brake device 210 brakes the left front wheel LF and the left rear wheel LR, and it is still necessary to reduce the average speed of the left wheel to obtain a larger left-centering torque to quickly return the electric vehicle 10. Fig.13 As shown, at the fifth moment T5 after the electric vehicle 10 brakes the left wheels LF and LR for a period of time, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically further increases the braking force F1 output by the wheel-end brake device 210 of the left front wheel LF and the braking force F2 output by the wheel-end brake device 210 of the left rear wheel LR at the fifth moment T5, thereby further quickly reducing the average rotation speed of the left wheel and generating a larger torque in the left return direction, so that the electric vehicle 10 quickly returns to the center.

[0106] In one embodiment, the electric vehicle 10 changes lanes at a very high speed, so that the speed of the electric vehicle 10 when turning is greater than the second preset speed threshold, or the road is a serpentine S-shaped curve, so that the steering wheel angle is greater than the second preset angle threshold, wherein the second preset speed threshold is greater than the first preset speed threshold, and the second preset angle threshold is greater than the first preset angle threshold. The electric vehicle 10 cannot return to the center after time T5, and it is necessary to rely on increasing the average speed of the right wheel to obtain a larger return torque to quickly return the electric vehicle 10 to the center. Fig.14 As shown, at the sixth moment T6 after the wheel-end brake device 210 increases the braking force of the left wheel to the maximum at T5, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically keeps the braking force output by the wheel-end brake device 210 of the left wheels LF and LR unchanged at the sixth moment T6, and automatically controls the motor controller 110 corresponding to the right rear wheel RR to control the drive motor 120 to increase the wheel speed of the right rear wheel RR, thereby increasing the average rotation speed of the right wheel and generating a larger torque in the left return direction to enable the electric vehicle 10 to return to the center quickly.

[0107] The steering return control method provided in the embodiment of the present application is used to control the wheel-end brake device of the electric vehicle to output braking force to brake the wheel during the process of the electric vehicle returning to the left after turning right. The steering return control method provided in the embodiment of the present application controls the wheel-end brake device of the electric vehicle to adjust the braking force of the two left wheels according to the right yaw angular velocity of the electric vehicle when one of the right wheels of the electric vehicle fails to brake or slips, so that the electric vehicle quickly reduces the right yaw and returns to the center.

[0108] like Fig.10 When the right front wheel RF fails to brake or slips, its wheel speed will be greater than the wheel speeds of the other three wheels. The steering return control method provided in the embodiment of the present application enables the electric vehicle 10 to control the wheel-end braking device 210 to adjust the braking force of the two left wheels to quickly reduce the average rotation speed of the left wheels, so that the electric vehicle 10 can quickly return to the center.

[0109] In one embodiment, when the electric vehicle 10 turns right, its left wheel is located on the outer side when turning, and when the electric vehicle 10 starts to return to the left after turning right, the average wheel speed of the left wheel will not decrease quickly. Under the condition that the wheel speed of the right front wheel RF of the electric vehicle 10 is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time, the controller 400 automatically controls the wheel end brake device 210 to output braking force to brake the left front wheel LF and the left rear wheel LR of the electric vehicle 10, so that the average rotation speed of the left wheel of the electric vehicle 10 is quickly reduced to less than the average rotation speed of the right wheel, thereby quickly generating a torque in the direction of returning to the left to help the electric vehicle 10 quickly return to the left.

[0110] The steering return control method provided in the embodiment of the present application is used to control the wheel-end brake device of the left wheel of the electric vehicle to increase the output braking force to brake the wheel during the process of the electric vehicle returning to the left after turning right, and to control the other right wheel to increase its wheel speed after the wheel-end brake device of the left wheel increases the output braking force to brake the wheel, so as to help the electric vehicle return to the center quickly.

[0111] Fig.15 Another schematic diagram of the steering return control method provided in an embodiment of the present application. Fig.16 Another schematic diagram of the steering return control method provided in the embodiment of the present application. Fig.15 As shown in FIG. 1 , time T7 represents that the control method of this embodiment is used to control the wheel-end brake device 210 to increase the braking force F1 of the left front wheel LF and the braking force F2 of the left rear wheel LR. Time T8 represents that the control method of this embodiment is used to control the motor controller 110 to control the right rear wheel RR to increase the speed n4 when the braking force output by the wheel-end brake device 210 for the left front wheel LF and the left rear wheel LR has reached the maximum. Fig.16 shown.

[0112] In one embodiment, the electric vehicle 10 changes lanes at a high speed or the road curve angle is large. After the wheel end brake device 210 brakes the left front wheel LF and the left rear wheel LR, the electric vehicle 10 cannot quickly return to the center. It is still necessary to reduce the average speed of the left wheel to obtain a larger left-centering torque to quickly return the electric vehicle 10 to the center. Fig.13 As shown, at the first moment T7 after the electric vehicle 10 brakes the left wheels LF and LR, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically further increases the braking force output by the wheel end brake devices 210 of the left front wheel LF and the left rear wheel LR at the first moment T7, thereby further quickly reducing the average rotation speed of the left wheel and generating a larger torque in the left return direction, so that the electric vehicle 10 quickly returns to the center.

[0113] In one embodiment, the electric vehicle 10 changes lanes at a high speed, so that when the electric vehicle 10 turns or the road is a serpentine S-shaped curve, the electric vehicle 10 cannot return to the center after time T7, and needs to rely on increasing the average speed of the right wheel to obtain a larger return torque to quickly return the electric vehicle 10 to the center. Fig.13 As shown, at the second moment T8 after the wheel-end brake device 210 increases the braking force of the left wheel to the maximum at moment T7, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically keeps the braking force output by the wheel-end brake device 210 of the left wheels LF and LR unchanged at the second moment T8, and automatically controls the motor controller 110 corresponding to the right rear wheel RR to control the drive motor 120 to increase the wheel speed of the right rear wheel RR, thereby increasing the average rotation speed of the right wheel and generating a larger torque in the left return direction to enable the electric vehicle 10 to return to the center quickly.

[0114] The steering return control method provided in the embodiment of the present application is also used for controlling the wheel-end braking device to brake the other left wheel of the electric vehicle according to the rightward yaw of the vehicle, or reducing the rotation speed of one left wheel after controlling the wheel-end braking device to increase the braking force on the other left wheel of the electric vehicle, during the process of the electric vehicle returning to the left after turning right, under the condition that the wheel speed of one left wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time, so as to enable the electric vehicle to quickly reduce the rightward yaw and quickly return to the center.

[0115] In one embodiment, before the electric vehicle 10 turns left after turning right or during the process of turning left after turning right, the driver operates the brake pedal of the electric vehicle 10, and the controller 400 controls the wheel-end brake devices 210 corresponding to the four wheels LF, LR, RF, and RR of the electric vehicle 10 to brake. Among them, the wheel-end brake device 210 corresponding to the left front wheel LF fails. Accordingly, the wheel speed of the left front wheel LF when the electric vehicle 10 turns right and changes lanes will be greater than the wheel speeds of the other three wheels.

[0116] In one embodiment, before the electric vehicle 10 turns left after turning right or during the process of turning left after turning right, the adhesion coefficient of the road surface passed by the left front wheel LF is smaller than the adhesion coefficients of the road surfaces passed by the other three wheels, and the left front wheel LF slips. Accordingly, the wheel speed of the left front wheel LF will be greater than the wheel speeds of the other three wheels.

[0117] Fig.17 Another schematic diagram of the steering return control method provided in an embodiment of the present application. Fig.18 Another schematic diagram of the steering return control method provided in the embodiment of the present application. Fig.17 As shown in FIG. 1 , the control method of this embodiment is used to control the wheel-end brake device 210 to increase the braking force F2 of the left rear wheel LR. The control method of this embodiment is used to control the motor controller 110 to control the left front wheel LF to reduce the speed n1 when the braking force F2 of the left rear wheel LR output by the wheel-end brake device 210 has reached the maximum. Fig.18 shown.

[0118] In one embodiment, when the electric vehicle 10 is returning to the left after turning right, under the condition that the wheel speed of the left front wheel LF is greater than the wheel speeds of the other three wheels of the electric vehicle 10 within a preset time, the average wheel speed of the left wheels of the electric vehicle 10 will be higher than the average wheel speed of the right wheels, thereby affecting the rapid return to the left of the electric vehicle 10. By controlling the wheel-end brake device 210 to brake the left rear wheel LR of the electric vehicle 10, the average wheel speed of the left wheel of the electric vehicle 10 can be reduced to less than the average wheel speed of the right wheel, thereby helping the electric vehicle 10 to generate a torque to return to the left, so that the electric vehicle 10 can return quickly.

[0119] In one embodiment, the electric vehicle 10 changes lanes at a high speed, so that the speed of the electric vehicle 10 when turning is greater than the first preset speed threshold, or the road is a serpentine S-shaped curve, so that the steering wheel angle is greater than the first preset angle threshold. The electric vehicle 10 cannot return to the center after the wheel-end brake device 210 brakes the left rear wheel, and it is still necessary to reduce the average speed of the left wheel to obtain a larger left-centering torque to quickly return the electric vehicle 10 to the center. Fig.17As shown, at the third moment T9 after the left rear wheel LR is braked, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically further increases the braking force output by the wheel end brake device 210 of the left rear wheel LR at the third moment T9, thereby further reducing the average rotation speed of the left wheel and generating a larger torque in the left return direction, so that the electric vehicle 10 quickly returns to the center.

[0120] In one embodiment, the electric vehicle 10 changes lanes at a very high speed, so that the speed of the electric vehicle 10 when turning is greater than the second preset speed threshold, or the road is a serpentine S-shaped curve, so that the steering wheel angle is greater than the second preset angle threshold, wherein the second preset speed threshold is greater than the first preset speed threshold, and the second preset angle threshold is greater than the first preset angle threshold, the electric vehicle 10 cannot return to the center after time T9, and it is necessary to further reduce the average speed of the left wheel to obtain a larger return torque to allow the electric vehicle 10 to return to the center quickly. Fig.18 As shown, at the fourth moment T10 after the wheel-end brake device 210 of the left rear wheel LR increases the braking force to the maximum at T1, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 of the electric vehicle 10 automatically keeps the braking force output by the wheel-end brake device 210 of the left rear wheel LR unchanged at the fourth moment T10, and simultaneously automatically controls the motor controller 110 corresponding to the left front wheel LF to control the drive motor 120 to reduce the wheel speed of the left front wheel LF, thereby further reducing the average rotation speed of the left wheel and generating a larger torque in the left return direction to allow the electric vehicle 10 to return to the center quickly.

[0121] In an embodiment of the present application, before the electric vehicle 10 returns to the left after turning right or during the process of returning to the left after turning right, the driver operates the brake pedal of the electric vehicle 10 for driving safety, and the controller 400 controls the wheel-end brake devices 210 corresponding to the four wheels LF, LR, RF, and RR of the electric vehicle 10 to brake. Among them, the wheel-end brake device 210 corresponding to the left front wheel LF fails. Accordingly, the wheel speed of the left front wheel LR will be greater than the wheel speeds of the other three wheels when the electric vehicle 10 turns right and changes lanes, and the electric vehicle 10 will yaw to the right. The motor controller 400 controls the end brake device 210 to reduce the braking force on the right wheel according to the right yaw angular velocity of the electric vehicle, so that the average wheel speed of the right side of the electric vehicle decreases slowly, thereby controlling the right yaw of the electric vehicle 10 and helping the electric vehicle 10 to maintain stable driving.

[0122] Fig.17 A schematic diagram of a steering return control method provided in an embodiment of the present application. Fig.17As shown, time T91 represents that the controller 400 controls the LR, RF, and RR output braking forces to keep the electric vehicle 10 running stably, and time T92 represents that the controller 400 controls the LR output braking force while reducing the RF and RR output braking forces to help the electric vehicle 10 return to the left.

[0123] In one embodiment, at the fifth moment T91 after the driver operates the brake pedal of the electric vehicle 10 to brake the four wheels and before the third moment T9, the right yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 adjusts and distributes the wheel-end brake devices 210 corresponding to the three wheels LR, RF, and RR of the electric vehicle 10 for braking. The controller 400 controls the braking force output by the wheel-end brake device 210 of LR and reduces the braking force output by the wheel-end brake devices 210 of RF and RR to slowly reduce the average wheel speed on the right side of the electric vehicle, thereby controlling the right yaw of the electric vehicle 10 and helping the electric vehicle 10 maintain stable driving.

[0124] In one embodiment, the speed of the electric vehicle 10 is relatively fast or the steering wheel turns to the right at a large angle. After the driver operates the brake pedal of the electric vehicle 10 for driving safety, the controller 400 controls the wheel-end brake devices 210 corresponding to the three wheels LR, RF, and RR of the electric vehicle 10 to brake to control the rightward yaw of the electric vehicle 10 after two adjustments. At the sixth moment T92 after the fifth moment T91 and before the third moment T9, the rightward yaw angular velocity monitored by the electric vehicle 10 is greater than the first preset yaw angular velocity threshold, and the controller 400 reduces the braking force output by the wheel-end brake devices 210 of RF and RR to zero to maintain the average wheel speed on the right side of the electric vehicle so that it no longer decreases, thereby quickly controlling the rightward yaw of the electric vehicle 10 and helping the electric vehicle 10 to maintain stable driving.

[0125] In summary, the embodiments of the present application provide a controller, a powertrain and a steering return control method for an electric vehicle, which are applied to the technical field of electric vehicles, so as to help the electric vehicle return to center quickly by adjusting the braking force of other wheels when the braking of a single wheel of the electric vehicle fails, thereby preventing the electric vehicle from becoming unstable.

[0126] In several embodiments provided in the present application, each functional module may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0127] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A controller for an electric vehicle, characterized in that: The controller is used to control the wheel end brake device of the electric vehicle, and the controller is used in the process of the electric vehicle returning to the left after turning right: Under the condition that the wheel speed of one left wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time period, the wheel end braking device is controlled to output braking force to brake the other left wheel of the electric vehicle.

2. The controller according to claim 1, characterized in that: The controller is further configured to: At a first moment after the wheel end brake device brakes the other left wheel, the wheel end brake device is controlled to increase the braking force for braking the other left wheel.

3. The controller according to claim 2, characterized in that: The controller is communicatively connected with the motor controller of the electric vehicle, and the controller is further used for: At a second moment after the first moment, the motor controller corresponding to the one left wheel in the electric vehicle controls the drive motor to reduce the wheel speed of the one left wheel.

4. The controller according to claim 3, characterized in that: The controller is further used for: during the process of the electric vehicle returning to the left after turning right on a low-load road surface: At a second moment after the first moment, a motor controller corresponding to the one left wheel in the electric vehicle controls the drive motor to output zero torque to reduce the wheel speed of the one left wheel.

5. The controller according to claim 2, characterized in that: The controller is further configured to: Before the working condition, receiving the braking signal and controlling the wheel-end braking device of the electric vehicle to brake the two left wheels and the two right wheels of the electric vehicle; At a third time after the wheel end brake device brakes the other left wheel and before the first time, the wheel end brake device is controlled to brake the other left wheel and two right wheels of the electric vehicle.

6. The controller according to claim 5, characterized in that: The controller is also used for: At a fourth moment after the third moment and before the first moment, the wheel end brake device of the electric vehicle is controlled to reduce the braking force for braking the two right wheels.

7. The controller according to claim 1, characterized in that: The controller is also used for: Under the condition that the wheel speed of one right wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within the preset time period, the wheel end braking device of the electric vehicle is controlled to brake the two left wheels of the electric vehicle.

8. The controller according to claim 7, characterized in that: The controller is further configured to: At a fifth moment after the wheel end brake device brakes the two left wheels, the wheel end brake device is controlled to increase the braking force for braking the two left wheels.

9. The controller according to claim 8, characterized in that: The controller is communicatively connected with the motor controller of the electric vehicle, and the controller is further used for: At a sixth moment after the fifth moment, the motor controller corresponding to the other right wheel in the electric vehicle controls the drive motor to increase the wheel speed of the other right wheel.

10. The controller according to any one of claims 1 to 9, characterized in that: The controller is also used for: during the process of the electric vehicle returning to the left after turning right: The braking force output by the wheel end brake device of the electric vehicle is controlled to increase with the increase of at least one of the return angle of the electric vehicle, the lateral acceleration of the electric vehicle, the yaw rate of the electric vehicle and the vehicle speed of the electric vehicle.

11. A powertrain for an electric vehicle, characterized in that: The powertrain includes a motor controller, a drive motor, a reducer and a controller as described in any one of claims 1 to 10, and the controller is also used to control the motor controller to drive the drive motor to drive at least one front wheel or at least one rear wheel of the electric vehicle.

12. A steering return control method for an electric vehicle, characterized in that: The steering return control method is used to control the wheel end brake device of the electric vehicle during the process of the electric vehicle returning to the left after turning right, and the electric vehicle control method includes: Under the condition that the wheel speed of one right wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within a preset time period, the wheel end braking device of the electric vehicle is controlled to brake the two left wheels of the electric vehicle.

13. The steering return control method according to claim 12, characterized in that: The steering return control method further includes: At a first moment after the wheel end brake device brakes the two left wheels, controlling the wheel end brake device to increase the braking force for braking the two left wheels; At a second moment after the first moment, a driving motor corresponding to another right wheel in the electric vehicle is controlled to increase the wheel speed of the other right wheel.

14. The steering return control method according to claim 13, characterized in that: The steering return control method further includes: Under the condition that the wheel speed of one left wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within the preset time period, controlling the wheel end braking device to brake the other left wheel of the electric vehicle; At a third moment after the wheel end brake device brakes the other left wheel, controlling the wheel end brake device to increase the braking force for braking the other left wheel; At a fourth moment after the third moment, the driving motor corresponding to the one left wheel in the electric vehicle is controlled to reduce the wheel speed of the one left wheel.

15. The steering return control method according to claim 14, characterized in that: The steering return control method further comprises: Before the wheel speed of one left wheel of the electric vehicle is greater than the wheel speeds of the other three wheels of the electric vehicle within the preset time period, receiving the braking signal and controlling the wheel-end braking device of the electric vehicle to brake the two left wheels and the two right wheels of the electric vehicle; At a fifth moment after the wheel-end brake device brakes the other left wheel and before the third moment, controlling the wheel-end brake device to brake the other left wheel and two right wheels of the electric vehicle; At a sixth moment after the fifth moment and before the third moment, the wheel end brake device of the electric vehicle is controlled to reduce the braking force for braking the two right wheels.

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