Electric vehicle escape control method, escape controller and electric vehicle

Abstract

The invention provides an electric vehicle escape control method, an escape controller and an electric vehicle. When the vehicle is trapped, the steering angle of a rear wheel can be controlled to continuously change in the process that a driving system outputs driving torque, so that the steering angle of the rear wheel can be continuously changed by controlling the steering angle of the rear wheel to continuously change; the positions where the rear wheels make contact with the ground are changed continuously, friction force generated by the surrounding ground is traversed, a ground area capable of providing enough friction force is found out, the friction force between the rear wheels and the ground is increased, and finally the trapped vehicle is helped to get out of the trap.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle technology, and in particular to an electric vehicle traction control method, traction controller, and electric vehicle. Background Technology

[0002] With the development of automotive technology, people's travel scenarios have become more diverse, and more and more vehicles are driving in environments such as grasslands, forests, deserts, and snowfields. Roads in these environments are mostly unpaved, with muddy, potholed, and other difficult-to-drive surfaces. When vehicles travel on these surfaces, their wheels can easily get stuck in the mud. When stuck, the vehicle cannot generate sufficient traction, thus becoming trapped.

[0003] Therefore, how to get stuck vehicles out of trouble is an urgent problem to be solved. Summary of the Invention

[0004] This application provides an electric vehicle traction control method, traction controller, and electric vehicle, which achieves the effect of traction control for trapped vehicles by continuously changing the steering angle of the rear wheels.

[0005] To achieve the above objectives, this application adopts the following technical solution: Firstly, a method for controlling the traction of an electric vehicle is provided. This method controls the rear-wheel steering system and drive system of the electric vehicle to enable the vehicle to escape traction after the traction mode is activated. The traction control method includes: Before the steering wheel of the electric vehicle is turned, while controlling the output of drive torque by the drive system, the rear-wheel steering system continuously changes the steering angle of the rear wheels until the vehicle speed increases or the duration of the continuous change in the steering angle of the rear wheels exceeds a preset duration. After the vehicle speed increases or the duration of the continuous change in the steering angle of the rear wheels exceeds the preset duration, the rear-wheel steering system stops changing the steering angle of the rear wheels.

[0006] In this embodiment, when an electric vehicle travels on difficult road surfaces such as mud or potholes, if its wheels (e.g., the rear wheels) get stuck, the wheels may become unable to move out, and the vehicle may become trapped. Once trapped, even if the electric vehicle's drive system is outputting drive torque, the vehicle's speed remains very low, making it difficult to move forward. In this scenario, this embodiment can automatically or manually activate the traction control mode to control the rear-wheel steering system and drive system of the electric vehicle to extricate it from the traction situation. Furthermore, in this embodiment, controlling the rear-wheel steering system to continuously change the steering angle of the rear wheels before the steering wheel is turned means that after the traction control mode is activated, the rear-wheel steering system does not passively follow the steering wheel's rotation to control the rear wheel's rotation, but actively controls the continuous change of the rear wheel's steering angle even before the steering wheel is turned.

[0007] As the steering angle changes, the contact point between the rear wheels and the ground continuously changes. The amount of friction that the ground provides to the rear wheels varies at different locations. Based on this, after the traction control mode is activated, by continuously changing the steering angle of the rear wheels, the surrounding ground can be traversed to find areas that provide sufficient friction to allow the vehicle to drive out of muddy or potholed areas, thus helping electric vehicles stuck in muddy conditions to get out. Simultaneously, the continuous changes in steering angle also alter the load distribution of the electric vehicle's suspension system, causing the vehicle body to sway. This swaying generates a tendency for the rear wheels to detach from the muddy surface, further assisting the electric vehicle in getting out of trouble.

[0008] Once the electric vehicle's speed increases, it can be considered that the electric vehicle has successfully escaped the predicament. If the duration of continuous changes in the rear wheel steering angle exceeds the preset duration, it can be considered that escaping the predicament cannot be achieved through rear wheel steering control for an extended period. At this point, the escaping mode can be discontinued.

[0009] In one implementation of the first aspect, the traction control method further includes: before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, controlling the rear wheel steering system to continuously change the steering angle of the rear wheels until the speed of the electric vehicle increases to a preset speed or the duration of the continuous change of the steering angle of the rear wheels is greater than a preset duration.

[0010] In some cases, the muddy area where electric vehicles get stuck may be quite large. If the steering angle of the rear wheels is stopped as soon as the vehicle speed begins to increase, the friction provided by the continuous changes in steering angle and the tendency to move away from the muddy surface will also disappear, making it very easy for the electric vehicle to get stuck in the mud again.

[0011] To prevent the electric vehicle from getting stuck again, this implementation method only controls the rear-wheel steering system to stop continuously changing the steering angle of the rear wheels after the electric vehicle's speed has increased to a preset speed. Specifically, when the electric vehicle's speed is detected to have increased to the preset speed, it can be considered that the electric vehicle has escaped the entrapment and can maintain normal speed. This ensures that after initially leaving the original stuck road surface, the electric vehicle is prevented from getting stuck again in subsequent muddy conditions, thus ensuring the effectiveness of the escape control.

[0012] In one implementation of the first aspect, the traction control method further includes: before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, controlling the steering angle of the rear wheel driven by the rear wheel steering system to alternately and continuously change between positive, negative and zero values.

[0013] This embodiment maximizes the rotation range of the rear wheels by continuously alternating between positive, negative, and zero values, thus expanding the area traversed by the rear wheels. This increases the probability of the rear wheels reaching areas with greater friction, ensuring that the electric vehicle can successfully extricate itself from muddy and potholed roads.

[0014] Meanwhile, this application controls the steering angle of the rear wheels to alternate and continuously change between positive, negative and zero values. This not only increases the range of the rear wheels, but also changes the load distribution of the suspension, causing the electric vehicle to sway. The swaying of the vehicle body causes the rear wheels to tend to move away from the muddy road surface, further assisting the increased ground friction to help the electric vehicle get out of trouble.

[0015] In one implementation of the first aspect, the traction control method further includes: during the process of controlling the output driving torque of the drive system, increasing the rate at which the steering angle of the rear wheels driven by the rear wheel steering system continuously changes. This embodiment can accelerate the speed at which the rear wheels traverse the road surface, thereby speeding up the traction control process of the electric vehicle.

[0016] In one implementation of the first aspect, the traction control method further includes: before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, controlling the steering angle of the left and right rear wheels of the rear wheel steering system to continuously change. Specifically, at any moment when the left rear wheel turns to the left, the right rear wheel turns to the right.

[0017] Electric vehicles have two rear wheels: a left rear wheel and a right rear wheel. To further improve the success rate of electric vehicles extricating themselves from muddy roads, the left and right rear wheels can be controlled separately. The left rear wheel can be controlled to turn left while the right rear wheel turns right, or vice versa; in other words, the left and right rear wheels can be controlled to turn in opposite directions. This ensures that at any given moment during a continuous change in steering angle, the left and right rear wheels are in a "pigeon-toed" or "pigeon-toed" position. This allows the two rear wheels to push and pull at the mud on the ground surface during these continuous changes in steering angle. The resulting counterforce from the mud propelling the rear wheels forward, thus assisting the electric vehicle in moving forward.

[0018] In one implementation of the first aspect, the traction control method further includes: before the steering wheel of the electric vehicle is turned, during the process of controlling the output of driving torque by the drive system, controlling the front wheel steering system of the electric vehicle to stop the change in the steering angle of the front wheels.

[0019] In this embodiment, by controlling the rear wheel steering system to continuously change the steering angle of the rear wheels while controlling the front wheel steering system to stop changing the steering angle of the front wheels, the front wheels are kept in a position that meets the driver's steering expectations, thus better ensuring the safety of the electric vehicle.

[0020] In one implementation of the first aspect, the traction control method further includes: before the steering wheel of the electric vehicle turns, during the process of controlling the output driving torque of the drive system, controlling the steering angle of the rear wheel steering system to continuously change, and controlling the steering angle of the front wheel steering system to continuously change. Specifically, at any moment when the front wheels turn to the left, the rear wheels turn to the right.

[0021] This control method also allows the front and rear wheels to be in a "pigeon-toed" or "pigeon-toed" state at any moment when the steering angle changes continuously. This allows the front and rear wheels to push and pull the mud on the ground, enabling the electric vehicle to move forward under the reverse force generated by the mud.

[0022] In one implementation of the first aspect, the traction control method further includes: before the steering wheel of the electric vehicle is turned, while controlling the drive system to output drive torque to drive the electric vehicle forward, controlling the rear wheel steering system to continuously change the steering angle of the rear wheels; and while controlling the drive system to output drive torque to drive the electric vehicle backward, controlling the rear wheel steering system to continuously change the steering angle of the rear wheels.

[0023] When an electric vehicle attempts to get out of a muddy or potholed area, if the vehicle is moving forward, the tires closer to the front of the vehicle will contact the ground during the extrication process; if the vehicle is moving backward, the tires closer to the rear of the vehicle will contact the ground. Therefore, the position of the tires in contact with the ground differs depending on the direction of travel, resulting in different areas of contact between the wheels and the ground, and consequently, different levels of friction between the electric vehicle and the ground.

[0024] In this embodiment, to improve the success rate of the electric vehicle getting out of trouble, the vehicle can be controlled to move forward first and then backward. This allows the rear wheels to traverse the ground sequentially during both forward and backward movements, thereby expanding the traversal range. A larger traversal range increases the probability that the electric vehicle will find a surface area that provides sufficient friction, ultimately improving the success rate of getting out of trouble.

[0025] In one implementation of the first aspect, the traction control method further includes: after the speed of the electric vehicle is greater than a preset speed or the duration of continuous change of the steering angle of the rear wheels is greater than a preset duration, when the steering angle of the rear wheels changes to zero, controlling the rear wheel steering system to stop driving the change of the steering angle of the rear wheels.

[0026] In this embodiment, when the steering angle of the rear wheels changes to zero, the rear wheel steering system can be controlled to stop driving the steering angle change of the rear wheels, thereby exiting the traction control mode. This ensures that the steering angle of the rear wheels is at zero after the electric vehicle exits the traction control mode, helping to ensure driving smoothness.

[0027] In one implementation of the first aspect, the traction control method further includes: when the electric vehicle is on a first type of road surface, controlling the rear-wheel steering system to continuously change the steering angle of the rear wheels at a first rate; and when the electric vehicle is on a second type of road surface, controlling the rear-wheel steering system to continuously change the steering angle of the rear wheels at a second rate different from the first rate. The first type of road surface and the second type of road surface have different road surface materials. The first type of road surface and the second type of road surface can be any of the following: gravel road surface, mud road surface, snow-covered road surface, and grass road surface.

[0028] The mechanisms by which electric vehicles get stuck differ depending on the road surface. On surfaces with a certain degree of viscosity, such as mud, electric vehicles are unable to escape due to the suction force generated by the mud enveloping the wheels. On dry, loose surfaces, such as sand, electric vehicles are unable to escape because the granular materials, like dry sand, cannot provide stable support. Therefore, by controlling the steering angle of the rear wheels to continuously vary at different rates, the sway rate of the rear wheels can be adapted to different road surfaces, thereby improving the electric vehicle's ability to get out of trouble.

[0029] Secondly, this application provides an traction control system for an electric vehicle. This traction control system is used to: before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, control the rear-wheel steering system to continuously change the steering angle of the rear wheels until the vehicle speed increases or the duration of the continuous change in the rear wheel steering angle exceeds a preset duration. After the vehicle speed increases or the duration of the continuous change in the rear wheel steering angle exceeds the preset duration, control the rear-wheel steering system to stop changing the steering angle of the rear wheels.

[0030] In one implementation of the second aspect, the traction controller is also used to: control the rear wheel steering system to continuously change the steering angle of the rear wheels during the process of controlling the output of driving torque of the drive system before the steering wheel of the electric vehicle is turned, until the speed of the electric vehicle increases to a preset speed or the duration of continuous change of the steering angle of the rear wheels is greater than a preset duration.

[0031] In one implementation of the second aspect, the traction controller is also used to: control the steering angle of the rear wheel steering system to alternate continuously between positive, negative and zero values ​​during the process of controlling the output driving torque of the drive system before the steering wheel of the electric vehicle is turned.

[0032] In one implementation of the second aspect, the traction controller is also used to: increase the rate at which the steering angle of the rear wheels driven by the rear wheel steering system continuously changes during the process of controlling the output driving torque of the drive system.

[0033] In one implementation of the second aspect, the traction controller is further configured to: control the rear-wheel steering system to continuously change the steering angles of the left and right rear wheels during the process of controlling the output of drive torque by the drive system before the steering wheel of the electric vehicle is turned. Specifically, at any moment when the left rear wheel turns to the left, the right rear wheel turns to the right.

[0034] In one implementation of the second aspect, the traction controller is also used to: control the front wheel steering system of the electric vehicle to stop the change in the steering angle of the front wheels before the steering wheel of the electric vehicle is turned, during the process of controlling the output of the driving torque of the drive system.

[0035] In one implementation of the second aspect, the traction controller is further configured to: control the rear-wheel steering system to continuously change the steering angle of the rear wheels while controlling the output of driving torque of the drive system before the steering wheel of the electric vehicle turns, and control the front-wheel steering system to continuously change the steering angle of the front wheels. Specifically, at any moment when the front wheels turn to the left, the rear wheels turn to the right.

[0036] In one implementation of the second aspect, the traction controller is also used to: control the rear wheel steering system to continuously change the steering angle of the rear wheels while controlling the drive system to output drive torque to drive the electric vehicle forward before the steering wheel of the electric vehicle is turned; and control the rear wheel steering system to continuously change the steering angle of the rear wheels while controlling the drive system to output drive torque to drive the electric vehicle backward.

[0037] In one implementation of the second aspect, the traction controller is further configured to: after the electric vehicle speed is greater than a preset speed or the duration of continuous change in the steering angle of the rear wheels is greater than a preset duration, when the steering angle of the rear wheels changes to zero, control the rear wheel steering system to stop driving the change in the steering angle of the rear wheels.

[0038] In one implementation of the second aspect, the traction controller is further configured to: when the electric vehicle is on a first type of road surface, control the rear-wheel steering system to continuously change the steering angle of the rear wheels at a first rate; and when the electric vehicle is on a second type of road surface, control the rear-wheel steering system to continuously change the steering angle of the rear wheels at a second rate different from the first rate. The first type of road surface and the second type of road surface have different road surface materials.

[0039] Thirdly, this application provides an electric vehicle including a drive system, a rear-wheel steering system, and a traction controller. The drive system outputs drive torque, and the rear-wheel steering system controls the steering angle of the rear wheels. The traction controller is used to execute the traction control methods as described in the first aspect and various embodiments thereof.

[0040] For details on other beneficial effects, please refer to the beneficial effects described in the first aspect, which will not be repeated here. Attached Figure Description

[0041] Figure 1 A schematic diagram of a vehicle architecture provided for an embodiment of this application; Figure 2 A schematic diagram of the structure of a drive system provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a rear-wheel steering system provided in an embodiment of this application; Figure 4 This is a schematic diagram of a front wheel steering system provided in an embodiment of this application; Figure 5 A timing diagram for vehicle extrication control provided in an embodiment of this application; Figure 6 A flowchart illustrating the status display control of a virtual button provided in this application embodiment; Figure 7This is a schematic diagram of the first wheel rotation state provided in an embodiment of this application; Figure 8 This is a schematic diagram of a second wheel rotation state provided in an embodiment of this application; Figure 9 This is a schematic diagram of a third wheel rotation state provided in an embodiment of this application; Figure 10 This is a schematic diagram of the fourth wheel rotation state provided in the embodiments of this application; Figure 11 This is a schematic diagram of the fifth wheel rotation state provided in the embodiments of this application; Figure 12 This is a vehicle control flowchart provided as an embodiment of the present application. Detailed Implementation

[0042] The technical solutions in this application will now be described in conjunction with the accompanying drawings. The detailed descriptions and drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments.

[0043] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0044] With the development of automotive technology, people's travel scenarios are becoming increasingly diverse, and vehicles frequently enter unpaved environments such as grasslands, forests, and snowfields. In these environments, the road surface is often unpaved, with a loose structure and low adhesion, easily forming muddy areas under rain, snow, or wet conditions. When a vehicle gets stuck in mud, on the one hand, the tire tread is easily filled with mud, reducing the contact area between the tire and the road surface; on the other hand, the coefficient of friction of the road surface also decreases, resulting in a significant drop in wheel grip. At this time, even if the drive wheels continue to rotate, it is difficult to obtain enough friction to convert into effective traction, resulting in wheel spin, sinking, or lateral slippage, ultimately trapping the vehicle.

[0045] In one possible approach, when a vehicle gets stuck in mud, the tires can be deflated to reduce tire pressure, thereby increasing the contact area between the wheels and the road surface and improving vehicle traction. However, this method requires the tires to be inflated promptly after the vehicle is freed. Given the limited resources and availability of inflation equipment in the wild, this method is highly dependent on external conditions and can negatively impact the vehicle's ability to continue driving after it has gotten out of trouble.

[0046] To address the aforementioned issues, this application provides an electric vehicle traction control method, a traction controller, and an electric vehicle. By continuously changing the steering angle of the rear wheels, the contact position between the rear wheels and the ground is constantly changed. This process traverses the friction forces generated by the surrounding ground, identifies areas that can provide sufficient friction, increases the friction between the rear wheels and the ground, and ultimately helps the trapped vehicle to escape.

[0047] The following section will introduce the vehicle architecture and system architecture on which this application is based.

[0048] See Figure 1 , Figure 1 This is a schematic diagram of a vehicle architecture provided in an embodiment of this application. Vehicle 10 may be an electric vehicle. Figure 1 As shown, vehicle 10 includes a drive system 110, a braking system 120, a power battery 130 connected to the drive system 110, a rear-wheel steering system 150, a front-wheel steering system 160, and a vehicle controller 140 connected to the drive system 110, braking system 120, rear-wheel steering system 150, and front-wheel steering system 160, respectively. The drive system 110 drives vehicle 10. The braking system 120 brakes vehicle 10. The power battery 130 provides electrical energy to the drive system 110. The rear-wheel steering system 150 controls the steering of the rear wheels 170. The front-wheel steering system 160 controls the steering of the front wheels 180. The vehicle controller 140 controls the drive system 110 to drive vehicle 10, controls the braking system 120 to brake vehicle 10, controls the rear-wheel steering system 150 to drive the rear wheels 170, and controls the front-wheel steering system 160 to drive the front wheels 180.

[0049] The four wheels of vehicle 10 can be divided into front wheels 180 and rear wheels 170 according to their position on the axle. Front wheels 180 are located on the front axle of vehicle 10, and rear wheels 170 are located on the rear axle. For two wheels on the same axle, based on their position relative to the vehicle body, front wheels 180 can be further divided into left front wheels 181 and right front wheels 182, and rear wheels 170 can be divided into left rear wheels 171 and right rear wheels 172. That is, among the four wheels of vehicle 10, left front wheels 181 and right front wheels 182 are co-axle wheels, and left rear wheels 171 and right rear wheels 172 are co-axle wheels; left front wheels 181 and left rear wheels 171 are wheels on the same side, and right front wheels 182 and right rear wheels 172 are wheels on the same side.

[0050] In this application embodiment, the vehicle 10 can be any type of vehicle such as a sedan, truck, or passenger bus, or it can be a tricycle, two-wheeled vehicle, train, or other transportation device for carrying passengers or goods, or other types of vehicles powered by the power battery 130. This application embodiment does not limit this. The vehicle 10 includes, but is not limited to, pure electric vehicles (pure EV / battery EV), hybrid electric vehicles (HEV), range-extended electric vehicles (REEV), and plug-in hybrid electric vehicles (plug-in hybrid electric vehicles). In hybrid electric vehicles (PHEVs), new energy vehicles (NEVs), etc.

[0051] The drive system 110 can be referred to as a powertrain. This application does not limit the specific type of the drive system 110; these are merely examples and not limitations. The structure of the drive system 110 can be as follows: Figure 2 A schematic diagram of a drive system is shown. Figure 2 In this configuration, the drive system 110 includes two drive motors 112 and a drive controller 111 connected to each of the two drive motors 112. The two drive motors 112 are connected to the front axle and the rear axle, respectively. The drive motor 112 connected to the front axle outputs torque to the front axle, and the drive motor 112 connected to the rear axle outputs torque to the rear axle. The drive controller 111 controls the two drive motors 112 to output drive torque to the front axle and the rear axle, respectively.

[0052] The braking system 120 can be either a hydraulic braking system 120 or an electromechanical braking system 120. A hydraulic braking system 120 uses brake fluid as an incompressible transmission medium, transmitting pedal force to the brake cylinders of each wheel via the master cylinder and oil lines to achieve braking. An electromechanical braking system eliminates the hydraulic lines, directly driving the brake calipers through a brake motor located at the wheel end to achieve braking.

[0053] The power battery 130 in this embodiment can be a lithium-ion battery, lithium metal battery, lead-acid battery, nickel-cadmium battery, nickel-metal hydride battery, lithium-sulfur battery, lithium-air battery, or sodium-ion battery, etc., and this application does not limit its application to this type. In terms of scale, the power battery 130 in this embodiment can be a single cell, a battery module, or a battery pack, and this application does not limit its application to this type. The power battery 130 can also supply power to other electrical devices in the vehicle 10, such as the vehicle's air conditioning and in-vehicle media player.

[0054] See Figure 3 The diagram illustrates the structure of a rear-wheel steering system 150. The rear-wheel steering system 150 includes multiple rear-wheel steering motors 151 and a rear-wheel steering controller 152 connected to the multiple rear-wheel steering motors 151. Each rear-wheel steering motor 151 is connected to the kingpin of the rear wheel 170 and drives the kingpin to rotate, thereby adjusting the deflection angle of the rear wheel 170. The rear-wheel steering motors 151 of the rear-wheel steering system 150 can be integrated into a single corner module with the shock absorbers of the vehicle 10 suspension system, the wheel-end brakes of the braking system 120, and the hub motors of the drive system 110, or they can be installed independently of the shock absorbers, wheel-end brakes, and hub motors.

[0055] The rear-wheel steering system 150 is a steer-by-wire system where there is no mechanical connection between the steering wheel and the rear wheels 170. The rear-wheel steering controller 152 can control the rear wheels 170 to rotate in the same direction as or opposite to the steering wheel, or decouple the rotation of the rear wheels 170 from the rotation of the steering wheel, depending on different control strategies of the vehicle 10. Taking the rear-wheel steering controller 152 controlling the rear wheels 170 to rotate in the same direction as the steering wheel as an example, the specific process of the rear-wheel steering system 150 controlling the steering of the rear wheels 170 can include: when the driver needs to steer, they transmit their steering intention by turning the steering wheel. Simultaneously, a steering wheel angle sensor mounted on the steering column collects the steering wheel angle and generates a steering wheel angle signal, which is sent to the rear-wheel steering controller 152. After receiving the steering wheel angle signal, the rear-wheel steering controller 152 determines the required target torque based on the steering wheel angle indicated by the signal and further controls the rear-wheel steering motor 151 to output the target torque to drive the rear wheels 170 to rotate in the same direction as the steering wheel.

[0056] In addition, vehicle 10 includes a front-wheel steering system 160, which can also be a steer-by-wire system, controlling the front wheels 180 to turn in the same or opposite direction as the steering wheel in the same manner as the rear-wheel steering system 150, or decoupling the rotation of the front wheels 180 from the rotation of the steering wheel. (Reference) Figure 4 The diagram shows a front-wheel steering system 160, which has a similar structure to the rear-wheel steering system 150 and may include, for example... Figure 4The structure shown is illustrated in the description of the front wheel steering system 160. For a more detailed description of the structure, please refer to the above description of the rear wheel steering system 150. In an optional embodiment, the front wheel steering controller 162 of the front wheel steering system 160 and the rear wheel steering controller 152 of the rear wheel steering system 150 can be integrated into the same controller.

[0057] The following combination Figures 1 to 4 The architecture of vehicle 10 is shown, and the method for getting out of trouble for vehicle 10 provided in this application is described in detail.

[0058] First, refer to Figure 5 The diagram shows a timing diagram for vehicle extrication control. Figure 5 In the diagram, t1 is the moment when the drive system 110 starts to output drive torque, t2 is the moment when the rear wheel 170 steering angle starts to change, and t3 is the moment when the vehicle speed of 10 starts to increase.

[0059] When vehicle 10 is driving on the road and accidentally gets stuck in mud or potholes, the driver can activate the get-out-of-trouble mode by using a physical button on the instrument panel of vehicle 10 or a virtual button on the central control screen. This allows the rear wheel steering system 150 and drive system 110 to work actively and cooperate with each other to get vehicle 10 out of the mud and potholes without the driver applying any control action.

[0060] If any one or more of the front wheels 180 and rear wheels 170 of vehicle 10 become stuck in muddy or potholed terrain, after the driver presses the button to activate the vehicle 10's off-road mode at time t1, before the steering wheel of vehicle 10 is turned, the drive system 110 is first controlled to output drive torque to at least one of the rear wheels 170 and the front wheels 180 at time t1. Then, during the process of the drive system 110 outputting drive torque to the rear wheels 170, starting from time t2, the rear wheel steering controller 152 controls the rear wheel steering motor 151 to continuously change the steering angle of the rear wheels 170.

[0061] During the continuous change of the rear wheel steering angle 170, when the vehicle speed of vehicle 10 starts to increase from time t3, it indicates that vehicle 10 has started to move. At this time, the steering angle of the rear wheel 170 can be controlled to stop changing.

[0062] As the steering angle changes, the contact position between the rear wheel 170 and the ground continuously changes. Different locations on the ground provide varying levels of friction to the rear wheel 170. Therefore, by continuously changing its steering angle, the rear wheel 170 can traverse the surrounding ground to identify areas that provide sufficient friction. Thus, by controlling the continuous change of the rear wheel 170's steering angle, this application increases the friction between the rear wheel 170 and the ground, thereby helping the vehicle 10, stuck on a muddy road, to escape.

[0063] After the vehicle speed of 10 exceeds the preset speed or the duration of continuous change in the steering angle of the rear wheels 170 exceeds the preset duration, it indicates that the vehicle 10 has successfully escaped the predicament or that the vehicle 10 has been confirmed to be unable to escape the predicament through rear wheel steering control. At this time, when the steering angle of the rear wheels 170 changes to zero, the rear wheel steering system 150 can be controlled to stop driving the steering angle change of the rear wheels 170, thereby ensuring the driving smoothness of the vehicle 10 after exiting the escaping mode.

[0064] In one alternative implementation, when the button for activating the escape mode is a virtual button, the color of the virtual button can also indicate to the user whether the escape mode is available. For example, see reference... Figure 6 The diagram illustrates a virtual button's status display control flowchart. When the driver's seatbelt is fastened, the driver's side door is closed, and the rear-wheel steering system 150 is active, the virtual button's color is set to a first color. When the driver's seatbelt is unfastened, the driver's side door is open, or the rear-wheel steering system 150 is inactive, the virtual button's color is set to a second color, different from the first color. When the traction control mode is active, the user can also deactivate it by pressing this virtual button. The first and second colors can be either colors.

[0065] Based on the above control measures, the rear wheel steering control can be further optimized by considering the range, rate, and direction of continuous changes in the steering angle, thereby improving the overall off-road capability of vehicle 10. Specifically: To increase the probability that the rear wheel 170 will traverse a region of high friction during the continuous change of steering angle, the steering angle of the rear wheel 170 can be continuously changed alternately between positive, negative, and zero values. In simpler terms, this means controlling the rear wheel 170 to swing left and right back and forth.

[0066] In this control method, "positive value" and "negative value" are vectors used to indicate the magnitude and direction of the steering angle. These include signs "+" (positive value) and "-" (negative value) indicating direction, and numbers indicating the magnitude of the steering angle. For example, a steering angle of "+5°" for the rear wheel 170 means the rear wheel 170 deflects 5° in the positive direction, and a steering angle of "-5°" for the rear wheel 170 means the rear wheel 170 deflects 5° in the negative direction. As an example, in this embodiment, the steering angle control method for the rear wheel 170 can specifically be to control the steering angle of the rear wheel 170 starting from a position of -a° (deflecting a° in the negative direction, where a° is, for example, 5°, 10°, etc.), gradually decreasing the negative angle, then passing a position with a steering angle of 0°, and continuing to increase the positive angle until it reaches a position of +b° (for example, deflecting b° in the positive direction, where b° is, for example, 5°, 10°, etc.). During the continuous change of the steering angle of the rear wheel 170, the maximum angle value b° in the positive direction and the maximum angle value a° in the negative direction of the rear wheel 170 may be equal or unequal.

[0067] In this embodiment, the positive and negative directions are defined manually. The direction in which the rear wheel 170 deviates to the left side of the vehicle 10 can be defined as the positive direction, and the direction in which the rear wheel 170 deviates to the right side of the vehicle 10 can be defined as the negative direction. Alternatively, the direction in which the rear wheel 170 deviates to the right side of the vehicle 10 can be defined as the positive direction, and the direction in which the rear wheel 170 deviates to the left side of the vehicle 10 can be defined as the negative direction.

[0068] This embodiment controls the steering angle of the rear wheel 170 to alternate continuously between positive, negative and zero values, thereby maximizing the rotation range of the rear wheel 170, expanding the area traversed by the rear wheel 170, increasing the probability that the rear wheel 170 traverses a larger friction area, and thus enabling the vehicle 10 to get out of the muddy and potholed road surface as soon as possible.

[0069] Meanwhile, this application controls the steering angle of the rear wheel 170 to change continuously between positive, negative and zero values. This not only increases the range of travel of the rear wheel 170, but also changes the load distribution of the suspension, causing the vehicle 10 to sway. The swaying of the vehicle body enables the rear wheel 170 to generate a tendency to move away from the muddy road surface, further assisting the increased ground friction to help the vehicle 10 get out of trouble.

[0070] Regarding the rate of continuous change of steering angle, during the process of controlling the output of drive torque by the drive system 110, the rate of continuous change of steering angle of the rear wheel 170 driven by the rear wheel steering system 150 can be increased. When the rate of continuous change of steering angle of the rear wheel 170 increases, the rear wheel 170 can traverse the road surface at a higher rate, thereby accelerating the process of vehicle 10 getting out of trouble.

[0071] Based on this, if the rate and range of continuous change in steering angle are simultaneously optimized, while controlling the steering angle of the rear wheel 170 to continuously change between positive, negative, and zero values, the rate of continuous change in the steering angle of the rear wheel 170 driven by the rear wheel steering system 150 is increased. This control method, which optimizes from different angles, can increase the vehicle's swaying frequency, allowing the rear wheel 170 to more easily leave the mud, thereby increasing the success rate of the vehicle 10 getting out of trouble.

[0072] In an alternative implementation, the rear-wheel steering system 150 can be controlled to continuously change the steering angle of the rear wheels 170 at different rates depending on the type of road surface the vehicle 10 is on. For example, when the vehicle 10 is on a first type of road surface, the steering angle of the rear wheels 170 driven by the rear-wheel steering system 150 is continuously changed at a first rate; when the vehicle 10 is on a second type of road surface, the steering angle of the rear wheels 170 driven by the rear-wheel steering system 150 is continuously changed at a second rate. The first type of road surface and the second type of road surface have different road surface materials. The first type of road surface and the second type of road surface can be any of the following: gravel road surface, dirt road surface, snow-covered road surface, and grass road surface.

[0073] The mechanisms by which vehicle 10 gets stuck differ on different road surfaces. On surfaces with a certain degree of viscosity, such as mud, vehicle 10 is unable to detach due to the suction force generated by the mud enveloping the wheels; on dry, loose surfaces, such as sand, vehicle 10 is unable to detach because the granular materials, such as dry sand, cannot provide stable support. Therefore, by controlling the steering angle of the rear wheel 170 to continuously change at different rates according to the different mechanisms by which vehicle 10 gets stuck, the sway rate of the rear wheel 170 can be adapted to different road surfaces, thereby improving the vehicle 10's ability to get out of trouble.

[0074] For directions where the steering angle changes continuously, the right rear wheel 172 can be controlled to turn right at any moment when the left rear wheel 171 turns left during the continuous change of the steering angle.

[0075] Vehicle 10 has two rear wheels 170: a left rear wheel 171 and a right rear wheel 172. To further improve the success rate of vehicle 10 extricating itself from muddy roads, the left rear wheel 171 and the right rear wheel 172 can be controlled separately. While controlling the right rear wheel 172 to turn right, the left rear wheel 171 can be controlled to turn left, or vice versa. This ensures that at any moment when the steering angle changes continuously, the left rear wheel 171 and the right rear wheel 172 are in either an "inward-pointing" or "outward-pointing" state. The "inward-pointing" state of the left rear wheel 171 and the right rear wheel 172 can be referenced as follows: Figure 7The first schematic diagram of wheel rotation shows the "outward-pointing" state of the left rear wheel 171 and right rear wheel 172, which can be referenced as follows: Figure 8 The diagram shows the second type of wheel rotation state.

[0076] The "inward" or "outward" swinging motion of the left rear wheel 171 and the right rear wheel 172 allows the rear wheel 170 to push and pull the soil on the ground surface during the continuous change of steering angle. The reverse force generated by the soil pushing and pulling on the rear wheel 170 propels the rear wheel 170 forward, thus assisting the vehicle 10 to move forward.

[0077] In one embodiment, the reaction force generated when the soil is pushed and raked can be increased by controlling the front wheel 180. Specifically, while controlling the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170, the front wheel steering system 160 is also controlled to continuously change the steering angle of the front wheel 180. At any moment when the front wheel 180 turns left, the rear wheel 170 turns right, or at any moment when the front wheel 180 turns right, the rear wheel 170 turns left.

[0078] This control method allows the front wheels 180 and rear wheels 170 to maintain an "inward" or "outward" stance at any given moment during continuous changes in steering angle. This allows the front wheels 180 and rear wheels 170 to push and gather the mud on the ground, propelling the vehicle 10 forward under the counterforce generated by the mud. The "inward" stance of the front wheels 180 and rear wheels 170 can be referenced as follows: Figure 9 The diagram showing the third wheel rotation state illustrates the "outward-pointing" state of the front wheel 180 and the rear wheel 170, which can be referenced as follows: Figure 10 The diagram shows the fourth wheel rotation state.

[0079] In an optional implementation, the two control methods for the direction of steering angle change described above can be combined. At any moment when the right front wheel 182 turns right, the left front wheel 181 and right rear wheel 172 are controlled to turn left, and the left rear wheel 171 is controlled to turn right. Alternatively, at any moment when the right front wheel 182 turns left, the left front wheel 181 and right rear wheel 172 are controlled to turn right, and the left rear wheel 171 is controlled to turn left. That is, the front wheels 180 and rear wheels 170 are aligned... Figure 11 The diagram shows the fifth type of wheel rotation state.

[0080] Controlling the steering angles of the front wheels 180 and rear wheels 170 to change simultaneously enhances the vehicle 10's ability to get out of trouble. However, changes in the steering angle of the front wheels 180 also alter the vehicle 10's direction of travel. If the vehicle 10 successfully gets out of trouble during the change in the steering angle of the front wheels 180, the rotating front wheels 180 could potentially cause the vehicle 10 to move in an unpredictable direction, leading to danger. Therefore, to avoid this danger, while controlling the rear wheel steering system 150 to continuously change the steering angle of the rear wheels 170, the front wheel steering system 160 can be controlled to stop changing the steering angle of the front wheels 180, thus keeping the front wheels 180 in a position consistent with the driver's steering expectations and ensuring the safety of the vehicle 10.

[0081] In an optional implementation, the front wheel steering system 160 can be controlled to change the steering angle of the front wheels 180 based on the magnitude of the driving torque output by the drive system 110. For example, when the driving torque output by the drive system 110 is less than or equal to a preset torque, the vehicle 10 can maintain a low speed after successfully escaping the treacherous terrain. Even if the vehicle 10 drives out of the muddy road in a direction unexpected by the driver, the driver can take timely control. Therefore, the front wheel steering system 160 can be controlled to continuously change the steering angle of the front wheels 180. When the driving torque output by the drive system 110 is greater than the preset torque, the vehicle 10 will increase its speed rapidly after successfully escaping the treacherous terrain. At this time, the vehicle 10 is in a more dangerous situation. Therefore, the front wheel steering system 160 should be controlled to stop continuously changing the steering angle of the front wheels 180.

[0082] In addition to optimizing the way the steering angle changes as described above, the way the drive system 110 outputs drive torque can also be optimized. Specifically, the drive torque output by the drive system 110 can be controlled to drive the vehicle 10 forward, and while the vehicle 10 is being driven forward by the drive torque, the steering angle of the rear wheels 170 can be continuously changed. Then, the drive torque output by the drive system 110 can be controlled to drive the vehicle 10 backward, and while the vehicle 10 is being driven backward by the drive torque, the steering angle of the rear wheels 170 can be continuously changed.

[0083] When vehicle 10 attempts to get out of a muddy, potholed road surface, if vehicle 10 is moving forward, the tire tread closest to the front of the vehicle will contact the ground during the extrication process; if vehicle 10 is moving backward, the tire tread closest to the rear of the vehicle will contact the ground during the extrication process. Therefore, the tire tread position in contact with the ground differs depending on the direction of vehicle 10's movement, resulting in different areas of contact between the wheels and the ground, and consequently, different frictional forces between vehicle 10 and the ground.

[0084] Since the friction between vehicle 10 and the ground varies depending on the direction of travel of vehicle 10, in order to improve the success rate of vehicle 10 getting out of trouble, vehicle 10 can be controlled to move forward first and then reverse. This allows the rear wheels 170 to traverse the ground sequentially during the forward and reverse movements of vehicle 10, thereby expanding the traversal range. A larger traversal range increases the probability that vehicle 10 will find a ground area that can provide sufficient friction, ultimately improving the success rate of vehicle 10 getting out of trouble.

[0085] In one alternative implementation, vehicle 10 can repeatedly switch its driving direction. By taking the above control action as a control cycle and repeating this control cycle multiple times, vehicle 10 can move forward and backward repeatedly while the steering angle of its rear wheels 170° changes continuously. This reciprocating forward and backward movement causes vibrations in the ground, altering the ground shape and ultimately helping vehicle 10 to escape from the stuck road surface.

[0086] In an alternative implementation, the drive torque output by the drive system 110 can also be increased as the steering angle of the rear wheels 170 changes continuously.

[0087] Based on the analysis of some embodiments of this application above, it can be seen that the method of continuously changing the steering angle of the rear wheel 170 can find an area that can provide sufficient friction, thereby helping the vehicle 10 to get off the stuck road surface. In addition, the continuous change of steering angle can also change the load distribution of the suspension, causing the vehicle 10 to sway. Through the swaying of the vehicle body, the rear wheel 170 can generate a tendency to move off the muddy road surface, further assisting the increased ground friction to help the vehicle 10 get off the stuck road.

[0088] Therefore, considering that the muddy area where vehicle 10 is stuck is usually quite large, if the steering angle of the rear wheels 170 is stopped changing as soon as the vehicle speed of 10 begins to increase, the tendency of the rear wheels 170 to move away from the muddy road surface due to the continuous change of steering angle will also disappear, making it very easy for vehicle 10 to get stuck in the mud again. To address this problem, in one embodiment, the rear wheel steering system 150 can be controlled to continuously change the steering angle of the rear wheels 170 until the vehicle speed of 10 increases to a preset speed. In this embodiment, the rear wheel steering system 150 is controlled to stop continuously changing the steering angle of the rear wheels 170 only after the vehicle speed of 10 has increased to the preset speed. This ensures that after the vehicle 10 initially leaves the original stuck road surface, it avoids getting stuck again in the subsequent muddy road surface, thus ensuring the effectiveness and thoroughness of the current escape control. The preset speed can be 5 km / h, 3 km / h, or 8 km / h.

[0089] Next, refer to Figure 12A vehicle control flowchart is shown below, illustrating the specific control flow of the traction control method of this application. The flowchart is as follows: At the beginning of this control flow, step S101 is executed first.

[0090] Step S101: In response to the user pressing the button to activate the escape mode, determine whether the steering system is available and whether the driver's side seat belt and the door are both closed.

[0091] If the conditions that the steering system is available and the driver's side seat belt and door are both closed are not met, proceed to step S102.

[0092] If the steering system is available and the driver's side seatbelt and door are both closed, proceed to step S103.

[0093] Step S102: Issue an alarm message indicating that the escape mode cannot be activated.

[0094] After step S102, the current control flow ends.

[0095] Step S103: Control the drive system 110 to output drive torque.

[0096] After step S103, proceed to step S104.

[0097] Step S104: Control the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170.

[0098] After step S104, proceed to step S105.

[0099] Step S105: Determine whether the speed of vehicle 10 has increased.

[0100] If the speed of vehicle 10 increases, proceed to step S106.

[0101] If the speed of vehicle 10 does not increase, proceed to step S107.

[0102] Step S106: Control the rear wheel steering system 150 to stop the continuous change of the steering angle of the rear wheel 170.

[0103] After step S106, the current control flow ends.

[0104] Step S107: Determine whether the duration of continuous change in steering angle is greater than the preset duration.

[0105] If the duration of continuous change in steering angle is less than or equal to the preset duration, then return to step S105.

[0106] If the duration of the continuous change in steering angle exceeds the preset duration, proceed to step S106.

[0107] In addition to the above Figure 12 In addition to steps S101 to S107 shown, the escape control method in several embodiments of this application can also be used to... Figure 12 Steps S101 to S107 shown are modified by deletion, substitution, and addition to obtain the result that is consistent with the original. Figure 12 Different control processes. These affect... Figure 12 Any control flow obtained by modifying the control flow shown herein, as long as it conforms to the basic control logic, should be considered to be covered within the scope of protection of this application.

[0108] In this embodiment of the application, a traction controller for an electric vehicle 10 is also provided, wherein the traction control method executed by the traction controller is the same as described above. Figures 1-12 The control functions implemented by the relevant escaping control methods correspond to the escaping controller, which can specifically be... Figure 1 The vehicle controller 140 shown is shown.

[0109] Specifically, the escape controller is used for: Before the steering wheel of vehicle 10 is turned, during the process of controlling the drive system 110 to output drive torque, the rear wheel steering system 150 continuously changes the steering angle of the rear wheels 170 until the vehicle speed of 10 increases or the duration of the continuous change in the steering angle of the rear wheels 170 exceeds a preset duration. After the vehicle speed of 10 increases or the duration of the continuous change in the steering angle of the rear wheels 170 exceeds the preset duration, the rear wheel steering system 150 stops changing the steering angle of the rear wheels 170.

[0110] Optionally, the traction controller is also used to: control the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170 during the process of controlling the drive system 110 to output drive torque before the steering wheel of the vehicle 10 is turned, until the vehicle speed of the vehicle 10 increases to a preset speed or the duration of the continuous change of the steering angle of the rear wheel 170 is greater than a preset duration.

[0111] Optionally, the traction controller is also used to: control the steering angle of the rear wheel 170 driven by the rear wheel steering system 150 to alternate between positive, negative and zero values ​​during the process of controlling the output of drive torque by the drive system 110 before the steering wheel of the vehicle 10 is turned.

[0112] Optionally, the traction controller is also used to: increase the rate at which the steering angle of the rear wheel 170 driven by the rear wheel steering system 150 changes continuously during the process of controlling the output driving torque of the drive system 110.

[0113] Optionally, the traction controller is also used to: control the rear wheel steering system 150 to continuously change the steering angle of the left rear wheel 171 and the right rear wheel 172 during the process of controlling the output of drive torque by the drive system 110 before the steering wheel of the vehicle 10 is turned. Specifically, at any moment when the left rear wheel 171 turns to the left, the right rear wheel 172 turns to the right.

[0114] Optionally, the traction controller is also used to: control the front wheel steering system 160 of the vehicle 10 to stop the change in steering angle of the front wheels 180 before the steering wheel of the vehicle 10 is turned, during the process of controlling the output of drive torque by the drive system 110.

[0115] Optionally, the traction controller is also used to: control the rear wheel steering system 150 to continuously change the steering angle of the rear wheels 170 while controlling the drive system 110 to output drive torque before the steering wheel of the vehicle 10 is turned, and control the front wheel steering system 160 of the vehicle 10 to continuously change the steering angle of the front wheels 180. Wherein, at any moment when the front wheels 180 turn to the left, the rear wheels 170 turn to the right.

[0116] Optionally, the traction controller is also used to: control the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170 during the process of controlling the drive system 110 to output drive torque to drive the vehicle 10 forward before the steering wheel of the vehicle 10 is turned; and control the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170 during the process of controlling the drive system 110 to output drive torque to drive the vehicle 10 backward.

[0117] Optionally, the traction controller is also used to: after the vehicle speed of the vehicle 10 is greater than a preset speed or the duration of continuous change of the steering angle of the rear wheel 170 is greater than a preset duration, when the steering angle of the rear wheel 170 changes to zero, control the rear wheel steering system 150 to stop driving the change of the steering angle of the rear wheel 170.

[0118] Optionally, the traction controller is also configured to: when the vehicle 10 is on a first type of road surface, control the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170 at a first rate; and when the vehicle 10 is on a second type of road surface, control the rear wheel steering system 150 to continuously change the steering angle of the rear wheel 170 at a second rate different from the first rate. The first type of road surface and the second type of road surface have different road surface materials.

[0119] In this embodiment of the application, an electric vehicle is also provided. The electric vehicle includes a drive system, a rear-wheel steering system, and a traction controller. The drive system is used to output drive torque, the rear-wheel steering system is used to control the change of the steering angle of the rear wheels, and the traction control method executed by the traction controller is the same as described above. Figures 1-12The control functions implemented by the relevant escape control methods correspond to the control functions.

[0120] For more detailed information on off-road controllers and electric vehicles, please refer to the previous text. Figures 1-12 This section introduces methods for controlling the traction of electric vehicles.

[0121] In the embodiments of this application, the words "exemplary," "for example," etc., are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0122] It should be understood that the term "embodiment" used throughout this specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout this specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0123] It should also be understood that in this application, "when," "if," "in the circumstances of," and "if" all refer to a situation where a corresponding action will be taken under certain objective circumstances, and are not time-limited. They do not require the device to perform a judgment action, nor do they imply any other limitations. Furthermore, in this application, the descriptions of conditions such as "when," "if," "in the circumstances of," and "if" can be understood as necessary conditions, without limiting whether the condition is a sufficient condition or a necessary and sufficient condition. For example, "in the case of A, execute B" can be understood as "if at least A is satisfied, execute B."

[0124] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling the traction of an electric vehicle, characterized in that, The traction control method is used to control the rear-wheel steering system and drive system of the electric vehicle to enable the electric vehicle to get out of trouble after the traction mode is activated. The traction control method includes: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed until the speed of the electric vehicle increases or the duration of the continuous change of the steering angle of the rear wheel exceeds a preset duration. After the speed of the electric vehicle increases or the duration of continuous change in the steering angle of the rear wheels exceeds a preset duration, the rear wheel steering system is controlled to stop driving the change in the steering angle of the rear wheels.

2. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed until the speed of the electric vehicle increases to a preset speed or the duration of the continuous change of the steering angle of the rear wheel is greater than the preset duration.

3. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed alternately between positive, negative and zero values.

4. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: During the process of controlling the output drive torque of the drive system, the rate at which the steering angle of the rear wheels driven by the rear wheel steering system changes continuously increases.

5. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output of the drive torque of the drive system, the steering angle of the left and right rear wheels of the rear wheel steering system is continuously changed. At any moment when the left rear wheel turns to the left, the right rear wheel turns to the right.

6. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the front wheel steering system of the electric vehicle is controlled to stop the change in the steering angle of the front wheels.

7. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed, and the steering angle of the front wheel driven by the front wheel steering system of the electric vehicle is continuously changed. At any moment when the front wheel turns to the left, the rear wheel turns to the right.

8. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: Before the steering wheel of the electric vehicle is turned, while controlling the drive system to output drive torque to drive the electric vehicle forward, the steering angle of the rear wheel steering system is continuously changed. Then, while controlling the drive system to output drive torque to drive the electric vehicle backward, the steering angle of the rear wheel steering system is continuously changed.

9. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: After the electric vehicle's speed exceeds a preset speed or the duration of continuous change in the steering angle of the rear wheels exceeds a preset duration, when the steering angle of the rear wheels changes to zero, the rear wheel steering system is controlled to stop driving the change in the steering angle of the rear wheels.

10. The method for controlling the traction of an electric vehicle according to claim 1, characterized in that, The escape control method also includes: When the electric vehicle is on a first type of road surface, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed at a first rate. When the electric vehicle is on a second type of road surface, the rear wheel steering system is controlled to drive the steering angle of the rear wheels to change continuously at a second rate different from the first rate; The road surface of the first type is made of a different material than that of the second type.

11. A traction control system for electric vehicles, characterized in that, The escape controller is used for: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed until the speed of the electric vehicle increases or the duration of the continuous change of the steering angle of the rear wheel exceeds a preset duration. After the speed of the electric vehicle increases or the duration of continuous change in the steering angle of the rear wheels exceeds a preset duration, the rear wheel steering system is controlled to stop driving the change in the steering angle of the rear wheels.

12. The electric vehicle traction controller according to claim 11, characterized in that, The escape controller is also used for: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output driving torque of the drive system, the steering angle of the rear wheel driven by the rear wheel steering system is continuously changed until the speed of the electric vehicle increases to a preset speed or the duration of the continuous change of the steering angle of the rear wheel is greater than the preset duration.

13. The electric vehicle traction controller according to claim 11, characterized in that, The escape controller is also used for: Before the steering wheel of the electric vehicle is turned, during the process of controlling the output of the drive torque of the drive system, the steering angle of the left and right rear wheels of the rear wheel steering system is continuously changed. At any moment when the left rear wheel turns to the left, the right rear wheel turns to the right.

14. The electric vehicle traction controller according to claim 11, characterized in that, The escape controller is also used for: Before the steering wheel of the electric vehicle is turned, while controlling the drive system to output drive torque to drive the electric vehicle forward, the steering angle of the rear wheel steering system is continuously changed. Then, while controlling the drive system to output drive torque to drive the electric vehicle backward, the steering angle of the rear wheel steering system is continuously changed.

15. An electric vehicle, characterized in that, The electric vehicle includes a drive system, a rear-wheel steering system, and a traction controller. The drive system is used to output drive torque, the rear-wheel steering system is used to control the change of the steering angle of the rear wheels, and the traction controller is used to execute the traction control method of the electric vehicle as described in any one of claims 1-10.

Images