Steering method, steering control device, control system, computing equipment and vehicle

Abstract

The embodiment of the invention provides a steering method, a steering control device, a control system, computing equipment and a vehicle, and is applied to the technical field of vehicle control. According to the embodiment of the invention, the first front wheel of the vehicle can be controlled to be static relative to the vehicle, the first rear wheel and the second rear wheel of the vehicle are driven to rotate, and the driving directions of the first rear wheel and the second rear wheel are controlled to be opposite, so that the vehicle steers around the first front wheel. The vehicle can rotate around the first front wheel to achieve steering under the condition that a steering system and a driving mode of the vehicle are not changed, the steering capacity of the vehicle can be improved, the flexibility and the passing ability of the vehicle are improved, and the vehicle can better cope with a narrow parking environment.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a steering method, a steering control device, a control system, a computing device and a vehicle. Background Art

[0002] With the advancement of industrial technology and the improvement of people's living standards, cars as a means of transportation play an increasingly important role in people's daily lives, and consumers' demand for cars is also increasing. In the process of using the vehicle, users may need to pass through narrow and curved areas or bypass obstacles that are difficult to cross, which puts high demands on the vehicle's steering ability. The steering ability of a vehicle is one of the basic properties of the vehicle, and the minimum turning radius of the vehicle is usually used as an important parameter to assess the steering ability of the vehicle. Among them, the minimum turning radius refers to the radius of the track circle that the center of the outer steering wheel rolls on the supporting plane when the steering wheel is turned to the extreme position and the vehicle is turning at the lowest stable speed. If the vehicle has a strong steering function, the minimum turning radius of the vehicle can be smaller, so that it can pass through narrow and curved areas or bypass obstacles that are difficult to cross when driving the vehicle.

[0003] Some tracked vehicles and all-wheel steering vehicles with steering mechanisms installed on each wheel have strong steering functions, such as the ability to turn on the spot, but tracked vehicles are only used for special purposes and have a narrow scope of application. All-wheel steering vehicles need to be equipped with additional steering systems, which require major changes to the steering system and drive mode, increasing vehicle costs and the complexity of the mechanical structure. Summary of the invention

[0004] The embodiments of the present application provide a steering method, a steering control device, a control system, a computing device and a vehicle, which can control the first front wheel to be stationary relative to the vehicle and drive the first rear wheel and the second rear wheel of the vehicle to rotate, and control the driving directions of the first rear wheel and the second rear wheel to be opposite so that the vehicle can be turned around the first front wheel. The vehicle can be turned around the first front wheel without changing the steering system and driving mode of the vehicle, thereby improving the steering ability of the vehicle and improving the flexibility and passability of the vehicle.

[0005] In a first aspect, an embodiment of the present application provides a steering method, the method comprising:

[0006] Controlling a first front wheel of the vehicle to be stationary relative to the vehicle;

[0007] The first rear wheel and the second rear wheel of the vehicle are driven to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

[0008] The present application can control the first front wheel to be stationary relative to the vehicle and drive the first rear wheel and the second rear wheel of the vehicle to rotate without changing the steering system and driving mode of the vehicle. By controlling the driving directions of the first rear wheel and the second rear wheel to be opposite, the vehicle is turned around the first front wheel, which can improve the steering ability of the vehicle, improve the flexibility and passability of the vehicle, and better cope with narrow parking environments.

[0009] In a possible implementation of the first aspect, controlling the first front wheel to be stationary relative to the vehicle includes:

[0010] The first front wheel is brake-locked to make the first front wheel stationary relative to the vehicle, or the first front wheel is controlled to be stationary relative to the vehicle by torque.

[0011] In another possible implementation manner of the first aspect, the method further includes:

[0012] According to the steering input information, a front wheel of the vehicle that needs to be stationary is determined, and the first front wheel is the front wheel of the vehicle that needs to be stationary.

[0013] In yet another possible implementation manner of the first aspect, the steering input information is further used to determine at least one of the following:

[0014] The vehicle's rotation direction and the vehicle's required rotation angle.

[0015] In another possible implementation of the first aspect, the driving directions of the first rear wheel and the second rear wheel are related to the rotation direction of the vehicle, wherein the rotation direction of the vehicle is clockwise and counterclockwise.

[0016] In another possible implementation of the first aspect, driving the first rear wheel of the vehicle to rotate includes:

[0017] determining the output torque of the first rear wheel according to the state information of the first rear wheel;

[0018] The first rear wheel is driven to rotate based on the output torque of the first rear wheel.

[0019] In yet another possible implementation manner of the first aspect, driving the second rear wheel of the vehicle to rotate includes:

[0020] determining the output torque of the second rear wheel according to the state information of the second rear wheel;

[0021] The second rear wheel is driven to rotate based on the output torque of the second rear wheel.

[0022] In another possible implementation of the first aspect, the status information of the first rear wheel includes at least one of the wheel speed of the first rear wheel, the wheel acceleration of the first rear wheel, the current slip rate of the first rear wheel, and the target slip rate of the first rear wheel, and the status information of the second rear wheel includes at least one of the wheel speed of the second rear wheel, the wheel acceleration of the second rear wheel, the current slip rate of the second rear wheel, and the target slip rate of the second rear wheel.

[0023] In yet another possible implementation manner of the first aspect, determining the output torque of the first rear wheel according to the state information of the first rear wheel includes:

[0024] The output torque of the first rear wheel is determined according to the target slip rate of the first rear wheel, the current slip rate of the first rear wheel and the torque control method for the first rear wheel, and the output torque of the first rear wheel is used to change the slip rate of the first rear wheel toward the target slip rate of the first rear wheel.

[0025] In another possible implementation manner of the first aspect, the method further includes:

[0026] A torque control method for the first rear wheel is determined according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel.

[0027] In another possible implementation of the first aspect, the torque control method for the first rear wheel is used to indicate at least one of a torque adjustment direction for the first rear wheel and a torque adjustment rate for the first rear wheel, the torque adjustment direction is one of increasing torque, reducing torque and maintaining torque, and the torque adjustment rate for the first rear wheel is used to indicate the intensity of adjusting the torque of the first rear wheel.

[0028] In yet another possible implementation manner of the first aspect, determining the output torque of the second rear wheel according to the state information of the second rear wheel includes:

[0029] The output torque of the second rear wheel is determined according to the target slip rate of the second rear wheel, the current slip rate of the second rear wheel and the torque control method for the second rear wheel, and the output torque of the second rear wheel is used to change the slip rate of the second rear wheel toward the target slip rate of the second rear wheel.

[0030] In yet another possible implementation manner of the first aspect, the method further includes: determining a torque control mode for the second rear wheel according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel.

[0031] In another possible implementation of the first aspect, the torque control method for the second rear wheel is used to indicate at least one of a torque adjustment direction for the second rear wheel and a torque adjustment rate for the second rear wheel, the torque adjustment direction is one of increasing torque, reducing torque and maintaining torque, and the torque adjustment rate for the second rear wheel is used to indicate the intensity of adjusting the torque of the second rear wheel.

[0032] In yet another possible implementation of the first aspect, the method further includes: driving a second front wheel of the vehicle to rotate.

[0033] In another possible implementation of the first aspect, driving the second front wheel of the vehicle to rotate includes:

[0034] determining an output torque of a second front wheel of the vehicle according to a current yaw rate of the vehicle and a target yaw rate of the vehicle;

[0035] The second front wheel is driven to rotate based on the output torque of the second front wheel, and the output torque of the second front wheel is used to change the yaw rate of the vehicle toward the target yaw rate of the vehicle.

[0036] In yet another possible implementation manner of the first aspect, before driving the first rear wheel and the second rear wheel of the vehicle to rotate, the method further includes:

[0037] Determine that the vehicle meets the rotation condition;

[0038] Among them, the rotation condition is related to the maximum output torque of the motor corresponding to the first rear wheel, the maximum output torque of the motor corresponding to the second rear wheel, the reduction ratio of the reducer of the motor corresponding to the first rear wheel and the second rear wheel, the effective rolling radius of the first rear wheel and the second rear wheel, the maximum longitudinal force coefficient between the first rear wheel and the current road surface, the maximum longitudinal force coefficient between the second rear wheel and the current road surface, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the driving force of the second front wheel, the lateral force coefficient of the first rear wheel, the longitudinal force coefficient of the second rear wheel, the lateral force coefficient of the second rear wheel, the wheelbase between the first rear wheel and the second rear wheel, the wheelbase of the vehicle, the rotational resistance of the first front wheel, the rotational inertia of the vehicle and at least one of the angular acceleration of the vehicle.

[0039] In yet another possible implementation manner of the first aspect, before driving the first rear wheel and the second rear wheel of the vehicle to rotate, the method further includes:

[0040] Determining that the first front wheel meets the non-slip condition;

[0041] Among them, the no-slip condition is related to the maximum lateral static friction of the first front wheel, the maximum longitudinal static friction of the first front wheel, the longitudinal force coefficient of the first rear wheel, the lateral force coefficient of the second rear wheel, the longitudinal force coefficient of the second rear wheel, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the reaction force of the driving force of the second front wheel and the axle design coefficient of the vehicle, and the axle design coefficient of the vehicle is related to at least one of the wheelbase between the first rear wheel and the second rear wheel and the wheelbase of the vehicle.

[0042] In another possible implementation manner of the first aspect, the method further includes:

[0043] When the vehicle satisfies the vehicle's steering exit conditions, the vehicle's steering function is exited.

[0044] In another possible implementation of the first aspect, the vehicle's steering exit conditions include one or more of the vehicle's turning angle reaching the vehicle's required turning angle, the vehicle's user stepping on the brake pedal, the vehicle's steering wheel angle being greater than a first threshold, the electronic handbrake being activated, the vehicle's gear changing, and the vehicle's user turning off the steering function.

[0045] In a second aspect, an embodiment of the present application provides a steering control device, the steering control device comprising a processing unit and a driving unit, the processing unit is used to control a first front wheel of a vehicle to be stationary relative to the vehicle. The driving unit is used to drive a first rear wheel and a second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

[0046] In a third aspect, an embodiment of the present application provides a control system, the control system comprising:

[0047] A control device is used to control the first front wheel of the vehicle to be stationary relative to the vehicle; and a drive device is used to drive the first rear wheel and the second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

[0048] In a possible implementation of the third aspect, the control device includes a brake and / or a first motor, the brake is used to brake and lock the first front wheel so that the first front wheel is stationary relative to the vehicle, and the first motor is used to control the first front wheel to be stationary relative to the vehicle through torque.

[0049] In another possible implementation of the third aspect, the driving device includes a second motor and a third motor, the second motor is used to drive the first rear wheel of the vehicle to rotate, and the third motor is used to drive the second rear wheel of the vehicle to rotate.

[0050] In another possible implementation of the third aspect, the first motor is also used to drive the second front wheel of the vehicle to rotate, or the driving device further includes a fourth motor, and the fourth motor is used to drive the second front wheel of the vehicle to rotate.

[0051] In yet another possible implementation of the third aspect, the control system further includes a steering controller for controlling the vehicle to steer around the first front wheel.

[0052] In another possible implementation of the third aspect, the control system is used to implement the method described in any one of the first aspect.

[0053] In a fourth aspect, an embodiment of the present application provides a computing device, which includes a processor and a memory, wherein a program is stored in the memory, and the processor executes the program stored in the memory so that the computing device implements the method described in any one of the first aspects above.

[0054] In a fifth aspect, the present application provides a vehicle comprising a first front wheel, a first rear wheel, a second rear wheel and the aforementioned steering control device, control system or the aforementioned computing device.

[0055] In a sixth aspect, an embodiment of the present application provides a computer-readable storage medium, which is used to store a computer program, wherein the computer program includes instructions for executing the method described in any one of the first aspects above.

[0056] In a seventh aspect, the present application provides a computer program product, which includes computer instructions. When the instructions are executed by a steering control device or a computing device, the steering control device or the computing device implements the method described in any one of the first aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The following is a brief introduction to the drawings required for describing the embodiments.

[0058] Figure 1 It is a flowchart of a steering method provided in an embodiment of the present application;

[0059] Figure 2 is a schematic diagram of determining the output torque of a first rear wheel provided in an embodiment of the present application;

[0060] Figure 3 is a schematic diagram of determining a torque control method for a first rear wheel provided in an embodiment of the present application;

[0061] Figure 4 is another schematic diagram of determining the output torque of the first rear wheel provided in an embodiment of the present application;

[0062] Figure 5 is a schematic diagram of determining the output torque of the second rear wheel provided in an embodiment of the present application;

[0063] Figure 6 is a schematic diagram of determining a torque control method for a second rear wheel provided in an embodiment of the present application;

[0064] Figure 7 is another schematic diagram of determining the output torque of the second rear wheel provided in an embodiment of the present application;

[0065] Figure 8 is a schematic diagram of determining the output torque of the second front wheel provided in an embodiment of the present application;

[0066] Fig. 9 is a schematic diagram of a longitudinal force coefficient and a lateral force coefficient under different slip rates provided in an embodiment of the present application;

[0067] Fig.10 This is a schematic diagram of the forces on the four wheels of a vehicle during a steering process provided by an embodiment of the present application;

[0068] Fig.11 This is a schematic diagram of a vehicle leaving a warehouse provided in an embodiment of the present application;

[0069] Fig.12 This is another schematic diagram of vehicle exit provided in an embodiment of the present application;

[0070] Fig.13 is a schematic diagram of the architecture of a vehicle provided in an embodiment of the present application;

[0071] Fig.14 It is a schematic diagram of the architecture of a rear-wheel independently driven vehicle provided in an embodiment of the present application;

[0072] Fig.15 It is a schematic diagram of the architecture of a distributed three-motor vehicle provided in an embodiment of the present application;

[0073] Fig.16 It is a schematic diagram of the architecture of a four-wheel independent drive vehicle provided in an embodiment of the present application;

[0074] Fig.17 is a structural schematic diagram of a steering control device provided in an embodiment of the present application;

[0075] Fig.18 It is a structural diagram of a computing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0076] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0077] The following describes the scenarios of the embodiments of the present application.

[0078] In some scenarios, when using a vehicle, the user may need to pass through narrow and curved areas or bypass insurmountable obstacles, and may even need the vehicle to turn, which places high demands on the vehicle's steering capabilities.

[0079] In some schemes, tracked vehicles or all-wheel steering vehicles with steering mechanisms installed on each wheel have steering functions, but tracked vehicles are only used for special purposes and have a narrow scope of application. All-wheel steering vehicles need to be equipped with additional steering systems, which require major changes to the steering system and drive mode, increasing vehicle costs and the complexity of the mechanical structure.

[0080] In view of this, the present application provides a steering method that can be applied to distributed three-motor vehicles, four-wheel independently driven vehicles and rear-wheel independently driven vehicles. By controlling the first front wheel to be stationary relative to the vehicle and driving the first rear wheel and the second rear wheel to rotate, and controlling the driving directions of the first rear wheel and the second rear wheel to be opposite, the vehicle can be turned around the first front wheel. The steering of the vehicle can be achieved without changing the steering system and driving mode of the vehicle, thereby improving the steering ability of the vehicle, improving the flexibility and passability of the vehicle, and being able to better cope with narrow parking environments, for example, it can achieve side entry and exit in narrow parking spaces.

[0081] The method of the embodiment of the present application is described in detail below.

[0082] See also Figure 1 , Figure 1 1 is a flow chart of a steering method provided in an embodiment of the present application. Optionally, the method can be applied to a vehicle, for example, the method can be applied to a steering control device in a vehicle.

[0083] like Figure 1 The steering method shown may include multiple steps in step S101-step S102. It should be understood that for the convenience of description, this application is described in the order of step S101-step S102, and is not intended to limit the execution to the above order. The embodiment of the application does not limit the execution order, execution time, execution number, etc. of the above one or more steps. Steps S101-step S102 are as follows:

[0084] Step S101: Control a first front wheel of the vehicle to be stationary relative to the vehicle.

[0085] As a possible implementation, the steering control device controls the first front wheel to be stationary relative to the vehicle. For example, the steering control device controls the first front wheel to be stationary relative to the support of the vehicle.

[0086] The steering control device is a device with data processing, communication and control capabilities, which may be arranged inside the vehicle, or may be a processing module integrated in the vehicle, such as a microcontroller unit MCU and / or an electronic control unit ECU. In some schemes, the steering control device may also be arranged outside the vehicle, such as a server, cloud, or host, etc., or it may be a virtual device, such as a virtual machine, software, program code, or container. Optionally, when the steering control device is installed on the vehicle, the functions implemented by the steering control device can also be regarded as implemented by the vehicle. Specifically, when the steering control device is installed on the vehicle, it can be a functional module, for example, the steering control device can be integrated into the central domain controller of the vehicle.

[0087] The vehicle is a vehicle provided in the present application whose rear wheels have independent driving capability. The vehicle may be a distributed three-motor vehicle, a four-wheel independent drive vehicle, or a rear-wheel independent drive vehicle, etc. The vehicle includes a first front wheel, a first rear wheel, and a second rear wheel.

[0088] The first front wheel is a front wheel selected by the user that needs to be stationary. Optionally, the steering control device can control the first front wheel to be stationary relative to the vehicle by braking and locking the first front wheel through a braking system. For example, the steering control device can output a control signal to the braking system, and the control signal instructs the braking system to brake and lock the first front wheel to control the first front wheel to be stationary relative to the vehicle. In this way, the braking system of the vehicle is coordinated to facilitate the control of the vehicle to keep the position of the first front wheel unchanged during the steering process, thereby improving the accuracy of the steering process.

[0089] Alternatively, if the vehicle is a distributed three-motor vehicle or a four-wheel independently driven vehicle, the steering control device may also control the first front wheel to be stationary relative to the vehicle by controlling the output torque of the motor corresponding to the first front wheel through the drive system. For example, the steering control device may output a control signal to the drive system, and the control signal instructs the drive system to control the output torque of the motor corresponding to the first front wheel to control the first front wheel to be stationary relative to the vehicle.

[0090] In this way, the vehicle's drive system is coordinated to facilitate control of the vehicle to maintain the position of the first front wheel unchanged during the steering process, thereby improving the accuracy of the steering process.

[0091] In the embodiment of the present application, the steering control device controls the driving directions of the first rear wheel and the second rear wheel to be opposite. Generally, since the driving directions of the first rear wheel and the second rear wheel are opposite, the two offset most of the longitudinal force of the vehicle. If the drive system is used to control the output torque of the motor corresponding to the first front wheel to make the first front wheel stationary, only a small output torque is required to keep the first front wheel in a relatively stationary state. Among them, the longitudinal direction refers to the moving direction or driving direction of the vehicle.

[0092] In a possible implementation, the difference between the torques of the two rear motors and the target wheel speed is weighted by a proportional integral differentiation (PID) control algorithm to obtain the output torque of the motor corresponding to the first front wheel.

[0093] Exemplarily, the output torque of the motor corresponding to the first front wheel satisfies the following formula (1):

[0094] Trq F =αβ△Trq R +(1-α)*PID F (1)

[0095] Among them, Trq F is the output torque of the motor corresponding to the first front wheel of the vehicle, α is the weighting coefficient, β is the torque adjustment coefficient (usually a negative value), △Trq R The difference in output torque between the two rear motors of the vehicle, PID F The torque value output by the PID table lookup for the first front wheel of the vehicle.

[0096] When the steering function is running and the rear wheel torque does not cause the rear wheels to slip, the value of the weighted coefficient α is 1. At this time, the difference between the motor torques of the two rear wheels is mainly used to adjust the output torque of the motor corresponding to the first front wheel to control the first front wheel to be stationary relative to the vehicle. When the output torque of the motors of the two rear wheels causes the two rear wheels to slip, the value of the weighted coefficient α gradually changes from 1 to 0. At this time, the output torque of the motor corresponding to the first front wheel is mainly adjusted by the target wheel speed table PID to control the first front wheel to be stationary relative to the vehicle. When the steering function is in the process of exiting, the two rear wheels change from a slipping state to a non-slipping state, and the value of the weighted coefficient α gradually changes from 0 to 1. At this time, the output torque of the motor corresponding to the first front wheel is mainly adjusted by the target wheel speed table PID to control the first front wheel to be stationary relative to the vehicle.

[0097] In a specific implementation case, the difference between the torques of the two rear motors is weighted by the target wheel speed lookup table PID to obtain the output torque of the motor corresponding to the first front wheel to make the first front wheel stationary relative to the vehicle. Other control methods such as incremental PID or sliding film control can also be used. The idea is to control the output torque of the motor corresponding to the first front wheel to make the first front wheel stationary relative to the vehicle.

[0098] As a possible implementation, before executing step S101, the steering control device may obtain steering input information, and determine the front wheel of the vehicle that needs to be stationary based on the steering input information. Further, the steering control device may also determine one or more of the rotation direction of the vehicle and the required rotation angle of the vehicle. The rotation direction of the vehicle includes clockwise rotation and counterclockwise rotation. Optionally, the steering input information is input by the user, for example, the user selects the left front wheel as the front wheel that the vehicle needs to be stationary, and selects the vehicle to rotate 180° counterclockwise around the left front wheel.

[0099] It should be noted that during the steering process, the stationary front wheel will serve as the rotation center of the vehicle. Choosing different stationary front wheels will result in different steering effects.

[0100] As a possible implementation, the first front wheel can be determined in a variety of ways, that is, the user or the vehicle can select the front wheel that needs to be stationary in a variety of ways. The way to determine the first front wheel includes but is not limited to one or more of vehicle selection, button selection, remote control selection and steering wheel selection. Exemplarily, the user can directly select the front wheel that needs to be stationary (i.e., the rotation center of the vehicle) by vehicle selection, button selection or remote control selection. For example, the user selects the left front wheel as the front wheel that needs to be stationary through the button. Another exemplary embodiment, the user selects the front wheel that needs to be stationary through the steering wheel, for example, the driver turns the steering wheel clockwise, and selects the right front wheel as the front wheel that needs to be stationary when the angle of the steering wheel reaches the second threshold, and the driver turns the steering wheel counterclockwise, and selects the left front wheel as the front wheel that needs to be stationary and braked when the angle of the steering wheel reaches the third threshold. Optionally, the second threshold and the third threshold can be pre-set values, or can be values ​​manually set by the user. Optionally, after the user selects the front wheel that needs to be stationary, the steering control device displays the user's selection information on the vehicle. For example, the display screen of the vehicle computer displays "the user selects the left front wheel as the front wheel that needs to be stationary". Another example is that the display screen of the vehicle computer displays a rotation diagram and indicates the rotation center, which is the first front wheel selected. For another example, if the user can set the second threshold to 100° in the setting interface, when the user turns the steering wheel to the left by more than 100°, the left front wheel is the front wheel that needs to be stationary. In this way, the stationary front wheel can be selected in a variety of ways to improve the steering accuracy and enhance the user experience.

[0101] As a possible implementation, the rotation direction of the vehicle can be determined in a variety of ways, including but not limited to one or more of vehicle selection, button selection, remote control selection and gear selection. Exemplarily, the user can directly select the rotation direction of the vehicle through vehicle selection, button selection or remote control selection. For example, the user selects the rotation direction of the vehicle as clockwise through the vehicle. Another exemplary method is to select the rotation direction of the vehicle through the gear, for example, the driver can select the rotation direction of the vehicle through the D gear (i.e., forward gear) or the R gear (i.e., reverse gear). Exemplarily, the driver can select the rotation direction of the vehicle as clockwise through the R gear (i.e., reverse gear), and can select the rotation direction of the vehicle as counterclockwise through the D gear (i.e., forward gear). Optionally, after the user selects the rotation direction of the vehicle, the steering control device displays the user's selection information on the vehicle. For example, "the user selects the rotation direction of the vehicle as clockwise" is displayed on the display screen of the vehicle, and another example is to display a rotation diagram through the display screen of the vehicle, and indicate the rotation direction. In this way, the rotation direction of the vehicle can be selected in a variety of ways, the steering accuracy is improved, and the user experience is improved.

[0102] As a possible implementation, the required turning angle of the vehicle can be determined in a variety of ways, including but not limited to one or more of vehicle computer selection, button selection, remote control selection and steering wheel selection. Exemplarily, the user can directly select the required turning angle of the vehicle through vehicle computer selection, button selection or remote control selection. For example, the user selects the required turning angle of the vehicle as 180° through the button. Optionally, after the user selects the required turning angle of the vehicle, the steering control device displays the user's selection information on the vehicle computer. For example, "The user selects the required turning angle of the vehicle as 180°" is displayed on the display screen of the vehicle computer. For another example, a rotation diagram is displayed on the display screen of the vehicle computer, and the direction and position of the vehicle after rotation are indicated.

[0103] Step S102: driving the first rear wheel and the second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel.

[0104] The driving directions of the first rear wheel and the second rear wheel are opposite, and the driving directions of the first rear wheel and the second rear wheel are related to the rotation direction of the vehicle. In a possible implementation, the steering control device drives the first rear wheel to rotate according to the output torque of the first rear wheel, and drives the second rear wheel to rotate according to the output torque of the second rear wheel.

[0105] Exemplarily, the first rear wheel is the left rear wheel, and the second rear wheel is the right rear wheel. When the rotation direction of the vehicle is clockwise, the driving direction of the first rear wheel is forward, and the driving direction of the second rear wheel is backward. The steering control device drives the first rear wheel forward based on the output torque of the first rear wheel, and drives the second rear wheel backward based on the output torque of the second rear wheel, so that the vehicle can achieve clockwise steering around the first front wheel.

[0106] Exemplarily, the first rear wheel is the right rear wheel, and the second rear wheel is the left rear wheel. When the rotation direction of the vehicle is clockwise, the driving direction of the first rear wheel is backward, and the driving direction of the second rear wheel is forward. The steering control device drives the first rear wheel backward based on the output torque of the first rear wheel, and drives the second rear wheel forward based on the output torque of the second rear wheel, so that the vehicle can achieve clockwise steering around the first front wheel.

[0107] Exemplarily, the first rear wheel is a left rear wheel, and the second rear wheel is a right rear wheel. When the rotation direction of the vehicle is counterclockwise, the driving direction of the first rear wheel is backward, and the driving direction of the second rear wheel is forward. The steering control device drives the first rear wheel backward based on the output torque of the first rear wheel, and drives the second rear wheel forward based on the output torque of the second rear wheel, so that the vehicle can achieve counterclockwise steering around the first front wheel.

[0108] Exemplarily, the first rear wheel is the right rear wheel, and the second rear wheel is the left rear wheel. When the rotation direction of the vehicle is counterclockwise, the driving direction of the first rear wheel is forward, and the driving direction of the second rear wheel is backward. The steering control device drives the first rear wheel forward based on the output torque of the first rear wheel, and drives the second rear wheel backward based on the output torque of the second rear wheel, so that the vehicle can achieve counterclockwise steering around the first front wheel.

[0109] Optionally, in this solution, the vehicle turns around the first front wheel, and the vehicle can also be said to have the ability to turn on the spot, which can improve the flexibility and passability of the vehicle and better cope with narrow parking environments.

[0110] A possible implementation method for determining the output torque of the first rear wheel is introduced below.

[0111] As a possible implementation manner, the steering control device determines the output torque of the first rear wheel according to the state information of the first rear wheel.

[0112] The first rear wheel and the first front wheel are located on the same side of the vehicle, and the state information of the first rear wheel includes at least one of the wheel speed of the first rear wheel, the wheel acceleration of the first rear wheel, the current slip rate of the first rear wheel, and the target slip rate of the first rear wheel. The output torque of the first rear wheel is used to change the slip rate of the first rear wheel toward the target slip rate of the first rear wheel. It should be understood that during the vehicle steering process, "the steering control device determines the output torque of the first rear wheel according to the state information of the first rear wheel" can be executed in real time and multiple times, so that the output torque of the first rear wheel is updated in real time during the steering process to control the first rear wheel, thereby completing the rotation of the vehicle.

[0113] As a possible implementation, the steering control device obtains the wheel speed of the first rear wheel through a wheel speed sensor, obtains the wheel acceleration of the first rear wheel and the current slip rate of the first rear wheel according to the wheel speed of the first rear wheel, and determines the torque control mode for the first rear wheel according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel. Further, the steering control device determines the output torque of the first rear wheel according to the target slip rate of the first rear wheel, the current slip rate of the first rear wheel and the torque control mode for the first rear wheel. Among them, the torque control mode for the first rear wheel is used to indicate at least one of the torque adjustment direction for the first rear wheel and the torque adjustment rate for the first rear wheel, the torque adjustment direction is one of increasing torque (or increasing torque / increasing torque), reducing torque (or reducing torque / reducing torque) and maintaining torque, and the torque adjustment rate for the first rear wheel is used to indicate the intensity of adjusting the torque of the first rear wheel. Among them, maintaining torque means keeping the torque unchanged.

[0114] For example, see Figure 2 , Figure 2 is a schematic diagram of determining the output torque of the first rear wheel provided in an embodiment of the present application. Figure 2 As shown, the steering control device compares the current slip rate of the first rear wheel (e.g., s1) with the target slip rate of the first rear wheel (e.g., s2), and obtains the slip rate difference between the current slip rate of the first rear wheel and the target slip rate of the first rear wheel (e.g., Δs1, which can also be referred to as the slip rate difference Δs1 of the first rear wheel). Further, the steering control device uses the slip rate difference of the first rear wheel (e.g., Δs1) as the input of the segmented PID control, and the steering control device determines the torque control mode for the first rear wheel according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel, and uses the torque control mode for the first rear wheel as the basis of the segmented PID control, that is, uses the torque control mode for the first rear wheel as the enable flag of the segmented PID control jump, and outputs the output torque of the first rear wheel. Among them, the function of enabling is to allow a certain pin, chip or module of the electronic device to start a certain preset function or enter a preset state.

[0115] In a possible implementation manner, the torque control method for the first rear wheel is divided into five stages: a high-rate torque increase stage, a low-rate torque increase stage, a stable stage, a low-rate torque reduction stage, and a high-rate torque reduction stage.

[0116] Exemplarily, when the first rear wheel is in a high-speed torque increase stage, the current enable flag may be "high-speed torque increase", and the corresponding torque adjustment direction is increase, and the high speed corresponds to a larger torque adjustment strength, for example, in the segmented PID control, a larger output torque is output, so that the slip rate of the first rear wheel is rapidly increased and changes toward the target slip rate of the first rear wheel. In another exemplary embodiment, when the first rear wheel is in a low-speed torque reduction stage, the current enable flag may be "low-speed torque reduction", and the corresponding torque adjustment direction is decrease, and the low speed corresponds to a smaller torque adjustment strength, for example, in the segmented PID control, a smaller output torque is output, so that the slip rate of the first rear wheel is slowly reduced and changes toward the target slip rate of the first rear wheel.

[0117] For example, see Figure 3 , Figure 3 is a schematic diagram of determining a torque control method for a first rear wheel provided in an embodiment of the present application. Figure 3As shown, when the wheel speed of the first rear wheel is less than the first wheel speed threshold, the torque control method for the first rear wheel is a high-rate torque increase stage, and the wheel speed of the first rear wheel needs to be increased as soon as possible. When the wheel speed of the first rear wheel does not meet the requirement of being less than the first wheel speed threshold, then when the wheel speed of the first rear wheel is less than the second wheel speed threshold, the torque control method for the first rear wheel is a low-rate torque increase stage, and the wheel speed of the first rear wheel needs to be increased slowly. When the wheel speed of the first rear wheel does not meet the requirement of being less than the second wheel speed threshold, then when the wheel speed of the first rear wheel is greater than the third wheel speed threshold and the wheel acceleration of the first rear wheel is less than the first wheel acceleration threshold, the torque control method for the first rear wheel is a stable control stage, and the wheel speed of the first rear wheel needs to be kept stable. In the case where the wheel speed of the first rear wheel does not satisfy the condition that it is greater than the third wheel speed threshold and the wheel acceleration of the first rear wheel does not satisfy the condition that it is less than the first wheel acceleration threshold, then in the case where the wheel speed of the first rear wheel is greater than the third wheel speed threshold and the wheel acceleration of the first rear wheel is greater than the first wheel acceleration threshold, the torque control mode for the first rear wheel is the low-rate torque reduction stage, at which time the wheel speed of the first rear wheel needs to be reduced slowly. In the case where the wheel speed of the first rear wheel does not satisfy the condition that it is greater than the third wheel speed threshold and the wheel acceleration of the first rear wheel does not satisfy the condition that it is greater than the first wheel acceleration threshold, then in the case where the wheel speed of the first rear wheel is greater than the fourth wheel speed threshold and the wheel acceleration of the first rear wheel is greater than the second wheel acceleration threshold, the torque control mode for the first rear wheel is the high-rate torque reduction stage, at which time the wheel speed of the first rear wheel needs to be reduced as soon as possible. Among them, the first wheel speed threshold, the second wheel speed threshold, the third wheel speed threshold, the fourth wheel speed threshold, the first wheel acceleration threshold and the second wheel acceleration threshold can all be pre-set values ​​or values ​​selected by the user.

[0118] In a possible implementation, during the steering process, when the vehicle rotates clockwise, the left rear motor outputs positive torque, causing the left rear wheel to rotate forward and slip, and the left rear wheel generates a forward driving force, and the right rear motor outputs negative torque, causing the right rear wheel to reversely slip, and the right rear wheel generates a backward driving force. When the vehicle rotates counterclockwise, the left rear motor outputs negative torque, causing the left rear wheel to reversely slip, and the left rear wheel generates a backward driving force, and the right rear motor outputs positive torque, causing the right rear wheel to rotate forward and slip, and the right rear wheel generates a forward driving force.

[0119] Since one rear wheel slips in the forward direction and the other rear wheel slips in the reverse direction, the longitudinal forces generated by the two rear wheels cancel each other out, and the first front wheel is controlled to be stationary relative to the vehicle. This application ensures that the vehicle will not move longitudinally during the steering process, so that the driver does not have to worry about the vehicle moving longitudinally, thereby improving the steering accuracy.

[0120] It should be noted that in order for the vehicle to turn, the first rear wheel needs to reach a certain slip rate. Since the driving force will drop significantly after the tire grip reaches its limit, the output torque of the first rear wheel needs to be controlled during the control process to prevent the first rear wheel from spinning.

[0121] It should be noted that the above-mentioned segmented PID control can quickly eliminate the integral term, avoid excessive integral terms, and improve system stability. Moreover, due to the segmented PID control, the control algorithm can obtain the best control stage according to the current wheel speed and wheel acceleration of the first rear wheel, so that the control strategy can better adapt to different road environments, improve the accuracy of the first rear wheel control during the steering process, and control the slip rate of the first rear wheel to change towards the target slip rate of the first rear wheel, thereby controlling the first rear wheel to maintain stability and improve the safety of steering. Among them, the integral term is the cumulative sum of errors, which is used to eliminate the static error of the control system. When the road adhesion is uniform, the use of ordinary PID or segmented PID can achieve a good control effect. The purpose of using segmented PID here is to deal with the situation where the slip rate (or wheel speed) of the first rear wheel is difficult to reach a steady state when the road adhesion changes suddenly. For example, when the road adhesion suddenly decreases significantly, the integral term of the ordinary PID can only slowly reduce the integral term by accumulating errors, which may cause the first rear wheel to fly suddenly and the vehicle to stall significantly. However, when a segmented PID is used, the current control stage can be obtained based on the current wheel speed and wheel speed difference of the first rear wheel. By jumping the stage (and adjusting the PID control parameters), the integral term can be quickly reduced or cleared to avoid sudden speed increases of the first rear wheel and vehicle jerking, thereby improving the robustness of the system.

[0122] Of course, other control methods may also be used, the core control idea being to control the current slip rate of the first rear wheel to be near the target slip rate of the first rear wheel, that is, to control the current slip rate of the first rear wheel to change toward the target slip rate of the first rear wheel, or to control the current wheel speed of the first rear wheel to be near the target wheel speed of the first rear wheel, that is, to control the current wheel speed of the first rear wheel to change toward the target wheel speed of the first rear wheel.

[0123] In some solutions, in the process of determining the output torque of the first rear wheel, in addition to the state information of the first rear wheel, other information may also be used, such as the yaw rate of the vehicle, etc. Some possible implementation methods are described below.

[0124] In some possible implementations, the steering control device may also determine the output torque of the first rear wheel according to the state information of the first rear wheel, the current yaw rate of the vehicle and the target yaw rate of the vehicle. Figure 4 , Figure 4 FIG. 1 is another schematic diagram of determining the output torque of the first rear wheel provided in an embodiment of the present application. Figure 4As shown, the steering control device compares the current slip rate of the first rear wheel (for example, s1) with the target slip rate of the first rear wheel (for example, s2) to obtain the slip rate difference between the current slip rate of the first rear wheel and the target slip rate of the first rear wheel (for example, Δs1, which may also be referred to as the slip rate difference Δs1 of the first rear wheel), and compares the current yaw angular velocity of the vehicle (for example, w1) with the target yaw angular velocity of the vehicle (for example, w2) to obtain the yaw angular velocity difference between the current yaw angular velocity of the vehicle and the target yaw angular velocity of the vehicle (for example, Δw, which may also be referred to as the yaw angular velocity difference Δw). Further, the steering control device uses the slip rate difference (e.g., Δs1) and the yaw rate difference (e.g., Δw) of the first rear wheel as inputs of the segmented PID control. The steering control device determines the torque control mode for the first rear wheel according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel, and uses the torque control mode for the first rear wheel as the basis for the segmented PID control, that is, the torque control mode for the first rear wheel is used as an enable flag for the segmented PID control jump, and outputs the output torque of the first rear wheel. For the torque control mode for the first rear wheel, see the above-mentioned related description. The target yaw rate of the vehicle can be a default initial value, and can also be set and selected by the driver.

[0125] It should be noted that the above-mentioned segmented PID control can quickly eliminate the integral term, avoid excessive integral terms, and improve system stability. Moreover, due to the use of segmented PID control, the control algorithm can obtain the best control stage according to the current wheel speed and wheel acceleration of the first rear wheel, so that the control strategy can better adapt to different road conditions. Of course, other control methods can also be used. The calculation process of the yaw moment is not limited to the use of PID control, and other control methods can also be used. The calculation idea is to generate a yaw moment to stabilize the vehicle body. The core control idea is to control the current slip rate of the first rear wheel to be near the target slip rate of the first rear wheel and control the current yaw angular velocity of the vehicle to be near the target yaw angular velocity, that is, to control the current slip rate of the first rear wheel to change toward the target slip rate of the first rear wheel and control the current yaw angular velocity of the vehicle to change toward the target yaw angular velocity.

[0126] A possible implementation method for determining the output torque of the second rear wheel is introduced below.

[0127] As a possible implementation manner, the steering control device determines the output torque of the second rear wheel according to the state information of the second rear wheel.

[0128] The second rear wheel and the first rear wheel are located on the opposite side of the vehicle, and the state information of the second rear wheel includes at least one of the wheel speed of the second rear wheel, the wheel acceleration of the second rear wheel, the current slip rate of the second rear wheel, and the target slip rate of the second rear wheel. The output torque of the second rear wheel is used to change the slip rate of the second rear wheel toward the target slip rate of the second rear wheel. Optionally, the target slip rate of the second rear wheel may be the same as or different from the target slip rate of the first rear wheel. It should be understood that during the vehicle steering process, "determining the output torque of the second rear wheel according to the state information of the second rear wheel" can be executed in real time and multiple times, so that the output torque of the second rear wheel is updated in real time during the steering process to control the second rear wheel, thereby completing the rotation of the vehicle.

[0129] As a possible implementation, the steering control device obtains the wheel speed of the second rear wheel through a wheel speed sensor, obtains the wheel acceleration of the second rear wheel and the current slip rate of the second rear wheel according to the wheel speed of the second rear wheel, and determines the torque control mode for the second rear wheel according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel. Further, the steering control device determines the output torque of the second rear wheel according to the target slip rate of the second rear wheel, the current slip rate of the second rear wheel and the torque control mode for the second rear wheel. Among them, the torque control mode for the second rear wheel is used to indicate at least one of the torque adjustment direction for the second rear wheel and the torque adjustment rate for the second rear wheel, the torque adjustment direction is one of increasing torque (or increasing torque / increasing torque), reducing torque (or reducing torque / reducing torque) and maintaining torque, and the torque adjustment rate for the second rear wheel is used to indicate the strength of adjusting the torque of the second rear wheel. Among them, maintaining torque means keeping the torque unchanged.

[0130] For example, see Figure 5 , Figure 5 is a schematic diagram of determining the output torque of the second rear wheel provided in an embodiment of the present application. Figure 5 As shown, the steering control device compares the current slip rate of the second rear wheel (e.g., s3) with the target slip rate of the second rear wheel (e.g., s4), and obtains the slip rate difference between the current slip rate of the second rear wheel and the target slip rate of the second rear wheel (e.g., Δs2, which may also be referred to as the slip rate difference Δs2 of the second rear wheel). Further, the steering control device uses the slip rate difference of the second rear wheel (e.g., Δs2) as the input of the segmented PID control, and the steering control device determines the torque control mode for the second rear wheel according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel, and uses the torque control mode for the second rear wheel as the basis of the segmented PID control, that is, the torque control mode for the second rear wheel is used as the enabling flag of the segmented PID control jump, and outputs the output torque of the second rear wheel.

[0131] In a possible implementation manner, the torque control method for the second rear wheel is divided into five stages: a high-rate torque increase stage, a low-rate torque increase stage, a stable stage, a low-rate torque reduction stage, and a high-rate torque reduction stage.

[0132] Exemplarily, when the second rear wheel is in a high-speed torque increase stage, the current enable flag may be "high-speed torque increase", and the corresponding torque adjustment direction is increase, and the high speed corresponds to a larger torque adjustment strength, for example, in the segmented PID control, a larger output torque is output, so that the slip rate of the second rear wheel is rapidly increased and changes toward the target slip rate of the second rear wheel. In another exemplary embodiment, when the second rear wheel is in a low-speed torque reduction stage, the current enable flag may be "low-speed torque reduction", and the corresponding torque adjustment direction is decrease, and the low speed corresponds to a smaller torque adjustment strength, for example, in the segmented PID control, a smaller output torque is output, so that the slip rate of the second rear wheel is slowly reduced and changes toward the target slip rate of the second rear wheel.

[0133] For example, see Figure 6 , Figure 6 is a schematic diagram of determining a torque control method for a second rear wheel provided in an embodiment of the present application. Figure 6 As shown, when the wheel speed of the second rear wheel is less than the fifth wheel speed threshold, the torque control method for the second rear wheel is a high-rate torque increase stage, and the wheel speed of the second rear wheel needs to be increased as soon as possible. When the wheel speed of the second rear wheel does not meet the requirement of being less than the fifth wheel speed threshold, then when the wheel speed of the second rear wheel is less than the sixth wheel speed threshold, the torque control method for the second rear wheel is a low-rate torque increase stage, and the wheel speed of the second rear wheel needs to be increased slowly. When the wheel speed of the second rear wheel does not meet the requirement of being less than the sixth wheel speed threshold, then when the wheel speed of the second rear wheel is greater than the seventh wheel speed threshold and the wheel acceleration of the second rear wheel is less than the third wheel acceleration threshold, the torque control method for the second rear wheel is a stable control stage, and the wheel speed of the second rear wheel needs to be kept stable. When the wheel speed of the second rear wheel does not satisfy the requirement of being greater than the seventh wheel speed threshold and the wheel acceleration of the second rear wheel does not satisfy the requirement of being less than the third wheel acceleration threshold, then when the wheel speed of the second rear wheel is greater than the seventh wheel speed threshold and the wheel acceleration of the second rear wheel is greater than the third wheel acceleration threshold, the torque control mode for the second rear wheel is the low-rate torque reduction stage, and at this time, the wheel speed of the second rear wheel needs to be reduced slowly. When the wheel speed of the second rear wheel does not satisfy the requirement of being greater than the seventh wheel speed threshold and the wheel acceleration of the second rear wheel does not satisfy the requirement of being greater than the third wheel acceleration threshold, then when the wheel speed of the second rear wheel is greater than the eighth wheel speed threshold and the wheel acceleration of the second rear wheel is greater than the fourth wheel acceleration threshold, the torque control mode for the second rear wheel is the high-rate torque reduction stage, and at this time, the wheel speed of the second rear wheel needs to be reduced as quickly as possible.

[0134] Among them, the fifth wheel speed threshold, the sixth wheel speed threshold, the seventh wheel speed threshold, the eighth wheel speed threshold, the third wheel acceleration threshold and the fourth wheel acceleration threshold can all be pre-set values ​​or values ​​selected by the user. The fifth wheel speed threshold can be the same as the aforementioned first wheel speed threshold, the sixth wheel speed threshold can be the same as the aforementioned second wheel speed threshold, the seventh wheel speed threshold can be the same as the aforementioned third wheel speed threshold, the eighth wheel speed threshold can be the same as the aforementioned fourth wheel speed threshold, the third wheel acceleration threshold can be the same as the aforementioned first wheel acceleration threshold, and the fourth wheel acceleration threshold can be the same as the aforementioned second wheel acceleration threshold.

[0135] In a possible implementation, during the steering process, when the vehicle rotates clockwise, the left rear motor outputs positive torque, causing the left rear wheel to rotate forward and slip, and the left rear wheel generates a forward driving force, and the right rear motor outputs negative torque, causing the right rear wheel to reversely slip, and the right rear wheel generates a backward driving force. When the vehicle rotates counterclockwise, the left rear motor outputs negative torque, causing the left rear wheel to reversely slip, and the left rear wheel generates a backward driving force, and the right rear motor outputs positive torque, causing the right rear wheel to rotate forward and slip, and the right rear wheel generates a forward driving force.

[0136] It should be noted that in order for the vehicle to turn, the second rear wheel needs to reach a certain slip rate. Since the driving force will drop significantly after the tire grip reaches its limit, the output torque of the second rear wheel needs to be controlled during the control process to prevent the second rear wheel from spinning.

[0137] It should be noted that the above-mentioned segmented PID control can quickly eliminate the integral term, avoid excessive integral terms, and improve system stability. Moreover, due to the use of segmented PID control, the control algorithm can obtain the best control stage according to the current wheel speed and wheel acceleration of the second rear wheel, so that the control strategy can better adapt to different road environments, improve the accuracy of the second rear wheel control during the steering process, and control the slip rate of the second rear wheel to change towards the target slip rate of the second rear wheel, thereby maintaining the stability of the second rear wheel and improving the safety of steering. Among them, the integral term is the cumulative sum of errors, which is used to eliminate the static error of the control system. When the road adhesion is uniform, the use of ordinary PID or segmented PID can achieve a good control effect. The purpose of using segmented PID here is to deal with the situation where the slip rate (or wheel speed) of the second rear wheel is difficult to reach a steady state when the road adhesion changes suddenly. For example, when the road adhesion suddenly decreases significantly, the integral term of the ordinary PID can only slowly reduce the integral term by accumulating errors, which may cause the second rear wheel to fly suddenly and the vehicle to stall significantly. However, when a segmented PID is used, the current control stage can be obtained based on the current wheel speed and wheel speed difference of the second rear wheel. By jumping the stage (and adjusting the PID control parameters), the integral term can be quickly reduced or cleared to avoid sudden speed increases of the second rear wheel and vehicle jerking, thereby improving the robustness of the system.

[0138] Of course, other control methods may also be used, the core control idea being to control the current slip rate of the second rear wheel to be near the target slip rate of the second rear wheel, that is, to control the current slip rate of the second rear wheel to change toward the target slip rate of the second rear wheel, or to control the current wheel speed of the second rear wheel to be near the target wheel speed of the second rear wheel, that is, to control the current wheel speed of the second rear wheel to change toward the target wheel speed of the second rear wheel.

[0139] In some solutions, in the process of determining the output torque of the second rear wheel, in addition to the state information of the second rear wheel, other information may also be used, such as the yaw rate of the vehicle, etc. Some possible implementation methods are described below.

[0140] In some possible implementations, the steering control device may also determine the output torque of the second rear wheel according to the state information of the second rear wheel, the current yaw rate of the vehicle and the target yaw rate of the vehicle. Figure 7 , Figure 7 FIG. 1 is another schematic diagram of determining the output torque of the second rear wheel provided in an embodiment of the present application. Figure 7 As shown, the steering control device compares the current slip rate of the second rear wheel (for example, s3) with the target slip rate of the second rear wheel (for example, s4) to obtain the slip rate difference between the current slip rate of the second rear wheel and the target slip rate of the second rear wheel (for example, Δs2, which may also be referred to as the slip rate difference Δs2 of the second rear wheel), and compares the current yaw angular velocity of the vehicle (for example, w1) with the target yaw angular velocity of the vehicle (for example, w2) to obtain the yaw angular velocity difference between the current yaw angular velocity of the vehicle and the target yaw angular velocity of the vehicle (for example, Δw, which may also be referred to as the yaw angular velocity difference Δw). Further, the steering control device uses the slip rate difference (e.g., Δs2) and the yaw rate difference (e.g., Δw) of the second rear wheel as inputs of the segmented PID control. The steering control device determines the torque control mode for the second rear wheel according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel, and uses the torque control mode for the second rear wheel as the basis for the segmented PID control, that is, the torque control mode for the second rear wheel is used as an enable flag for the segmented PID control jump, and the output torque of the second rear wheel is output. For the torque control mode for the second rear wheel, refer to the above-mentioned related description. The target yaw rate of the vehicle can be a default initial value, and can also be set and selected by the driver.

[0141] It should be noted that the above-mentioned segmented PID control can quickly eliminate the integral term, avoid excessive integral terms, and improve system stability. Moreover, due to the use of segmented PID control, the control algorithm can obtain the best control stage according to the current wheel speed and wheel acceleration of the second rear wheel, so that the control strategy can better adapt to different road conditions. Of course, other control methods can also be used. The calculation process of the yaw moment is not limited to PID control, and other control methods can also be used. The calculation idea is to generate a yaw moment to stabilize the vehicle body. The core control idea is to control the current slip rate of the second rear wheel to be near the target slip rate of the second rear wheel and control the current yaw angular velocity of the vehicle to be near the target yaw angular velocity, that is, to control the current slip rate of the second rear wheel to change toward the target slip rate of the second rear wheel and control the current yaw angular velocity of the vehicle to change toward the target yaw angular velocity.

[0142] As a possible implementation mode, the above is to describe in detail the calculation process of the output torque of each wheel, so the determination process of the output torque of each wheel is introduced separately. In actual use, the steering control device can calculate the output torque of the first rear wheel, the output torque of the second rear wheel, and the output torque of the second front wheel in a segmented PID control according to the input of each wheel.

[0143] As a possible implementation manner, when the turning angle of the vehicle reaches the required turning angle of the vehicle, the steering control device controls the vehicle to stop turning.

[0144] Specifically, during the steering process, the vehicle's turning angle needs to be recorded in real time. When the turning angle is about to reach the required turning angle of the vehicle, the steering function will perform a pre-exit process. The steering control device integrates the yaw rate output by the yaw rate sensor to obtain the vehicle's turning angle. For example, the vehicle's turning angle satisfies the following formula (2):

[0145]

[0146] Among them, θ yaw is the turning angle of the vehicle, t is the duration of the turn, w i is the real-time yaw rate of the vehicle, T i is the sampling time step.

[0147] Optionally, when the vehicle meets the vehicle's steering exit condition, the steering control device controls the vehicle to exit the steering function. For example, the steering control device controls the motor corresponding to the first rear wheel to slowly unload the output torque, and controls the motor corresponding to the second rear wheel to slowly unload the output torque. When the output torque of the first rear wheel and the second rear wheel drops below the torque threshold, the braking pressure of the first front wheel is controlled to be unloaded to release the brake lock of the first front wheel. If the first front wheel uses torque control to keep the first front wheel stationary, the motor corresponding to the first front wheel is controlled to slowly unload the output torque, and the vehicle exits steering. If the vehicle does not meet the vehicle's steering exit condition, the steering control device controls the vehicle to continue steering around the first front wheel. Among them, the torque threshold is a preset value.

[0148] Optionally, when the vehicle starts to turn, the steering control device controls the motors corresponding to the first rear wheel and the second rear wheel to slowly increase, and when the vehicle exits turning, the steering control device controls the motors corresponding to the first rear wheel and the second rear wheel to slowly decrease, so as to reduce the sense of frustration when the vehicle starts to turn and exits turning.

[0149] Optionally, the vehicle's steering exit conditions include the vehicle's turning angle reaching the vehicle's required turning angle, the vehicle's user pressing the brake pedal, the vehicle's steering wheel angle being greater than a first threshold, the electric parkbrake (EPB) being activated, the vehicle's gear changing, and the vehicle's user turning off the steering function. The first threshold may be a default initial value, and may also be set and selected by the driver. In this way, when the vehicle reaches the vehicle's steering exit conditions, such as the vehicle's user pressing the brake pedal or turning the steering wheel angle beyond a certain angle, the vehicle's steering is immediately exited, further ensuring the vehicle's controllability.

[0150] For a distributed three-motor vehicle, one of the motors in the vehicle can drive the left front wheel and the right front wheel. For a four-wheel independent drive vehicle, the left front wheel and the right front wheel can be driven independently.

[0151] As a possible implementation manner, for these two types of vehicles, the vehicle includes a second front wheel, and the steering control device can drive the second front wheel to rotate.

[0152] Exemplarily, the second front wheel and the second rear wheel are located on the same side of the vehicle, and the steering control device can determine the output torque of the second front wheel according to the current yaw rate of the vehicle and the target yaw rate of the vehicle, and drive the second front wheel to rotate based on the output torque of the second front wheel. The output torque of the second front wheel is used to change the yaw rate of the vehicle toward the target yaw rate of the vehicle.

[0153] For example, see Figure 8 , Figure 8is a schematic diagram of determining the output torque of the second front wheel provided in an embodiment of the present application. Figure 8 As shown, the steering control device compares the current yaw rate of the vehicle (e.g., w1) with the target yaw rate of the vehicle (e.g., w2), and obtains the yaw rate difference (e.g., Δw, also referred to as yaw rate difference Δw) between the current yaw rate of the vehicle and the target yaw rate of the vehicle. Further, the steering control device uses the yaw rate difference (e.g., Δw) as the input of the segmented PID control, and outputs the output torque of the second front wheel. In this way, the present application can generate a yaw torque, control the current yaw rate of the vehicle to change toward the target yaw rate of the vehicle, and control the stability of the yaw rate of the vehicle by the second front wheel, so that the vehicle is more stable and controllable during the steering process, improve the safety of steering, and improve the user experience.

[0154] exist Figure 8 In the method, segmented PID control is used, which can quickly eliminate the integral term, avoid excessive integral terms, and improve system stability. Of course, other control methods can also be used. The calculation process of the yaw moment is not limited to PID control, and other control methods can also be used. The calculation idea is to generate a yaw moment to stabilize the vehicle body. The core control idea is to control the current yaw angular velocity of the vehicle near the target yaw angular velocity, that is, to control the current yaw angular velocity of the vehicle to change toward the target yaw angular velocity.

[0155] In some schemes, in order to ensure that the vehicle can achieve steering, it is possible to confirm in advance whether the vehicle meets the rotation conditions, and perform a rotation operation on the vehicle when the rotation conditions are met. For example, the rotation conditions include: the torque generated by the driving wheels of the vehicle meets the rotation conditions, the first front wheel does not generate displacement, etc. Among them, the torque generated by the driving wheel meets the conditions in order to ensure that the torque generated by the driving wheel can cause the vehicle to rotate. The first front wheel does not generate displacement in order to ensure that the first front wheel (i.e., the front wheel that needs to be stationary) as the center of rotation does not move during the rotation of the vehicle. It can be seen that by checking the rotation conditions, the feasibility of the rotation can be improved and the safety of the vehicle can be improved. The condition checking process is exemplarily introduced below in conjunction with step S405.

[0156] In some implementations, after step S101 and before step S102, Figure 1 The steering method shown may further include step S103.

[0157] Step S103: Determine whether the vehicle satisfies the rotation condition of the vehicle and / or the non-slip condition of the first front wheel based on at least the vertical load of the first rear wheel, the vertical load of the second rear wheel, the slip rate of the first rear wheel and the slip rate of the second rear wheel.

[0158] Optionally, before driving the first rear wheel and the second rear wheel of the vehicle to rotate, the steering control device needs to determine that the vehicle meets the rotation condition.

[0159] Optionally, before driving the first rear wheel and the second rear wheel of the vehicle to rotate, the steering control device needs to determine that the first front wheel meets the non-slip condition.

[0160] As a possible implementation manner, the steering control device determines whether the vehicle satisfies the vehicle's rotation condition and / or the non-slip condition of the first front wheel based at least on the vertical load of the first rear wheel, the vertical load of the second rear wheel, the slip rate of the first rear wheel and the slip rate of the second rear wheel.

[0161] The vertical loads of the first rear wheel and the second rear wheel can be directly obtained by a load sensor or indirectly obtained by estimation, and the slip rates of the first rear wheel and the second rear wheel can be calculated by relevant parameters. Exemplarily, the slip rate of the first rear wheel is related to the angular velocity of the first rear wheel, the effective rolling radius of the first rear wheel, the angular velocity of the vehicle rotating around the first front wheel, and the distance between the first rear wheel and the first front wheel. The slip rate of the second rear wheel is related to the angular velocity of the second rear wheel, the effective rolling radius of the second rear wheel, the angular velocity of the vehicle rotating around the first front wheel, and the distance between the second rear wheel and the first front wheel.

[0162] For example, the slip rate of the first rear wheel satisfies the following formula (3):

[0163]

[0164] Among them, w r1 is the angular velocity of the first rear wheel, r1 is the effective rolling radius of the first rear wheel, w is the angular velocity of the vehicle rotating around the first front wheel, and R1 is the distance between the first rear wheel and the first front wheel.

[0165] The slip rate of the second rear wheel satisfies the following formula (4):

[0166]

[0167] Among them, w r2 is the angular velocity of the second rear wheel, r2 is the effective rolling radius of the second rear wheel, w is the angular velocity of the vehicle rotating around the first front wheel, and R1 is the distance between the second rear wheel and the first front wheel.

[0168] Optionally, when the vehicle satisfies both the vehicle rotation condition and the first front wheel non-slip condition, the steering control device performs the above step S102. Optionally, when the vehicle does not satisfy either of the vehicle rotation condition and the first front wheel non-slip condition, the steering control device controls the vehicle's brake fluid pressure and motor torque to slowly unload to 0, and displays "steering function cannot be entered" on the vehicle display screen (such as the vehicle instrument).

[0169] Optionally, the rotation condition is related to at least one of the maximum output torque of the motor corresponding to the first rear wheel, the maximum output torque of the motor corresponding to the second rear wheel, the reduction ratio of the reducer of the motor corresponding to the first rear wheel and the second rear wheel, the effective rolling radius of the first rear wheel and the second rear wheel, the maximum longitudinal force coefficient between the first rear wheel and the current road surface, the maximum longitudinal force coefficient between the second rear wheel and the current road surface, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the driving force of the second front wheel, the lateral force coefficient of the first rear wheel, the longitudinal force coefficient of the second rear wheel, the lateral force coefficient of the second rear wheel, the driving force of the second front wheel, the wheelbase between the first rear wheel and the second rear wheel, the wheelbase of the vehicle, the rotation resistance of the first front wheel, the rotational inertia of the vehicle, and the angular acceleration of the vehicle. Among them, the maximum longitudinal force coefficient between the first rear wheel and the current road surface and the maximum longitudinal force coefficient between the second rear wheel and the current road surface are related to the ground adhesion coefficient of the current road surface. Among them, the lateral direction is the left and right horizontal direction of the vehicle, which is perpendicular to the direction of movement or driving.

[0170] The non-slip condition is related to the maximum lateral static friction of the first front wheel, the maximum longitudinal static friction of the first front wheel, the longitudinal force coefficient of the first rear wheel, the lateral force coefficient of the second rear wheel, the longitudinal force coefficient of the second rear wheel, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the reaction force of the driving force of the second front wheel and the axle design coefficient of the vehicle, and the axle design coefficient of the vehicle is related to at least one of the wheelbase between the first rear wheel and the second rear wheel and the wheelbase of the vehicle. In this way, it is determined by multiple parameters whether the vehicle meets the rotation condition and whether the first front wheel meets the non-slip condition, so as to improve the accuracy and safety of the steering process.

[0171] Among them, the longitudinal force coefficient of the first rear wheel and the lateral force coefficient of the first rear wheel are related to the slip rate of the first rear wheel, and the longitudinal force coefficient of the second rear wheel and the lateral force coefficient of the second rear wheel are related to the slip rate of the second rear wheel. Among them, the longitudinal force coefficient of the wheel is expressed as the ratio of the longitudinal force to the vertical load on the wheel, and the lateral force coefficient is the ratio of the lateral force to the vertical load on the wheel when the sideslip angle of the vehicle is 16°. It should be noted that, according to the adhesion ellipse of the wheel, under the same slip rate, when the sideslip angle of the vehicle increases to 16°, the lateral force coefficient of the wheel no longer increases, so the lateral force coefficient when the sideslip angle is 16° is taken as the basis for calculating the lateral force on the wheel.

[0172] For example, see Fig. 9 , Fig. 9 is a schematic diagram of longitudinal force coefficient and lateral force coefficient under different slip rates provided by an embodiment of the present application. Optionally, the steering control device may be based on Fig. 9 Get the longitudinal force coefficient of the first rear wheel at the current slip rate and the lateral force coefficient For example, Fig. 9 As shown, the maximum longitudinal force coefficient of the first rear wheel on a dry asphalt road is Greater than the maximum longitudinal force coefficient of the first rear wheel on a dry cement road

[0173] Specifically, the following describes the rotation conditions of the aforementioned vehicle and the non-slip conditions of the first front wheel, assuming that the left front wheel is the front wheel that needs to be stationary (i.e., the left front wheel is the first front wheel) and the rotation direction of the vehicle is counterclockwise.

[0174] For example, see Fig.10 , Fig.10 Schematic diagram of the forces on the four wheels of a vehicle during a steering process provided by an embodiment of the present application. Fig.10 As shown, the left front wheel is the front wheel that needs to be stationary (i.e., the first front wheel is the left front wheel), and the vehicle's rotation direction is counterclockwise, that is, during the turning process, the vehicle will rotate counterclockwise with the left front wheel as the rotation center. The driving force generated by the second front wheel of the vehicle (i.e., the right front wheel) is F FR The driving force generated by the first rear wheel (i.e. the left rear wheel) of the vehicle is F RL The driving force generated by the second rear wheel (i.e. the right rear wheel) of the vehicle is F RR The steering control device determines whether the vehicle can be steered at this time, that is, the steering control device determines whether the vehicle meets the rotation condition of the vehicle and whether the first front wheel meets the non-slip condition.

[0175] The rotation conditions of the vehicle satisfy the following formulas (5), (6) and (7):

[0176] F RL ≥f lrl _ max (5)

[0177] F RR ≥f lrr _ max (6)

[0178]

[0179] Among them, F RL is the driving force of the first rear wheel (i.e. the left rear wheel), F RR is the driving force of the second rear wheel (i.e. the right rear wheel), F FR is the driving force of the second front wheel (i.e. the right front wheel), f lrl _ max is the maximum longitudinal static friction of the first rear wheel (i.e. the left rear wheel), f lrr _ maxis the maximum longitudinal static friction of the second rear wheel (i.e. the right rear wheel), B is the wheelbase of the vehicle, L is the wheelbase of the vehicle, and f srl is the lateral friction resistance of the first rear wheel (i.e. the left rear wheel), f srr is the lateral friction resistance of the second rear wheel (i.e. the right rear wheel), f FL is the rotational resistance of the first front wheel (i.e., the left front wheel), J C is the moment of inertia of the vehicle, is the angular acceleration of the vehicle.

[0180] The non-slip condition of the first front wheel satisfies the following formula (8) and formula (9):

[0181] f sideway ≥F′ crr cosδ (8)

[0182] f longitudinal ≥|F′ RL -F′ crr sinδ-F′ FR | (9)

[0183] Among them, f sideway is the maximum lateral static friction of the first front wheel (i.e. the left front wheel), f longitudinal is the maximum longitudinal static friction of the first front wheel (i.e. the left front wheel), F′ RL is the driving force F of the first rear wheel (i.e. the left rear wheel) RL The reaction force, F′ crr The component force F of the driving force of the second rear wheel (i.e. the right rear wheel) crr The reaction force, F′ FR is the driving force F of the second front wheel FR The reaction force of the vehicle is δ, where δ = arctan (B / L), F trr It is the component of the driving force of the second rear wheel (i.e. the right rear wheel).

[0184] Furthermore, after the vehicle slips, the steering control device can look up the table to obtain the longitudinal force coefficient and lateral force coefficient of the current wheel, and then obtain the longitudinal friction resistance and lateral friction resistance of the current wheel. Fig. 9 The longitudinal force coefficient and the lateral force coefficient of the first rear wheel at the current slip rate and the longitudinal force coefficient and the lateral force coefficient of the second rear wheel at the current slip rate are obtained.

[0185] For example, the lateral friction resistance of the first rear wheel satisfies the following formula (10), the longitudinal friction resistance of the first rear wheel satisfies the following formula (11), the lateral friction resistance of the second rear wheel satisfies the following formula (12), and the longitudinal friction resistance of the second rear wheel satisfies the following formula (13):

[0186]

[0187] in, is the lateral force coefficient of the first rear wheel at the current slip rate, is the longitudinal force coefficient of the first rear wheel at the current slip rate, is the lateral force coefficient of the second rear wheel at the current slip rate, is the longitudinal force coefficient of the second rear wheel at the current slip rate, F zrl is the vertical load on the first rear wheel, F zrr is the vertical load on the second rear wheel.

[0188] In a possible implementation manner, the longitudinal friction resistance of the first rear wheel can be considered to be proportional to the driving force F of the first rear wheel. RL The longitudinal friction resistance of the second rear wheel can be considered equal to the driving force F of the second rear wheel. RR Equal in size.

[0189] Substituting formula (10)-formula (13) into the vehicle's rotation conditions, we can obtain the following formula (14)-formula (16):

[0190]

[0191] Among them, T RL_max is the maximum torque of the motor corresponding to the first rear wheel, T RR_max is the maximum torque of the motor corresponding to the second rear wheel, i is the reduction ratio of the reducer of the motor corresponding to the first rear wheel and the second rear wheel, is the maximum longitudinal force coefficient between the first rear wheel and the current road surface, is the maximum longitudinal force coefficient between the second rear wheel and the current road surface.

[0192] Substituting formula (10)-formula (13) into the non-slip condition of the first front wheel, the following formula (17) and formula (18) can be obtained:

[0193]

[0194] From the above formula (14)-formula (18), it can be obtained that the steering control device can be Fig. 9 Get the maximum longitudinal force coefficient between the first rear wheel and the current road surface (i.e. ), the steering control device can be Fig. 9 Get the maximum longitudinal force coefficient between the second rear wheel and the current road surface (i.e. ), according to the slip rate of the first rear wheel (i.e. s1) Fig. 9 Get the longitudinal force coefficient of the first rear wheel at the current slip rate (i.e. ) and the lateral force coefficient of the first rear wheel at the current slip rate (i.e. ), according to the slip rate of the second rear wheel (i.e. s2) Fig. 9 Get the longitudinal force coefficient of the second rear wheel at the current slip rate (i.e. ) and the lateral force coefficient of the second rear wheel at the current slip rate (i.e. ).

[0195] Furthermore, the steering control device determines whether the vehicle satisfies the rotation condition of the vehicle and the non-slip condition of the first front wheel based on the above formula (14) to formula (18).

[0196] For example, see Fig.11 , Fig.11 This is a schematic diagram of a vehicle leaving the warehouse provided in an embodiment of the present application. Fig.11 In the process of turning around the center of the vehicle, four-wheel independent drive vehicles are used, but this method requires a large lateral space. Fig.11 In the narrow parking space shown, the steering method of the four-wheel independent drive vehicle will not be able to complete the entry and exit due to insufficient lateral space.

[0197] For example, see Fig.12 , Fig.12 This is another schematic diagram of a vehicle leaving the warehouse provided in the embodiment of the present application. Fig.12 In the embodiment of the present application, the vehicle includes a left front wheel, a right front wheel, a left rear wheel and a right rear wheel. The method of the embodiment of the present application is used to coordinate the braking system of the vehicle to lock the left front wheel to stop, or to control the left front wheel to stop by the output torque of the motor corresponding to the left front wheel, and to drive the left rear wheel by the output torque of the left rear wheel, and to drive the right rear wheel by the output torque of the right rear wheel, so that the vehicle rotates around the left front wheel to achieve vehicle steering. When the distance between the left front wheel and the rear obstacle is greater than the distance between the vehicle body and the farthest distance of the left front wheel, the vehicle can successfully complete the side parking in a narrow parking space. Compared with Figure 1 The steering method shown in the embodiment of the present application requires a small lateral space, can improve the flexibility and passability of the vehicle, and can better cope with narrow parking environments.

[0198] exist Figure 1 In the illustrated embodiment, the steering control device can control the first front wheel to be stationary relative to the vehicle, and drive the first rear wheel and the second rear wheel to rotate, and control the driving directions of the first rear wheel and the second rear wheel to be opposite, so that the vehicle can be turned around the first front wheel. The vehicle can be turned around the first front wheel without changing the steering system and driving mode of the vehicle, which can improve the steering ability of the vehicle, improve the flexibility and passability of the vehicle, and can better cope with narrow parking environments, for example, it can realize side entry and exit of narrow parking spaces.

[0199] The following is an introduction to the system architecture of the embodiment of the present application. It should be noted that the system architecture and business scenarios described in this application are intended to more clearly illustrate the technical solution of this application, and do not constitute a limitation on the technical solution provided by this application. It is known to those skilled in the art that with the evolution of the system architecture and the emergence of new business scenarios, the technical solution provided by this application is also applicable to similar technical problems.

[0200] See also Fig.13 , Fig.13 Schematic diagram of a vehicle structure provided by an embodiment of the present application. Fig.13 As shown, the vehicle 130 includes a steering control device 1305 and a plurality of wheels. The plurality of wheels may be distributed on both sides along the traveling direction of the vehicle, i.e., a left wheel and a right wheel. For example, a left front wheel 1301, a right front wheel 1302, a left rear wheel 1303, and a right rear wheel 1304.

[0201] The vehicle 130 is a vehicle provided in the present application with rear wheels having independent drive capability. The vehicle 130 may be a distributed three-motor vehicle, a four-wheel independent drive vehicle, or a rear-wheel independent drive vehicle.

[0202] The steering control device 1305 is a module with data processing and control capabilities, and is used to process the relevant data of the vehicle 130 and control the vehicle 130 to complete relevant functions. Figure 1 The steering method may include, for example, the steering control device 1305 may control the left front wheel 1301 to be stationary, determine the output torque of the left rear wheel 1303 according to the status information of the left rear wheel 1303, determine the output torque of the right rear wheel 1304 according to the status information of the right rear wheel 1304 and drive the left rear wheel 1303 based on the output torque of the left rear wheel 1303, and drive the right rear wheel 1304 based on the output torque of the right rear wheel 1304, so that the vehicle 130 can be turned around the stationary front wheel (i.e., the left front wheel 1301).

[0203] As a possible implementation, the steering control device 1305 may be a physical device, for example, the steering control device 1305 may include one or more of the following modules: a central processing unit (CPU), a microprocessor (MPU), an application specific-integrated circuit (ASIC), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), a coprocessor (to assist the central processor in completing corresponding processing and applications), a microcontroller unit (MCU), and / or an electronic control unit (ECU). Of course, the above description is based on the example that the steering control device 1305 is a vehicle-mounted device. In some solutions, the steering control device 1305 may be a physical device set outside the vehicle, such as a server, a cloud, or a host. As a possible implementation, the steering control device 1305 may be a software module, such as a virtual machine, software, program code, or a container.

[0204] In the above-mentioned manner, it is mentioned that the steering control device 1305 can be arranged outside the vehicle. It should be understood that when the steering control device 1305 is arranged outside the vehicle 130, the vehicle 130 and the steering control device 1305 can be connected in communication, for example, the two are directly connected through a wired communication method, such as a tangible medium such as a metal wire or an optical fiber, or the two are indirectly connected through a wireless communication method, such as ultra-wideband (UWB) technology, long term evolution (LTE) communication technology, fifth generation mobile communication technology (5th generation mobile networks or 5th generation wireless systems, 5th-Generation, referred to as 5G or 5G technology), global system for mobile communications (GSM), general packet radio service (GPRS), or universal mobile telecommunications system (UMTS).

[0205] Optionally, the above is an exemplary vehicle provided for the purpose of facilitating the understanding of the present solution, and is not intended to limit the application scenarios of the present solution. The solution provided by the present application is also applicable to similar devices that use wheeled devices for traveling and have data processing capabilities, such as logistics robots. In addition, Fig.13 The number of wheels of the vehicle 130 shown is also an example. In a specific implementation, the vehicle 130 may include more (eg, six wheels, eight wheels) or fewer (eg, three wheels) wheels.

[0206] See also Fig.14 , Fig.14 Schematic diagram of the structure of a vehicle with independent rear wheel drive provided in an embodiment of the present application. Fig.14 As shown, the vehicle 140 includes a steering mechanism 1405, a brake control 1406, a vehicle controller 1407, a yaw rate sensor 1408, a first wheel speed sensor 1409, a second wheel speed sensor 1410, a first reducer 1411, a first motor 1412, a second motor 1413, a second reducer 1414 and a plurality of wheels. The plurality of wheels may be distributed on both sides along the direction of travel of the vehicle, i.e., a left wheel and a right wheel. For example, a left front wheel 1401, a right front wheel 1402, a left rear wheel 1403 and a right rear wheel 1404. The vehicle 140 may drive the left rear wheel 1403 through the first motor 1412, and drive the right rear wheel 1404 through the second motor 1413.

[0207] The steering mechanism 1405 is used to control the driving direction of the vehicle. For example, the steering mechanism 1405 can control the steering of the left front wheel 1401 and the right front wheel 1402 of the vehicle, thereby controlling the driving direction of the vehicle.

[0208] The brake control 1406 is used to perform brake control on the left front wheel 1401 and the right front wheel 1402. For example, the brake control 1406 brakes and locks the left front wheel 1401 to control the left front wheel 1401 to be stationary.

[0209] The vehicle controller 1407 is used to collect signals, control the vehicle, and forward relevant information of each device. For example, the vehicle controller 1407 obtains wheel speed information collected by the first wheel speed sensor 1409 and the second wheel speed sensor 1410. For another example, the vehicle controller 1407 sends a steering instruction to the steering mechanism 1405 to control the driving direction of the vehicle. For another example, the vehicle controller 1407 sends an instruction to the brake control 1406 to brake the left front wheel 1401 and the right front wheel 1402.

[0210] The yaw rate sensor 1408 is used to collect the yaw information of the vehicle. For example, the yaw rate sensor 1408 collects the lateral acceleration of the vehicle or the yaw angular velocity of the vehicle, and sends the collected yaw information of the vehicle to the vehicle controller 1407.

[0211] The first wheel speed sensor 1409 is used to collect wheel speed information of the left rear wheel 1403 , and send the collected wheel speed information of the left rear wheel 1403 to the vehicle controller 1407 .

[0212] The second wheel speed sensor 1410 is used to collect wheel speed information of the right rear wheel 1404, and send the collected wheel speed information of the right rear wheel 1404 to the vehicle controller 1407. Optionally, the vehicle speed is calculated by the wheel speed information of the left rear wheel 1403 and the wheel speed information of the right rear wheel 1404.

[0213] The first speed reducer 1411 is used to change the rotation speed and adjust the wheel speed of the left rear wheel 1403.

[0214] The first motor 1412 is used to drive the left rear wheel 1403 .

[0215] The second motor 1413 is used to drive the right rear wheel 1404 .

[0216] The second reducer 1414 is used to change the rotation speed and adjust the wheel speed of the right rear wheel 1404. Optionally, the reduction ratios of the first reducer 1411 and the second reducer 1414 may be the same.

[0217] Each device can communicate with each other via the vehicle's CAN network.

[0218] As a possible implementation method, the present application embodiment can realize the above Figure 1 The present application can control the left front wheel 1401 or the right front wheel 1402 to be stationary by braking and locking the left front wheel 1401 or the right front wheel 1402 through the braking control 1406 (for example, controlling the left front wheel 1401 to be stationary by braking and locking the left front wheel 1401), determine the output torque of the left rear wheel 1403 according to the status information of the left rear wheel 1403, determine the output torque of the right rear wheel 1404 according to the status information of the right rear wheel 1404, and drive the left rear wheel 1403 through the first motor 1412 based on the output torque of the left rear wheel 1403, and drive the right rear wheel 1404 through the second motor 1413 based on the output torque of the right rear wheel 1404, and control the driving directions of the left rear wheel 1403 and the right rear wheel 1404 to be opposite, so that the vehicle 140 can be turned around the stationary front wheel (i.e., the left front wheel 1401). In this way, the vehicle can be steered without changing the steering system and driving mode of the vehicle, thereby improving the steering ability of the vehicle and improving the flexibility and passability of the vehicle.

[0219] See also Fig.15 , Fig.15 Schematic diagram of a distributed three-motor vehicle provided in an embodiment of the present application. Fig.15As shown, the vehicle 150 may further include a differential 1415, a third speed reducer 1416, a third motor 1417, a third wheel speed sensor 1418, and a fourth wheel speed sensor 1419 on the basis of the vehicle 140. The vehicle 150 may drive the left front wheel 1401 and the right front wheel 1402 through the third motor 1417, drive the left rear wheel 1403 through the first motor 1412, and drive the right rear wheel 1404 through the second motor 1413.

[0220] The differential 1415 enables the left front wheel 1401 and the right front wheel 1402 to rotate at different speeds.

[0221] The third speed reducer 1416 is used to change the rotation speed and adjust the wheel speed of the left front wheel 1401 and the right front wheel 1402 .

[0222] The third motor 1417 is used to drive the left front wheel 1401 and the right front wheel 1402. For example, the left front wheel 1401 is controlled to be stationary by the torque of the third motor 1417.

[0223] The third wheel speed sensor 1418 is used to collect wheel speed information of the left front wheel 1401 , and send the collected wheel speed information of the left front wheel 1401 to the vehicle controller 1407 .

[0224] The fourth wheel speed sensor 1419 is used to collect wheel speed information of the right front wheel 1402, and send the collected wheel speed information of the right front wheel 1402 to the vehicle controller 1407. Optionally, the vehicle speed is calculated by the wheel speed information of the left rear wheel 1403 and the wheel speed information of the right rear wheel 1404.

[0225] As a possible implementation method, the present application embodiment can realize the above Figure 1 The present application can control the left front wheel 1401 or the right front wheel 1402 to be stationary by braking and locking the left front wheel 1401 or the right front wheel 1402 through the braking control 1406 (for example, braking and locking the left front wheel 1401 to control the left front wheel 1401 to be stationary) or control the left front wheel 1401 to be stationary through the torque of the third motor 1417, determine the output torque of the left rear wheel 1403 according to the status information of the left rear wheel 1403, determine the output torque of the right rear wheel 1404 according to the status information of the right rear wheel 1404, and drive the left rear wheel 1403 through the first motor 1412 based on the output torque of the left rear wheel 1403, and drive the right rear wheel 1404 through the second motor 1413 based on the output torque of the right rear wheel 1404, and control the driving directions of the left rear wheel 1403 and the right rear wheel 1404 to be opposite, so that the vehicle 150 can be steered around the stationary front wheel (i.e., the left front wheel 1401). In this way, the vehicle can be steered without changing the steering system and driving mode of the vehicle, thereby improving the steering ability of the vehicle and improving the flexibility and passability of the vehicle.

[0226] Furthermore, the embodiment of the present application can also determine the output torque of the right front wheel 1402, and drive the right front wheel 1402 through the third motor 1417 based on the output torque of the right front wheel 1402, thereby controlling the stability of the yaw angular velocity of the vehicle 150, making the vehicle 150 more stable and controllable during the turning process.

[0227] See also Fig.16 , Fig.16 Schematic diagram of the architecture of a four-wheel independent drive vehicle provided in an embodiment of the present application. Fig.16 As shown, the vehicle 160 may further include a fourth reducer 1420, a fourth motor 1421, a fifth motor 1422, a fifth reducer 1423, a third wheel speed sensor 1418, and a fourth wheel speed sensor 1419 on the basis of the vehicle 140. The vehicle 160 may drive the left front wheel 1401 through the fourth motor 1421, drive the right front wheel 1402 through the fifth motor 1422, drive the left rear wheel 1403 through the first motor 1412, and drive the right rear wheel 1404 through the second motor 1413.

[0228] The fourth motor 1421 is used to convert chemical energy into kinetic energy of the vehicle, thereby driving the left front wheel 1401 to rotate. For example, the left front wheel 1401 is controlled to be stationary by the torque of the fourth motor 1421.

[0229] The fourth speed reducer 1420 is used to change the rotation speed and adjust the wheel speed of the left front wheel 1401.

[0230] The fifth motor 1422 is used for converting chemical energy into kinetic energy of the vehicle, thereby driving the right front wheel 1402 to rotate.

[0231] The fifth reducer 1423 is used to change the rotation speed and adjust the wheel speed of the right front wheel 1402. Optionally, the reduction ratios of the fourth reducer 1420 and the fifth reducer 1423 may be the same.

[0232] The third wheel speed sensor 1418 is used to collect wheel speed information of the left front wheel 1401 , and send the collected wheel speed information of the left front wheel 1401 to the vehicle controller 1407 .

[0233] The fourth wheel speed sensor 1419 is used to collect wheel speed information of the right front wheel 1402 and send the collected wheel speed information of the right front wheel 1402 to the vehicle controller 1407 .

[0234] As a possible implementation method, the present application embodiment can realize the above Figure 1The present application can control the left front wheel 1401 or the right front wheel 1402 to be stationary by braking and locking the left front wheel 1401 or the right front wheel 1402 through the braking control 1406 (for example, braking and locking the left front wheel 1401 to control the left front wheel 1401 to be stationary) or control the left front wheel 1401 to be stationary through the torque of the fourth motor 1421, determine the output torque of the left rear wheel 1403 according to the status information of the left rear wheel 1403, determine the output torque of the right rear wheel 1404 according to the status information of the right rear wheel 1404, and drive the left rear wheel 1403 through the first motor 1412 based on the output torque of the left rear wheel 1403, and drive the right rear wheel 1404 through the second motor 1413 based on the output torque of the right rear wheel 1404, and control the driving directions of the left rear wheel 1403 and the right rear wheel 1404 to be opposite, so that the vehicle 160 can be steered around the stationary front wheel (i.e., the left front wheel 1401). In this way, the vehicle can be steered without changing the steering system and driving mode of the vehicle, thereby improving the steering ability of the vehicle and improving the flexibility and passability of the vehicle.

[0235] Furthermore, the embodiment of the present application can also determine the output torque of the right front wheel 1402, and drive the right front wheel 1402 through the fifth motor 1422 based on the output torque of the right front wheel 1402, thereby controlling the stability of the yaw angular velocity of the vehicle 160, making the vehicle 160 more stable and controllable during the turning process.

[0236] The method of the embodiment of the present application is described in detail above, and the device of the embodiment of the present application is provided below.

[0237] See also Fig.17 , Fig.17 1 is a schematic diagram of a steering control device provided in an embodiment of the present application. The steering control device 170 is included in a vehicle, the vehicle includes a first front wheel, a first rear wheel and a second rear wheel, and the steering control device 170 may include a processing unit 1701 and a driving unit 1702. The steering control device 170 is used to implement the aforementioned steering method, for example Figure 1 The steering method in the illustrated embodiment.

[0238] It should be noted that the division of the above multiple units is only a logical division based on functions, and does not limit the specific structure of the steering control device 170. In specific implementations, some functional modules may be subdivided into more small functional modules, and some functional modules may be combined into one functional module.

[0239] In a possible implementation, the processing unit 1701 is used to control the first front wheel of the vehicle to be stationary relative to the vehicle. The driving unit 1702 is used to drive the first rear wheel and the second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel. The driving directions of the first rear wheel and the second rear wheel are opposite.

[0240] In a possible implementation manner, the processing unit 1701 is further configured to brake and lock the first front wheel to make the first front wheel stationary relative to the vehicle, or control the first front wheel to be stationary relative to the vehicle through torque.

[0241] In a possible implementation, the processing unit 1701 is further configured to determine the front wheel of the vehicle that needs to be stationary according to the steering input information, wherein the first front wheel is the front wheel of the vehicle that needs to be stationary.

[0242] In a possible implementation manner, the steering input information is further used to determine at least one of the following: a rotation direction of the vehicle, and a required turning angle of the vehicle.

[0243] In a possible implementation, the driving directions of the first rear wheel and the second rear wheel are related to the rotation direction of the vehicle, wherein the rotation direction of the vehicle is clockwise and counterclockwise.

[0244] Optionally, the front wheels to be stationary and the required rotation angle of the vehicle can be selected by vehicle computer selection, button selection, remote control selection, steering wheel selection, etc. The rotation direction of the vehicle can be selected by vehicle computer selection, button selection, remote control selection, gear selection, etc.

[0245] In a possible implementation, the processing unit 1701 is further configured to determine the output torque of the first rear wheel according to the state information of the first rear wheel, and the driving unit 1702 is further configured to drive the first rear wheel to rotate based on the output torque of the first rear wheel.

[0246] In a possible implementation, the processing unit 1701 is further configured to determine the output torque of the second rear wheel according to the state information of the second rear wheel, and the driving unit 1702 is further configured to drive the first rear wheel to rotate based on the output torque of the second rear wheel.

[0247] In one possible implementation, the status information of the first rear wheel includes at least one of the wheel speed of the first rear wheel, the wheel acceleration of the first rear wheel, the current slip rate of the first rear wheel, and the target slip rate of the first rear wheel, and the status information of the second rear wheel includes at least one of the wheel speed of the second rear wheel, the wheel acceleration of the second rear wheel, the current slip rate of the second rear wheel, and the target slip rate of the second rear wheel.

[0248] In a possible implementation, the processing unit 1701 is further configured to determine the output torque of the first rear wheel according to the target slip rate of the first rear wheel, the current slip rate of the first rear wheel, and the torque control method for the first rear wheel, and the output torque of the first rear wheel is used to change the slip rate of the first rear wheel toward the target slip rate of the first rear wheel. Optionally, the output torque of the first rear wheel can be determined by a PID control algorithm.

[0249] Preferably, the difference between the current slip rate of the first rear wheel and the target slip rate of the first rear wheel is used as the input of the segmented PID control, and the torque control mode for the first rear wheel is used as the enable flag for the segmented PID control stage jump to output the output torque of the first rear wheel.

[0250] In a possible implementation manner, the processing unit 1701 is further configured to determine a torque control mode for the first rear wheel according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel.

[0251] In one possible implementation, the torque control method for the first rear wheel is used to indicate a torque adjustment direction for the first rear wheel and a torque adjustment rate for the first rear wheel, the torque adjustment direction being one of increasing torque, decreasing torque and maintaining torque, and the torque adjustment rate for the first rear wheel is used to indicate the intensity of adjusting the torque of the first rear wheel.

[0252] In a possible implementation, the processing unit 1701 is further configured to determine the output torque of the second rear wheel according to the target slip rate of the second rear wheel, the current slip rate of the second rear wheel, and the torque control method for the second rear wheel, and the output torque of the second rear wheel is used to change the slip rate of the second rear wheel toward the target slip rate of the second rear wheel. Optionally, the output torque of the second rear wheel can be determined by a segmented PID control algorithm.

[0253] Preferably, the difference between the current slip rate of the second rear wheel and the target slip rate of the second rear wheel is used as the input of the segmented PID control, and the torque control mode for the second rear wheel is used as the enable flag for the segmented PID control stage jump to output the output torque of the second rear wheel.

[0254] In a possible implementation manner, the processing unit 1701 is further configured to determine a torque control mode for the second rear wheel according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel.

[0255] In one possible implementation, the torque control method for the second rear wheel is used to indicate a torque adjustment direction for the second rear wheel and a torque adjustment rate for the second rear wheel, the torque adjustment direction being one of increasing torque, decreasing torque and maintaining torque, and the torque adjustment rate for the second rear wheel is used to indicate the intensity of adjusting the torque of the second rear wheel.

[0256] In a possible implementation manner, the driving unit 1702 is also used to drive the second front wheel of the vehicle to rotate.

[0257] In a possible implementation, the processing unit 1701 is further used to determine the output torque of the second front wheel of the vehicle according to the current yaw rate of the vehicle and the target yaw rate of the vehicle. The driving unit 1702 is further used to drive the second front wheel to rotate based on the output torque of the second front wheel. The output torque of the second front wheel is used to make the yaw rate of the vehicle change toward the target yaw rate of the vehicle. Optionally, the output torque of the second front wheel can be determined by a segmented PID control algorithm.

[0258] Preferably, the difference between the current yaw rate of the vehicle and the target yaw rate of the vehicle is used as an input of the segmented PID control to output the output torque of the second front wheel.

[0259] In a possible implementation, the processing unit 1701 is further used to determine that the vehicle satisfies a rotation condition before driving the first rear wheel and the second rear wheel of the vehicle to rotate. The rotation condition is related to at least one of the maximum output torque of the motor corresponding to the first rear wheel, the maximum output torque of the motor corresponding to the second rear wheel, the reduction ratio of the reducer of the motor corresponding to the first rear wheel and the second rear wheel, the effective rolling radius of the first rear wheel and the second rear wheel, the maximum longitudinal force coefficient between the first rear wheel and the current road surface, the maximum longitudinal force coefficient between the second rear wheel and the current road surface, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the driving force of the second front wheel, the lateral force coefficient of the first rear wheel, the longitudinal force coefficient of the second rear wheel, the lateral force coefficient of the second rear wheel, the driving force of the second front wheel, the wheelbase between the first rear wheel and the second rear wheel, the wheelbase of the vehicle, the rotational resistance of the first front wheel, the rotational inertia of the vehicle, and the angular acceleration of the vehicle.

[0260] In a possible implementation, the processing unit 1701 is further used to determine that the first front wheel meets a non-slip condition before the first rear wheel and the second rear wheel of the driving vehicle rotate. The non-slip condition is related to the maximum lateral static friction of the first front wheel, the maximum longitudinal static friction of the first front wheel, the longitudinal force coefficient of the first rear wheel, the lateral force coefficient of the second rear wheel, the longitudinal force coefficient of the second rear wheel, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the reaction force of the driving force of the second front wheel, and the axle design coefficient of the vehicle, and the axle design coefficient of the vehicle is related to at least one of the wheelbase between the first rear wheel and the second rear wheel and the wheelbase of the vehicle.

[0261] In a possible implementation, the processing unit 1701 is further configured to exit the steering function of the vehicle when the vehicle satisfies a steering exit condition of the vehicle. The steering exit condition of the vehicle includes one or more of the following: the turning angle of the vehicle reaches the required turning angle of the vehicle, the user of the vehicle steps on the brake pedal, the steering wheel angle of the vehicle is greater than a first threshold, the electronic handbrake is activated, the gear position of the vehicle changes, and the user of the vehicle turns off the steering function.

[0262] It should be noted that the above modules (processing unit 1701 and driving unit 1702) are used to execute the relevant steps of the above method. For example, the processing unit 1701 is used to execute the relevant contents of step S101 and step S103, and the driving unit 1702 is used to execute the relevant contents of step S102.

[0263] Fig.18 The figure shows a schematic diagram of the structure of a computing device provided in an embodiment of the present application. A computing device is a device with processing capabilities, and the device here can be a physical device, such as a server (such as a rack server), a host, etc., or a virtual device, such as a virtual machine, a container, etc.

[0264] like Fig.18 As shown, the computing device 180 includes: a processor 1801 and a memory 1802 and one or more programs, and may include a communication interface 1803. It should be understood that the present application does not limit the number of processors and memories in the computing device 180.

[0265] Processor 1801 is a module for performing calculations, and may include a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), a digital signal processor (DSP), a microcontroller unit (MCU), or one or more integrated circuits for controlling the execution of the above program.

[0266] The memory 1802 is used to provide a storage space, and the storage space can optionally store application data, user data, operating system, computer programs, etc. The memory 1802 may include a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, and may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0267] The memory 1802 may exist independently and be connected to the processor 1801 via a bus. The memory 1802 may also be integrated with the processor 1801.

[0268] The communication interface 1803 is used to provide information input or output for the at least one processor. And / or, the communication interface 1803 can be used to receive data sent externally and / or send data to the outside. The communication interface 1803 can be a wired link interface including an Ethernet cable, etc., or a wireless link (Wi-Fi, Bluetooth, general wireless transmission and other wireless communication technologies, etc.) interface. Optionally, the communication interface 1803 can also include a transmitter (such as a radio frequency transmitter, an antenna, etc.) coupled to the interface, or a receiver, etc.

[0269] In the embodiment of the present application, the one or more programs are stored in the memory 1802 in the form of program codes and are configured to be executed by the processor 1801. The programs include instructions for implementing the steps in the aforementioned steering method. Figure 1 That is, the memory 1802 stores executable instructions, and the processor 1801 executes the executable instructions to implement the aforementioned steering method, for example Figure 1 That is, the memory 1802 stores instructions for executing the steering method.

[0270] Alternatively, executable instructions are stored in the memory 1802, and the processor 1801 executes the executable instructions to respectively implement the functions of one or more units (or devices) in the aforementioned processing unit and driving unit, thereby realizing the steering method.

[0271] The present application also provides a control system, which includes:

[0272] A control device is used to control the first front wheel of the vehicle to be stationary relative to the vehicle; and a drive device is used to drive the first rear wheel and the second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

[0273] In a possible implementation, the control device includes a brake and / or a first motor, the brake is used to brake and lock the first front wheel so that the first front wheel is stationary relative to the vehicle, and the first motor is used to control the first front wheel to be stationary relative to the vehicle through torque. Fig.14 The braking control 1406 shown. In another exemplary embodiment, the first motor is Fig.15 The third motor 1417 is shown. In another exemplary embodiment, the first motor is Fig.16 A fourth motor 1421 is shown.

[0274] In a possible implementation, the driving device includes a second motor and a third motor, the second motor is used to drive the first rear wheel of the vehicle to rotate, and the third motor is used to drive the second rear wheel of the vehicle to rotate. Fig.14 The first motor 1412 shown, the third motor is Fig.14 The second motor 1413 is shown.

[0275] In a possible implementation, the first motor is also used to drive the second front wheel of the vehicle to rotate, or the driving device further includes a fourth motor, and the fourth motor is used to drive the second front wheel of the vehicle to rotate. Fig.16 A fifth motor 1422 is shown.

[0276] In a possible implementation, the control system further includes a steering controller for controlling the vehicle to steer around the first front wheel. Fig.14 The steering mechanism 1405 shown, or Fig.14 The vehicle controller 1407 is shown.

[0277] In a possible implementation manner, the control device is further configured to determine the front wheel of the vehicle that needs to be stationary according to the steering input information, wherein the first front wheel is the front wheel of the vehicle that needs to be stationary.

[0278] In a possible implementation manner, the steering input information is further used to determine at least one of the following: a rotation direction of the vehicle, and a required turning angle of the vehicle.

[0279] In a possible implementation, the driving directions of the first rear wheel and the second rear wheel are related to the rotation direction of the vehicle, wherein the rotation direction of the vehicle is clockwise and counterclockwise.

[0280] In a possible implementation manner, the control device is further used to determine the output torque of the first rear wheel according to the state information of the first rear wheel, and the drive device is further used to drive the first rear wheel to rotate based on the output torque of the first rear wheel.

[0281] In a possible implementation manner, the control device is further used to determine the output torque of the second rear wheel according to the state information of the second rear wheel, and the drive device is further used to drive the first rear wheel to rotate based on the output torque of the second rear wheel.

[0282] In one possible implementation, the status information of the first rear wheel includes at least one of the wheel speed of the first rear wheel, the wheel acceleration of the first rear wheel, the current slip rate of the first rear wheel, and the target slip rate of the first rear wheel, and the status information of the second rear wheel includes at least one of the wheel speed of the second rear wheel, the wheel acceleration of the second rear wheel, the current slip rate of the second rear wheel, and the target slip rate of the second rear wheel.

[0283] In a possible implementation, the control device is further used to determine the output torque of the first rear wheel based on the target slip rate of the first rear wheel, the current slip rate of the first rear wheel and the torque control method for the first rear wheel, and the output torque of the first rear wheel is used to make the slip rate of the first rear wheel change toward the target slip rate of the first rear wheel.

[0284] In a possible implementation manner, the control device is further configured to determine a torque control mode for the first rear wheel according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel.

[0285] In one possible implementation, the torque control method for the first rear wheel is used to indicate a torque adjustment direction for the first rear wheel and a torque adjustment rate for the first rear wheel, the torque adjustment direction being one of increasing torque, decreasing torque and maintaining torque, and the torque adjustment rate for the first rear wheel is used to indicate the intensity of adjusting the torque of the first rear wheel.

[0286] In a possible implementation, the control device is further used to determine the output torque of the second rear wheel based on the target slip rate of the second rear wheel, the current slip rate of the second rear wheel and the torque control method for the second rear wheel, and the output torque of the second rear wheel is used to make the slip rate of the second rear wheel change toward the target slip rate of the second rear wheel.

[0287] In a possible implementation manner, the control device is further configured to determine a torque control mode for the second rear wheel according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel.

[0288] In one possible implementation, the torque control method for the second rear wheel is used to indicate a torque adjustment direction for the second rear wheel and a torque adjustment rate for the second rear wheel, the torque adjustment direction being one of increasing torque, decreasing torque and maintaining torque, and the torque adjustment rate for the second rear wheel is used to indicate the intensity of adjusting the torque of the second rear wheel.

[0289] In a possible implementation manner, the driving device is also used to drive the second front wheel of the vehicle to rotate.

[0290] In a possible implementation manner, the control device is further used to determine the output torque of the second front wheel of the vehicle according to the current yaw rate of the vehicle and the target yaw rate of the vehicle. The drive device is further used to drive the second front wheel to rotate based on the output torque of the second front wheel. The output torque of the second front wheel is used to make the yaw rate of the vehicle change toward the target yaw rate of the vehicle.

[0291] In a possible implementation, the control device is further used to determine that the vehicle satisfies a rotation condition before driving the first rear wheel and the second rear wheel of the vehicle to rotate. The rotation condition is related to at least one of the maximum output torque of the motor corresponding to the first rear wheel, the maximum output torque of the motor corresponding to the second rear wheel, the reduction ratio of the reducer of the motor corresponding to the first rear wheel and the second rear wheel, the effective rolling radius of the first rear wheel and the second rear wheel, the maximum longitudinal force coefficient between the first rear wheel and the current road surface, the maximum longitudinal force coefficient between the second rear wheel and the current road surface, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the driving force of the second front wheel, the lateral force coefficient of the first rear wheel, the longitudinal force coefficient of the second rear wheel, the lateral force coefficient of the second rear wheel, the driving force of the second front wheel, the wheelbase between the first rear wheel and the second rear wheel, the wheelbase of the vehicle, the rotational resistance of the first front wheel, the rotational inertia of the vehicle, and the angular acceleration of the vehicle.

[0292] In a possible implementation, the control device is further used to determine that the first front wheel meets the non-slip condition before driving the first rear wheel and the second rear wheel of the vehicle to rotate. The non-slip condition is related to the maximum lateral static friction of the first front wheel, the maximum longitudinal static friction of the first front wheel, the longitudinal force coefficient of the first rear wheel, the lateral force coefficient of the second rear wheel, the longitudinal force coefficient of the second rear wheel, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the reaction force of the driving force of the second front wheel, and the axle design coefficient of the vehicle, and the axle design coefficient of the vehicle is related to at least one of the wheelbase between the first rear wheel and the second rear wheel and the wheelbase of the vehicle.

[0293] In a possible implementation, the control device is further used to exit the steering function of the vehicle when the vehicle satisfies the steering exit condition of the vehicle. The steering exit condition of the vehicle includes one or more of the following: the turning angle of the vehicle reaches the required turning angle of the vehicle, the user of the vehicle steps on the brake pedal, the steering wheel angle of the vehicle is greater than a first threshold, the electronic handbrake is activated, the gear position of the vehicle changes, and the user of the vehicle turns off the steering function.

[0294] The control system is used to implement the aforementioned steering method, such as Figure 1 The steering method in the embodiment of the present invention.

[0295] The present application also provides a vehicle, which is one of a distributed three-motor vehicle, a four-wheel independent drive vehicle, and a rear-wheel independent drive vehicle, and the vehicle includes a first front wheel, a first rear wheel, a second rear wheel, and the aforementioned steering control device 170, a control system or the aforementioned computing device 180, and the vehicle is used to implement the aforementioned steering method, for example Figure 1 The steering method in the embodiment of the present invention.

[0296] The present application also provides a computer program product including instructions. The computer program product may be software or a program product including instructions that can be run on a computing device or stored in any available medium. The computer program instructions are used to implement the aforementioned steering method, for example, Figure 1 The steering method in the embodiment of the present invention.

[0297] The present application also provides a computer-readable storage medium. The computer-readable storage medium includes instructions for implementing the aforementioned steering method, for example Figure 1 The steering method in the embodiment of the present invention.

[0298] The computer-readable storage medium may be any available medium that can be stored in the steering control device, or a data storage device such as a data center containing one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive), etc.

[0299] In the embodiments of the present application, the words "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0300] The "at least one" mentioned in the embodiments of the present application refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can be represented by: a, b, c, (a and b), (a and c), (b and c), or (a and b and c), where a, b, c can be single or multiple. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can be represented by: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0301] Furthermore, unless otherwise specified, the ordinal numbers such as "first" and "second" used in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of the multiple objects. For example, the first rear wheel and the second rear wheel are only for the convenience of description, and do not indicate the difference in the deployment order, importance, etc. of the first rear wheel and the second rear wheel.

[0302] Those skilled in the art will appreciate that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk, or an optical disk, etc.

[0303] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steering method, characterized in that: The method comprises: controlling a first front wheel of a vehicle to be stationary relative to the vehicle; The first rear wheel and the second rear wheel of the vehicle are driven to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

2. The method according to claim 1, characterized in that The controlling the first front wheel of the vehicle to be stationary relative to the vehicle comprises: The first front wheel is brake-locked to make the first front wheel stationary relative to the vehicle, or the first front wheel is controlled to be stationary relative to the vehicle by torque.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: A front wheel of the vehicle that needs to be stationary is determined according to the steering input information, wherein the first front wheel is the front wheel of the vehicle that needs to be stationary.

4. The method according to claim 3, characterized in that The steering input information is further used to determine at least one of the following: a rotation direction of the vehicle, and a required turning angle of the vehicle.

5. The method according to claim 4, characterized in that The driving directions of the first rear wheel and the second rear wheel are related to the rotation direction of the vehicle.

6. The method according to any one of claims 1 to 5, characterized in that: The driving of the first rear wheel of the vehicle to rotate comprises: determining an output torque of the first rear wheel according to the state information of the first rear wheel; The first rear wheel is driven to rotate based on the output torque of the first rear wheel.

7. The method according to any one of claims 1 to 5, characterized in that: The driving of the second rear wheel of the vehicle to rotate comprises: determining an output torque of the second rear wheel according to the state information of the second rear wheel; The second rear wheel is driven to rotate based on the output torque of the second rear wheel.

8. The method according to claim 6 or 7, characterized in that: The state information of the first rear wheel includes at least one of the wheel speed of the first rear wheel, the wheel acceleration of the first rear wheel, the current slip rate of the first rear wheel, and the target slip rate of the first rear wheel; the state information of the second rear wheel includes at least one of the wheel speed of the second rear wheel, the wheel acceleration of the second rear wheel, the current slip rate of the second rear wheel, and the target slip rate of the second rear wheel.

9. The method according to claim 6, characterized in that The step of determining the output torque of the first rear wheel according to the state information of the first rear wheel comprises: An output torque of the first rear wheel is determined according to a target slip rate of the first rear wheel, a current slip rate of the first rear wheel, and a torque control method for the first rear wheel, wherein the output torque of the first rear wheel is used to change the slip rate of the first rear wheel toward the target slip rate of the first rear wheel.

10. The method according to claim 9, characterized in that The method further comprises: The torque control mode for the first rear wheel is determined according to the wheel speed of the first rear wheel and the wheel acceleration of the first rear wheel.

11. The method according to claim 9 or 10, characterized in that: The torque control method for the first rear wheel is used to indicate at least one of a torque adjustment direction for the first rear wheel and a torque adjustment rate for the first rear wheel, the torque adjustment direction is one of increasing torque, reducing torque and maintaining torque, and the torque adjustment rate is used to indicate the intensity of adjusting the torque of the first rear wheel.

12. The method according to claim 7, characterized in that The step of determining the output torque of the second rear wheel according to the state information of the second rear wheel comprises: The output torque of the second rear wheel is determined according to the target slip rate of the second rear wheel, the current slip rate of the second rear wheel and the torque control method for the second rear wheel, and the output torque of the second rear wheel is used to change the slip rate of the second rear wheel toward the target slip rate of the second rear wheel.

13. The method according to claim 12, characterized in that The method further comprises: The torque control mode for the second rear wheel is determined according to the wheel speed of the second rear wheel and the wheel acceleration of the second rear wheel.

14. The method according to claim 12 or 13, characterized in that The torque control method for the second rear wheel is used to indicate at least one of a torque adjustment direction for the second rear wheel and a torque adjustment rate for the second rear wheel, the torque adjustment direction is one of increasing torque, reducing torque and maintaining torque, and the torque adjustment rate is used to indicate the intensity of adjusting the torque of the second rear wheel.

15. The method according to any one of claims 1 to 14, characterized in that: The method further includes driving a second front wheel of the vehicle to rotate.

16. The method according to claim 15, characterized in that The driving of the second front wheel of the vehicle to rotate comprises: determining an output torque of the second front wheel according to a current yaw rate of the vehicle and a target yaw rate of the vehicle; The second front wheel is driven to rotate based on the output torque of the second front wheel, and the output torque of the second front wheel is used to change the yaw rate of the vehicle toward a target yaw rate of the vehicle.

17. The method according to claim 1, characterized in that Before driving the first rear wheel and the second rear wheel of the vehicle to rotate, the method further includes: Determining that the vehicle satisfies a rotation condition; Among them, the rotation condition is related to at least one of the maximum output torque of the motor corresponding to the first rear wheel, the maximum output torque of the motor corresponding to the second rear wheel, the reduction ratio of the reducer of the motor corresponding to the first rear wheel and the second rear wheel, the effective rolling radius of the first rear wheel and the second rear wheel, the maximum longitudinal force coefficient between the first rear wheel and the current road surface, the maximum longitudinal force coefficient between the second rear wheel and the current road surface, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the driving force of the second front wheel, the lateral force coefficient of the first rear wheel, the longitudinal force coefficient of the second rear wheel, the lateral force coefficient of the second rear wheel, the wheelbase between the first rear wheel and the second rear wheel, the wheelbase of the vehicle, the rotational resistance of the first front wheel, the moment of inertia of the vehicle and the angular acceleration of the vehicle.

18. The method according to claim 1, characterized in that Before driving the first rear wheel and the second rear wheel of the vehicle to rotate, the method further includes: Determining that the first front wheel satisfies a non-slip condition; Among them, the no-slip condition is related to the maximum lateral static friction of the first front wheel, the maximum longitudinal static friction of the first front wheel, the longitudinal force coefficient of the first rear wheel, the lateral force coefficient of the second rear wheel, the longitudinal force coefficient of the second rear wheel, the vertical load of the first rear wheel, the vertical load of the second rear wheel, the reaction force of the driving force of the second front wheel and the axle design coefficient of the vehicle, and the axle design coefficient of the vehicle is related to at least one of the wheelbase between the first rear wheel and the second rear wheel and the wheelbase of the vehicle.

19. The method according to claim 1, characterized in that The method further comprises: When the vehicle satisfies a steering exit condition of the vehicle, the steering function of the vehicle is exited.

20. The method according to claim 19, characterized in that The steering exit conditions of the vehicle include one or more of the vehicle's turning angle reaching the required turning angle of the vehicle, the vehicle's user stepping on the brake pedal, the vehicle's steering wheel angle being greater than a first threshold, the electronic handbrake being activated, the vehicle's gear changing, and the vehicle's user turning off the steering function.

21. A steering control device, characterized in that: The steering control device comprises a processing unit and a driving unit. The processing unit is used to control a first front wheel of the vehicle to be stationary relative to the vehicle; and The driving unit is used to drive the first rear wheel and the second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

22. A control system, characterized in that: The control system comprises: a control device for controlling a first front wheel of the vehicle to be stationary relative to the vehicle; and A driving device is used to drive the first rear wheel and the second rear wheel of the vehicle to rotate so that the vehicle can turn around the first front wheel, wherein the driving directions of the first rear wheel and the second rear wheel are opposite.

23. The control system according to claim 22, characterized in that: The control device includes a brake and / or a first motor, wherein the brake is used to brake and lock the first front wheel so that the first front wheel is stationary relative to the vehicle, and the first motor is used to control the first front wheel to be stationary relative to the vehicle through torque.

24. The control system according to claim 22 or 23, characterized in that: The driving device includes a second motor and a third motor, wherein the second motor is used to drive the first rear wheel of the vehicle to rotate, and the third motor is used to drive the second rear wheel of the vehicle to rotate.

25. The control system according to claim 23, characterized in that: The first motor is also used to drive the second front wheel of the vehicle to rotate, or the driving device further includes a fourth motor, and the fourth motor is used to drive the second front wheel of the vehicle to rotate.

26. The control system according to any one of claims 22 to 25, characterized in that: The control system further comprises a steering controller for controlling the vehicle to steer around the first front wheel.

27. The control system according to any one of claims 22 to 26, characterized in that: The control system is used to implement the method according to any one of claims 1-20.

28. A computing device, characterized in that The computing device includes a processor and a memory, wherein the memory stores a program, and the processor executes the program stored in the memory, so that the computing device implements the method according to any one of claims 1 to 20.

29. A vehicle, characterized in that: The vehicle comprises a first front wheel, a first rear wheel, a second rear wheel and the steering control device according to claim 21, the control system according to any one of claims 22-27 or the computing device according to claim 28.

30. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program, wherein the computer program includes instructions for executing the method according to any one of claims 1 to 20.

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