Rear wheel aligning device, steering system, vehicle and control method and device

Abstract

A rear wheel aligning device (8) belongs to the technical field of vehicles and comprises a shell (81), a first sliding body (82), a second sliding body (83) and a driving component (84), and the first sliding body (82) and the second sliding body (83) are linked with a tie rod (3). When the tie rod (3) needs to return, the driving component (84) is switched into a first state with large driving force, the first sliding body (82) or the second sliding body (83) is driven to slide, and the first sliding body (82) or the second sliding body (83) drives the tie rod (3) to return. When the rear wheel steering system is normal, the first sliding body (82) and the second sliding body (83) slide along with the tie rod (3), the driving component (84) is switched to be in a second state with small driving force, resistance generated by the first sliding body (82) and the second sliding body (83) is reduced, and vehicle driving safety is improved. The invention further relates to a rear wheel steering system, a vehicle and a rear wheel return control method and device.

Description

Rear wheel realignment device, steering system, vehicle, control method and device

[0001] The present disclosure relates to the technical field of vehicles, and particularly relates to a rear wheel realignment device, a steering system, a vehicle, a control method and a device.

[0002] As an active chassis control technology, the rear wheel steering system can control the rear wheels to generate a certain tire deflection angle according to the vehicle dynamics state, which can improve the handling stability, safety and comfort of the vehicle.

[0003] Generally speaking, in the low-speed driving condition, the rear wheels generate a deflection angle opposite to that of the front wheels, which significantly reduces the turning radius of the vehicle, enhances the yaw response, makes the vehicle more sensitive and more maneuverable. In the high-speed driving condition, the rear wheels generate a deflection angle in the same direction as the front wheels, and the lateral force on the rear axle can be quickly established, improving the lateral acceleration response and significantly improving the handling stability of the vehicle.

[0004] However, once the rear wheel steering system fails, it may cause uncontrollable movement of the rear wheels, seriously affecting the driving safety of the vehicle.

[0005]

[0006] The present disclosure provides a rear wheel realignment device, a steering system, a vehicle, a control method and a device. The first sliding body and the second sliding body in the rear wheel realignment device provided by the present disclosure are linked with the tie rod. When the rear wheel steering system cannot normally drive the rear wheels to steer, the driving component in the rear wheel realignment device drives the first sliding body or the second sliding body to slide, and then the first sliding body or the second sliding body drives the tie rod to realign as an active part, so that the vehicle is converted from four-wheel steering to front-wheel steering, improving the driving safety of the vehicle. The technical solutions of the rear wheel realignment device, the steering system, the vehicle, the control method and the device are as follows:

[0007] In a first aspect, the present disclosure provides a rear wheel realignment device, which includes a housing, a first sliding body, a second sliding body and a driving component. The housing is used to be fixed to the vehicle. The first sliding body and the second sliding body are located inside the housing and are linked with the tie rod of the rear wheel steering system. The driving component has a first state and a second state, and the driving force of the driving component in the first state is greater than that in the second state. In the first state, the driving component drives the first sliding body or the second sliding body to slide, and the first sliding body or the second sliding body drives the tie rod to realign.

[0008] Among them, the sliding bodies (the first sliding body and the second sliding body) are linked with the cross tie rod, which can also be understood as the sliding bodies being drivingly connected to the cross tie rod. The linkage between the sliding bodies and the cross tie rod means that the positions of the sliding bodies are associated with the position of the cross tie rod. A change in the position of the cross tie rod will cause a change in the position of the sliding bodies. Similarly, a change in the position of the sliding bodies will also cause a change in the position of the cross tie rod. Therefore, by controlling the driving component to apply a sufficiently large driving force to the sliding bodies, the sliding bodies can be used as the driving members to drive the cross tie rod to return to the straight position. In addition, during the normal rear-wheel steering process of the vehicle, the sliding bodies move following the cross tie rod, which will generate a certain resistance to the cross tie rod or the rear-wheel steering drive device.

[0009] The technical solution provided by the present disclosure enables the driving component to switch to the first state with a larger driving force when the rear-wheel return device needs to drive the cross tie rod to return to the straight position by setting the driving component to have a first state and a second state with different driving forces. Thus, the driving component outputs sufficient driving force to drive the first sliding body or the second sliding body to slide, and the first sliding body or the second sliding body drives the cross tie rod to return to the straight position as the driving member.

[0010] In a possible implementation, in the second state, the first sliding body or the second sliding body slides under the drive of the rear-wheel steering drive device or the cross tie rod of the rear-wheel steering system. Since the sliding bodies provide resistance during the normal rear-wheel steering process of the vehicle, by setting the driving component to switch to the second state with a smaller driving force, the resistance received by the cross tie rod or the rear-wheel steering drive device is reduced, and the energy consumption of the rear-wheel steering drive device is reduced.

[0011] In a possible implementation, when the first sliding body and the second sliding body are respectively located at the first position and the second position, the cross tie rod is in the straight position. Therefore, by driving the first sliding body and the second sliding body to slide towards the first position and the second position respectively, the cross tie rod can be driven to return to the straight position. In a possible implementation, the driving component is configured to apply a driving force towards the first position to the first sliding body and a driving force towards the second position to the second sliding body, and the driving force output by the driving component in the first state is greater than the driving force output in the second state. In the first state, under the action of the driving force of the driving component, the first sliding body slides towards the first position or remains at the first position, and the second sliding body slides towards the second position or remains at the second position.

[0012] In a possible implementation, when the first sliding body is located at the first position and the second sliding body is located between the first position and the second position, the cross tie rod is in the first offset state. Then, when the cross tie rod needs to be switched from the first offset state to the straight position, the driving component switches to the first state, and the driving component drives the second sliding body to slide towards the second position. At the same time, the driving component can also drive the first sliding body to remain at the first position.

[0013] In a possible implementation, when the first sliding body is between the first position and the second position and the second sliding body is at the second position, the cross tie rod is in the second offset state. Then, when the cross tie rod needs to switch from the second offset state to the straightened state, the driving component switches to the first state, and the driving component drives the first sliding body to slide towards the first position. At the same time, the driving component can also drive the second sliding body to remain at the second position.

[0014] Wherein, one of the first offset state and the second offset state is the left offset state, and the other is the right offset state.

[0015] In a possible implementation, the first sliding body and the second sliding body are sleeved on the cross tie rod and are located between two first flanges of the cross tie rod. When the first sliding body and the second sliding body are at the first position and the second position respectively, the first sliding body and the second sliding body are in contact with the two first flanges respectively.

[0016] During the normal rear wheel steering process, the cross tie rod moves under the action of the rear wheel steering drive device. During the movement of the cross tie rod, a certain first flange on the cross tie rod drives the first sliding body or the second sliding body to slide.

[0017] During the process of the rear wheel return device driving the cross tie rod to return to the straight state, the first sliding body or the second sliding body, under the action of the driving force of the driving component, acts as an active part and pushes the cross tie rod to return to the straight state through the corresponding first flange.

[0018] In a possible implementation, the rear wheel return device is arranged on the transmission shaft between the rear wheel steering motor and the reduction unit. In this way, since the rear wheel return device is located at the input end of the reduction unit, the rear wheel return device can drive the cross tie rod to return to the straight state with a smaller driving force. Thereby reducing the driving force required for the rear wheel return device to output in the first state, reducing the energy consumption of the rear wheel return device, reducing the volume of the rear wheel return device, and making it easier to arrange the rear wheel return device.

[0019] In a possible implementation, the rear wheel return device further includes a first lead screw and a first nut. The first lead screw is fixed on the transmission shaft between the rear wheel steering motor and the reduction unit of the rear wheel steering system. The first nut is sleeved on the first lead screw. Then, the first nut and the first lead screw form a lead screw nut mechanism or a ball screw mechanism. The first nut has two second flanges. The first sliding body and the second sliding body are located between the two second flanges. And when the first sliding body and the second sliding body are at the first position and the second position respectively, the first sliding body and the second sliding body are in contact with the two second flanges respectively.

[0020] During normal rear-wheel steering, the rear-wheel steering motor drives the drive shaft to rotate. The drive shaft drives the first lead screw to rotate, and the first lead screw drives the first nut to slide. During the sliding of the first nut, the first nut pushes the first sliding body or the second sliding body to slide through the second flange. At the same time, the drive shaft also drives the tie rod to deflect through a reduction unit to achieve the steering of the rear wheels.

[0021] During the process of the rear-wheel return device driving the tie rod to return to the original position, the first sliding body or the second sliding body, under the driving force of the driving component, pushes the first nut to slide through the corresponding second flange. During the sliding of the first nut, the first nut drives the first lead screw to rotate, the first lead screw drives the drive shaft to rotate, and the drive shaft drives the tie rod to return to the original position through a reduction unit.

[0022] In a possible implementation, the drive shaft includes a first shaft section, a second shaft section, and a clutch. The first shaft section and the second shaft section are connected by the clutch. The second shaft section is connected to the reduction unit, and the first lead screw is fixed on the second shaft section.

[0023] In a possible implementation, the driving force output by the driving component in the second state is 0.

[0024] In a possible implementation, the driving force output by the driving component in the second state is greater than 0. In this way, in the second state, under the action of the driving force output by the driving component, the first sliding body and the second sliding body either stably stay at the first position or the second position, or closely adhere to the first flange or the second flange, and the first sliding body and the second sliding body will not have uncontrollable sliding.

[0025] In a possible implementation, the driving component includes a first electromagnetic coil and a second electromagnetic coil. The first electromagnetic coil and the second electromagnetic coil are fixed inside the housing, and the first sliding body and the second sliding body are located between the first electromagnetic coil and the second electromagnetic coil.

[0026] In the first state, the first electromagnetic coil and the second electromagnetic coil are energized. The first electromagnetic coil attracts the first sliding body to slide towards or stay at the first position, and the second electromagnetic coil attracts the second sliding body to slide towards or stay at the second position. During the sliding of the first sliding body or the second sliding body, the first sliding body or the second sliding body drives the tie rod to return to the original position.

[0027] In a possible implementation, in the second state, the first electromagnetic coil and the second electromagnetic coil are energized, and the current passed through is less than the current passed through by the first electromagnetic coil and the second electromagnetic coil in the first state. In this way, it is achieved that the driving force of the driving component in the second state is less than the driving force in the first state.

[0028] In a possible implementation, in the second state, the first electromagnetic coil and the second electromagnetic coil are powered off. In this way, the energy consumption of the driving component can be reduced, and the service life of the driving component can be extended. Moreover, the driving force of the driving component in the second state is made smaller than that in the first state.

[0029] In a possible implementation, the driving component includes a solenoid valve, which is respectively connected to the high-pressure air circuit, the low-pressure air circuit on the vehicle, and the chamber between the first sliding body and the second sliding body.

[0030] In the first state, the solenoid valve connects the chamber to the high-pressure air circuit, high-pressure gas enters the chamber, and pushes the first sliding body to slide towards or stay at the first position, and pushes the second sliding body to slide towards or stay at the second position. During the sliding process of the first sliding body or the second sliding body, the first sliding body or the second sliding body drives the tie rod to return to the straight position.

[0031] In the second state, the solenoid valve connects the chamber to the low-pressure air circuit, and the high-pressure gas is discharged through the low-pressure air circuit. The driving forces received by the first sliding body and the second sliding body become smaller.

[0032] In a possible implementation, the driving component further includes an elastic member, and both ends of the elastic member are respectively abutted against the first sliding body and the second sliding body. The elastic member can be used to apply a driving force towards the first position to the first sliding body and a driving force towards the second position to the second sliding body in the second state. Moreover, since the elastic member does not need to be connected to a power source, the energy consumption of the driving component in the second state is 0 or very low.

[0033] In a possible implementation, the rear-wheel return-to-straight device further includes a brake, which is configured to lock the position of the tie rod after the tie rod returns to the straight position.

[0034] In this way, the position of the tie rod can be locked in the straight position by the brake. After that, the driving component can be switched back to the second state without having to always remain in the first state with a larger driving force, reducing the energy consumption of the driving component.

[0035] In a possible implementation, the brake is arranged on the transmission shaft between the rear-wheel steering motor and the reduction unit of the rear-wheel steering system.

[0036] In a possible implementation, the transmission shaft includes a first shaft section, a second shaft section and a clutch. The first shaft section and the second shaft section are connected by the clutch, the second shaft section is connected to the reduction unit, and the brake is arranged on the second shaft section.

[0037] In this way, after the clutch is disengaged, the brake can still lock the position of the tie rod.

[0038] In a possible implementation, the driving component further has a third state, and the driving force of the driving component in the third state is greater than that in the second state and less than that in the first state. In the third state, the driving component drives the first sliding body and the second sliding body to be respectively held at the first position and the second position.

[0039] In this way, after the tie rod returns to the straight position, the driving component can be controlled to switch from the first state to the third state to reduce the energy consumption of the driving component.

[0040] In a possible implementation, after the tie rod returns to the straight position, the driving component remains in the first state.

[0041] In a second aspect, the present disclosure provides a rear-wheel steering system, which includes a rear-wheel steering control unit, a rear-wheel steering drive device, a tie rod, and the rear-wheel straightening device according to any one of the first aspect. The rear-wheel steering drive device is in transmission connection with the tie rod, and the rear-wheel steering control unit is configured to: determine that the rear-wheel straightening device is required to drive the tie rod to return to the straight position, and control the driving component to switch to the first state.

[0042] Wherein, the rear-wheel steering control unit includes one or both of a vehicle control unit and a rear-wheel steering electronic control unit.

[0043] The rear-wheel steering drive device includes a rear-wheel steering motor, a transmission shaft, a reduction unit, a conversion unit, and a stroke sensor. The rear-wheel steering motor can be a brushless motor. The rear-wheel steering motor is connected to the reduction unit through the transmission shaft. The reduction unit is connected to the conversion unit, and the conversion unit is connected to the tie rod. The conversion unit is used to convert rotation into the linear motion of the tie rod, thereby realizing the linear motion of the tie rod driven by the rear-wheel steering motor. The stroke sensor is arranged on the tie rod and is used to detect the position of the tie rod.

[0044] The technical solution provided by the present disclosure, by applying the rear-wheel straightening device of the first aspect in the rear-wheel steering system, enables the driving component to be controlled to switch to the first state when it is determined that the rear-wheel straightening device is required to drive the tie rod to return to the straight position. In the first state, the driving component drives the first sliding body or the second sliding body to slide, and the first sliding body or the second sliding body acts as a driving part to drive the tie rod to return to the straight position.

[0045] In a possible implementation, the rear-wheel steering system further includes a left connection component and a right connection component, and both ends of the tie rod are respectively connected to the left connection component and the right connection component.

[0046] Wherein, the left connection component and the right connection component are respectively used to connect with the left rear wheel and the right rear wheel. The left connection component includes a left steering tie rod and a left steering knuckle arm, and the right connection component includes a right steering tie rod and a right steering knuckle arm. When the cross tie rod moves, the cross tie rod drives the left rear wheel and the right rear wheel to steer through the left connection component and the right connection component respectively.

[0047] In a possible implementation, the rear wheel steering system further includes a left rear wheel and a right rear wheel.

[0048] In a possible implementation, the rear wheel steering control unit is further configured to control the drive component to switch to or remain in the second state when it is determined that the rear wheel alignment device is not required to drive the cross tie rod to return to the straight position. In the second state, the driving force output by the drive component is small. Therefore, the resistance brought by the first sliding body and the second sliding body can be reduced.

[0049] In a possible implementation, the rear wheel steering control unit is configured to determine that the rear wheel alignment device is required to return the cross tie rod to the straight position when it is determined that the rear wheel steering system is in the first failure state.

[0050] Wherein, the first failure state refers to a state in which the rear wheel steering drive device cannot drive the cross tie rod to return to the straight position.

[0051] In a possible implementation, the first failure state includes one or more of the following states: a power failure of the rear wheel steering drive device, a power failure of the rear wheel steering motor of the rear wheel steering drive device, and a sensor failure in the rear wheel steering drive device, wherein the sensor is used to determine the position of the cross tie rod.

[0052] In a possible implementation, when the rear wheel alignment device includes a brake, after controlling the drive component to switch to the first state, the rear wheel steering control unit is further configured to control the brake to lock the position of the cross tie rod when it is determined that the cross tie rod is in the straight position. In this way, the cross tie rod can be kept in the straight position.

[0053] In a possible implementation, after controlling the brake to lock the position of the cross tie rod, the rear wheel steering control unit controls the drive component to switch to the second state to reduce the energy consumption of the drive component.

[0054] In a possible implementation, if the rear wheel steering drive device drives the cross tie rod to return to the straight position, after controlling the brake to lock the position of the cross tie rod, the rear wheel steering motor in the rear wheel steering drive device is controlled to be turned off to reduce the energy consumption.

[0055] In one possible implementation, when the driving component has the third state, after controlling the driving component to switch to the first state, the rear-wheel steering control unit is further configured to, when it is determined that the tie rod is in a return state, control the driving component to switch to the third state, thereby reducing the energy consumption of the driving component.

[0056] In a possible implementation, the rear-wheel steering control unit is further configured to: when it is determined that the rear-wheel steering system is in the second fault state, control the rear-wheel steering drive device to drive the tie rod to return to the center.

[0057] The second fault state refers to a state in which the rear wheel steering system fails but the ability to drive the tie rod to return to the center position is still retained.

[0058] In a possible implementation, the second fault state includes one or more of the following states: the rear wheel steering motor of the rear wheel steering drive device is overheated or overloaded, and the rear wheel steering control unit cannot receive the rear wheel steering angle signal.

[0059] In a possible implementation, the rear-wheel steering drive device includes a rear-wheel steering motor, a transmission shaft and a reduction unit connected in sequence, and the reduction unit is connected to the tie rod in a transmission manner. The transmission shaft includes a first shaft section, a second shaft section and a clutch, and the first shaft section and the second shaft section are connected through a clutch. Before the control driving component is switched to the first state, the rear-wheel steering control unit is further configured to control the clutch to be disengaged. Thereby, the mechanical connection between the tie rod and the rear-wheel steering motor can be disconnected, so as to prevent the rear-wheel steering motor from affecting the return of the tie rod.

[0060] In a third aspect, the present disclosure provides a vehicle, comprising the rear wheel straightening device as described in any one of the first aspect or the rear wheel steering system as described in any one of the second aspect.

[0061] In a fourth aspect, the present disclosure provides a control method for rear wheel return, the control method is applied in a rear wheel steering control unit of a rear wheel steering system as described in any one of the second aspects, the control method comprising: if it is determined that the rear wheel return device needs to drive the tie rod to return, controlling the driving component to switch to a first state. After the driving component switches to the first state, the driving component drives the first sliding body or the second sliding body to slide, and the second sliding body or the second sliding body drives the tie rod to return.

[0062] In a possible implementation, if it is determined that the rear wheel return device does not need to drive the tie rod to return, the drive component is controlled to switch to or remain in the second state. In the second state, the driving force output by the drive component is small, so the resistance caused by the first sliding body and the second sliding body can be reduced.

[0063] In a possible implementation, when it is determined that the rear-wheel steering system is in a first failure state, it is determined that the rear-wheel alignment device is required to drive the tie rod to return to the correct position.

[0064] Among them, the first failure state refers to a state in which the rear-wheel steering drive device cannot drive the tie rod to return to the correct position.

[0065] In a possible implementation, the first failure state includes one or more of the following states: power failure of the rear-wheel steering drive device, power failure of the rear-wheel steering motor of the rear-wheel steering drive device, sensor failure of the rear-wheel steering drive device, where the sensor is used to determine the position of the tie rod, and the sensor can be a stroke sensor.

[0066] In a possible implementation, when the rear-wheel alignment device further includes a brake, after controlling the drive component to switch to the first state, if it is determined that the tie rod is in the aligned state, control the brake to lock the position of the tie rod.

[0067] In a possible implementation, after controlling the brake to lock the position of the tie rod, control the drive component to switch to the second state to reduce the energy consumption of the drive component.

[0068] In a possible implementation, if the rear-wheel steering drive device drives the tie rod to return to the correct position, after controlling the brake to lock the position of the tie rod, control the rear-wheel steering motor in the rear-wheel steering drive device to turn off to reduce energy consumption.

[0069] In a possible implementation, when the drive component has a third state, after controlling the drive component to switch to the first state, if it is determined that the tie rod is in the aligned state, control the drive component to switch to the third state. Since the driving force of the drive component in the third state is less than that in the first state, the drive component switching to the third state can reduce the energy consumption of the drive component.

[0070] In a possible implementation, when the rear-wheel steering drive device includes a clutch, before controlling the drive component to switch to the first state, control the clutch to disengage, thereby disconnecting the mechanical connection between the tie rod and the rear-wheel steering motor to prevent the rear-wheel steering motor from affecting the return of the tie rod to the correct position.

[0071] In a possible implementation, the control method further includes: determining that the rear-wheel steering system is in a second failure state, and controlling the rear-wheel steering drive device to drive the tie rod to return to the correct position.

[0072] Among them, the second failure state refers to a state in which the rear-wheel steering system fails but still retains the ability to drive the tie rod to return to the correct position.

[0073] In a possible implementation, the second fault state includes one or more of the following states: the rear-wheel steering motor in the rear-wheel steering drive device is overheated or overloaded, and the rear-wheel steering control unit fails to receive the rear-wheel steering angle signal.

[0074] In a fifth aspect, the present disclosure provides a control device for rear-wheel realignment. The control device is located in the rear-wheel steering control unit of the rear-wheel steering system according to any one of the second aspect. The control device includes: a determination module, configured to determine that it is necessary for the rear-wheel realignment device to drive the tie rod to realign; and a control module, configured to control the drive component to switch to the first state.

[0075] In a possible implementation, the determination module is configured to: when it is determined that the rear-wheel steering system is in the first fault state, determine that it is necessary for the rear-wheel realignment device to drive the tie rod to realign.

[0076] Wherein, the first fault state includes one or more of the following states: a power supply fault of the rear-wheel steering drive device, a power failure of the rear-wheel steering motor in the rear-wheel steering drive device, a sensor fault of the rear-wheel steering drive device, and the sensor is used to determine the position of the tie rod.

[0077] In a possible implementation, when the rear-wheel realignment device further includes a brake, after controlling the drive component to switch to the first state, the determination module is further configured to determine that the tie rod is in the realigned state, and the control module is further configured to control the brake to lock the position of the tie rod and control the drive component to switch to the second state.

[0078] In a possible implementation, when the drive component has a third state, after controlling the drive component to switch to the first state, the determination module is further configured to determine that the tie rod is in the realigned state, and the control module is further configured to control the drive component to switch to the third state.

[0079] In a possible implementation, when the rear-wheel steering drive device includes a clutch, before controlling the drive component to switch to the first state, the control module is further configured to control the clutch to disengage.

[0080] In a possible implementation, the determination module is further configured to determine that the rear-wheel steering system is in the second fault state, and the control module is further configured to control the rear-wheel steering drive device to drive the tie rod to realign.

[0081] Wherein, the second fault state includes one or more of the following states: the rear-wheel steering motor in the rear-wheel steering drive device is overheated or overloaded, and the rear-wheel steering control unit fails to receive the rear-wheel steering angle signal.

[0082] Sixth aspect, the present disclosure provides a computer-readable storage medium, in which at least one instruction is stored, and the instruction is loaded and executed by a controller to implement the control method for rear wheel alignment as described in any one of the fourth aspect.

[0083] Seventh aspect, the present disclosure provides a computer program product, the computer program product includes at least one instruction, and the instruction is executed by a controller, so that the controller implements the control method for rear wheel alignment as described in any one of the fourth aspect.

[0084] Eighth aspect, the present disclosure provides a chip, the chip includes a controller, and the controller is used to call and run the instruction stored in the memory, so that the electronic control unit installed with the chip executes the control method for rear wheel alignment as described in any one of the fourth aspect.

[0085] In a possible implementation, the electronic control unit is the rear wheel steering control unit in the second aspect.

[0086] Ninth aspect, the present disclosure provides another chip, the chip includes: an input interface, an output interface, a controller and a memory, the input interface, the output interface, the controller and the memory are connected through an internal connection path, and the controller is used to execute the code in the memory. When the code is executed, the controller is used to execute the control method for rear wheel alignment as described in any one of the fourth aspect.

[0087] Tenth aspect, the present disclosure provides an electronic control unit, the electronic control unit includes a controller, and the controller is coupled with a memory. At least one instruction is stored in the memory, and the instruction is loaded and executed by the controller to implement the control method for rear wheel alignment as described in any one of the fourth aspect.

[0088] In a possible implementation, the electronic control unit is the rear wheel steering control unit in the second aspect.

[0089] FIG. 1 is a schematic diagram of a steering system provided by an embodiment of the present disclosure;

[0090] FIG. 2 is a schematic diagram of a rear wheel steering system provided by an embodiment of the present disclosure;

[0091] FIG. 3 is a schematic diagram of the working process of a rear wheel alignment device provided by an embodiment of the present disclosure;

[0092] FIG. 4 is a schematic diagram of a rear wheel steering system provided by an embodiment of the present disclosure;

[0093] FIG. 5 is a schematic diagram of the working process of a rear wheel alignment device provided by an embodiment of the present disclosure;

[0094] FIG. 6 is a schematic diagram of a rear wheel steering system provided by an embodiment of the present disclosure;

[0095] Figure 7 is a schematic diagram of a rear-wheel steering system provided by an embodiment of the present disclosure;

[0096] Figure 8 is a schematic diagram of the working process of a rear-wheel centering device provided by an embodiment of the present disclosure;

[0097] Figure 9 is a schematic diagram of an air supply system of an air suspension on a vehicle provided by an embodiment of the present disclosure;

[0098] Figure 10 is a schematic diagram of an air supply system of an air suspension on a vehicle provided by an embodiment of the present disclosure;

[0099] Figure 11 is a flowchart of a method for determining a fault handling mode provided by an embodiment of the present disclosure;

[0100] Figure 12 is a flowchart of a fault handling mode 1 provided by an embodiment of the present disclosure;

[0101] Figure 13 is a flowchart of a fault handling mode 1 provided by an embodiment of the present disclosure;

[0102] Figure 14 is a flowchart of a fault handling mode 2 provided by an embodiment of the present disclosure;

[0103] Figure 15 is a flowchart of a fault handling mode 2 provided by an embodiment of the present disclosure;

[0104] Figure 16 is a flowchart of a fault handling mode 2 provided by an embodiment of the present disclosure;

[0105] Figure 17 is a flowchart of a fault handling mode 2 provided by an embodiment of the present disclosure;

[0106] Figure 18 is a flowchart of a control method for rear-wheel centering provided by an embodiment of the present disclosure;

[0107] Figure 19 is a schematic structural diagram of a control device for rear-wheel centering provided by an embodiment of the present disclosure;

[0108] Figure 20 is a schematic diagram of an electronic control unit provided by an embodiment of the present disclosure.

[0109] Legend Explanation

[0110] 100, vehicle control unit; 200, steering wheel; 300, steering wheel angle sensor; 400, vehicle speed sensor; 500, yaw rate sensor; 600, lateral acceleration sensor; 700, rear-wheel steering ECU;

[0111] 1, rear-wheel steering control unit;

[0112] 2. Rear-wheel steering drive device, 21. Rear-wheel steering motor, 22. Transmission shaft, 221. First shaft section, 222. Second shaft section, 223. Clutch, 23. Reduction unit, 231. Driving wheel, 232. Driven wheel, 233. Transmission belt, 24. Conversion unit, 241. Second nut, 242. Second lead screw, 25. Stroke sensor;

[0113] 3. Tie rod, 31. First flange;

[0114] 4. Left connection assembly, 41. Left steering tie rod, 42. Left steering knuckle arm, 5. Right connection assembly, 51. Right steering tie rod, 52. Right steering knuckle arm, 6. Left rear wheel, 7. Right rear wheel;

[0115] 8. Rear-wheel self-aligning device, 80. Chamber, 81. Housing, 82. First sliding body, 83. Second sliding body, 84. Driving component, 841. First electromagnetic coil, 842. Second electromagnetic coil, 843. Solenoid valve, 844. High-pressure gas path, 845. Low-pressure gas path, 846. Elastic member, 85. First lead screw, 86. First nut, 861. Second flange, 87. Brake, 88. Sealing ring;

[0116] 9. Air supply system, 91. Distribution valve, 92. Air supply system control unit, 93. High-pressure gas tank, 94. Air compressor.

[0117] The steering system of a vehicle is mainly used to control the yaw and lateral movement of the vehicle. For a front-wheel steering vehicle, the driver turns the steering wheel to generate a tire deflection angle of the front wheels, and then the vehicle travels along the desired trajectory.

[0118] As an active chassis control technology, the rear-wheel steering system can control the rear wheels to generate a certain tire deflection angle according to the vehicle dynamics state, which can greatly improve the handling stability, safety and comfort of the vehicle. Generally speaking, under low-speed driving conditions, the rear wheels are controlled to generate a deflection angle opposite to that of the front wheels, so that the turning radius of the vehicle is significantly reduced, the yaw response is enhanced, the vehicle becomes more sensitive and has better maneuverability. Under high-speed driving conditions, the rear wheels are controlled to generate a deflection angle in the same direction as the front wheels, and the lateral force of the rear axle can be quickly established, improving the lateral acceleration response and significantly improving the handling stability of the vehicle. The active rear-wheel steering technology can significantly change the steering characteristics of the vehicle and has an important impact on vehicle safety.

[0119] To better understand the technical solutions provided by the embodiments of the present disclosure, the vehicle steering system will be described below:

[0120] As shown in Figure 1, the steering system of the vehicle includes a vehicle control unit 100, a steering wheel 200, a steering wheel angle sensor 300, a vehicle speed sensor 400, a yaw rate sensor 500, a lateral acceleration sensor 600, a rear wheel steering electronic control unit (ECU) 700, and a rear wheel steering (RWS) system. The rear wheel steering system includes a rear wheel steering drive device 2, a tie rod 3, a left connection assembly 4, a right connection assembly 5, a left rear wheel 6, and a right rear wheel 7. Additionally, it can also be considered that at least one of the vehicle control unit 100 and the rear wheel steering ECU 700 serves as the rear wheel steering control unit 1 and belongs to the rear wheel steering system.

[0121] The rear wheel steering drive device 2 includes a rear wheel steering motor 21, a transmission shaft 22, a reduction unit 23, a conversion unit 24, and a stroke sensor 25.

[0122] The rear wheel steering motor 21 can be a brushless motor. The rear wheel steering motor 21 is connected to the reduction unit 23 through the transmission shaft 22. The reduction unit 23 is connected to the conversion unit 24, and the conversion unit 24 is connected to the tie rod 3. The conversion unit 24 is used to convert the rotation into the linear motion of the tie rod 3. Thus, the rear wheel steering motor 21 drives the linear motion of the tie rod 3. The stroke sensor 25 is arranged on the tie rod 3 and is used to detect the position of the tie rod 3. For example, it detects whether the tie rod 3 is in the centered state or the offset state, as well as the offset stroke of the tie rod 3, etc.

[0123] In some examples, as shown in Figure 1, the reduction unit 23 includes a driving wheel 231, a driven wheel 232, and a transmission belt 233. The driving wheel 231 is fixed on the transmission shaft 22. The transmission belt 233 connects the driving wheel 231 and the driven wheel 232. The diameter of the driving wheel 231 is smaller than that of the driven wheel 232. Thus, the rotational speed of the driven wheel 232 is lower than that of the driving wheel 231, achieving speed reduction. In addition to the belt reduction mechanism shown in the figure, in other examples, the reduction unit 23 can also select a planetary gear reduction mechanism, etc.

[0124] In some examples, as shown in Figure 1, the conversion unit 24 includes a second nut 241 and a second lead screw 242. The second lead screw 242 is fixed on the tie rod 3. The second nut 241 sleevs the second lead screw 242, and the second nut 241 is arranged on the driven wheel 232 (or it can be understood that the second nut 241 and the driven wheel 232 are the same component). Then, during the rotation of the driven wheel 232 (the second nut 241), it can drive the linear motion of the second lead screw 242. Further, the second lead screw 242 drives the linear motion of the tie rod 3. In addition to the lead screw - nut mechanism shown in the figure, in other examples, the conversion unit 24 can also select a rack - and - pinion mechanism.

[0125] Both ends of the transverse tie rod 3 are respectively connected to the left rear wheel 6 and the right rear wheel 7 through a left connecting assembly 4 and a right connecting assembly 5. The left connecting assembly 4 includes a left steering tie rod 41 and a left steering knuckle arm 42, and the right connecting assembly 5 includes a right steering tie rod 51 and a right steering knuckle arm 52. When the transverse tie rod 3 moves, the transverse tie rod 3 drives the left rear wheel 6 and the right rear wheel 7 to turn through the left connecting assembly 4 and the right connecting assembly 5 respectively.

[0126] Next, the control logic of the rear-wheel steering system will be described:

[0127] During normal steering driving, the vehicle control unit 100 receives the steering wheel angle signal from the steering wheel angle sensor 300, the vehicle speed signal from the vehicle speed sensor 400, the yaw rate signal from the yaw rate sensor 500, and the lateral acceleration signal from the lateral acceleration sensor 600, and outputs a rear-wheel angle signal to the rear-wheel steering ECU 700 after calculation.

[0128] The rear-wheel steering ECU 700 controls the actuation of the rear-wheel steering motor 21 according to the rear-wheel angle signal and the position of the transverse tie rod 3 detected by the stroke sensor 25. The rotation of the rear-wheel steering motor 21 is converted into a linear motion of the transverse tie rod 3 through the reduction unit 23 and the conversion unit 24, and the transverse tie rod 3 drives the left rear wheel 6 and the right rear wheel 7 to turn.

[0129] When a failure occurs in the rear-wheel steering system, for example, the rear-wheel steering motor 21 rotates uncontrollably, which may cause uncontrollable movement of the rear wheels, seriously affecting driving safety. To avoid uncontrollable movement of the rear wheels, a mechanical self-locking device is used in the related art to lock the last angular position when a failure occurs to prevent uncontrollable movement of the rear wheels. However, if the last angular position where the failure occurs is not the centered position, there will always be a fixed angle of the rear wheels, significantly changing the steering characteristics of the vehicle, and the vehicle will still exhibit unexpected steering behavior and is prone to accidents.

[0130] In view of the above technical problems, the embodiment of the present disclosure provides a rear-wheel centering device 8, which can drive the transverse tie rod 3 to return to the center when the rear-wheel steering system cannot return to the normal position, enabling the vehicle to switch from four-wheel steering to front-wheel steering, improving the driving safety of the vehicle. Moreover, when the rear-wheel steering system is normal, the rear-wheel centering device 8 can reduce the driving force for returning the transverse tie rod 3 to the center to reduce the resistance encountered when the transverse tie rod 3 or the rear-wheel steering drive device 2 moves.

[0131] Next, an exemplary description of the rear-wheel centering device 8 provided by the embodiment of the present disclosure will be given:

[0132] As shown in Fig. 2 to Fig. 8, the rear wheel return device 8 includes a housing 81, a first sliding body 82, a second sliding body 83 and a driving component 84. The housing 81 is used to be fixed to the vehicle. The first sliding body 82 and the second sliding body 83 are located inside the housing 81 and are linked with the tie rod 3 of the rear wheel steering system. The driving component 84 has a first state and a second state, and the driving force of the driving component 84 in the first state is greater than the driving force in the second state. In the first state, the driving component 84 drives the first sliding body 82 or the second sliding body 83 to slide, and the first sliding body 82 or the second sliding body 83 drives the tie rod 3 to return.

[0133] The sliding body (first sliding body 82, second sliding body 83) is linked with the tie rod 3, which can also be understood as the sliding body being in transmission connection with the tie rod 3. The sliding body is linked with the tie rod 3, which means that the position of the sliding body is related to the position of the tie rod 3, and the position change of the tie rod 3 will cause the position change of the sliding body, and similarly, the position change of the sliding body will also cause the position change of the tie rod 3. Therefore, by controlling the driving component 84 to apply a sufficiently large driving force to the sliding body, the sliding body can be used as an active component to drive the tie rod 3 to return to the normal position.

[0134] In addition, during normal rear wheel steering of the vehicle, the sliding body moves with the tie rod 3, which will generate a certain resistance to the tie rod 3 or the rear wheel steering drive device 2. For example, if the driving force applied by the driving component 84 to the sliding body to return the tie rod 3 to the center always exists, the rear wheel steering drive device 2 always needs to overcome this driving force during the process of driving the tie rod 3 to move.

[0135] The technical solution provided by the embodiment of the present disclosure sets the driving component 84 to have a first state and a second state with different driving forces, so that when the rear wheel return device 8 is needed to drive the tie rod 3 to return, the driving component 84 can be switched to the first state with a larger driving force. As a result, the driving component 84 outputs sufficient driving force to drive the first sliding body 82 or the second sliding body 83 to slide, and the first sliding body 82 or the second sliding body 83 acts as an active component to drive the tie rod 3 to return.

[0136] When the rear wheel return device 8 is not needed to drive the tie rod 3 to return, since the sliding body provides resistance, the driving component 84 can be switched to the second state with a smaller driving force, thereby reducing the resistance of the tie rod 3 or the rear wheel steering drive device 2 and reducing the energy consumption of the rear wheel steering drive device 2. That is, in the second state, the first sliding body 82 or the second sliding body 83 slides under the drive of the rear wheel steering drive device 2 or the tie rod 3 of the rear wheel steering system.

[0137] The embodiment of the present disclosure does not limit the linkage mode between the sliding body and the tie rod 3. An exemplary description is given below:

[0138] In some examples, as shown in the middle parts of FIGS. 3, 5 or 8, when the first sliding body 82 and the second sliding body 83 are respectively located at the first position and the second position, the cross tie rod 3 is in the centered state. Therefore, the driving component 84 can drive the cross tie rod 3 to return to the centered state by applying a driving force towards the first position to the first sliding body 82 and a driving force towards the second position to the second sliding body 83, and can keep the cross tie rod 3 in the centered state.

[0139] In some examples, as shown in the upper parts of FIGS. 3, 5 or 8, when the first sliding body 82 is located at the first position and the second sliding body 83 is located between the first position and the second position, the cross tie rod 3 is in the first offset state. Moreover, the more the second sliding body 83 deviates from the second position (or is understood as being closer to the first position), the greater the offset stroke of the cross tie rod 3. That is to say, in the first offset state, the first sliding body 82 is stable at the first position, and the second sliding body 83 is linked with the cross tie rod 3. Therefore, if it is necessary to drive the cross tie rod 3 to return to the centered state when the cross tie rod 3 is in the first offset state, the driving component 84 is configured to drive the second sliding body 83 to slide towards the second position in the first state. At the same time, the driving component 84 can also be configured to keep the first sliding body 82 stable at the first position in the first state.

[0140] In some examples, as shown in the lower parts of FIGS. 3, 5 or 8, when the first sliding body 82 is located between the first position and the second position and the second sliding body 83 is located at the second position, the cross tie rod 3 is in the second offset state. Moreover, the more the first sliding body 82 deviates from the first position (or is understood as being closer to the second position), the greater the offset stroke of the cross tie rod 3. That is to say, in the second offset state, the second sliding body 83 is stable at the second position, and the first sliding body 82 is linked with the cross tie rod 3. Therefore, if it is necessary to drive the cross tie rod 3 to return to the centered state when the cross tie rod 3 is in the second offset state, the driving component 84 is configured to drive the first sliding body 82 to slide towards the first position in the first state. At the same time, the driving component 84 can also be configured to keep the second sliding body 83 stable at the first position in the first state.

[0141] Wherein, one of the above first offset state and second offset state is the left offset state, and the other is the right offset state.

[0142] In addition, according to the relevant description of the above steering system, it can be determined that the rear wheel steering motor 21 can drive the cross tie rod 3 to move. Correspondingly, when the rear wheel centering device 8 drives the cross tie rod 3 to return to the centered state, the cross tie rod 3 will also drive the rear wheel steering motor 21 to rotate. At this time, the rear wheel steering motor 21 provides resistance to the movement of the cross tie rod 3, and even in some cases, the cross tie rod 3 may not be able to return to the normal centered state due to the inability of the rear wheel steering motor 21 to rotate.

[0143] To prevent the rear-wheel steering motor 21 from affecting the return of the rear wheels by the rear-wheel return device 8 that drives the tie rod 3 to return, in some examples, as shown in FIGS. 2, 6, or 7, a clutch 223 can be provided on the transmission shaft 22 between the rear-wheel steering motor 21 and the reduction unit 23. In this way, before controlling the rear-wheel return device 8 to drive the tie rod 3 to return, first control the clutch 223 to disengage, disconnecting the mechanical connection between the tie rod 3 and the rear-wheel steering motor 21, so that the rear-wheel steering motor 21 does not hinder the return of the tie rod 3.

[0144] Exemplarily, as shown in FIG. 2, the transmission shaft 22 includes a first shaft section 221, a second shaft section 222, and a clutch 223. The first shaft section 221 and the second shaft section 222 are connected by the clutch 223. The second shaft section 222 is connected to the reduction unit 23, and the first shaft section 221 is connected to the rear-wheel steering motor 21. Since the clutch 223 needs to be in a closed (or engaged) state when the rear-wheel steering system is normal, a normally closed clutch can be selected for the clutch 223.

[0145] In addition, the driving component 84 provided in the embodiments of the present disclosure can have its state switched by the rear-wheel steering control unit 1, so the rear-wheel steering control unit 1 is electrically connected to the driving component 84. Moreover, the rear-wheel steering control unit 1 can also be electrically connected to the rear-wheel steering motor 21, the clutch 223, and the stroke sensor 25.

[0146] Among them, the rear-wheel steering control unit 1 can be the rear-wheel steering ECU 700, or the vehicle control unit 100, or both the vehicle control unit 100 and the rear-wheel steering ECU 700.

[0147] The embodiments of the present disclosure do not limit the position where the rear-wheel return device 8 is located. Below, an exemplary description is given:

[0148] (1) In some examples, as shown in FIGS. 2, 3, or 6 - 8, the rear-wheel return device 8 is provided on the tie rod 3, so that the rear-wheel return device 8 can directly drive the tie rod 3 to return.

[0149] Exemplarily, as shown in FIGS. 2, 3, or 6 - 8, the first sliding body 82 and the second sliding body 83 are sleeved around the tie rod 3. There are two first flanges 31 on the tie rod 3, and the first sliding body 82 and the second sliding body 83 are located between the two first flanges 31. As shown in FIGS. 3 and 8, when the first sliding body 82 and the second sliding body 83 are respectively located at the first position and the second position, the first sliding body 82 and the second sliding body 83 are respectively in contact with or abutted against the two first flanges 31.

[0150] The process of the rear-wheel steering drive device 2 driving the tie rod 3 is as described below:

[0151] As shown in the middle part of FIG. 3 (or FIG. 8), assuming that the transverse tie rod 3 is initially in the centered state, the first slider 82 and the second slider 83 are respectively in contact with the two first flanges 31.

[0152] When the transverse tie rod 3 needs to move to the first offset state, as shown from the middle part to the upper part of FIG. 3, the rear wheel steering drive device 2 drives the transverse tie rod 3 to offset. During the offset process of the transverse tie rod 3, the first flange 31 on the transverse tie rod 3 drives the second slider 83 to slide to the first position. At the same time, the first slider 82 remains at the first position.

[0153] When the transverse tie rod 3 needs to move to the second offset state, as shown from the middle part to the lower part of FIG. 3, the rear wheel steering drive device 2 drives the transverse tie rod 3 to offset. During the offset process of the transverse tie rod 3, the first flange 31 on the transverse tie rod 3 drives the first slider 83 to slide to the second position. At the same time, the second slider 83 remains at the second position.

[0154] It can be seen from the process of the rear wheel steering drive device 2 driving the transverse tie rod 3 that in the first offset state, the second slider 83 hinders the movement of the transverse tie rod 3, and in the second offset state, the first slider 82 hinders the movement of the transverse tie rod 3.

[0155] In order to reduce the resistance on the transverse tie rod 3, in some examples, the driving force output by the driving component 84 in the second state can be set to 0.

[0156] In other examples, in order to make the second slider 83 closely adhere to the corresponding first flange 31 during the process of switching from the first offset state to the centered state, and the first slider 82 closely adhere to the corresponding first flange 31 during the process of switching from the second offset state to the centered state, to avoid uncontrollable sliding of the first slider 82 and the second slider 83, the driving component 84 can also be set to apply a driving force towards the first position to the first slider 82 and a driving force towards the second position to the second slider 83 in the second state.

[0157] It should be noted that the purpose of the driving component 84 outputting a driving force in the second state is not to make the slider become an active component to drive the transverse tie rod 3 to move, but to prevent uncontrollable sliding of the first slider 82 and the second slider 83, so that the first slider 82 and the second slider 83 either stably stay at the corresponding first position or second position, or closely adhere to the first flange 31. Therefore, the driving force of the driving component 84 in the second state can be much smaller than that in the first state.

[0158] The process of the rear wheel centering device 8 driving the transverse tie rod 3 to center is described as follows:

[0159] As shown in the upper part of FIG. 3 (or FIG. 8), assuming that the tie rod 3 is in the first offset state and the rear wheel alignment device 8 is required to drive the tie rod 3 to return to the correct position. Then the driving member 84 switches to the first state. Under the driving force of the driving member 84, the second sliding body 83 slides towards the second position. The second sliding body 83 drives the tie rod 3 to return to the correct position through the first flange 31 until it changes to the state shown in the middle part of FIG. 3. At the same time, under the driving force of the driving member 84, the first sliding body 82 is stabilized at the first position.

[0160] As shown in the lower part of FIG. 3 (or FIG. 8), assuming that the tie rod 3 is in the second offset state and the rear wheel alignment device 8 is required to drive the tie rod 3 to return to the correct position. Then the driving member 84 switches to the first state. Under the driving force of the driving member 84, the first sliding body 82 slides towards the first position. The first sliding body 82 drives the tie rod 3 to return to the correct position through the first flange 31 until it changes to the state shown in the middle part of FIG. 3. At the same time, under the driving force of the driving member 84, the second sliding body 83 is stabilized at the second position.

[0161] (2) In some other examples, as shown in FIG. 4, the rear wheel alignment device 8 is provided on the transmission shaft 22 between the rear wheel steering motor 21 and the reduction unit 23. Then, since the rear wheel alignment device 8 is located at the input end of the reduction unit 23, the rear wheel alignment device 8 can drive the tie rod 3 to return to the correct position with a smaller driving force. Thus, the driving force required to be output by the rear wheel alignment device 8 in the first state is reduced, the energy consumption of the rear wheel alignment device 8 is reduced, the volume of the rear wheel alignment device 8 is reduced, and it is easier to arrange the rear wheel alignment device 8.

[0162] In some examples, as shown in FIG. 5, the rear wheel alignment device 8 includes a first lead screw 85 (or referred to as a first screw) and a first nut 86. The first lead screw 85 is fixed on the transmission shaft 22, and the first nut 86 is sleeved around the first lead screw 85. The first lead screw 85 and the first nut 86 form a lead screw-nut mechanism or a ball screw mechanism. The first nut 86 has two second flanges 861, and the first sliding body 82 and the second sliding body 83 are located between the two second flanges 861. When the first sliding body 82 and the second sliding body 83 are respectively located at the first position and the second position, the first sliding body 82 and the second sliding body 83 are respectively in contact with or abutted against the two second flanges 861.

[0163] Further, in some examples, as shown in FIG. 5, when the transmission shaft 22 includes a clutch 223, the first lead screw 85 is fixed on the second shaft section 222.

[0164] The process of the rear wheel steering drive device 2 driving the tie rod 3 is described as follows:

[0165] As shown in the middle part of FIG. 5, assuming that the transverse tie rod 3 is in the centered state initially, the first sliding body 82 and the second sliding body 83 are respectively in contact with the two second flanges 861.

[0166] When it is necessary to deflect the transverse tie rod 3 to the first deflection state, as shown from the middle part to the upper part of FIG. 5, the rear-wheel steering motor 21 drives the transmission shaft 22 to rotate. The transmission shaft 22 drives the first lead screw 85 to rotate, and the first lead screw 85 drives the first nut 86 to slide. During the sliding process of the first nut 86, the first nut 86 drives the second sliding body 83 to slide to the first position through the second flange 861, while the first sliding body 82 remains at the first position. At the same time, the transmission shaft 22 also drives the transverse tie rod 3 to deflect to the first deflection state through the reduction unit 23 and the conversion unit 24.

[0167] When it is necessary to deflect the transverse tie rod 3 to the second deflection state, as shown from the middle part to the lower part of FIG. 5, the rear-wheel steering motor 21 drives the transmission shaft 22 to rotate. The transmission shaft 22 drives the first lead screw 85 to rotate, and the first lead screw 85 drives the first nut 86 to slide. During the sliding process of the first nut 86, the first nut 86 drives the first sliding body 82 to slide to the second position through the second flange 861, while the second sliding body 83 remains at the second position. At the same time, the transmission shaft 22 also drives the transverse tie rod 3 to deflect to the second deflection state through the reduction unit 23 and the conversion unit 24.

[0168] It can be seen from the process of the rear-wheel steering drive device 2 driving the transverse tie rod 3 that in the first deflection state, the second sliding body 83 hinders the sliding of the first nut 86, and in the second deflection state, the first sliding body 82 hinders the sliding of the first nut 86.

[0169] In order to reduce the resistance received by the first nut 86, in some examples, the driving force output by the driving component 84 in the second state can be set to 0.

[0170] In other examples, in order to make the second sliding body 83 closely adhere to the corresponding second flange 861 during the process of switching from the first deflection state to the centered state, and the first sliding body 82 closely adheres to the corresponding second flange 861 during the process of switching from the second deflection state to the centered state, to avoid uncontrollable sliding of the first sliding body 82 and the second sliding body 83, the driving component 84 can also be set to apply a driving force towards the first position to the first sliding body 82 and a driving force towards the second position to the second sliding body 83 in the second state.

[0171] It should be noted that the purpose of the driving component 84 to output a driving force in the second state is not to make the sliding body an active component to drive the first nut 86 to slide, but to prevent the first sliding body 82 and the second sliding body 83 from sliding uncontrollably, so that the first sliding body 82 and the second sliding body 83 either stably stay at the corresponding first position or second position, or closely adhere to the second flange 861. Therefore, the driving force of the driving component 84 in the second state can be much smaller than that in the first state.

[0172] The process of the rear wheel alignment device 8 driving the tie rod 3 to return to the correct position is described as follows:

[0173] As shown in the upper part of FIG. 5, assume that the tie rod 3 is in the first offset state and the rear wheel alignment device 8 is required to drive the tie rod 3 to return to the correct position. Then the driving component 84 switches to the first state. Under the driving force of the driving component 84, the second sliding body 83 slides towards the second position, and at the same time drives the first nut 86 to slide towards the centered position through the second flange 861 until it changes to the state shown in the middle part of FIG. 5. During the sliding process of the first nut 86, the first nut 86 drives the first lead screw 85 to rotate, the first lead screw 85 drives the transmission shaft 22 to rotate, and the transmission shaft 22 drives the tie rod 3 to return to the correct position through the reduction unit 23 and the conversion unit 24.

[0174] As shown in the lower part of FIG. 5, assume that the tie rod 3 is in the second offset state and the rear wheel alignment device 8 is required to drive the tie rod 3 to return to the correct position. Then the driving component 84 switches to the first state. Under the driving force of the driving component 84, the first sliding body 82 slides towards the first position, and at the same time drives the first nut 86 to slide towards the centered position through the second flange 861 until it changes to the state shown in the middle part of FIG. 5. During the sliding process of the first nut 86, the first nut 86 drives the first lead screw 85 to rotate, the first lead screw 85 drives the transmission shaft 22 to rotate, and the transmission shaft 22 drives the tie rod 3 to return to the correct position through the reduction unit 23 and the conversion unit 24.

[0175] The embodiments of the present disclosure do not limit the implementation manner of the driving component 84, as long as the driving component 84 can achieve the first state and the second state with different driving forces. Hereinafter, the implementation manner of the driving component 84 will be exemplarily described:

[0176] (1) In some examples, as shown in FIGS. 2, 3, 5 or 6, the driving component 84 includes a first electromagnetic coil 841 and a second electromagnetic coil 842. The first electromagnetic coil 841 and the second electromagnetic coil 842 are fixed inside the housing 81, and the first sliding body 82 and the second sliding body 83 are located between the first electromagnetic coil 841 and the second electromagnetic coil 842.

[0177] In some examples, as shown in FIGS. 2, 3, 5 or 6, the first electromagnetic coil 841 and the second electromagnetic coil 842 are respectively located at both ends of the housing 81.

[0178] In some examples, as shown in FIGS. 2, 3, 5 or 6, when the first sliding body 82 is in the first position, the first electromagnetic coil 841 contacts the first sliding body 82, and when the second sliding body 83 is in the second position, the second electromagnetic coil 842 contacts the second sliding body 83.

[0179] The driving component 84 can achieve the first state and the second state with different driving forces by changing the magnitude of the current passed through, or by energizing and de-energizing.

[0180] In the first state, the first electromagnetic coil 841 and the second electromagnetic coil 842 are energized. Thus, the first electromagnetic coil 841 and the second electromagnetic coil 842 generate electromagnetic forces, and respectively attract the first sliding body 82 and the second sliding body 83 to slide to (or stay at) the first position and the second position.

[0181] In some examples, in the second state, the first electromagnetic coil 841 and the second electromagnetic coil 842 are also energized, but the current passed through the first electromagnetic coil 841 and the second electromagnetic coil 842 in the second state is less than that in the first state.

[0182] In this way, in the second state, the first electromagnetic coil 841 exerts a driving force towards the first position on the first sliding body 82, and the second electromagnetic coil 842 exerts a driving force towards the second position on the second sliding body 83, so as to ensure that the first sliding body 82 and the second sliding body 83 will not have uncontrollable sliding.

[0183] In other examples, in the second state, the first electromagnetic coil 841 and the second electromagnetic coil 842 are de-energized. In order to enable the driving component 84 to output a driving force in the second state even when the first electromagnetic coil 841 and the second electromagnetic coil 842 are de-energized, in some examples, as shown in FIGS. 3 and 5, the driving component 84 further includes an elastic member 846. Both ends of the elastic member 846 respectively abut against the first sliding body 82 and the second sliding body 83. Then, the elastic member 846 exerts a driving force towards the first position on the first sliding body 82 and a driving force towards the second position on the second sliding body 83. Among them, the elastic member 846 can be a spring, which can be called a return spring, and is used to drive the first sliding body 82 to slide to the first position and drive the second sliding body 83 to slide to the second position.

[0184] In this way, the first electromagnetic coil 841 and the second electromagnetic coil 842 do not need to be continuously energized, reducing energy consumption and increasing the service life of the driving component 84.

[0185] (2) In some examples, the driving component 84 can also be a pneumatic driving component, which communicates with the chamber 80 between the first sliding body 82 and the second sliding body 83, and can change the driving force on the first sliding body 82 and the second sliding body 83 by changing the air pressure in the chamber 80, thereby realizing the driving of different first states and second states.

[0186] In some examples, as shown in FIGS. 7 and 8, the driving component 84 includes a solenoid valve 843, and the solenoid valve 843 communicates with the high-pressure gas path 844, the low-pressure gas path 845 on the vehicle, and the chamber 80 between the first sliding body 82 and the second sliding body 83 respectively.

[0187] In the first state, the solenoid valve 843 connects the chamber 80 with the high-pressure gas path 844, then the high-pressure gas flows into the chamber 80 through the high-pressure gas path 844, and pushes the first sliding body 82 or the second sliding body 83 to slide to the first position and the second position respectively. During the sliding process, the first sliding body 82 or the second sliding body 83 drives the cross tie rod 3 to return to the neutral position.

[0188] In the second state, the solenoid valve 843 connects the chamber 80 with the low-pressure gas path 845. Then the high-pressure gas is discharged through the low-pressure gas path 845.

[0189] In some examples, after the chamber 80 communicates with the low-pressure gas path 845, the gas in the chamber 80 can still apply a driving force towards the first position to the first sliding body 82 and a driving force towards the second position to the second sliding body 83, thereby ensuring that the first sliding body 82 and the second sliding body 83 do not undergo uncontrollable sliding.

[0190] In other examples, if the gas in the chamber 80 is not sufficient to drive the first sliding body 82 and the second sliding body 83 not to undergo uncontrollable sliding after the chamber 80 communicates with the low-pressure gas path 845. Then the driving component 84 can include an elastic member 846, and both ends of the elastic member 846 abut against the first sliding body 82 and the second sliding body 83 respectively. In this way, the elastic member 846 can apply a driving force towards the first position to the first sliding body 82 and a driving force towards the second position to the second sliding body 83.

[0191] In some examples, when the solenoid valve 843 is not powered on, the chamber 80 communicates with the low-pressure gas path 845, and when the solenoid valve 843 is powered on, the chamber 80 communicates with the high-pressure gas path 844. In this way, the solenoid valve 843 can be not powered on most of the time, which is beneficial to reducing energy consumption.

[0192] The embodiments of the present disclosure do not limit the sources of the high-pressure gas path 844 and the low-pressure gas path 845 on the vehicle. In some examples, the high-pressure gas path 844 and the low-pressure gas path 845 can be a gas supply system separately arranged for the rear wheel return device 8.

[0193] In some other examples, the high-pressure air path 844 and the low-pressure air path 845 can also reuse the air path of the air supply system 9 of the air suspension on the vehicle, without the need to separately arrange a set of air supply systems.

[0194] Next, an exemplary description of the air supply system 9 of the air suspension will be given:

[0195] As shown in FIG. 9, the air supply system 9 includes a distribution valve 91, a high-pressure air path 844, a low-pressure air path 845, and an air supply system control unit 92. The high-pressure air path 844 has a high-pressure air tank 93. The low-pressure air path 845 is in communication with the atmosphere, and an air compressor 94 is provided on the low-pressure air path 845. The air supply system control unit 92 is electrically connected to the air compressor 94 and the distribution valve 91 respectively.

[0196] The distribution valve 91 connects the high-pressure air path 844, the low-pressure air path 845, and the four air springs. The distribution valve 91 is used to connect the high-pressure air path 844 or the low-pressure air path 845 to the four air springs. Moreover, when the air pressure in the high-pressure air tank 93 is relatively low, the air compressor 94 can be started and replenish the pressure of the high-pressure air tank 93 through the distribution valve 91, or directly supply air to the four air springs.

[0197] The solenoid valve 843 provided in the embodiment of the present disclosure can connect the high-pressure air path 844 and the low-pressure air path 845 of the air supply system 9 and communicate with the chamber 80 in the rear wheel alignment device 8. Among them, the solenoid valve 843 can be called a two-position three-way solenoid valve.

[0198] In some examples, as shown in FIG. 10, the solenoid valve 843 can also be integrated with the distribution valve 91.

[0199] In some examples, in order to ensure the sealing performance of the chamber 80, as shown in FIG. 8, sealing rings 88 can be provided between the first sliding body 82 and the housing 81, and between the second sliding body 83 and the housing 81. And sealing rings 88 can be provided between the first sliding body 82 and the cross tie rod 3, and between the second sliding body 83 and the cross tie rod 3.

[0200] In addition, for the case where the rear wheel alignment device 8 is provided on the transmission shaft 22 between the rear wheel steering motor 21 and the reduction unit 23, sealing rings 88 can be provided between the first sliding body 82 and the first nut 86, and between the second sliding body 83 and the first nut 86.

[0201] After the cross tie rod 3 is aligned by the rear wheel alignment device 8, it is also necessary to keep the cross tie rod 3 in the aligned state so that the vehicle can stably run in the form of front wheel steering.

[0202] The embodiments of the present disclosure do not limit the implementation manner of keeping the tie rod 3 in the straightening state. In some examples, the driving component 84 can be set to always remain in the first state. In this way, under the action of the driving force output by the driving component 84 in the first state, the tie rod 3 is restricted to the straightening state.

[0203] In other examples, as shown in FIG. 6, the rear wheel straightening device 8 further includes a brake 87, and the brake 87 is configured to lock the position of the tie rod 3 after the tie rod 3 is straightened. That is, the driving component 84 is used to drive the tie rod 3 to switch from the offset state to the straightening state, while the brake 87 is used to lock the position of the tie rod 3 so that the tie rod 3 remains in the straightening state. Among them, the brake 87 can be an electromagnetic multi-disc brake.

[0204] In this way, after the brake 87 locks the position of the tie rod 3, the driving component 84 can be switched to the second state, thereby reducing the energy consumption of the driving component 84. For example, when the driving component 84 includes a first electromagnetic coil 841 and a second electromagnetic coil 842, after the brake 87 locks the position of the tie rod 3, the first electromagnetic coil 841 and the second electromagnetic coil 842 can be switched from the energized state to the de-energized state.

[0205] The embodiments of the present disclosure do not limit the position where the brake 87 is provided. In some examples, as shown in FIG. 6, the brake 87 is provided on the transmission shaft 22 between the rear wheel steering motor 21 and the reduction unit 23 of the rear wheel steering system. Then, when the brake 87 brakes, the transmission shaft 22 is locked and cannot rotate. Correspondingly, both the reduction unit 23 and the conversion unit 24 cannot operate, and the position of the tie rod 3 is locked.

[0206] Further, as shown in FIG. 6, the brake 87 can be provided on the second shaft section 222, so that after the clutch 223 is disengaged, the brake 87 can still lock the position of the tie rod 3.

[0207] Of course, in other examples, the brake 87 can also be provided on the first shaft section 221. For this case, it is necessary to first control the clutch 223 to engage before the brake 87 can lock the position of the tie rod 3.

[0208] It should be noted that the brake 87 can also be considered to belong to the rear wheel steering drive device 2.

[0209] In addition to the above technical solution of setting the brake 87, in order to reduce the energy consumption of the driving component 84, in some other examples, the driving component 84 can also be set to have a third state, and the driving force of the driving component 84 in the third state is greater than the driving force in the second state and less than the driving force in the first state. The driving component 84 is configured to drive the first sliding body 82 to remain in the first position and drive the second sliding body 83 to remain in the second position in the third state.

[0210] For example, when the driving component 84 includes a first electromagnetic coil 841 and a second electromagnetic coil 842, the current passed through the first electromagnetic coil 841 and the second electromagnetic coil 842 in the first state is greater than the current passed through the first electromagnetic coil 841 and the second electromagnetic coil 842 in the third state. Thus, the energy consumption of the driving component 84 in the third state is lower than the energy consumption in the first state. Among them, the current passed through the first electromagnetic coil 841 and the second electromagnetic coil 842 in the third state is greater than the current passed through the first electromagnetic coil 841 and the second electromagnetic coil 842 in the second state.

[0211] Next, an exemplary description of the control logic for the return of the tie rod 3 is given:

[0212] When the rear-wheel steering system fails, in order to avoid unexpected deflection of the rear wheels, it is necessary to control the tie rod 3 to return to the original position, so that the vehicle changes from four-wheel steering to front-wheel steering.

[0213] The return of the tie rod 3 can be driven by the rear-wheel return device 8 or by the rear-wheel steering drive device 2. Therefore, when the rear-wheel steering system fails, it is necessary to first determine whether the tie rod 3 is driven to return by the rear-wheel return device 8 or by the rear-wheel steering drive device 2.

[0214] In some examples, the failure states of the rear-wheel steering system include a first failure state and a second failure state.

[0215] Among them, the first failure state refers to the state where the rear-wheel steering drive device 2 cannot drive the tie rod 3 to return. Then, when the rear-wheel steering system is in the first failure state, it is determined that the rear-wheel return device 8 needs to drive the tie rod 3 to return. The first failure state can include a first sub-state and a second sub-state. The first sub-state refers to the state where the rear-wheel steering drive device 2 loses power. For example, the power supply of the rear-wheel steering drive device 2 fails, or the rear-wheel steering motor 21 of the rear-wheel steering drive device 2 loses power (loses power). The second sub-state refers to the state where the power of the rear-wheel steering drive device 2 is normal, but the position of the tie rod 3 cannot be determined. For example, the sensor in the rear-wheel steering drive device 2 fails. This sensor is used to determine the position (or state) of the tie rod 3, and this sensor can be a stroke sensor 25.

[0216] The second failure state refers to the state where the rear-wheel steering system fails, but the tie rod 3 can still be returned to the neutral position. When the rear-wheel steering system is in the second failure state, the tie rod 3 can be returned to the neutral position by the rear-wheel steering drive device 2, without the need for the rear-wheel return device 8 to drive the tie rod 3 back to the neutral position. In some examples, the second failure state includes the state where the rear-wheel steering motor 21 of the rear-wheel steering drive device 2 is overheated or overloaded, but has not lost power. In other examples, the second failure state includes the state where the rear-wheel steering control unit 1 cannot receive the rear-wheel steering angle signal. For example, there is a communication failure between the rear-wheel steering ECU 700 and the vehicle control unit 100. In this state, the rear-wheel steering control unit 1 cannot determine the required offset of the tie rod 3, but the rear-wheel steering control unit 1 can control the tie rod 3 to return to the neutral position.

[0217] For the sake of convenience of description, driving the tie rod 3 to return to the neutral position by the rear-wheel return device 8 is called the fault handling mode 2, and driving the tie rod 3 to return to the neutral position by the rear-wheel steering drive device 2 is called the fault handling mode 1.

[0218] Next, the process of determining which fault handling mode to adopt will be described first with reference to FIG. 11:

[0219] In step 1101, the rear-wheel steering control unit 1 reads the fault information of the rear-wheel steering system and determines the fault handling mode to be adopted according to the read fault information.

[0220] In step 1102, it is determined whether the rear-wheel steering motor 21 is overloaded or overheated. If so, it is determined to adopt the fault handling mode 1.

[0221] In step 1103, it is determined whether the communication of the rear-wheel steering system is faulty (such as the rear-wheel steering control unit 1 cannot receive the rear-wheel steering angle signal). If so, it is determined to adopt the fault handling mode 1.

[0222] In step 1104, it is determined whether the power supply of the rear-wheel steering system is faulty. If so, it is determined to adopt the fault handling mode 2.

[0223] In step 1105, it is determined whether the travel sensor 25 is faulty. If so, it is determined to adopt the fault handling mode 2.

[0224] In step 1106, it is determined whether the rear-wheel steering motor 21 of the rear-wheel steering system has a power failure (such as losing power). If so, it is determined to adopt the fault handling mode 2.

[0225] If it is determined that the rear-wheel steering system has no faults, normal rear-wheel steering control is executed.

[0226] Next, the processing flows of the fault handling mode 1 and the fault handling mode 2 will be described in combination with the specific implementation manner of the rear-wheel return device 8:

[0227] Fault handling mode 1:

[0228] As shown in FIG. 12, for the implementation where the rear wheel alignment device 8 does not include the brake 87, the processing flow of fault handling mode 1 is as follows:

[0229] In step 1201, the rear wheel steering motor 21 actuates to return to the zero position. Since there is a possibility that the rear wheel steering system switches from the second fault state to the first fault state during the actuation of the rear wheel steering motor 21 to return to the zero position. Therefore, during the operation of the rear wheel steering motor 21, the processes of step 1202 and step 1203 are executed.

[0230] In step 1202, determine whether the travel sensor 25 is normal. If not, switch to fault handling mode 2.

[0231] In step 1203, determine whether the rear wheel steering motor 21 has a power failure (loses power). If so, switch to fault handling mode 2.

[0232] In step 1204, determine whether the tie rod 3 is centered. If not, continue to control the rear wheel steering motor 21 to actuate. If centered, end.

[0233] As shown in FIG. 13, for the implementation where the rear wheel alignment device 8 includes the brake 87, the processing flow of fault handling mode 1 is as follows:

[0234] The processing procedures of steps 1301 to 1303 are the same as those of steps 1201 to 1203, and will not be elaborated here.

[0235] In step 1304, determine whether the tie rod 3 is centered. If not, continue to control the rear wheel steering motor 21 to actuate. If centered, go to step 1305.

[0236] In step 1305, the brake 87 locks, and the brake 87 locks the tie rod 3 in the aligned state. After that, the rear wheel steering motor 21 can be powered off to reduce power consumption.

[0237] Fault handling mode 2:

[0238] As shown in FIG. 14, for the implementation where the drive component 84 includes the first electromagnetic coil 841 and the second electromagnetic coil 842, and the rear wheel alignment device 8 does not include the brake 87, the processing flow of fault handling mode 2 is as follows:

[0239] In step 1401, the clutch 223 disengages. In this way, the rear-wheel steering motor 21 is disconnected from the reduction unit 23, and the rear-wheel steering motor 21 does not affect the rear-wheel return device 8 to drive the tie rod 3 to move.

[0240] In step 1402, the rear-wheel steering motor 21 is powered off. In this way, the energy consumption is reduced, and the uncontrolled rotation of the rear-wheel steering motor 21 can be prevented.

[0241] In step 1403, the electromagnetic coil is energized. That is, the driving component 84 is switched to the first state, and the first electromagnetic coil 841 and the second electromagnetic coil 842 are energized. Under the magnetic attraction of the first electromagnetic coil 841 and the second electromagnetic coil 842, the tie rod 3 gradually returns to the correct position.

[0242] In step 1404, it is determined whether the tie rod 3 has returned to the correct position. It should be noted that to determine whether the tie rod 3 has returned to the correct position, it can be detected and determined by the travel sensor 25. For the case of a failure of the travel sensor 25, it can be determined that the tie rod 3 has returned to the correct position after the target energization duration of the first electromagnetic coil 841 and the second electromagnetic coil 842. Exemplarily, the target duration can be 3s - 10s. If it is determined that the tie rod 3 has not returned to the correct position, the electromagnetic coil is controlled to continue to be energized. If it is determined that the tie rod 3 has returned to the correct position, the process proceeds to step 1405 for processing.

[0243] In step 1405, the electromagnetic coil remains energized. In some examples, the current for the electromagnetic coil to remain energized in step 1405 is the same as the current for the electromagnetic coil to be energized in step 1403. That is, in step 1405, the driving component 84 still remains in the first state. In other examples, the current for the electromagnetic coil to remain energized in step 1405 is less than the current for the electromagnetic coil to be energized in step 1403. That is, in step 1405, the driving component 84 remains in the third state, and in step 1403, the driving component 84 remains in the first state.

[0244] As shown in FIG. 15, for the implementation manner in which the driving component 84 includes the first electromagnetic coil 841 and the second electromagnetic coil 842, and the rear-wheel return device 8 includes the brake 87, the processing flow of the fault handling mode 2 is as follows:

[0245] The processing procedures of steps 1501 to 1503 are the same as those of steps 1401 to 1403, and will not be described herein again.

[0246] In step 1504, it is determined whether the tie rod 3 is returned to the neutral position. It should be noted that to determine whether the tie rod 3 is returned to the neutral position, it can be detected and determined by the travel sensor 25. For the case of a failure of the travel sensor 25, it can be determined that the tie rod 3 is returned to the neutral position after the target energization duration of the first electromagnetic coil 841 and the second electromagnetic coil 842. Exemplarily, the target duration can be 3 s - 10 s. If it is determined that the tie rod 3 is not returned to the neutral position, the electromagnetic coil continues to be energized. If it is determined that the tie rod 3 is returned to the neutral position, the process proceeds to step 1505 for processing.

[0247] In step 1505, the brake 87 is locked, and the brake 87 locks the tie rod 3 in the returned-to-neutral position. Thereafter, the first electromagnetic coil 841 and the second electromagnetic coil 842 can be controlled to be de-energized, thereby reducing the power consumption of the drive component 84.

[0248] As shown in FIG. 16, for the implementation manner in which the drive component 84 includes the solenoid valve 843, the processing flow of the fault handling mode 2 is as follows:

[0249] In step 1601, the clutch 223 is disengaged. In this way, the rear-wheel steering motor 21 is disconnected from the reduction unit 23, and the rear-wheel steering motor 21 does not affect the movement of the tie rod 3 driven by the rear-wheel return device 8.

[0250] In step 1602, the rear-wheel steering motor 21 is de-energized. In this way, on the one hand, the energy consumption is reduced, and on the other hand, it is prevented that the rear-wheel steering motor 21 rotates uncontrollably.

[0251] In step 1603, the solenoid valve 843 is energized. The chamber 80 of the rear-wheel return device 8 is communicated with the high-pressure gas path 844, and under the action of the high-pressure gas, the first slider 82 or the second slider 83 drives the tie rod 3 to return to the neutral position.

[0252] In step 1604, pressure is maintained and locked. The chamber 80 of the rear-wheel return device 8 is kept in communication with the high-pressure gas path 844. Under the action of the high-pressure gas, the first slider 82 and the second slider 83 are respectively kept in the first position and the second position, and the tie rod 3 is kept in the returned-to-neutral position.

[0253] As shown in FIG. 17, for the implementation manner in which the solenoid valve 843 multiplexes the air supply system 9 of the air suspension, the processing flow of the fault handling mode 2 is as follows:

[0254] In step 1701, the clutch 223 is disengaged. In this way, the rear-wheel steering motor 21 is disconnected from the reduction unit 23, and the rear-wheel steering motor 21 does not affect the movement of the tie rod 3 driven by the rear-wheel return device 8.

[0255] In step 1702, the rear-wheel steering motor 21 is de-energized. In this way, on the one hand, the energy consumption is reduced, and on the other hand, it is prevented that the rear-wheel steering motor 21 rotates uncontrollably.

[0256] In step 1703, the solenoid valve 843 is energized.

[0257] In step 1704 , it is determined whether the pressure of the high-pressure gas tank 83 reaches a threshold value. If it reaches the threshold value, the process proceeds to step 1705 . If it does not reach the threshold value, the process proceeds to step 1707 .

[0258] In step 1705, the solenoid valve 843 is controlled to connect to the high-pressure gas tank 93, and the high-pressure gas flows into the chamber 80 of the rear wheel return device 8 through the solenoid valve 843. Under the action of the high-pressure gas, the first sliding body 82 or the second sliding body 83 drives the transverse tie rod 3 to return.

[0259] In step 1706, the pressure is maintained and locked, so that the chamber 80 of the rear wheel return device 8 is connected to the high-pressure gas tank 93 or the working air compressor 94, and under the action of the high-pressure gas, the first sliding body 82 and the second sliding body 83 are respectively maintained at the first position and the second position, and the tie rod 3 is maintained in the return state.

[0260] In step 1707 , the solenoid valve 843 turns on the air compressor 94 .

[0261] In step 1708, the air compressor 94 is started, and the high-pressure gas in the air compressor 94 flows into the chamber 80 of the rear wheel return device 8 through the solenoid valve 843. Under the action of the high-pressure gas, the first sliding body 82 or the second sliding body 83 drives the transverse tie rod 3 to return.

[0262] It should be noted that when the tie rod 3 is in the return state, the rear wheel is also returned to the center. The return state can also be called the centering state.

[0263] The embodiment of the present disclosure also provides a rear wheel steering system, as shown in Figures 2, 4, 6 and 7, the rear wheel steering system includes a rear wheel steering control unit 1, a rear wheel steering drive device 2, a tie rod 3 and a rear wheel return device 8. The rear wheel steering drive device 2 is connected to the tie rod 3 in a transmission manner.

[0264] The rear-wheel steering control unit 1 may include at least one of a vehicle control unit 100 and a rear-wheel steering ECU 700 .

[0265] The rear-wheel steering drive device 2 includes a rear-wheel steering motor 21, a transmission shaft 22, a reduction unit 23, a conversion unit 24, and a stroke sensor 25. The rear-wheel steering motor 21 can be a brushless motor. The rear-wheel steering motor 21 is connected to the reduction unit 23 through the transmission shaft 22. The reduction unit 23 is connected to the conversion unit 24. The conversion unit 24 is connected to the tie rod 3. The conversion unit 24 is configured to convert rotation into linear motion of the tie rod 3. Thus, the rear-wheel steering motor 21 drives the tie rod 3 to move. The stroke sensor 25 is disposed on the tie rod 3, and the stroke sensor 25 is configured to detect the position of the tie rod 3.

[0266] In some examples, the rear-wheel steering system further includes a left connection assembly 4 and a right connection assembly 5. Two ends of the tie rod 3 are respectively connected to the left connection assembly 4 and the right connection assembly 5.

[0267] Wherein, the left connection assembly 4 and the right connection assembly 5 are respectively configured to be connected to a left rear wheel 6 and a right rear wheel 7. The left connection assembly 4 includes a left steering tie rod 41 and a left steering knuckle arm 42. The right connection assembly 5 includes a right steering tie rod 51 and a right steering knuckle arm 52. When the tie rod 3 moves, the tie rod 3 drives the left rear wheel 6 and the right rear wheel 7 to steer through the left connection assembly 4 and the right connection assembly 5 respectively.

[0268] In some examples, the rear-wheel steering system further includes a left rear wheel 6 and a right rear wheel 7.

[0269] For the specific implementation manners of the rear-wheel steering drive device 2, the tie rod 3, the left connection assembly 4, the right connection assembly 5, the left rear wheel 6, the right rear wheel 7, and the rear-wheel centering device 8, reference may be made to the foregoing content, which will not be elaborated herein.

[0270] In some examples, the rear-wheel steering control unit 1 is configured to: determine that it is necessary for the rear-wheel centering device 8 to drive the tie rod 3 to return to the original position, and control the drive component 84 to switch to the first state. In the first state, the drive component 84 drives the first slider 82 or the second slider 83 to slide, and the first slider 82 or the second slider 83 drives the tie rod 3 to return to the original position.

[0271] The embodiments of the present disclosure do not limit in which state the rear-wheel steering system is when it is determined that it is necessary for the rear-wheel centering device 8 to drive the tie rod 3 to return to the original position. In some examples, the rear-wheel steering control unit 1 is configured to: when it is determined that the rear-wheel steering system fails, determine that it is necessary for the rear-wheel centering device 8 to drive the tie rod 3 to return to the original position. That is, as long as the rear-wheel steering system fails, it is determined that it is necessary for the rear-wheel centering device 8 to drive the tie rod 3 to return to the original position.

[0272] In other examples, it may also be that only when it is determined that the rear-wheel steering system is in certain failure states, it is determined that it is necessary for the rear-wheel centering device 8 to drive the tie rod 3 to return to the original position. Hereinafter, an exemplary description will be given:

[0273] In some examples, the fault states of the rear-wheel steering system include a first fault state and a second fault state.

[0274] Among them, the first fault state refers to the state where the rear-wheel steering drive device 2 cannot drive the tie rod 3 to return to the straight position. Then, when the rear-wheel steering system is in the first fault state, the rear-wheel steering control unit 1 can determine that the rear-wheel return device 8 is required to drive the tie rod 3 to return to the straight position. The first fault state may include a first sub-state and a second sub-state. The first sub-state refers to the state where the power of the rear-wheel steering drive device 2 fails (loses power). For example, the power supply of the rear-wheel steering drive device 2 fails, or the power of the rear-wheel steering motor 21 fails (loses power). The second sub-state refers to the state where the power of the rear-wheel steering drive device 2 is normal, but the position of the tie rod 3 cannot be determined. For example, the sensor of the rear-wheel steering drive device 2 fails. The sensor is used to determine the position of the tie rod 3, and the sensor can be a stroke sensor 25.

[0275] The second fault state refers to the state where the rear-wheel steering system fails, but it can still drive the tie rod 3 to return to the straight position. Then, when the rear-wheel steering system is in the second fault state, the rear-wheel steering control unit 1 can be configured to control the rear-wheel steering drive device 2 to drive the tie rod 3 to return to the straight position. In some examples, the second fault state includes the state where the rear-wheel steering motor 21 of the rear-wheel steering drive device 2 is overheated or overloaded, but does not lose power. In other examples, the second fault state includes that the rear-wheel steering control unit 1 cannot receive the rear-wheel steering angle signal.

[0276] After the rear-wheel return device 8 or the rear-wheel steering drive device 2 drives the tie rod 3 to return to the straight position, it is also necessary to keep the tie rod 3 in the straight position. Next, an exemplary description of the implementation method for keeping the tie rod 3 in the straight position is given:

[0277] In some examples, when the rear-wheel return device 8 includes a brake 87, after the rear-wheel steering control unit 1 determines that the tie rod 3 is in the straight position, it controls the brake 87 to lock the position of the tie rod 3. Thus, under the action of the brake 87, the tie rod 3 is kept in the straight position.

[0278] For the case where the tie rod 3 is driven to return to the straight position by the rear-wheel return device 8, after the brake 87 locks the position of the tie rod 3, the rear-wheel steering control unit 1 can control the drive component 84 in the rear-wheel return device 8 to switch to the second state. For example, it controls the first electromagnetic coil 841 and the second electromagnetic coil 842 to be powered off. Thus, the energy consumption of the drive component 84 is reduced.

[0279] For the case where the tie rod 3 is driven to return to the neutral position by the rear wheel steering drive device 2, after the brake 87 locks the position of the tie rod 3, the rear wheel steering control unit 1 can control the rear wheel steering motor 21 to shut down to reduce the energy consumption of the rear wheel steering motor 21.

[0280] In some examples, when the drive component 84 is in the third state, after the rear wheel steering control unit 1 determines that the tie rod 3 is in the return-to-neutral state, it controls the drive component 84 to switch to the third state so that the tie rod 3 remains in the return-to-neutral state and reduces the power consumption of the drive component 84. For example, reducing the current in the first electromagnetic coil 841 and the second electromagnetic coil 842.

[0281] In some examples, after the rear wheel steering control unit 1 determines that the tie rod 3 is in the return-to-neutral state, it can also control the drive component 84 to remain in the first state so that the tie rod 3 remains in the return-to-neutral state. For example, keeping the current in the first electromagnetic coil 841 and the second electromagnetic coil 842 unchanged. For another example, keeping the chamber 80 between the first slider 82 and the second slider 83 always filled with high-pressure gas.

[0282] In addition, as shown in FIG. 6, for the case where the transmission shaft 22 has a clutch 223, in order to prevent the rear wheel steering motor 21 from hindering the rear wheel return device 8 from driving the tie rod 3 to return to the neutral position, before controlling the drive component 84 to switch to the first state, the rear wheel steering control unit 1 is further configured to control the clutch 223 to disengage.

[0283] The embodiment of the present disclosure also provides a control method for rear wheel return. The control method is applied to the rear wheel steering control unit 1 of the rear wheel steering system. As shown in FIG. 18, the control method includes:

[0284] In step 1801, it is determined that the rear wheel return device 8 is required to drive the tie rod 3 to return to the neutral position.

[0285] The embodiment of the present disclosure does not limit in what state the rear wheel steering system is when it is determined that the rear wheel return device 8 is required to drive the tie rod 3 to return to the neutral position. In some examples, when it is determined that the rear wheel steering system fails, it is determined that the rear wheel return device 8 is required to return the tie rod 3 to the neutral position. That is, as long as the rear wheel steering system fails, it is determined that the rear wheel return device 8 is required to drive the tie rod 3 to return to the neutral position.

[0286] In other examples, it may also be that only when the rear wheel steering system is in certain failure states, it is determined that the rear wheel return device 8 is required to drive the tie rod 3 to return to the neutral position. Hereinafter, an exemplary description will be given:

[0287] In some examples, the failure states of the rear wheel steering system include a first failure state and a second failure state.

[0288] Among them, the first failure state refers to the state where the rear-wheel steering drive device 2 cannot drive the tie rod 3 to return to the straight position. When the rear-wheel steering system is in the first failure state, it is determined that the rear-wheel return device 8 is required to drive the tie rod 3 to return to the straight position. The first failure state may include a first sub-state and a second sub-state. The first sub-state refers to the state where the rear-wheel steering drive device 2 loses power (or is powered off), for example, a power supply failure of the rear-wheel steering drive device 2, or a power failure (loss of power) of the rear-wheel steering motor 21 of the rear-wheel steering drive device 2. The second sub-state refers to the state where the rear-wheel steering drive device 2 has normal power, but the position of the tie rod 3 cannot be determined, for example, a sensor failure of the rear-wheel steering drive device 2, and this sensor is used to determine the position of the tie rod 3, and this sensor can be a stroke sensor 25.

[0289] The second failure state refers to the state where the rear-wheel steering system fails, but can still drive the tie rod 3 to return to the straight position. When the rear-wheel steering system is in the second failure state, the rear-wheel steering drive device 2 can be controlled to drive the tie rod 3 to return to the straight position, without the need for the rear-wheel return device 8 to drive the tie rod 3 to return to the straight position. In some examples, the second failure state includes the state where the rear-wheel steering motor 21 of the rear-wheel steering drive device 2 is overheated or overloaded, but has not lost power. In other examples, the second failure state includes the state where the rear-wheel steering control unit 1 cannot receive the rear-wheel steering angle signal.

[0290] In step 1802, the control drive component 84 is switched to the first state.

[0291] After the drive component 84 is switched to the first state, the drive component 84 drives the first slider 82 or the second slider 83 to slide, and the second slider 83 or the second slider 83 drives the tie rod 3 to return to the straight position.

[0292] Of course, if it is previously determined that the rear-wheel steering drive device 2 is required to drive the tie rod 3 to return to the straight position, then the rear-wheel steering drive device 2 drives the tie rod 3 to return to the straight position.

[0293] After the rear-wheel return device 8 or the rear-wheel steering drive device 2 drives the tie rod 3 to return to the straight position, it is also necessary to keep the tie rod 3 in the straight position. Next, an exemplary description of the implementation manner of keeping the tie rod 3 in the straight position is given:

[0294] In some examples, when the rear-wheel return device 8 further includes a brake 87, after it is determined that the tie rod 3 is in the straight position, the brake 87 is controlled to lock the position of the tie rod 3. Thus, under the action of the brake 87, the tie rod 3 is kept in the straight position.

[0295] For the case where the tie rod 3 is returned to the straight position by the rear wheel return device 8, after the brake 87 locks the position of the tie rod 3, the drive component 84 can be controlled to switch to the second state. For example, the first electromagnetic coil 841 and the second electromagnetic coil 842 are controlled to be de-energized to reduce the energy consumption of the drive component 84.

[0296] For the case where the tie rod 3 is returned to the straight position by the rear wheel steering drive device 2, after the brake 87 locks the position of the tie rod 3, the rear wheel steering motor 21 can be controlled to shut down to reduce the energy consumption of the rear wheel steering motor 21.

[0297] In some examples, when the drive component 84 has a third state, after determining that the tie rod 3 is in the straightening state, the drive component 84 is controlled to switch to the third state so that the tie rod 3 remains in the straightening state and the power consumption of the drive component 84 is reduced. For example, the current in the first electromagnetic coil 841 and the second electromagnetic coil 842 is reduced.

[0298] In some examples, after determining that the tie rod 3 is in the straightening state, the drive component 84 can also be controlled to remain in the first state so that the tie rod 3 remains in the straightening state. For example, the current in the first electromagnetic coil 841 and the second electromagnetic coil 842 is kept unchanged. For another example, the chamber 80 between the first slider 82 and the second slider 83 is always filled with high-pressure gas.

[0299] In addition, as shown in FIG. 6, for the case where the transmission shaft 22 has a clutch 223, in order to prevent the rear wheel steering motor 21 from affecting the return of the tie rod 3 by the rear wheel return device 8, the clutch 223 is controlled to disengage before the drive component 84 is controlled to switch to the first state.

[0300] It should be noted that for the detailed content of the control method for rear wheel return, reference can be made to the relevant content of the aforementioned rear wheel return device 8 and the rear wheel steering system.

[0301] The embodiment of the present disclosure also provides a control device for rear wheel return. The control device is located in the rear wheel steering control unit 1 of the rear wheel steering system. As shown in FIG. 19, the control device includes:

[0302] A determination module 1901, configured to determine that the tie rod 3 needs to be returned to the straight position by the rear wheel return device 8.

[0303] A control module 1902, configured to control the drive component 84 to switch to the first state.

[0304] In some examples, the determination module 1901 is configured to: when it is determined that the rear wheel steering system is in the first fault state, determine that the tie rod 3 needs to be returned to the straight position by the rear wheel return device 8.

[0305] Among them, the first fault state includes one or more of the following states: power failure of the rear-wheel steering drive device 2, power failure of the rear-wheel steering motor 21 of the rear-wheel steering drive device 2, and sensor failure of the rear-wheel steering drive device 2, where the sensor is used to determine the position of the tie rod 3.

[0306] In some examples, when the rear-wheel alignment device 8 further includes a brake 87, after the control drive component 84 is switched to the first state, the determination module 1901 is further configured to determine that the tie rod 3 is in the aligned state. The control module 1902 is further configured to control the brake 87 to lock the position of the tie rod 3 and control the drive component 84 to switch to the second state.

[0307] In some examples, when the drive component 84 has a third state, after the control drive component 84 is switched to the first state, the determination module 1901 is further configured to determine that the tie rod 3 is in the aligned state. The control module 1902 is further configured to control the drive component 84 to switch to the third state.

[0308] In some examples, when the rear-wheel steering drive device 2 includes a clutch 223, before the control drive component 84 is switched to the first state, the control module 1902 is further configured to control the clutch 223 to disengage.

[0309] In some examples, the determination module 1901 is further configured to determine that the rear-wheel steering system is in a second fault state.

[0310] The control module 1902 is further configured to control the rear-wheel steering drive device 2 to drive the tie rod 3 to return to the aligned position.

[0311] Among them, the second fault state includes one or more of the following states: over-temperature or over-load of the rear-wheel steering motor 21 of the rear-wheel steering drive device 2, and the rear-wheel steering control unit 1 fails to receive the rear-wheel rotation angle signal.

[0312] The embodiments of the present disclosure further provide an electronic control unit, which includes a controller. The controller is coupled to a memory, and at least one instruction is stored in the memory. The at least one instruction is loaded and executed by the controller to implement the above-described control method for rear-wheel alignment.

[0313] Among them, the electronic control unit may be the above-described rear-wheel steering control unit 1.

[0314] Referring to FIG. 20, FIG. 20 shows a schematic structural diagram of an electronic control unit 2000 provided by the embodiments of the present disclosure. The electronic control unit 2000 shown in FIG. 20 may be the above-described rear-wheel steering control unit 1.

[0315] As shown in FIG. 20, the electronic control unit 2000 includes at least one processor 2001 (or referred to as a controller), a memory 2002, and at least one communication interface 2003.

[0316] The processor 2001 is, for example, a general-purpose central controller (central processing unit, CPU), a digital signal controller (digital signal processor, DSP), a network processor (network processer, NP), a graphics controller (graphics processing unit, GPU), a neural network controller (neural-network processing units, NPU), a data processing unit (data processing unit, DPU), a microcontroller, or one or more integrated circuits for implementing the solutions of the embodiments of the present disclosure. For example, the processor 2001 includes an application-specific integrated circuit (application-specific integrated circuit, ASIC), a programmable logic device (programmable logic device, PLD), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The PLD is, for example, a complex programmable logic device (complex programmable logic device, CPLD), a field-programmable gate array (field-programmable gate array, FPGA), a generic array logic (generic array logic, GAL), or any combination thereof. It can implement or execute various logic blocks, modules, and circuits described in connection with the disclosure of the embodiments of the present disclosure. The processor 2001 can also be a combination for implementing computing functions, such as including a combination of one or more microcontrollers, a combination of a DSP and a microcontroller, and so on.

[0317] In some examples, the electronic control unit 2000 further includes a bus. The bus is used to transfer information between the components of the electronic control unit 2000. The bus can be a peripheral component interconnect standard (peripheral component interconnect, abbreviated as PCI) bus, a PCIe, or an extended industry standard architecture (extended industry standard architecture, abbreviated as EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of simplicity, only a thick line is shown in FIG. 20, but it does not mean that there is only one bus or one type of bus.

[0318] The memory 2002 is, for example, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, such as a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, such as 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 compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, 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. The memory 2002 exists independently, for example, and is connected to the processor 2001 via a bus. The memory 2002 can also be integrated with the processor 2001.

[0319] The communication interface 2003 uses any device such as a transceiver for communicating with other devices or communication networks, and the communication network can be an Ethernet, a radio access network (RAN) or a wireless local area network (WLAN), etc. The communication interface 2003 can include a wired communication interface and can also include a wireless communication interface. Specifically, the communication interface 2003 can be an Ethernet interface, a fast ethernet (FE) interface, a gigabit ethernet (GE) interface, an asynchronous transfer mode (ATM) interface, a WLAN interface, a cellular network communication interface or a combination thereof. The Ethernet interface can be an optical interface, an electrical interface or a combination thereof. In the embodiments of the present disclosure, the communication interface 2003 can be used for the electronic control unit 2000 to communicate with other devices.

[0320] In some examples, the processor 2001 can include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 20. Each of these processors can be a single-CPU processor or a multi-CPU processor. The processor here can refer to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0321] In some examples, the electronic control unit 2000 may include multiple processors, such as processors 2001 and 2004 shown in FIG. 20. Each of these processors may be a single-core controller or a multi-core controller. The processors herein may refer to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0322] In some examples, the electronic control unit 2000 may further include an output device and an input device. The output device communicates with the processor 2001 and can display information in various ways. For example, the output device may be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device communicates with the processor 2001 and can receive user input in various ways. For example, the input device may be a mouse, a keyboard, a touch screen device, or a sensing device, etc.

[0323] In some examples, the memory 2002 is used to store the program code 2010 for implementing the solutions of the embodiments of the present disclosure, and the processor 2001 can execute the program code 2010 stored in the memory 2002. The program code 2010 may include one or more software modules. Optionally, the processor 2001 itself may also store the program code or instructions for implementing the solutions of the embodiments of the present disclosure.

[0324] Among them, each step executed by the control method for the rear wheel alignment shown in FIG. 18 is completed through the integrated logic circuit of the processor 2001 or instructions in the form of software. The steps of the method disclosed in combination with the embodiments of the present disclosure can be directly embodied as being executed and completed by a hardware controller, or by a combination of hardware and software modules in the controller. The software modules may be located in mature storage media in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. This storage media is located in the memory, and the controller reads the information in the memory and combines its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0325] The embodiments of the present disclosure also provide another electronic control unit, which may be the above-mentioned rear-wheel steering control unit 1. The electronic control unit includes: a transceiver, a memory, and a controller. Among them, the transceiver, the memory, and the controller communicate with each other through an internal connection path. The memory is used to store instructions, and the controller is used to execute the instructions stored in the memory to control the transceiver to receive signals and control the transceiver to send signals. And when the controller executes the instructions stored in the memory, the controller executes the above-mentioned rear-wheel straightening control method.

[0326] It should be understood that the above-mentioned controller may be a central controller, or other general-purpose controllers, digital signal controllers, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose controller may be a microcontroller or any conventional controller, etc. It is worth noting that the controller may be a controller that supports the advanced RISC machines (ARM) architecture.

[0327] Further, in some examples, the above-mentioned memory may include a read-only memory and a random access memory, and provide instructions and data to the controller. The memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0328] The memory may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available. For example, static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0329] Embodiments of the present disclosure also provide a computer-readable storage medium, in which at least one instruction is stored, and the instruction is loaded and executed by a controller to enable the controller to implement the above-mentioned control method for rear wheel alignment.

[0330] Embodiments of the present disclosure also provide a computer program product. When the computer program product is executed by an electronic control unit (such as the rear wheel steering control unit 1), the electronic control unit can be enabled to execute the corresponding steps and / or processes in the above method embodiments.

[0331] Embodiments of the present disclosure also provide a chip, which includes a controller. The controller is used to call and run the instructions stored in the memory, so that the electronic control unit (such as the rear wheel steering control unit 1) equipped with the chip executes the above-mentioned control method for rear wheel alignment.

[0332] Another chip provided by an embodiment of the present disclosure includes: an input interface, an output interface, a controller, and a memory. The input interface, the output interface, the controller, and the memory are connected through an internal connection path. The controller is configured to execute the code in the memory. When the code is executed, the controller is configured to execute the above-mentioned control method for back swing correction.

[0333] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer (electronic control unit), the processes or functions described in the embodiments of the present disclosure are generated in whole or in part. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk).

[0334] To clearly illustrate the interchangeability of hardware and software, the steps and components of each embodiment have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those of ordinary skill in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present disclosure.

[0335] The computer program code for implementing the method of the embodiments of the present disclosure can be written in one or more programming languages. These computer program codes can be provided to a general-purpose computer, a special-purpose computer, or other programmable controllers, such that when the program codes are executed by the computer or other programmable controllers, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program codes can be executed entirely on the computer, partially on the computer, as an independent software package, partially on the computer and partially on a remote computer, or entirely on a remote computer or server.

[0336] In the context of the embodiments of the present disclosure, the computer program code or relevant data can be carried by any suitable carrier so that the device, apparatus or controller can execute the various processes and operations described above. Examples of carriers include signals, computer-readable media, and the like. Examples of signals can include electrical, optical, radio, acoustic or other forms of propagated signals, such as carrier waves, infrared signals, etc.

[0337] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, apparatuses and modules described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0338] In several embodiments provided by the present disclosure, it should be understood that the disclosed systems, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division, and there can be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed couplings or direct couplings or communication connections to each other can be indirect couplings or communication connections through some interfaces, devices or modules, and can also be electrical, mechanical or other forms of connections.

[0339] The modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they can be located in one place, or can be distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present disclosure.

[0340] In addition, the functional modules in the various embodiments of the present disclosure can be integrated into one processing module, or each module can exist physically alone, or two or more modules can be integrated into one module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0341] The terms "first", "second", etc. in the present disclosure are used to distinguish the same items or similar items with basically the same functions and effects. It should be understood that there is no logical or temporal dependency between "first", "second", "nth", and there is no limitation on the quantity and execution order. It should also be understood that although the following description uses the terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another.

[0342] It should also be understood that in various embodiments of the present disclosure, the magnitude of the serial numbers of the various processes does not imply the order of execution, and the order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present disclosure.

[0343] In the present disclosure, the meaning of the term "at least one" refers to one or more, and the meaning of the term "a plurality" refers to two or more.

[0344] It should be understood that the terms used in the description of the various examples herein are only for describing specific examples and are not intended to be limiting. As used in the description of the various examples and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0345] It should also be understood that when the term "comprises" (also referred to as "includes", "including", "comprises", and / or "comprising") is used in this specification, it specifies the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or their groups.

[0346] It should also be understood that, depending on the context, the phrase "if it is determined that..." or "if [the stated condition or event] is detected" can be interpreted to mean "when it is determined that..." or "in response to determining..." or "when [the stated condition or event] is detected" or "in response to detecting [the stated condition or event]".

[0347] It should be understood that determining B based on A does not mean determining B solely based on A, and B can also be determined based on A and / or other information.

[0348] It should also be understood that throughout the specification, the references to "one embodiment", "an embodiment", "some examples", "a possible implementation" mean that a particular feature, structure, or characteristic related to the embodiment or implementation is included in at least one embodiment of the present disclosure. Thus, the appearances of "in one embodiment" or "in an embodiment", "in some examples", "a possible implementation" throughout the specification do not necessarily refer to the same embodiment. In addition, these particular features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0349] The above are only optional embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

A rear wheel alignment device Characterized in that the rear wheel alignment device includes a housing (81), a first sliding body (82), a second sliding body (83) and a driving component (84); the housing (81) is used for being fixed to a vehicle; the first sliding body (82) and the second sliding body (83) are located inside the housing (81) and are linked with a tie rod (3) of a rear wheel steering system; the driving component (84) has a first state and a second state, and the driving force of the driving component (84) in the first state is greater than that in the second state; In the first state, the driving component (84) drives the first sliding body (82) or the second sliding body (83) to slide, and the first sliding body (82) or the second sliding body (83) drives the tie rod (3) to return to the correct position. The rear wheel alignment device according to claim 1 Characterized in that In the second state, the first sliding body (82) or the second sliding body (83) slides under the drive of a rear wheel steering drive device (2) or the tie rod (3) of the rear wheel steering system. The rear wheel alignment device according to claim 1 or 2 Characterized in that When the first sliding body (82) and the second sliding body (83) are respectively located at a first position and a second position, the tie rod (3) is in an aligned state; when the first sliding body (82) is located at the first position and the second sliding body (83) is located between the first position and the second position, the tie rod (3) is in a first offset state; when the first sliding body (82) is located between the first position and the second position and the second sliding body (83) is located at the second position, the tie rod (3) is in a second offset state; the driving component (84) is configured to apply a driving force towards the first position to the first sliding body (82) and a driving force towards the second position to the second sliding body (83), and the driving force of the driving component (84) in the first state is greater than that in the second state. The rear wheel alignment device according to claim 3 Characterized in that The first sliding body (82) and the second sliding body (83) surround the tie rod (3) and are located between two first flanges (31) of the tie rod (3); when the first sliding body (82) and the second sliding body (83) are respectively located at the first position and the second position, the first sliding body (82) and the second sliding body (83) are respectively in contact with the two first flanges (31). The rear wheel alignment device according to claim 3 Characterized in that The rear wheel realignment device further includes a first lead screw (85) and a first nut (86); the first lead screw (85) is fixed on a transmission shaft (22) between a rear wheel steering motor (21) and a reduction unit (23) of the rear wheel steering system, and the first nut (86) sleevingly surrounds the first lead screw (85); the first nut (86) has two second flanges (861), and the first sliding body (82) and the second sliding body (83) are located between the two second flanges (861); when the first sliding body (82) and the second sliding body (83) are respectively located at the first position and the second position, the first sliding body (82) and the second sliding body (83) are respectively in contact with the two second flanges (861). The rear wheel realignment device according to claim 5, wherein, the transmission shaft (22) includes a first shaft section (221), a second shaft section (222) and a clutch (223), and the first shaft section (221) and the second shaft section (222) are connected by the clutch (223); the second shaft section (222) is connected to the reduction unit (23), and the first lead screw (85) is fixed on the second shaft section (222). The rear wheel realignment device according to any one of claims 1-6, wherein, the driving component (84) includes a first electromagnetic coil (841) and a second electromagnetic coil (842); the first electromagnetic coil (841) and the second electromagnetic coil (842) are fixed inside the housing (81), and the first sliding body (82) and the second sliding body (83) are located between the first electromagnetic coil (841) and the second electromagnetic coil (842); in the first state, the first electromagnetic coil (841) and the second electromagnetic coil (842) are energized, and the first electromagnetic coil (841) and the second electromagnetic coil (842) respectively attract the first sliding body (82) and the second sliding body (83). The rear wheel realignment device according to claim 7, wherein, in the second state, the first electromagnetic coil (841) and the second electromagnetic coil (842) are de-energized. The rear wheel realignment device according to any one of claims 1-6, wherein, the driving component (84) includes a solenoid valve (843); the solenoid valve (843) is respectively communicated with a high-pressure air circuit (844), a low-pressure air circuit (845) on the vehicle and a chamber (80) between the first sliding body (82) and the second sliding body (83); in the first state, the solenoid valve (843) communicates the chamber (80) with the high-pressure air circuit (844), and in the second state, the solenoid valve (843) communicates the chamber (80) with the low-pressure air circuit (845). The rear wheel realignment device according to any one of claims 7-9, wherein, The driving component (84) further includes an elastic member (846), and two ends of the elastic member (846) are respectively abutted against the first sliding body (82) and the second sliding body (83). The rear wheel alignment device according to any one of claims 1-10, characterized in that, the rear wheel alignment device further includes a brake (87), and the brake (87) is configured to lock the position of the tie rod (3) after the tie rod (3) is aligned. The rear wheel alignment device according to claim 11, characterized in that, the brake (87) is arranged on a transmission shaft (22) between a rear wheel steering motor (21) and a reduction unit (23) of the rear wheel steering system. The rear wheel alignment device according to claim 12, characterized in that, the transmission shaft (22) includes a first shaft section (221), a second shaft section (222) and a clutch (223), and the first shaft section (221) and the second shaft section (222) are connected by the clutch (223); the second shaft section (222) is connected to the reduction unit (23), and the brake (87) is arranged on the second shaft section (222). The rear wheel alignment device according to any one of claims 1-10, characterized in that, the driving component (84) further has a third state, and the driving force of the driving component (84) in the third state is greater than the driving force in the second state and less than the driving force in the first state; in the third state, the driving component (84) drives the first sliding body (82) and the second sliding body (83) to be respectively held at a first position and a second position, wherein when the first sliding body (82) and the second sliding body (83) are respectively located at the first position and the second position, the tie rod (3) is in an aligned state. A rear wheel steering system, characterized in that, the rear wheel steering system includes a rear wheel steering control unit (1), a rear wheel steering drive device (2), a tie rod (3) and a rear wheel alignment device (8) according to any one of claims 1-14; the rear wheel steering drive device (2) is in transmission connection with the tie rod (3); the rear wheel steering control unit (1) is configured to: determine that it is necessary for the rear wheel alignment device (8) to drive the tie rod (3) to be aligned; control the driving component (84) to switch to the first state. The rear wheel steering system according to claim 15, characterized in that, the rear wheel steering control unit (1) is configured to: when it is determined that the rear wheel steering system is in a first fault state, determine that it is necessary for the rear wheel alignment device (8) to drive the tie rod (3) to be aligned; wherein, the first fault state includes one or more of the following states: a power supply fault of the rear wheel steering drive device (2); a power failure of the rear wheel steering motor (21) of the rear wheel steering drive device (2); a sensor fault of the rear wheel steering drive device (2), and the sensor is used to determine the position of the tie rod (3). The rear-wheel steering system according to claim 15 or 16, characterized in that, when the rear-wheel straightening device (8) includes a brake (87), after the control of the driving component (84) is switched to the first state, the rear-wheel steering control unit (1) is further configured to: determine that the tie rod (3) is in a straightened state; control the brake (87) to lock the position of the tie rod (3); control the driving component (84) to be switched to the second state. The rear-wheel steering system according to claim 15 or 16, characterized in that, when the driving component (84) has a third state, after the control of the driving component (84) is switched to the first state, the rear-wheel steering control unit (1) is further configured to: determine that the tie rod (3) is in a straightened state; control the driving component (84) to be switched to the third state. The rear-wheel steering system according to any one of claims 15-18, characterized in that, the rear-wheel steering control unit (1) is further configured to: determine that the rear-wheel steering system is in a second fault state; control the rear-wheel steering drive device (2) to drive the tie rod (3) to be straightened; wherein, the second fault state includes one or more of the following states: the rear-wheel steering motor (21) of the rear-wheel steering drive device (2) is overheated or overloaded; the rear-wheel steering control unit (1) cannot receive a rear-wheel rotation angle signal. The rear-wheel steering system according to any one of claims 15-19, characterized in that, the rear-wheel steering drive device (2) includes a rear-wheel steering motor (21), a transmission shaft (22) and a reduction unit (23) connected in sequence, the reduction unit (23) is in transmission connection with the tie rod (3); the transmission shaft (22) includes a first shaft section (221), a second shaft section (222) and a clutch (223), the first shaft section (221) and the second shaft section (222) are connected by the clutch (223); before the control of the driving component (84) is switched to the first state, the rear-wheel steering control unit (1) is further configured to: control the clutch (223) to disengage. A vehicle, characterized in that, the vehicle includes the rear-wheel straightening device (8) according to any one of claims 1-14 or the rear-wheel steering system according to any one of claims 15-20. A control method for rear-wheel straightening, characterized in that, the control method is applied to the rear-wheel steering control unit (1) of the rear-wheel steering system according to any one of claims 15-20, and the control method includes: determining that the rear-wheel straightening device (8) is required to drive the tie rod (3) to be straightened; controlling the driving component (84) to be switched to the first state. According to the control method of claim 22, characterized in that, Determining that the rear wheel alignment device (8) is required to drive the tie rod (3) to return to the correct position includes: when it is determined that the rear wheel steering system is in a first failure state, determining that the rear wheel alignment device (8) is required to drive the tie rod (3) to return to the correct position; wherein, the first failure state includes one or more of the following states: a power failure of the rear wheel steering drive device (2); a power failure of the rear wheel steering motor (21) of the rear wheel steering drive device (2); a sensor failure of the rear wheel steering drive device (2), and the sensor is used to determine the position of the tie rod (3). The control method according to claim 22 or 23, characterized in that, when the rear wheel alignment device (8) includes a brake (87), after the control of the driving component (84) is switched to the first state, the control method further includes: determining that the tie rod (3) is in the aligned state; controlling the brake (87) to lock the position of the tie rod (3); controlling the driving component (84) to be switched to the second state. The control method according to claim 22 or 23, characterized in that, when the driving component (84) has a third state, after the control of the driving component (84) is switched to the first state, the control method further includes: determining that the tie rod (3) is in the aligned state; controlling the driving component (84) to be switched to the third state. The control method according to any one of claims 22-25, characterized in that, when the rear wheel steering drive device (2) includes a clutch (223), before the control of the driving component (84) is switched to the first state, the control method further includes: controlling the clutch (223) to disengage. The control method according to any one of claims 22-26, characterized in that, the control method further includes: determining that the rear wheel steering system is in a second failure state; controlling the rear wheel steering drive device (2) to drive the tie rod (3) to return to the correct position; wherein, the second failure state includes one or more of the following states: the rear wheel steering motor (21) of the rear wheel steering drive device (2) is overheated or overloaded; the rear wheel steering control unit (1) cannot receive the rear wheel angle signal. A control device for rear wheel alignment, characterized in that, the control device is located in the rear wheel steering control unit (1) of the rear wheel steering system according to any one of claims 15-20, and the control device includes: a determination module for determining that the rear wheel alignment device (8) is required to drive the tie rod (3) to return to the correct position; a control module for controlling the driving component (84) to be switched to the first state. A computer-readable storage medium, characterized in that, at least one instruction is stored in the computer-readable storage medium, and the instruction is loaded and executed by a controller to implement the control method for rear wheel alignment according to any one of claims 22-27. A computer program product, characterized in that, The computer program product includes at least one instruction that is executed by a controller, so that the controller implements the control method for post-round steering as described in any one of claims 22-27.

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