Vehicle steering method and device and vehicle

Abstract

The invention provides a vehicle steering method and device and a vehicle. The method comprises the steps that a second set of tires are braked, so that the second set of tires are in a non-rotating state; driving a first group of tires, wherein the torque directions of driving forces corresponding to the tires in the first group of tires are the same; and under the condition that the driving force for driving the first group of tires is greater than the tire adhesive force of the first group of tires and the steering angle of the first group of tires is greater than a first steering angle, controlling the vehicle to steer based on the driving force and the steering angle of the first group of tires. The vehicle trafficability under the steering working condition is improved while the minimum turning radius of the vehicle is reduced.

Description

Technical Field

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

[0002] Generally speaking, when the steering wheel of a car is turned to the extreme position and the car is turning at a low and stable speed, the radius of the track circle that the center plane of the outer steering wheel rolls on the supporting plane is called the minimum turning radius of the car. The smaller the minimum turning radius of the car, the better the vehicle's passability in the turning condition.

[0003] In some vehicle steering methods, all four wheels of the vehicle are used as steering wheels, and the steering angle of the four wheels is controlled by the steering motor to the maximum angle, and the vehicle is driven by the wheel hub motor, so that the vehicle can be controlled to turn with a very small turning radius, and the vehicle can turn or turn around in place. However, this method requires that all four wheels can be steered and needs to be used together with the wheel hub motor, which is greatly limited in practical application.

[0004] Therefore, how to reduce the turning radius of a car when turning while improving the vehicle's passability in turning conditions has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] The present application provides a vehicle steering method, device and vehicle, which can reduce the turning radius of the vehicle when turning and improve the vehicle's passability in turning conditions.

[0006] In a first aspect, the present application provides a vehicle steering method, which is applied to a vehicle, wherein the vehicle includes a first group of tires and a second group of tires, wherein the first group of tires are front wheels and the second group of tires are rear wheels, or the first group of tires are rear wheels and the second group of tires are front wheels, and the method includes: braking the second group of tires so that the second group of tires are in a non-rotating state; driving the first group of tires, wherein the torque direction of the driving force corresponding to each tire in the first group of tires is the same; when the driving force driving the first group of tires is greater than the tire adhesion of the first group of tires and the steering angle of the first group of tires is greater than the first steering angle, controlling the steering of the vehicle based on the driving force and the steering angle of the first group of tires, the steering angle of the first group of tires being the angle between the first group of tires and the body of the vehicle.

[0007] In an embodiment of the present application, when the driving force of the first group of tires is greater than the tire adhesion of the first group of tires, the driving force of the first group of tires causes the first group of tires to slip, and the dynamic friction generated by the tire slippage provides longitudinal traction for the vehicle, so that the vehicle turns with a smaller turning radius based on the lateral traction provided by the first group of tires. That is, the vehicle steering method provided by the present application improves the vehicle's passability in turning conditions while reducing the turning radius of the vehicle when turning.

[0008] In some possible implementations, before driving the first set of tires, the method further includes: obtaining gear information of the vehicle, the gear information including forward gear and reverse gear; obtaining throttle depth information; driving the first set of tires includes: controlling the motor of the vehicle to output corresponding torque magnitude and torque direction based on the throttle depth information and the gear information to drive the first set of tires.

[0009] In some possible implementations, the method further includes: when the driving force output by the motor for driving the first group of tires is still less than or equal to the tire adhesion of the first group of tires after reaching the peak motor torque and the vehicle is stationary, outputting first indication information and controlling the vehicle to exit steering control, wherein the first indication information is used to indicate that the mass of the object carried by the vehicle exceeds the maximum load mass for achieving vehicle steering using the steering control method.

[0010] In some possible implementations, braking the second group of tires includes: using a braking force to brake the left rear wheel and the right rear wheel respectively, the braking force is greater than or equal to the tire adhesion corresponding to one of the tires in the second group of tires, and the second group of tires includes the left rear wheel and the right rear wheel.

[0011] In some possible implementations, when the driving force driving the first group of tires is greater than the tire adhesion of the first group of tires and the steering angle of the first group of tires is greater than the first steering angle, before controlling the steering of the vehicle based on the driving force and the steering angle of the first group of tires, the method also includes: determining the steering angle of the first group of tires based on the turning angle of the steering wheel acquired by an angle sensor in the steering mechanism.

[0012] In some possible implementations, the peak torque of the motor corresponding to the first group of tires is greater than a first value, and the first value is determined based on the tire adhesion of the first group of tires, the speed ratio of the vehicle reducer, and the tire radius of the first group of tires.

[0013] In some possible implementations, a first distance between the center of mass of the vehicle and the center of the first set of tires is greater than a second distance between the center of mass of the vehicle and the center of the second set of tires.

[0014] In some possible implementations, before the vehicle enters the steering control mode, the method further includes: obtaining a maximum mass that can be driven by the motor corresponding to the first group of tires, the maximum mass being related to the maximum driving force corresponding to the peak torque of the motor; obtaining a total mass of the vehicle, the total mass including the vehicle curb mass and the mass of objects actually carried by the vehicle; and controlling the vehicle to enter the steering control mode in response to operational information input by the user to instruct the vehicle to enter the steering control mode, including: when the maximum mass is greater than the total mass, the vehicle enters the steering control mode in response to operational information input by the user to instruct the vehicle to enter the steering control mode.

[0015] In some possible implementations, the method further includes: in a case where the maximum mass is less than the vehicle curb mass, in response to operation information input by the user for instructing the vehicle to enter a steering control mode, outputting second indication information, the second indication information being used to indicate that the performance of the vehicle does not support entering the steering control mode; in a case where the maximum mass is greater than the vehicle curb mass and less than the total mass, in response to operation information input by the user for instructing the vehicle to enter a steering control mode, outputting third indication information, the third indication information being used to indicate that the mass of the object carried by the vehicle exceeds the maximum mass of the vehicle to enter the steering control mode.

[0016] In some possible implementations, the method further includes: when the driving force of the first group of tires is less than or equal to the tire adhesion of the first group of tires, or the steering angle of the first group of tires is less than a first steering angle, the vehicle is stationary or the vehicle moves a small distance.

[0017] In a second aspect, the present application provides a vehicle steering device, comprising: a braking unit for braking a second group of tires so that the second group of tires is in a non-rotating state; a driving unit for driving the first group of tires; a control unit for controlling the steering of the vehicle based on the driving force and the steering angle of the first group of tires when the driving force of the driving unit to drive the first group of tires is greater than the tire adhesion of the first group of tires and the steering angle of the first group of tires is greater than the first steering angle, the steering angle of the first group of tires being the angle between the first group of tires and the body of the vehicle, the first group of tires being the front wheels and the second group of tires being the rear wheels, or the first group of tires being the rear wheels and the second group of tires being the front wheels.

[0018] In a third aspect, the present application provides a vehicle, comprising a controller, a motor controller, a brake controller, a first group of tires, and a second group of tires, wherein the first group of tires are front wheels and the second group of tires are rear wheels, or the first group of tires are rear wheels and the second group of tires are front wheels, and the controller is used to request the brake controller to brake the second group of tires, and to request the motor control unit to drive the first group of tires, so as to implement the above-mentioned vehicle steering method and realize vehicle steering.

[0019] In a fourth aspect, the present application provides a vehicle steering system, the system comprising a steering control unit, a first group of tires, a second group of tires, a braking force control unit, a motor controller, a motor, and a steering mechanism, wherein the first group of tires are front wheels and the second group of tires are rear wheels, or the first group of tires are rear wheels and the second group of tires are front wheels, the steering control unit is used to request the braking force control unit to brake the second group of tires so that the second group of tires is in a non-rotating state; the steering mechanism is used to change the steering angle of the first group of tires; the steering control unit is used to request the motor controller to control the motor output torque so that the motor drives the first group of tires; the steering control unit is also used to control the vehicle to steer when the steering angle of the first group of tires is greater than the first steering angle and the driving force output by the motor is greater than the tire adhesion of the first group of tires.

[0020] In some possible implementations, the system further includes a steering control mode request input device and an in-vehicle network, wherein the steering control mode request input device is used to receive operation information input by a user requesting to enter the steering control mode; the steering control unit is specifically used to determine to enter the steering control mode in response to the operation information input by the user requesting to enter the steering control mode, and brake the second group of tires through the braking force control unit based on the steering control mode, so that the second group of tires is in a non-rotating state; the steering control unit is also used to obtain the throttle depth and the gear state based on the in-vehicle network, and determine the motor torque magnitude of the motor output controlled by the motor controller based on the throttle depth, and determine the motor torque direction of the motor output controlled by the motor controller based on the gear state; the steering control unit is also used to request the motor controller to control the motor to output a torque corresponding to the motor torque magnitude and the motor torque direction; the steering mechanism is specifically used to determine the steering angle of the first group of tires based on the steering wheel rotation angle obtained by the angle sensor; the motor controller is specifically used to control the torque corresponding to the motor output according to the motor torque direction and the motor torque magnitude requested by the steering control unit to drive the first group of tires.

[0021] It can be understood that the vehicle steering system provided in the second aspect, the vehicle steering transposition provided in the third aspect, and the vehicle provided in the fourth aspect are all used to execute the vehicle steering method shown in the first aspect of the embodiment of the present application or any implementation of the first aspect. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments are briefly introduced below.

[0023] Figure 1 A schematic diagram of a process flow of a vehicle steering method provided in an embodiment of the present application;

[0024] Figure 2 A schematic flow chart of another vehicle steering method provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of a vehicle steering system provided in an embodiment of the present application;

[0026] Figure 4 A schematic structural diagram of a vehicle steering device provided in an embodiment of the present application;

[0027] Figure 5 A schematic structural diagram of another vehicle steering device provided in an embodiment of the present application;

[0028] Figure 6 A schematic diagram of the structure of an electronic hydraulic brake system provided in an embodiment of the present application;

[0029] Figure 7 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The present application is described in further detail below in conjunction with the accompanying drawings.

[0031] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "a", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear indication to the contrary in the context.

[0032] In the present application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three and more than three, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c".

[0033] The following combination Figure 1 A vehicle steering method provided in an embodiment of the present application is introduced.

[0034] In an embodiment of the present application, the vehicle to which the vehicle steering method is applied includes a first set of tires and a second set of tires, the first set of tires are front wheels and the second set of tires are rear wheels, or the first set of tires are rear wheels and the second set of tires are front wheels.

[0035] In the embodiment of the present application, the execution subject of the vehicle steering method may be the vehicle provided by the present application, the controller in the vehicle, or the steering control unit in the vehicle, or it may be executed by the various units in the vehicle steering system provided by the present application, which is not limited in this article. Figure 1 and Figure 2 The vehicle steering method shown omits relevant descriptions about the execution entity.

[0036] like Figure 1 As shown, the vehicle steering method includes the following steps:

[0037] S101, braking the second set of tires so that the second set of tires is in a non-rotating state.

[0038] In the embodiment of the present application, the second set of tires includes at least one tire. It should be noted that when the number of tires included in the second set of tires is greater than or equal to 2, braking the second set of tires means braking each tire in the second set of tires.

[0039] Specifically, the second set of tires is braked so that the braking force of the second set of tires reaches the maximum design value to maintain the second set of tires in a non-rotating state, which can also be understood as a locked state.

[0040] For example, the braking force of the second set of tires is greater than or equal to the tire adhesion corresponding to the second set of tires, so that the braking force of the second set of tires reaches the maximum design value. It should be noted that the effective braking force of the second set of tires is provided by the tire adhesion, so that the maximum effective braking force of the braking force of the second set of tires is the tire adhesion of the second set of tires. For the convenience of description below, the tire adhesion corresponding to the second set of tires is referred to as the second adhesion.

[0041] The second adhesion is related to the total mass of the vehicle (including the curb weight of the vehicle and the mass of the object carried by the vehicle), the acceleration of gravity, the ground adhesion coefficient, the distance between the center of the second set of tires and the center of mass of the vehicle, and the distance between the center of the first set of tires and the center of mass of the vehicle. As an example, when the first set of tires includes a left front wheel and a right front wheel, the left front wheel and the right front wheel are connected by a front axle, and the second set of tires includes a left rear wheel and a right rear wheel, and the left rear wheel and the right rear wheel are connected by a rear axle, the distance between the center of the first set of tires and the center of mass of the vehicle is the distance between the center of the front axle and the center of mass of the vehicle, and the distance between the center of the second set of tires and the center of mass of the vehicle is the distance between the center of the rear axle and the center of mass of the vehicle. The center of mass of the vehicle refers to the center of the curb weight of the vehicle when the vehicle is in an unloaded state on a horizontal ground with no tilt angle.

[0042] As an example, it can be assumed that the mass of the object carried by the vehicle is a preset mass, for example, the preset mass can be a preset single person mass (that is, the mass of the driver alone), for example, the preset single person mass is any mass value greater than or equal to 75 kg and less than or equal to 100 kg. Or the preset mass can also be a preset full load mass (that is, the full load mass of the vehicle). Based on the preset mass, the maximum value of the second adhesion force can be determined, and then based on the maximum value of the second adhesion force, the minimum braking force output by the vehicle can be determined, and the correlation coefficient of the brake control device corresponding to the vehicle can be designed based on the minimum braking force.

[0043] Wherein, in the case where the braking force control unit in the vehicle controls the braking of each tire in the second set of tires separately, the braking force of braking each tire in the second set of tires is respectively greater than or equal to the tire adhesion of the corresponding tire. For example, the second set of tires includes a left rear wheel and a right rear wheel, the braking force of braking the left rear wheel is greater than or equal to the tire adhesion of the left rear wheel, and the braking force of braking the right rear wheel is greater than or equal to the tire adhesion of the right rear wheel.

[0044] In some possible implementations, before braking the second set of tires, the method further includes: controlling the vehicle to enter a steering control mode in response to operation information input by a user for instructing the vehicle to enter a steering control mode. Braking the second set of tires includes: braking the second set of tires based on the steering control mode.

[0045] In a possible implementation, the braking force control device for braking the second group of tires may be an electronic hydraulic braking system or an electronic parking brake system.

[0046] S102, driving a first set of tires.

[0047] In an embodiment of the present application, the first group of tires includes at least one tire, and the number of tires included in the first group of tires is less than or equal to the number of tires included in the second group of tires. Preferably, the number of tires included in the first group of tires is equal to the number of tires included in the second group of tires. If the number of tires included in the first group of tires is less than the number of tires included in the second group of tires, the difference in the number of tires should not be too large. It should be noted that, when the number of tires included in the first group of tires is greater than or equal to 2, driving the first group of tires means driving each tire in the first group of tires.

[0048] In the embodiment of the present application, when the number of tires included in the first set of tires is greater than or equal to 2, the driving mode for driving the first set of tires can be a single-motor or multi-motor driving mode. In the single-motor driving mode, the motor driving each tire in the first set of tires is the same motor, and in the multi-motor driving mode, the motors driving every two tires in the first set of tires can be different. In addition, in the embodiment of the present application, the torque direction of the driving force driving each tire in the first set of tires is the same.

[0049] As an example, the first group of tires includes a left front wheel and a right front wheel, and the left front wheel and the right front wheel are connected by a front axle. In a single-motor drive mode, the motor can be used to drive the front axle, and the purpose of driving the left front wheel and the right front wheel is achieved by driving the front axle by the motor, and the torque direction and magnitude of the driving force driving each tire in the first group of tires can be the same.

[0050] In some possible implementations, the vehicle further includes a throttle and a gear. Before step S102, the vehicle steering method provided by the present application further includes: obtaining the gear information of the vehicle based on the user's operation information on the gear, the gear information including forward gear and reverse gear; obtaining the throttle depth information based on the user's operation information on the throttle. Step S102 driving the first set of tires specifically includes: controlling the motor of the first set of tires to output the corresponding torque magnitude and torque direction based on the throttle depth information and the gear information to drive the first set of tires.

[0051] S103, when the driving force driving the first set of tires is greater than the tire adhesion of the first set of tires and the steering angle of the first set of tires is greater than a first steering angle, control the vehicle steering based on the driving force and the steering angle of the first set of tires.

[0052] In the embodiment of the present application, when the driving force of the first set of tires is greater than the tire adhesion of the first set of tires, the driving force of the first set of tires causes the first set of tires to slip, and the dynamic friction generated by the tire slipping provides longitudinal traction for the vehicle, and the static friction generated by the locking of the second set of tires provides longitudinal braking force for the vehicle. In the case of the same vehicle and the tire adhesion coefficients being not much different, the dynamic friction is less than the static friction, that is, the longitudinal braking force cannot move the vehicle in the longitudinal direction. However, when the first set of tires slips and the steering angle of the first set of tires is greater than the first steering angle, the first set of tires provides lateral force for the vehicle, that is, generates a yaw moment for the vehicle, while the second set of tires is in a non-rotating state, and the lateral force generated by the second set of tires that can suppress the yaw moment is very small, so that the vehicle turns with a smaller turning radius based on the lateral force provided by the first set of tires.

[0053] Furthermore, the vehicle steering method provided in the present application has the following hardware requirements for the vehicle: the first set of tires must belong to both the driving wheels and the steering wheels, and the second set of tires must belong to the brake wheels. This requirement can be met by most vehicles, such as front-wheel drive and front-wheel steering vehicles, rear-wheel drive and rear-wheel steering vehicles, and four-wheel drive and front-wheel steering and / or rear-wheel steering vehicles. Therefore, the vehicle steering method provided in the present application can reduce the minimum turning radius of the vehicle while improving the vehicle's passability in turning conditions.

[0054] Among some other methods for achieving vehicle steering to reduce the vehicle turning radius, there are three as follows.

[0055] The first method is to change the vehicle's drive system so that the driving force of the inner wheel of the vehicle is opposite to that of the outer wheel when turning. For example, by setting up a front axle drive mechanism to rigidly connect the steering wheels, the wheels on both sides rotate in opposite directions to achieve a U-turn in place in a manner similar to a track turn.

[0056] The second method is to change the vehicle's steering system so that all four wheels can steer. For example, the steering motor controls the steering angle of the four wheels, and the hub motor controls the driving force to control the vehicle to turn with a smaller turning radius. This method requires adding a steering drive device to change the rear wheels into steering wheels, and the required steering angle is large, which often needs to be used in conjunction with the hub motor, which is subject to greater limitations in practice.

[0057] The third method is to add a device that can turn on the spot to the bottom plate of the vehicle. When turning on the spot, the device first lifts the vehicle until the four wheels leave the ground, and then drives the vehicle to turn by turning on the spot by the device itself or drives the tray used to lift the vehicle to rotate relative to the ground to make the vehicle turn, and finally put the vehicle back to the ground. For example, the support plate is placed on the ground as a support point, and the vehicle is lifted by a telescopic cylinder. The motor drives the vehicle to rotate relative to the support plate to achieve vehicle steering. This method requires adding a new device to the vehicle chassis, which not only increases the curb weight of the vehicle, but also reduces the ground clearance of the vehicle, reducing the vehicle's passability. It is more suitable as a temporary rescue tool, but not suitable for long-term assembly as a component on the vehicle.

[0058] These three methods of reducing the turning radius of the vehicle all require adding new components to the original vehicle structure or making major changes to the original drive or steering system. They are subject to certain limitations in practical applications and are not very versatile. However, with the steering method provided by the present application, the hardware requirements for the vehicle can only include that the first set of tires are both steering wheels and drive wheels and the second set of tires are brake wheels. Generally, cars can meet such requirements. With the steering method provided by the present application, when the second set of tires of the vehicle does not rotate and is driven to the first set of tires to slip, the longitudinal movement distance of the vehicle can be very small, so that the turning radius corresponding to the vehicle turning is small, thereby achieving the effect of reducing the turning radius of the car when turning while improving the vehicle's passability in turning conditions.

[0059] Specifically, compared with the above three other vehicle steering methods, the advantages of the vehicle steering method provided by the present application include:

[0060] 1) The system is simple and easy to implement. The vehicle steering method provided by the present application requires relatively little modification to the original vehicle design, and its components are all from the common drive system, steering system and braking system of existing ordinary vehicles, without adding new components.

[0061] The reason is that this application uses collaborative control to achieve drive slippage of the first set of tires when the second set of tires are braked and not rotated, and uses the lateral force of the front axle to generate the vehicle yaw torque while suppressing the longitudinal movement of the entire vehicle, thereby achieving vehicle steering without the need for new components. On roads with a small adhesion coefficient such as ice, the motor driving force is sufficient to exceed the adhesion of the tires to cause slippage, and there is basically no need to increase the motor torque to the motor torque design value corresponding to the maximum driving force. In order to prevent the first set of tires of front-wheel drive electric vehicles from frequently slipping on conventional concrete roads with a small adhesion coefficient, the maximum driving force of the front axle is generally designed to be slightly lower than the maximum adhesion of the front axle under the adhesion coefficient. If the present application is to be applied to conventional road conditions with a large adhesion coefficient, the design value of the maximum driving force of the front axle must be increased, which can be achieved by increasing the peak torque of the motor or increasing the speed ratio of the reducer, which is easier to achieve than changing the drive system to a distributed drive or changing the steering system.

[0062] 2) The control method is simple and reliable, and easy for the driver to master. During the control process, after the driver turns the steering wheel to a certain angle, the motor output torque is linearly controlled by the throttle depth. When the first set of tires begins to slip, the vehicle continues to turn. If the throttle is released and the first set of tires stop slipping, the vehicle quickly returns to a stationary state. The control method is simple and reliable, and the control process conforms to the operating habits of ordinary drivers, and is easy for the driver to master. If the driver encounters an emergency and needs to stop steering, he only needs to release the throttle. The emergency handling method is completely in line with the driver's intuitive reaction.

[0063] 3) The combination of two extreme working conditions, the second set of tires not rotating under braking and the first set of tires slipping under driving, allows ordinary drivers to easily master the same on-the-spot drifting skills as professional racing drivers. The control process is accompanied by the "tire noise" and "tire burning" effects of driving slipping, allowing ordinary drivers to experience the atmosphere and fun of drifting.

[0064] The present application can change the heading angle of the vehicle in an extremely confined space, achieving convenient exiting and entering the parking lot, and greatly improving the convenience of the vehicle in extreme parking conditions.

[0065] In some possible implementations, the turning angle of the steering wheel may be acquired based on an angle sensor in a steering mechanism included in the vehicle, and the steering angle of the first group of tires may be determined based on the turning angle of the steering wheel.

[0066] In the embodiment of the present application, the first steering angle is greater than 0, and illustratively, the first steering angle is 20°. The detailed value of the first steering angle can be determined according to the critical steering angle for the vehicle to achieve steering by executing the vehicle steering method provided by the present application under different experimental conditions (specifically, different vehicle performance conditions, different ground road conditions, etc.), and this document does not limit this.

[0067] It should be noted that the steering angle of each tire included in the steering angle of the first group of tires may be the same or may have a certain error range, and the steering angle of the first group of tires being greater than the first steering angle may mean that the steering angle of one or more tires in the first group of tires is greater than the first steering angle, or the average value of the steering angles of all tires in the first group of tires is greater than the first steering angle. For example, the first group of tires includes a left front wheel and a right front wheel, and the steering angle of the first group of tires being greater than the first steering angle may mean that the steering angle of the left front wheel is greater than the first steering angle, the steering angle of the first group of tires being greater than the first steering angle may also mean that the steering angle of the right front wheel is greater than the first steering angle, or the steering angle of the first group of tires being greater than the first steering angle may also mean that the average value of the sum of the steering angles of the left front wheel and the right front wheel is greater than the first steering angle, which is not limited in this article.

[0068] In an embodiment of the present application, in combination with the vehicle's throttle depth information, gear information, and the steering angle of the first group of tires, the vehicle's steering direction can be the left front direction, the right front direction, the right rear direction, or the left rear direction.

[0069] For the convenience of description below, the tire adhesion of the first group of tires is referred to as the first adhesion.

[0070] In some possible implementations, to ensure that the driving force is greater than the first adhesion, the performance requirements for the vehicle include: the peak torque of the motor corresponding to the first set of tires is greater than a first value. The first value is determined based on the speed ratio of the reducer, the tire adhesion of the first set of tires, and the tire radius. It can also be understood that the maximum driving force provided by the motor corresponding to the first set of tires to the first set of tires is greater than the first adhesion.

[0071] In an embodiment of the present application, the peak torque of the motor corresponding to the first group of tires is greater than a first value, which is a performance requirement for the motor corresponding to the first group of tires. The peak torque of the motor meets the performance requirements, so that the driving force can be greater than the tire adhesion of the first group of tires, causing the first group of tires to slip.

[0072] As an example, it can be assumed that the mass of the object carried by the vehicle is a preset mass, for example, the preset mass can be a preset mass of a single person, or the preset mass can be a preset fully loaded mass. Then, based on the preset mass, the maximum value of the first adhesion force can be determined, and based on the maximum value of the first adhesion force, the minimum value that the maximum driving force output by the motor needs to meet can be determined, and based on the minimum value that the maximum driving force needs to meet, the lower limit of the maximum output torque of the motor is designed.

[0073] It should be noted that when the peak torque of the vehicle's motor meets the performance requirements, the driving force can be greater than the first adhesion. However, the driving force can be greater than the first adhesion not only when the peak torque of the vehicle's motor meets the performance requirements. Other conditions can also make the driving force greater than the first adhesion. For example, the ground contacted by the first set of tire locks is made smoother, so that the ground friction coefficient is smaller and the first adhesion is smaller, so that the driving force is greater than the first adhesion.

[0074] In the embodiment of the present application, the first set of tires is driven, and after the driving force is greater than the first adhesion force, the first set of tires is in a slipping state, and the longitudinal traction force generated by the driving force on the vehicle is very small, which is much smaller than the longitudinal braking force provided by the second set of tires to the vehicle to prevent the vehicle from moving longitudinally, so the longitudinal driving force generated by the motor can hardly cause the vehicle to move longitudinally. However, based on the driving force being greater than the first adhesion force and the steering angle of the first set of tires being greater than 0, the vehicle generates lateral traction, and because the second set of tires is in a non-rotating state, the second set of tires almost loses the ability to output lateral force, for example, the lateral traction generated by the driving force on the vehicle is 100N (Newton), and the lateral restraining force generated by the second set of tires to restrain the lateral traction is 51N, so that the vehicle can turn with a smaller turning radius based on the lateral traction, and the vehicle performs a yaw motion that is almost turning in place. The specific value of the turning radius is determined based on the change of the vehicle correlation coefficient, for example, the turning radius is related to the size of the first steering angle and the distance between the center of the first set of tires and the center of the second set of tires.

[0075] In the embodiment of the present application, before the driving force of the first set of tires increases to the point where the first set of tires slips (that is, the driving force of the first set of tires is less than or equal to the tire adhesion of the first set of tires), if the driving force can overcome the longitudinal braking force of the second set of tires (the maximum longitudinal effective braking force of the second set of tires is the tire adhesion of the second set of tires), the driving force can drive the vehicle to move forward longitudinally. However, since the tire adhesion of the first set of tires is generally not much different from that of the second set of tires, when the driving force is less than or equal to the tire adhesion of the first set of tires, the driving force is generally also less than the tire adhesion of the second set of tires, so before the driving force of the first set of tires increases to the point where the first set of tires slips, the distance the vehicle moves is almost zero or small.

[0076] However, assuming that the first distance from the center of mass of the vehicle to the center of the first set of tires is equal to the second distance from the center of mass of the vehicle to the center of the second set of tires, and the ground adhesion coefficients corresponding to the first set of tires and the second set of tires are the same, then under the condition of the same load-bearing mass, the tire adhesion of the first set of tires is equal to the tire adhesion of the second set of tires. However, when the user implements the vehicle steering method provided by the present application, generally only the driver's seat and the co-driver's seat are in a passenger-carrying state, then the load-bearing mass corresponding to the first set of tires will be greater than the load-bearing mass of the second set of tires, and the tire adhesion corresponding to the first set of tires will be greater than the tire adhesion of the second set of tires, so that before the driving force increases to be greater than the tire adhesion of the first set of tires, the driving force will first be greater than the tire adhesion of the second set of tires, driving the vehicle to move.

[0077] In view of this, in some possible implementations of the present application, the first distance is designed to be slightly larger than the second distance, so that when the load-bearing capacity of the first group of tires is greater than the load-bearing capacity of the second group of tires, the tire adhesion of the second group of tires is greater than or equal to the tire adhesion of the first group of tires, effectively preventing the vehicle from moving after the driving force of the first group of tires increases to a level greater than the tire adhesion of the second group of tires and before it becomes less than the tire adhesion of the second group of tires.

[0078] The first distance is only slightly larger than the second distance to avoid the first distance being too large and the second distance being too small, which may cause the vehicle to roll over. For example, assuming that the first distance is a and the second distance is b, b is greater than or equal to a first preset multiple, which is less than 1 and greater than or equal to 0.95. For example, b is greater than or equal to 0.95a and less than or equal to 0.999a.

[0079] It should be noted that the method of making the first distance greater than the second distance so that the tire adhesion of the second group of tires is greater than or equal to the tire adhesion of the first group of tires is only an example, and the tire adhesion of the second group of tires can also be made greater than or equal to the tire adhesion of the first group of tires by other methods, which is not limited in this article, such as by making the ground adhesion coefficient of the second group of tires greater than the ground adhesion coefficient of the first group of tires.

[0080] In some possible implementations, Figure 1 The method shown also includes: when the driving force output by the motor used to drive the first group of tires reaches the peak motor torque and is still less than or equal to the tire adhesion of the first group of tires and the vehicle is stationary, outputting first indication information and controlling the vehicle to exit steering control, wherein the first indication information is used to indicate that the mass of the object carried by the vehicle exceeds the maximum load mass for achieving vehicle steering using the vehicle steering method.

[0081] In an embodiment of the present application, when the driving force output by the motor after reaching the peak motor torque is still less than or equal to the tire adhesion of the first group of tires, the above-mentioned first indication information is output, which can provide the user with guidance on the correct use of the vehicle steering method provided by the present application, enhance user interaction, and improve user experience.

[0082] In some possible implementations, after receiving the operation information input by the user to instruct the vehicle to enter the steering control mode, and before the vehicle enters the steering control mode, the above method also includes: obtaining the maximum mass that the motor corresponding to the first group of tires can drive, and the maximum mass is related to the maximum driving force corresponding to the peak torque of the motor (a parameter set when the motor leaves the factory); and obtaining the real-time total mass of the vehicle, the total mass includes the vehicle curb mass and the mass of the objects actually carried by the vehicle, wherein the mass of the objects actually carried by the vehicle can be determined by adding a height sensor to the suspension of the vehicle and combining it with the known suspension stiffness; the above-mentioned control of the vehicle to enter the steering control mode in response to the operation information input by the user to instruct the vehicle to enter the steering control mode includes: when the maximum mass is greater than the total mass, in response to the operation information input by the user to instruct the vehicle to enter the steering control mode, controlling the vehicle to enter the steering control mode.

[0083] In some possible implementations, the method further includes: when the maximum mass is less than the curb mass of the vehicle, in response to the operation information input by the user to instruct the vehicle to enter a steering control mode, outputting a second indication information, the third indication information being used to indicate that the performance of the vehicle does not support entering a steering control mode (that is, it does not support executing the steering method provided in the present application to steer the vehicle); when the maximum mass is greater than the curb mass of the vehicle and less than the total mass, in response to the operation information input by the user to instruct the vehicle to enter a steering control mode, outputting a third indication information, the third indication information being used to indicate that the mass of the object carried by the vehicle exceeds the maximum mass for the vehicle to enter a steering control mode (that is, the vehicle cannot be steered by executing the steering method provided in the present application because the object carried is too heavy).

[0084] The following combination Figure 2 , taking the first set of tires including the left front wheel and the right front wheel, the left front wheel and the right front wheel are connected by the front axle, the second set of tires including the left rear wheel and the right rear wheel, the left rear wheel and the right rear wheel are connected by the rear axle, the motor drive mode of the left front wheel and the right front wheel is a single motor drive mode (specifically, the first motor drives the front axle to drive the left front wheel and the right front wheel), and the braking force control unit in the vehicle separately controls the braking of the left rear wheel and the right rear wheel as an example, an application of the vehicle steering method provided by the present application is described. For the convenience of description below, the front wheel is used to refer to the left front wheel and the right front wheel, and the rear wheel is used to refer to the left rear wheel and the right rear wheel.

[0085] like Figure 2 As shown, the vehicle steering method includes:

[0086] S201, receiving an operation request from a driver to enter a steering control mode.

[0087] In the embodiment of the present application, the steering control mode may also be referred to as a steering mode with a smaller turning radius or may be referred to as other appropriate names, and the specific name of the steering control mode is not limited.

[0088] S202, determining whether a first preset condition for entering a steering control mode is satisfied.

[0089] In the embodiment of the present application, the first preset condition may include but is not limited to one or more of the following: the vehicle is in P gear (parking gear), the vehicle has sufficient power (for example, sufficient oil, sufficient power, etc.), and the vehicle's components are in a normal usable state (no failure). When the vehicle meets each of the first preset conditions, it is determined that the vehicle meets the first preset condition for entering the steering control mode.

[0090] If it is determined that the first preset condition for entering the steering control mode is met, execute step S203; if it is determined that the first preset condition for entering the steering control mode is not met, return to S201 and wait for the next driver's operation request to enter the steering control mode.

[0091] In some possible implementations, when it is determined that the first preset condition for entering the steering control mode is not met, a third prompt information may also be output, and the third prompt information is used to indicate the specific reason why the steering control mode is not met. For example, if the vehicle power is in a critical condition and the steering control mode is not met, the third indication information is used to indicate that the reason why the steering control mode is not met is that the vehicle power is insufficient.

[0092] S203, brake the rear wheel.

[0093] Exemplarily, when it is determined that the first preset condition for entering the steering control mode is met, the vehicle is controlled to enter the steering control mode, and the rear wheel braking is triggered based on the steering control mode so that the braking force of the rear wheel reaches the maximum design value to maintain the state where the rear wheel does not rotate. Alternatively, it can also be understood that after receiving the driver's operation request to enter the steering control mode, braking the rear wheel indicates that the vehicle has entered the steering control mode.

[0094] In the embodiment of the present application, tire adhesion refers to the limit value of the tangential reaction force of the tire on the ground (contact surface), and braking force refers to the friction between the brake friction pad and the brake disc. The brake disc is rigidly connected to the tire. The tire is kept stationary by controlling the friction between the brake friction pad and the brake disc, and finally an effective braking force is provided by the ground friction, wherein the maximum effective braking force of the brake tire is the tire adhesion.

[0095] As an example, the above-mentioned braking of the rear wheel specifically includes: braking the left rear wheel and the right rear wheel respectively, and the braking force of the left rear wheel is greater than or equal to the tire adhesion corresponding to the left rear wheel, and the braking force of the right rear wheel is greater than or equal to the tire adhesion corresponding to the right rear wheel. Exemplarily, assuming that the tire adhesion of the left rear wheel and the right rear wheel is equal, the braking force of a single rear wheel satisfies the following formula 1, where F b is the braking force of a single rear wheel, S b is the tire adhesion of a single rear wheel, is the calculation formula for the tire adhesion of a single rear wheel. Among them, M is the vehicle's curb weight, m ​​is the mass of the object carried by the vehicle, g is the acceleration of gravity, μ is the ground adhesion coefficient (generally greater than or equal to 0.95 and less than or equal to 1.2), a is the distance from the center of mass of the vehicle to the center of the front axle, and b is the distance from the center of mass of the vehicle to the center of the rear axle.

[0096]

[0097] In a possible implementation, m may be a preset mass (the preset mass of the object carried by the vehicle), for example, the preset mass may be a preset mass of a single person, or the preset mass may also be a preset fully loaded mass. Based on the preset mass, S b The maximum value of S b The maximum value of F b The minimum value of F b The minimum value of the correlation coefficient of the braking control device corresponding to the designed vehicle.

[0098] S204: Determine the steering angle of the front wheels based on the driver's operation information on the steering wheel.

[0099] Specifically, the front wheels are connected to a steering mechanism, which includes a steering wheel, a steering column, and a steering tie rod. The steering mechanism can obtain the steering wheel rotation angle through a steering wheel angle sensor (angle sensor), and then calculate the tire.

[0100] S205, based on the user's operation information on the accelerator and the gear, the first motor outputs the corresponding torque to drive the front wheels.

[0101] Specifically, the throttle depth is obtained based on the user's operation information on the throttle, the magnitude of the output torque of the first motor (the motor corresponding to the front wheel) is determined based on the throttle depth, and the direction of the output torque of the first motor is obtained based on the driver's operation information on the gear position, where the gear position includes a forward gear and a reverse gear. In the embodiment of the present application, the first motor drives the left front wheel and the right front wheel by driving the front axle.

[0102] S206, the vehicle is stationary when the front axle driving force output by the first motor corresponding to the front wheel is less than or equal to the tire adhesion of the front wheel, or the steering angle of the front wheel is less than or equal to the first steering angle.

[0103] It is understandable that, since the materials, number of tires, and ground adhesion coefficients of the front and rear wheels are generally equal, the tire adhesion of the first set of tires is generally not much different from the tire adhesion of the second set of tires. In other words, before the front axle driving force increases to be greater than the tire adhesion of the front wheels, the front axle driving force is generally also less than the tire adhesion of the rear wheels when they are not rotating (the maximum effective braking force in the longitudinal direction of the vehicle), so that before the front axle driving force increases to be greater than the tire adhesion of the front wheels, the distance the vehicle moves is almost zero or small.

[0104] In some possible implementations, to further reduce the distance that the vehicle moves after the front axle driving force increases to be greater than the tire adhesion of the rear wheels and before being greater than the tire adhesion of the front wheels, the ground adhesion coefficient of the rear wheels is greater than the ground adhesion coefficient of the front wheels, and / or the first distance a between the center of mass of the vehicle and the center of the front axle is greater than the second distance b between the center of mass of the vehicle and the center of the rear axle. For example, b is greater than or equal to 0.95a and less than or equal to 0.999a.

[0105] S207: When the front axle driving force is greater than the tire adhesion of the front wheels and the steering angle of the front wheels is greater than the first steering angle, the vehicle turns.

[0106] When the front axle driving force output by the first motor corresponding to the front wheel is greater than the tire adhesion of the front wheel, the front wheel is in a slipping state, and the longitudinal traction force generated by the front axle driving force on the front wheel is less than the longitudinal braking force generated by the rear wheel, and the vehicle cannot move longitudinally based on the traction of the front wheel. However, the front axle driving force is greater than the tire adhesion of the front wheel and the steering angle of the front axle is greater than the first steering angle, and the front axle generates a front axle lateral force to generate a yaw moment on the vehicle, and the rear wheel is in a non-rotating state, and the rear axle almost loses the ability to generate a rear axle lateral force, and the rear wheel cannot stop the vehicle from yaw motion, so the vehicle turns with a small turning radius based on the front axle lateral force, which can be specifically understood as the vehicle undergoing a yaw motion that is almost rotating on the spot.

[0107] The value of the turning radius corresponding to the vehicle turning is related to the magnitude of the first steering angle and the distance between the center of the first group of tires and the center of the second group of tires.

[0108] As an example, the front axle driving force D and the front wheel tire adhesion S a The following formula 2 is satisfied. Where, T max is the peak torque of the front motor, i is the speed ratio of the reducer, r is the tire radius, M is the vehicle curb weight, and m is the mass of the object carried by the vehicle.

[0109]

[0110] Specifically, based on Formula 2, the peak torque of the first motor is greater than a first value, and the first value is determined based on the tire adhesion of the front wheels, the speed ratio of the reducer, and the tire radius. The specific calculation formula of the first value can be derived according to Formula 2.

[0111] As an example, m in Formula 2 may be a preset mass (the preset mass of the object carried by the vehicle), for example, the preset mass may be a preset mass of a single person, or the preset mass may also be a preset fully loaded mass. Based on the preset mass, S a The maximum value of S a The maximum value of determines the minimum value of D, and the lower limit of the peak torque of the first motor is determined based on the minimum value of D.

[0112] In the embodiment of the present application, in combination with the throttle position of the vehicle and the steering angle of the front axle, the direction in which the vehicle turns may be the left front direction, the right front direction, the right rear direction, or the left rear direction.

[0113] As an example, the vehicle gears include forward gear (D gear) and reverse gear (R gear), and the driver determines the direction of the vehicle's steering by the gear and the steering wheel angle. In D gear, if the steering wheel is turned left, the vehicle turns to the left front direction, and in D gear, if the steering wheel is turned right, the vehicle turns to the right front direction. In R gear, if the steering wheel is turned left, the vehicle turns to the right rear direction, and in R gear, if the steering wheel is turned right, the vehicle turns to the left rear direction.

[0114] S208: Determine whether a second preset condition for exiting the steering control mode is met.

[0115] As an example, the second preset condition includes but is not limited to one or more of the following: receiving an operation request message from a user requesting to exit the steering control mode, vehicle overheating, vehicle power shortage, or other equipment failure. When the vehicle meets any one of the second preset conditions, it is determined that the vehicle meets the second preset condition for exiting the steering control mode.

[0116] If it is determined that the second preset condition is met, steps S209 and S210 are executed in sequence; if it is determined that the second preset condition is not met, steps S204 to S208 are continued to be executed.

[0117] S209, unloading the output torque of the first motor.

[0118] Specifically, the torque of the first motor is unloaded to 0.

[0119] S210, unloading the braking force of the rear wheels.

[0120] Specifically, the braking force of the rear wheels is unloaded to 0.

[0121] In combination with the vehicle steering method described above, the present application also provides a vehicle steering system, the system comprising a steering control unit, a first group of tires, a second group of tires, a braking force control unit, a motor controller, a motor, and a steering mechanism, wherein the first group of tires are front wheels and the second group of tires are rear wheels, or the first group of tires are rear wheels and the second group of tires are front wheels, the steering control unit is used to request the braking force control unit to brake the second group of tires so that the second group of tires is in a non-rotating state; the steering mechanism is used to change the steering angle of the first group of tires; the steering control unit is used to request the motor controller to control the motor output torque so that the motor drives the first group of tires; the steering control unit is also used to control the vehicle to steer when the steering angle of the first group of tires is greater than the first steering angle and the driving force output by the motor is greater than the tire adhesion of the first group of tires.

[0122] In some possible implementations, the system further includes a steering control mode request input device and an in-vehicle network, wherein the steering control mode request input device is used to receive operation information of a user requesting to enter the steering control mode; the steering control unit is specifically used to determine to enter the steering control mode in response to the operation information of the user input requesting to enter the steering control mode, and request the braking force control unit to brake the second group of tires based on the steering control mode, so that the second group of tires is in a non-rotating state; the steering control unit is also used to obtain the throttle depth and the gear state based on the in-vehicle network, and determine the motor torque magnitude of the motor output controlled by the motor controller based on the throttle depth, and determine the motor torque direction of the motor output controlled by the motor controller based on the gear state; the steering control unit is also used to request the motor controller to control the motor to output a torque corresponding to the motor torque magnitude and the motor torque direction; the steering mechanism is specifically used to determine the steering angle of the first group of tires based on the steering wheel rotation angle obtained by the angle sensor; the motor controller is specifically used to control the torque corresponding to the motor output according to the motor torque direction and the motor torque magnitude requested by the steering control unit to drive the first group of tires.

[0123] For example, the first set of tires includes a left front wheel and a right front wheel, the second set of tires includes a left rear wheel and a right rear wheel, and the driving mode of the motor corresponding to the first set of tires is a single motor. Figure 3 A vehicle steering system provided by the present application is described.

[0124] like Figure 3 The vehicle steering system provided by the present application includes: a steering control mode request input device 301, a steering control unit 302, a front wheel 303, a rear wheel 304, a braking force control unit 305, an on-board network 306, a motor controller 307, a first motor 308, a main reducer 309, a steering mechanism 310, a front axle 311, and a rear axle 312. Among them, the front axle 311 is used to connect the left front wheel and the right front wheel of the front wheel 303, the rear axle 312 is used to connect the left rear wheel and the right rear wheel of the rear wheel 304, and the steering mechanism 310 is connected to the front wheel 303.

[0125] The steering control mode request input device 301 is used to receive operation information of a user requesting to enter a steering control mode.

[0126] The steering control unit 302 is used to respond to the operation information of the user requesting to enter the steering control mode, determine to enter the steering control mode, and based on the steering control mode, request the braking force control unit 305 to brake the rear wheel 304 so that the rear wheel 304 is in a non-rotating state. Specifically, the left rear wheel and the right rear wheel can be braked respectively, wherein the braking force of braking the left rear wheel and the right rear wheel is greater than or equal to the adhesion corresponding to one of the tires of the rear wheels (refer to the above formula 1).

[0127] The steering mechanism 310 is used to determine the steering angle of the front wheels based on the rotation angle of the steering wheel obtained by the angle sensor.

[0128] The steering control unit 302 is further configured to obtain the throttle depth and the gear state based on the vehicle network 306, and determine the magnitude of the motor torque output by the motor controller 307 to control the first motor 308 based on the throttle depth, and determine the direction of the motor torque output by the first motor 308 controller to control the motor based on the gear state;

[0129] The steering control unit 302 is further used to request the motor controller to control the motor to output a torque corresponding to the motor torque magnitude and the motor torque direction, so as to drive the front axle 311 to drive the front wheels; the steering control unit 302 is further used to control the vehicle to steer when the steering angle of the front wheels is greater than the first steering angle and the driving force corresponding to the torque magnitude output by the first motor 308 is greater than the tire adhesion of the front wheels. The tire adhesion of the front wheels (also referred to as the front axle adhesion) is the sum of the adhesion corresponding to the left front wheel and the adhesion corresponding to the right front wheel.

[0130] In some possible implementations, the peak torque of the first motor 308 is greater than a first value, which is determined based on the tire adhesion of the front wheel 303, the speed ratio of the final reducer 309, and the tire radius of the front wheel 303. For a specific calculation method of the first value, reference may be made to the above description, for example, reference may be made to the above description of Formula 2.

[0131] In some possible implementations, the tire adhesion of the front wheels is determined based on the vehicle mass, the preset single-person mass, the contact surface friction coefficient, the gravitational acceleration, the first distance between the center of mass of the vehicle and the center of the front axle 311, and the second distance between the center of mass of the vehicle and the center of the rear axle 312.

[0132] In some possible implementations, a first distance between the center of mass of the vehicle and the center of the front axle is greater than a second distance between the center of mass of the vehicle and the center of the rear axle.

[0133] In some possible implementations, the steering control unit 302 is also used to output a first indication message and control the vehicle to exit the steering control mode when the driving force output by the motor of the first group of tires is still less than or equal to the tire adhesion of the front wheels and the vehicle is stationary after the motor reaches the peak torque of the motor, and the vehicle is stationary. The first indication message is used to indicate that the mass of the object carried by the vehicle exceeds the maximum load mass for achieving vehicle steering using the steering control mode.

[0134] It should be noted that Figure 3 In the vehicle steering system shown, the steering angle of the rear wheels of the vehicle is 0, but in actual applications, the steering angle of the rear wheels of the vehicle may not be 0, and the different steering angles of the rear wheels of the vehicle have different effects on the braking effect achieved by the vehicle and the turning radius corresponding to the implementation of the vehicle steering method. This article does not limit this.

[0135] In some possible implementations, the steering control unit 302 is further used to obtain the maximum mass that the first motor 308 can drive, and the maximum mass is related to the maximum driving force corresponding to the peak torque of the first motor 308; the steering control unit 302 is also used to obtain the total mass of the vehicle, and the total mass includes the vehicle's curb mass and the mass of the object actually carried by the vehicle, which can be specifically obtained by adding a height sensor to the vehicle's suspension and then combining it with the known suspension stiffness to obtain the mass of the object actually carried by the vehicle; the steering control unit 302 is specifically used to control the vehicle to enter a steering control mode in response to operation information input by a user to instruct the vehicle to enter a steering control mode when the maximum mass is greater than the total mass.

[0136] In some possible implementations, the steering control unit 302 is further used to, when the maximum mass is less than the curb mass of the vehicle, in response to operation information input by the user for instructing the vehicle to enter a steering control mode, control the vehicle to output second indication information, the second indication information being used to indicate that the performance of the vehicle does not support entering the steering control mode; and when the maximum mass is greater than the curb mass of the vehicle and less than the total mass, in response to operation information input by the user for instructing the vehicle to enter a steering control mode, control the vehicle to output third indication information, the third indication information being used to indicate that the mass of the object carried by the vehicle exceeds the maximum mass for the vehicle to enter the steering control mode.

[0137] It should be noted that the specific implementation process can be found in Figure 1 or Figure 2 The specific description of the illustrated embodiment will not be repeated here.

[0138] Understandably, Figure 3 The vehicle steering system provided is used to perform Figure 1 or Figure 2The system of the vehicle steering method shown, therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method, and will not be repeated here.

[0139] In combination with the vehicle steering method described above, the present application also provides a vehicle steering device, referring to Figure 4 The device is applied to a vehicle, the vehicle comprises a first set of tires and a second set of tires, the first set of tires are front wheels, and the second set of tires are rear wheels, or the first set of tires are rear wheels, and the second set of tires are front wheels, the device comprises:

[0140] A braking unit 401 is used for braking the second set of tires so that the second set of tires is in a non-rotating state;

[0141] A steering unit 402, used to control the steering angle of the first set of tires;

[0142] A driving unit 403, used to drive the first set of tires;

[0143] The first control unit 404 is used to control the vehicle steering based on the driving force and the steering angle of the first set of tires when the driving force driving the first set of tires is greater than the tire adhesion of the first set of tires and the steering angle of the first set of tires is greater than the first steering angle.

[0144] In some possible implementations, the peak torque of the motor corresponding to the first set of tires is greater than a first value, and the first value is determined based on the tire adhesion of the first set of tires, the speed ratio of the reducer, and the tire radius of the first set of tires.

[0145] In some possible implementations, the ground adhesion coefficient corresponding to the second group of tires is greater than the ground adhesion coefficient corresponding to the first group of tires, and / or a first distance between the center of mass of the vehicle and the center of the first group of tires is greater than a second distance between the center of mass of the vehicle and the center of the second group of tires.

[0146] In some possible implementations, such as Figure 5 The device further includes: a second control unit 405, which is used to control the vehicle to enter the steering control mode in response to the information that the vehicle enters the steering control mode. Specifically, the second control unit 405 includes: a receiving subunit 4051, which is used to receive the operation information input by the user to instruct the vehicle to enter the steering control mode; and a control subunit 4052, which is used to control the vehicle to enter the steering control mode in response to the operation information input by the user to instruct the vehicle to enter the steering control mode.

[0147] In some possible implementations, the vehicle further includes a throttle and a gear, and the device further includes: a first acquisition unit 406, used to acquire the gear information of the vehicle, the gear information including forward gear and reverse gear; specifically, the first acquisition unit 406 can be used to acquire the gear information of the vehicle based on the user's operation information for the gear; a second acquisition unit 407, used to acquire throttle depth information. Specifically, the second acquisition unit 407 can be used to acquire throttle depth information based on the user's operation information for the throttle. The drive unit 403 is specifically used to control the motor of the vehicle to output the corresponding torque magnitude and torque direction based on the throttle depth information and the gear information to drive the first set of tires.

[0148] In some possible implementations, the steering unit 402 is specifically configured to determine the steering angle of the first group of tires based on the rotation angle of the steering wheel acquired by the angle sensor.

[0149] In some possible implementations, the above-mentioned device also includes: an output unit 408, which is used to output first indication information and control the vehicle to exit steering control when the driving force output after the driving unit drives the motor of the first group of tires to reach the peak motor torque is still less than or equal to the tire adhesion of the first group of tires and the vehicle is stationary, and the first indication information is used to indicate that the mass of the object carried by the vehicle exceeds the maximum load mass for achieving vehicle steering using the vehicle steering method.

[0150] In some possible implementations, the above-mentioned device also includes: a third acquisition unit 409, used to obtain the maximum mass that can be driven by the motor corresponding to the first group of tires, the maximum mass is related to the maximum driving force corresponding to the peak torque of the motor; a fourth acquisition unit 410, used to obtain the total mass of the vehicle, the total mass includes the vehicle's curb weight and the mass of the objects actually carried by the vehicle; the above-mentioned second control unit 405 is specifically used to, when the maximum mass is greater than the total mass, respond to the operation information input by the user to instruct the vehicle to enter the steering control mode, so that the vehicle enters the steering control mode.

[0151] In some possible implementations, the output unit 408 is further used to, when the maximum mass is less than the curb mass of the vehicle, output second indication information in response to operation information input by the user for instructing the vehicle to enter a steering control mode, the second indication information being used to indicate that the performance of the vehicle does not support entering the steering control mode; and, when the maximum mass is greater than the curb mass of the vehicle and less than the total mass, output third indication information in response to operation information input by the user for instructing the vehicle to enter a steering control mode, the third indication information being used to indicate that the mass of the object carried by the vehicle exceeds the maximum mass for the vehicle to enter the steering control mode.

[0152] In some possible implementations, the first group of tires includes a left front wheel and a right front wheel, the second group of tires includes a left rear wheel and a right rear wheel, the vehicle also includes a first motor and a front axle, the front axle is used to connect the left front wheel and the right front wheel, the first motor is used to drive the left front wheel and the right front wheel through the front axle, and the first adhesion is the sum of the adhesion corresponding to the left front wheel and the adhesion corresponding to the right front wheel; the braking unit 401 is specifically used to individually control the braking state of the left rear wheel and the right rear wheel; the braking unit 401 is specifically used to respectively brake the left rear wheel and the right rear wheel using a first braking force, the first braking force is greater than the first adhesion, and the first adhesion is the adhesion corresponding to one of the tires in the second group of tires.

[0153] As an example, Figure 3 The braking force control unit 305 in the vehicle steering system can be used to implement Figure 4 The steps or functions performed by the braking unit 401, the motor controller 307 and the first motor 308 can be used to implement the steps or functions performed by the driving unit 403, the steering mechanism can be used to implement the steps and functions performed by the steering unit 402, the steering control unit 302 can be used to implement the steps or functions performed by the second control unit 405 and the first control unit 404, and the on-board network 306 can be used to implement the steps or functions performed by the first acquisition unit 406 and the second acquisition unit 407.

[0154] As an example, the brake unit 401 may be a brake force control unit in an electronic hydraulic brake system. The structure of the electronic hydraulic brake system may be as follows: Figure 6 shown.

[0155] Among them, the braking force control unit in the electronic hydraulic braking system controls the hydraulic cylinder pressure of the rear wheel braking force control device through the solenoid valve, and then controls the braking force applied to the brake disc. The specific way to apply the maximum braking force to the rear wheel alone is that the braking force control unit first closes all the boost valves and the pressure relief valves, controls the cylinder pressure of the brake master cylinder to reach the maximum value through the wheel cylinder motor, maintains the front wheel boost valve closed, opens the rear wheel boost valve, and after the rear wheel brake cylinder pressure stabilizes, closes the boost valve, maintains the rear wheel cylinder pressure at the maximum braking pressure, and then controls the wheel cylinder motor to restore the brake master cylinder pressure to normal value. The specific way to unload the braking force to the rear wheel alone is to keep the rear wheel boost valve closed and open the rear wheel pressure relief valve. After a certain period of time, the rear wheel cylinder pressure drops to 0, closes the pressure relief valve, and unloads the rear wheel braking force to 0.

[0156] As another example, the braking unit 401 may also be a braking force control unit in an electronic parking brake system.

[0157] Among them, the braking force control unit in the electronic parking brake system mechanically limits the hydraulic cylinder pressure of the rear wheel braking force control device through the rear wheel parking motor, thereby controlling the braking force applied to the brake disc to reach the maximum design value. The electronic parking brake system itself can control the rear wheel braking force to maintain the maximum value. Generally, the electronic parking system will actively unload the rear wheel braking force after monitoring that the vehicle driving torque reaches a certain threshold to meet the driver's driving intention from parking to driving. In this embodiment, the electronic parking system outputs the driving force after receiving the rear wheel braking request from the steering control unit, but the electronic parking system will not write the rear wheel braking force based on the driving force being greater than a certain threshold. The electronic parking system will keep the rear wheel in a braking state and will not actively unload the rear wheel braking force. Instead, it will unload the rear wheel braking force after determining that the second preset condition for exiting the steering control mode is met and the driving force is unloaded.

[0158] It should be noted that the specific implementation process can be found in Figure 1 or Figure 2 The specific description of the illustrated embodiment will not be repeated here.

[0159] Understandably, Figure 4 The vehicle steering device provided is used to perform Figure 1 or Figure 2 The device of the vehicle steering method shown, therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method, and will not be repeated here.

[0160] The present application also provides a vehicle, the vehicle comprising a controller, a motor controller, a brake controller, a first set of tires, and a second set of tires, the first set of tires being the front wheels and the second set of tires being the rear wheels, or the first set of tires being the rear wheels and the second set of tires being the front wheels, the controller being used to request the brake force controller to brake the second set of tires, and to request the motor control unit to drive the first set of tires, so as to perform Figure 1 or Figure 2 Any possible vehicle steering method can be used to achieve vehicle steering. As an example, Figure 7 As shown, taking the case where the first set of tires of the vehicle includes the left front wheel and the right front wheel, and the second set of tires includes the left rear wheel and the right rear wheel as an example, the structural schematic diagram of the vehicle provided by the present application is shown.

[0161] Exemplarily, the controller can be used to implement the steps or functions performed by the steering control unit above. In some possible implementations, the motor controller can be used in the above (for example Figure 3 The steps or functions performed by the motor controller in the above text may be implemented by the brake controller, and the controller may also be used to implement the steps or functions performed by the steering control mode request input device in the above text.

[0162] As used in the above embodiments, the term "when..." may be interpreted to mean "if..." or "after..." or "in response to determining..." or "in response to detecting...", depending on the context. Similarly, the phrases "upon determining..." or "if (the stated condition or event) is detected" may be interpreted to mean "if determining..." or "in response to determining..." or "upon detecting (the stated condition or event)" or "in response to detecting (the stated condition or event)", depending on the context.

[0163] 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, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, a data center, etc. that contains one or more available media integration. The available medium can be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk), etc.

[0164] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

Claims

1. A vehicle steering method, characterized in that: include: braking the second set of tires so that the second set of tires is in a non-rotating state; driving a first set of tires, wherein the torque direction of the driving force corresponding to each tire in the first set of tires is the same; When the driving force driving the first group of tires is greater than the tire adhesion of the first group of tires, and the steering angle of the first group of tires is greater than a first steering angle, the steering of the vehicle is controlled based on the driving force and the steering angle of the first group of tires, the steering angle of the first group of tires is the angle between the first group of tires and the body of the vehicle, the first group of tires are the front wheels of the vehicle, and the second group of tires are the rear wheels of the vehicle, or the first group of tires are the rear wheels of the vehicle, and the second group of tires are the front wheels of the vehicle.

2. The method according to claim 1, characterized in that Prior to braking the second set of tires, the method further comprises: In response to the information that the vehicle enters the steering control mode, controlling the vehicle to enter the steering control mode; The braking of the second set of tires comprises: Based on the steering control mode, the second set of tires is braked.

3. The method according to claim 1 or 2, characterized in that: Prior to driving the first set of tires, the method further includes: Acquiring gear information of the vehicle, the gear information including forward gear and reverse gear; Get throttle depth information; The driving of the first set of tires comprises: The motor of the vehicle is controlled to output a corresponding torque magnitude and torque direction based on the throttle depth information and the gear information to drive the first set of tires.

4. The method according to claim 1 or 2, characterized in that: The method further comprises: When the driving force output by the motor for driving the first group of tires is still less than or equal to the tire adhesion of the first group of tires after reaching the peak motor torque and the vehicle is stationary, a first indication information is output and the vehicle is controlled to exit steering control, wherein the first indication information is used to indicate that the mass of the object carried by the vehicle exceeds the maximum load mass for achieving vehicle steering using the vehicle steering method.

5. The method according to claim 1 or 2, characterized in that: The braking second set of tires comprises: The left rear wheel and the right rear wheel are braked respectively by using a braking force, wherein the braking force is greater than or equal to a tire adhesion corresponding to one of the tires in the second group of tires, and the second group of tires includes the left rear wheel and the right rear wheel.

6. A vehicle steering device, characterized in that: include: A braking unit, used for braking the second set of tires so that the second set of tires is in a non-rotating state; a driving unit, configured to drive the first set of tires; A first control unit is used to control the steering of the vehicle based on the driving force of the driving unit driving the first group of tires is greater than the tire adhesion of the first group of tires, and the steering angle of the first group of tires is greater than a first steering angle, the steering angle of the first group of tires is the angle between the first group of tires and the body of the vehicle, the first group of tires are front wheels, and the second group of tires are rear wheels, or the first group of tires are rear wheels, and the second group of tires are front wheels.

7. The device according to claim 6, characterized in that The device also includes: a second control unit, configured to control the vehicle to enter a steering control mode in response to information indicating that the vehicle enters a steering control mode; The braking unit is specifically configured to brake the second set of tires based on the steering control mode.

8. The device according to claim 6 or 7, characterized in that The device also includes: A first acquisition unit, used to acquire gear information of the vehicle, wherein the gear information includes a forward gear and a reverse gear; A second acquisition unit, used for acquiring throttle depth information; The driving unit is specifically used to control the motor of the vehicle to output corresponding torque magnitude and torque direction based on the throttle depth information and the gear information to drive the first set of tires.

9. The device according to claim 6 or 7, characterized in that The device also includes: An output unit is used to output first indication information and control the vehicle to exit steering control when the driving force output after the driving unit drives the motor of the first group of tires to reach the peak torque of the motor is still less than or equal to the tire adhesion of the first group of tires and the vehicle is stationary, wherein the first indication information is used to indicate that the mass of the object carried by the vehicle exceeds the maximum load mass for achieving vehicle steering using the vehicle steering method.

10. A vehicle, characterized in that: The vehicle includes a controller, a motor controller, a brake controller, a first group of tires, and a second group of tires, the first group of tires being the front wheels and the second group of tires being the rear wheels, or the first group of tires being the rear wheels and the second group of tires being the front wheels, the controller being used to request the brake controller to brake the second group of tires, and to request the motor control unit to drive the first group of tires, so as to implement the steering method as described in any one of claims 1-5, thereby realizing vehicle steering.

Images