CN111874099A

CN111874099A - Control method for vehicle steering and steer-by-wire apparatus for vehicle

Info

Publication number: CN111874099A
Application number: CN202010651989.8A
Authority: CN
Inventors: 宋俊良
Original assignee: Evergrande New Energy Automobile Investment Holding Group Co Ltd
Current assignee: Evergrande New Energy Automobile Investment Holding Group Co Ltd
Priority date: 2020-07-08
Filing date: 2020-07-08
Publication date: 2020-11-03

Abstract

The application relates to a control method for vehicle steering and a steer-by-wire device of a vehicle, belonging to the technical field of steering systems of automobiles. The method includes controlling a power steering component of the vehicle to drive a steering wheel of the vehicle to steer when a steering operation is determined to steer the vehicle; acquiring target braking forces required for respective wheels of the vehicle when it is determined that a steering operation is performed and the steering assist unit is disabled, the target braking forces being determined from state information of the vehicle; applying corresponding target braking forces to the respective wheels to steer the vehicle. By adopting the method and the device, the vehicle with the steer-by-wire function can be prevented from losing the steering function when the steering power-assisted part of the vehicle is invalid, so that the safety of the vehicle can be improved.

Description

Control method for vehicle steering and steer-by-wire apparatus for vehicle

Technical Field

The present application relates to the field of automotive steering systems, and more particularly, to a method for controlling steering of a vehicle and a steer-by-wire apparatus for a vehicle.

Background

The steer-by-wire apparatus is a steering system that controls a power steering unit of an automobile to steer by an electric signal. For example, when the power steering component receives the electric steering signal, the steering driving motor of the power steering component can drive the steered wheels (e.g., the front left wheel and the front right wheel) to steer.

In order to avoid a failure of the power steering component, the failure may be a case where the power steering component does not receive the electric steering signal, or a case where the power steering component does not receive the electric steering signal. To avoid the above, a clutch is disposed between a steering output shaft of a steering wheel and a steering input shaft of a steering assist member in the steer-by-wire apparatus. In a normal state, that is, in a case where the steering assist member does not fail, the clutch is in a disengaged state, and the steering assist member performs steering in accordance with a steering electric signal, whereas in a failed state, the clutch is in an engaged state, and a driver operates the steering wheel to transmit a steering angle and torque of the steering wheel to the steered wheels through a steering output shaft of the steering wheel and a steering input shaft of the steering assist member, so that the steered wheels are steered.

When the power-assisted steering component works normally, the clutch is easy to be combined in a fault mode, and the steering function of the vehicle is influenced to cause safety accidents due to the fact that the clutch is suddenly combined in a fault mode.

Disclosure of Invention

The present application provides a control method of vehicle steering and a steer-by-wire apparatus of a vehicle, which can overcome the problems in the related art. The technical scheme is as follows:

in one aspect, a method of controlling steering of a vehicle is provided, the method comprising:

controlling a steering assist part of a vehicle to drive a steering wheel of the vehicle to steer when a steering operation is determined to steer the vehicle;

acquiring target braking forces required for respective wheels of the vehicle when it is determined that a steering operation is performed and the steering assist unit is disabled, the target braking forces being determined from state information of the vehicle;

applying a corresponding target braking force to each wheel to steer the vehicle.

In another aspect, a steer-by-wire apparatus of a vehicle is provided, the steer-by-wire apparatus comprising a control part and a steering assist part, wherein the steering assist part is connected to a steered wheel of the vehicle;

the control component is used for controlling the power steering component to drive the steering wheel of the vehicle to steer so as to steer the vehicle when the steering operation is determined;

the control means is further configured to, when it is determined that a steering operation is performed and the power steering assist means is disabled, acquire a target braking force required for each wheel of the vehicle and apply a corresponding target braking force to each wheel to steer the vehicle, the target braking force being determined from the state information of the vehicle.

In the embodiment of the present application, when the vehicle is steered by using the above method, the steering of the vehicle may be achieved by controlling the power steering unit to perform steering when the power steering unit is in a normal state, and the steering of the vehicle may be achieved by applying a required target braking force to each wheel when the power steering unit fails. Therefore, compared with the method of using the clutch as the redundant backup of the power steering component, the vehicle using the method does not use the redundant backup of the clutch, so that safety accidents caused by the failure of the clutch can be avoided, and the safety of the vehicle can be improved. In addition, when the vehicle uses the method for steering, the steer-by-wire can be carried out when the power steering component is normal, and the steer-by-wire can also be carried out when the power steering component fails, so that the full steer-by-wire function of the steer-by-wire device can be realized.

Drawings

Fig. 1 is a schematic structural view of a steer-by-wire apparatus of a vehicle shown according to an embodiment;

FIG. 2 is a flow chart diagram illustrating a method of controlling vehicle steering, according to an embodiment;

FIG. 3 is a flow chart diagram illustrating a method of controlling vehicle steering, according to an embodiment;

FIG. 4 is a flow chart diagram illustrating a method of controlling vehicle steering, according to an embodiment;

FIG. 5 is a schematic structural diagram of a steer-by-wire apparatus of a vehicle according to an embodiment;

FIG. 6 is a flow chart diagram illustrating a method of controlling vehicle steering, according to an embodiment;

fig. 7 is a schematic structural view of a steer-by-wire apparatus of a vehicle shown according to an embodiment;

FIG. 8 is a flow chart diagram illustrating a method of controlling vehicle steering, according to an embodiment;

fig. 9 is a schematic structural diagram of a steer-by-wire apparatus of a vehicle shown according to an embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

The embodiment of the present application provides a control method for vehicle steering, which may be performed by a vehicle, for example, by a vehicle controller of the vehicle, by a steer-by-wire apparatus of the vehicle, by coordination of two or three of the vehicle controller, the steering controller and a braking apparatus of the vehicle, and so on, and will be described in detail below.

To introduce the present solution more clearly, the structure and positional relationship of the main components of the vehicle that performs the method that need to be engaged in performing the steering function, and the like, will be first described.

As shown in fig. 1, the vehicle includes a steer-by-wire apparatus 1, a brake apparatus 2, and wheels, wherein the steer-by-wire apparatus 1 includes a steering controller 11 and a steering assist member 12. The number of the wheels is plural, for example, four, six, or the like, and this embodiment is not limited to this, and four wheels may be used for example. As shown in fig. 1, the wheels may include a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel. The power steering unit 12 may include a housing 121, a steering driving motor 122, and a steering rack 123, wherein the steering driving motor 122 is mounted on the housing 121, and both ends of the steering rack 123 are connected to the left and right front wheels through the housing 121 and the steering driving motor 122, respectively, for example, both ends of the steering rack 123 may be connected to the left and right front wheels through left and

right tie rods

124 and 125, respectively.

For example, a first end of the steering rack 123 is mounted on the left front wheel by a left track rod 124, and a second end of the steering rack 123 is mounted on the right front wheel by a right track rod 125. Wherein the left tie rod 124 may be rotatably connected to a first end of the steering rack 123, and the right tie rod 125 may be rotatably connected to a second end of the steering rack 123. The lengths of the left tie rod 124 and the right tie rod 125 can be flexibly selected by a technician according to actual requirements, which is not limited in this embodiment.

The steering driving motor 122 of the power steering unit 12 indirectly drives the steered wheels through the steering rack 123 and the tie rod. The power steering component 12 can also adopt a lead screw nut or a conveyor belt to indirectly drive the steering wheel to steer. The power steering unit 12 may be driven by a steering drive motor 122 to directly drive the steered wheels. In the present embodiment, the specific manner in which the power steering assistance member 12 drives the steered wheels is not limited, and the power steering assistance member 12 may drive the steered wheels to steer after receiving the electric steering signal under normal conditions. For convenience of description, it is exemplified that the steering assist member 12 drives the steered wheels in the form of a steering rack 123 and a tie rod.

As shown in fig. 1, the steer-by-wire apparatus 1 further includes a steering wheel 13 and a steering column 14, and in order to provide the driver with the feeling of rotating the steering wheel 13, correspondingly, the steer-by-wire apparatus 1 further includes a damper 15, and the steering wheel 13 and the damper 15 are connected by the steering column 14. In order to enable the vehicle to acquire the operation information of the steering wheel 13 by the driver, correspondingly, the steer-by-wire device further comprises a torque steering angle sensor 16, the torque steering angle sensor 16 can output the steering angle and the torque of the steering wheel 13, and the vehicle can acquire the operation information of the steering wheel 13 by the driver through the torque steering angle sensor 16, so that the vehicle can perform corresponding operation according to the intention of the driver.

The number of the torque rotation angle sensors 16 may be one, two, or more than two, so that the vehicle can acquire the rotation angle and the torque of the steering wheel 13.

In this way, the steering-by-wire apparatus 1 may control the steering assist member 12 to perform the steering function by an electric signal, in which when the steering controller 11 obtains the steering operation of the driver by the torque angle sensor 16, the steering assist member 12 transmits a steering electric signal, and after receiving the steering electric signal, the steering assist member 12 may control the steering drive motor 122 to rotate a certain angle in a certain direction, for example, rotate a certain angle clockwise or rotate a certain angle counterclockwise, based on the steering electric signal. In the process of rotating the steering driving motor 122, as the driving shaft of the steering driving motor 122 is in threaded connection with the steering rack 123, the steering rack 123 can be moved leftwards or rightwards, and the steering wheel can be driven to turn leftwards or rightwards by the left tie rod 124 and the right tie rod 125. Wherein the steered wheels may be left and right front wheels.

The above is the implementation structure and the brief process of the steering controller 11 in the steer-by-wire device controlling the steering assist part 12 to drive the left front wheel and the right front wheel to steer through the electric signal.

On the other hand, when the steer-by-wire apparatus 1 cannot perform the steer-by-wire function, for example, the steering assist unit 12 does not receive the steering electric signal transmitted from the steering controller 11, or when the steering assist unit 12 cannot perform steering although it can receive the steering electric signal transmitted from the steering controller 11, the above situation may be referred to as failure of the steering assist unit 12.

In the event of a failure of the steer-by-wire function, the vehicle can also be steered normally as intended by the driver by means of a brake device 2, wherein the brake device 2 can be a hydraulic brake device.

As shown in fig. 2, the braking device 2 may include a brake controller 21, a master cylinder (not shown) and a plurality of brakes 22, wherein the master cylinder is connected to the brakes 22 through a brake pipe, one brake 22 is installed at each wheel, and the master cylinder may apply a certain pressure value to the brakes 22 through the brake pipe, so that the brakes 22 apply a braking force corresponding to the pressure value to the connected wheel.

In order to avoid the situation that the Brake master cylinder outputs excessive Brake pressure to the Brake 22 to cause the wheels to be locked, the vehicle further comprises an anti-lock Brake System (ABS), and when the pressure value in the Brake pipeline is larger to cause the wheels to slide under the condition of locking, the ABS can be started to reduce the pressure value in the Brake pipeline to avoid the vehicle from being in an accident.

Under the condition that the vehicle has a failure in the wire-controlled steering function, when the vehicle turns to the left, the pressure value in the brake pipeline of the left front wheel is greater than the pressure value in the brake pipeline of the right front wheel, and the pressure value in the brake pipeline of the right rear wheel is greater than the pressure value in the brake pipeline of the left rear wheel, wherein the pressure values in the brake pipelines of the left rear wheel and the right rear wheel are used for limiting the yaw velocity and the lateral acceleration of the vehicle so as to stabilize the vehicle and avoid the vehicle from turning over, and the larger the turning angle of a steering wheel is, the larger the pressure difference value in the brake pipelines of the left side and the right side is, the more the vehicle. According to the principle, the braking force of each wheel can be controlled under the condition that the steer-by-wire function of the vehicle is failed, namely, the pressure value in the braking pipeline of each wheel is controlled, so that the vehicle can run according to the intention of a driver.

The pressure value in the brake pipeline of the wheel and the braking force of the wheel have a direct proportion corresponding relation, the larger the pressure value in the brake pipeline is, the larger the braking force applied to the wheel is, and the embodiment can control the braking force applied to the wheel by controlling the pressure value in the brake pipeline.

Based on the above structure, the process of the vehicle performing steering may be performed according to the flow shown in fig. 2:

in step 201, when a steering operation is determined, a steering assist part of the vehicle is controlled to drive a steered wheel of the vehicle to steer so as to steer the vehicle.

In one possible application scenario, the driver manipulates the steering wheel 13 to steer, and the controller of the vehicle may acquire the steering angle and torque applied to the steering wheel 13 by the driver through the torque steering angle sensor 16. For steer-by-wire, the steering gear ratio, which is the ratio of the angle of rotation of the steerable wheels to the angle of rotation of the steering wheel, is typically related to the vehicle speed, and the controller of the vehicle can then determine the steering gear ratio based on the current vehicle speed of the vehicle. For example, a corresponding relation table between the vehicle speed and the steering gear ratio is stored in advance in a controller of the vehicle, and the steering gear ratio corresponding to the current vehicle speed is determined by table lookup. Then, the turning angle of the steered wheels can be calculated from the turning angle of the steering wheel 13.

The controller of the vehicle also stores the corresponding relationship between the rotation angle of the steering wheel and the rotation information of the steering drive motor 122, wherein the rotation information includes the rotation direction and the rotation angle. Thus, the controller of the vehicle can determine the rotation information for rotating the steering drive motor 122 according to the rotation angle of the steered wheel.

The controller of the vehicle may be a vehicle controller of the vehicle, or a steering controller of a steer-by-wire apparatus, or a brake steer controller that is added to the vehicle and integrated with a steering function and a braking function, and the execution processes of each controller will be described in detail below.

For example, if the calculation process is a vehicle controller of a vehicle, the steer-by-wire apparatus may obtain a steering electric signal for driving the steering assist unit to perform steering from the vehicle controller, where the steering electric signal carries rotation information of the steering driving motor.

For another example, if the calculation process is a steering controller of a steer-by-wire apparatus, the steering controller may obtain a steering electric signal for driving the steering assist unit to perform steering through the calculation.

Then, the steering controller of the steer-by-wire apparatus may transmit a steering electric signal carrying rotation information to the steering drive motor 122 of the steering assist unit 12, and the steering drive motor 122 may rotate according to the rotation information after receiving the steering electric signal. The steering rack 123 can be moved left or right, and the steered wheels can be driven to steer left or right by the left and

right tie rods

124 and 125.

Wherein, when the vehicle is turning, if the power steering component fails, the operation is executed according to step 202.

In step 202, when it is determined that the steering is operated and the steering assist unit is disabled, target braking forces required for the respective wheels of the vehicle are acquired, the target braking forces being determined from the state information of the vehicle.

The state information of the vehicle is various parameter characteristics of the vehicle, such as the steering angle and torque of the steering wheel 13, the traveling speed of the vehicle, whether the vehicle is in a braking state or a braking release state, and the like.

As one example, the state information of the vehicle may include position information of a brake pedal of the vehicle, a pressure value of a brake master cylinder of the vehicle, a vehicle speed of the vehicle, a steering angle and torque of a steering wheel of the vehicle, and the like. The state information of the vehicle may further include a yaw rate and a lateral acceleration of the vehicle.

The state information of the vehicle may be acquired by a sensor part of the vehicle, and the sensor part may include a plurality of sensors such as a brake pedal position sensor, a master cylinder pressure sensor, a speed sensor, a rotation speed sensor, a yaw rate sensor, and the like.

For example, the position information of the brake pedal may be acquired by a brake pedal position sensor. The pressure value of the brake master cylinder can also be obtained by a brake master cylinder pressure sensor. The vehicle speed of the vehicle may be obtained by a speed sensor or a rotation speed sensor installed at each wheel, as shown in fig. 1, a rotation speed sensor 23 is installed at each wheel, the rotation speed of each wheel may be read by the rotation speed sensor 23, and the vehicle speed of the vehicle may be calculated based on the rotation speed of each wheel. The steering angle and torque of the steering wheel of the vehicle can be acquired by a torque angle sensor 16 as shown in fig. 1. The yaw rate and the lateral acceleration of the vehicle can be acquired by a yaw rate sensor.

In this way, the vehicle can calculate the target braking force that each wheel needs to apply when the vehicle performs steering, based on the current state information acquired by the vehicle. For a four-wheeled vehicle, it is necessary to calculate a target braking force for the front left wheel, a target braking force for the front right wheel, a target braking force for the rear left wheel, and a target braking force for the rear right wheel, these four target braking forces are not necessarily equal, and in the case of performing steering, the four target braking forces are usually not equal

Wherein the calculation process of the target braking force required to be applied by each wheel may be performed after the state information of the vehicle is acquired, before it is determined that the steering assist unit is disabled. For example, the vehicle acquires state information of the vehicle, and calculates and stores target braking forces required for the respective wheels based on the state information of the vehicle. The steering assist member is calculated and stored in advance, so that the condition that the steering assist member fails can be prevented, and the safety of the vehicle can be improved.

Since the processing of the controller of the vehicle is relatively fast, the calculation of the target braking force required to be applied by each wheel may also be performed when it is determined that the steering assist unit is disabled in order to save the wear of the vehicle. For example, state information of the vehicle is acquired; when it is determined that the steering operation is performed and the steering assist member is disabled, the target braking force required for each wheel of the vehicle is calculated based on the state information of the vehicle. Thus, the vehicle recalculates when the target braking force is needed, and only collects the state information of the vehicle without calculation when the target braking force is not needed, so that the power consumption of the vehicle can be reduced.

However, in the present embodiment, the time point at which the target braking force of each wheel is calculated based on the state information of the vehicle is not limited, and the target braking force required by each wheel may be quickly acquired when the vehicle determines that the steering assist unit is disabled.

In step 203, the corresponding target braking force is applied to each wheel to steer the vehicle.

In one example, after the vehicle acquires the target braking force required for each wheel, a corresponding target braking force may be applied to each wheel, so that the vehicle may achieve the effect of steering in accordance with the manipulation of the steering wheel 13 by the driver.

For example, after the vehicle acquires the target braking force required by each wheel, the pressure value in the brake pipeline of the wheel can be controlled according to the corresponding relationship between the pressure value in the brake pipeline of the wheel and the braking force of the wheel, so that the brake of the wheel applies the corresponding target braking force to the wheel, and the braking force of the wheel reaches the target braking force, thereby achieving the effect of applying the target braking force to the wheel.

Based on the above, when the vehicle is steered by using the method, when the power steering component is in a normal state, the power steering component can be controlled to perform steering, so that the steering of the vehicle is realized, when the power steering component fails, the required braking force can be applied to each wheel, so that the steering of the vehicle is realized, the condition that the vehicle cannot steer is avoided, and the safety of the vehicle can be improved.

In one example, the process of calculating the target braking force required for each wheel from the state information may be as follows:

firstly, first, according to the state information of the vehicle, a first braking force generated by a brake pedal of the vehicle of each wheel can be determined; then, calculating second braking force required by steering of each wheel according to the state information of the vehicle; and finally, calculating the target braking force required by each wheel according to the sum of the first braking force and the corresponding second braking force of each wheel.

The first braking force and the second braking force of each wheel of the vehicle may be processed simultaneously or sequentially, which is not limited in this embodiment.

In one example, the vehicle may determine the first braking force of each wheel based on the position information of the brake pedal and the pressure value of the master cylinder. For example, if the vehicle determines that the brake pedal is in the released state and the pressure value in the master cylinder is zero, the first braking force of each wheel is zero. The application scenario corresponding to this situation may be that the driver may not step on the brake pedal when steering at a low speed, and the braking force borne by each wheel is all from the steering requirement.

For another example, if the vehicle determines that the brake pedal is in a depressed state and the pressure value in the master cylinder is not zero, the first braking force of each wheel may be determined by the pressure value in the master cylinder. In this case, the driver may steer while braking at a high speed, and the braking force applied to each wheel may be required by the pedal brake and the steering.

Wherein, since the first braking force of each wheel is required from pedal braking, the first braking force of each wheel is equal when the pedal is braked.

In one example, the vehicle may determine the second braking force required for each wheel in turning, based on the vehicle speed, the rotation angle of the steering wheel 13, and the torque. For example, a relationship table between the state information of the vehicle and the second braking force of the wheel during steering may be stored in advance in the controller of the vehicle, the controller may search for the second braking force of each corresponding wheel according to the current state information, and then apply a pressure value corresponding to the second braking force to the brake pipe of the wheel according to the correspondence between the braking force of the wheel and the pressure value in the brake pipe of the wheel. For another example, a calculation formula of the second braking force of each wheel may be stored in advance in the controller of the vehicle, the controller may calculate the second braking force of each wheel according to the current state information, and then apply a pressure value corresponding to the second braking force to the brake pipe of the wheel according to the correspondence relationship between the braking force of the wheel and the pressure value in the brake pipe of the wheel.

The relationship table of the state information and the second braking force of the wheel, which is stored in the controller in advance, or the second braking force formula for calculating the wheel can be determined through theoretical calculation and experimental tests.

The present embodiment does not limit the specific manner of calculating the target braking force required by each wheel, and the target braking force of each wheel may be determined according to the current state information of the vehicle.

In one example, the vehicle may detect whether the power steering component 12 is disabled in various ways, for example, one way may be that, as shown in fig. 1, the power steering component 12 includes a steering rack 123 and a rack position sensor 126, the rack position sensor 126 is used for detecting the position information of the steering rack 123, and the vehicle may acquire the position information of the steering rack 123 sent by the rack position sensor 126; the vehicle can then determine that the power steering component 12 is disabled based on the position information of the steering rack 123 not matching the steering angle of the steering wheel 13 of the vehicle.

As shown in fig. 1, a rack position sensor 126 may be mounted on the housing 121 of the steering assist unit 12, and may monitor position information of the steering rack 123 that moves left and right in the housing 121. The number of the rack position sensors 126 may be one or more, and in the case of a plurality of rack position sensors 126, there may be a priority ranking, and the rack position sensor having a higher priority may be preferentially used by the vehicle. Alternatively, the vehicle may use data sent by any of the rack position sensors 126. This embodiment is not limited to this.

After the vehicle acquires the position information of the steering rack sent by the rack position sensor 126, whether the power steering component 12 is failed or not can be detected by judging whether the steering rack 126 is displaced or not and the displacement change condition, and then comparing the displacement change condition of the steering rack 123 with the rotation angle change condition of the steering wheel 13.

As an example, if the position information of the steering rack 123 determined by the rack position sensor 126 coincides with the rotation angle of the steering wheel 13 determined by the torque rotation angle sensor 16, the steering assist unit 12 is not deactivated, and if not, the steering assist unit 12 is deactivated.

In one example, the position information of the steering rack 123 matches the rotation angle of the steering wheel 13, for example, a correspondence table between the position information of the steering rack 123 and the rotation angle of the steering wheel 13 is stored in advance in the steering controller, and if the correspondence between the current position information of the steering rack 123 and the current rotation angle of the steering wheel 13 matches the relationship in the correspondence table, the two match, whereas if the correspondence between the current position information of the steering rack 123 and the current rotation angle of the steering wheel 13 does not match the relationship in the correspondence table, the two do not match.

For example, when the vehicle determines that the driver has operated the steering wheel 13 by the torque angle sensor, but determines that the steering rack 123 has not changed in position by the rack position sensor, the steering assist member 12 may be disabled.

Another way to detect whether a failure of the power steering assist unit 12 has occurred may be that the vehicle may further include a yaw rate sensor that may be used to detect the yaw rate and lateral acceleration of the vehicle. In this way, the vehicle can acquire the yaw rate and the lateral acceleration of the vehicle sent by the yaw rate sensor; the failure of the power steering component may then be determined based on the yaw rate and the lateral acceleration of the vehicle not coinciding with the steering angle of the steering wheel of the vehicle.

In one example, the yaw rate and the lateral acceleration of the vehicle coincide with the turning angle of the steering wheel of the vehicle, for example, the controller of the vehicle stores in advance the correspondence relationship between the yaw rate, the lateral acceleration, and the turning angle of the steering wheel, and if the correspondence relationship between the current yaw rate, the lateral acceleration, and the turning angle of the steering wheel 13 of the vehicle matches the relationship in the correspondence relationship table. And if the relation in the corresponding relation table is not met, the relation is not matched.

For example, the case where the vehicle determines that the driver has operated the steering wheel 13 by the torque angle sensor 16, but determines that the yaw rate of the vehicle has not changed by the yaw rate sensor and the lateral acceleration is zero indicates that the power steering unit 12 has failed.

Based on the above, when the driver operates the steering wheel 13 to perform steering, the steering controller in the steer-by-wire apparatus of the vehicle can control the power steering component to drive the steering wheel to steer by the steering electric signal. When the steering assist unit fails, the vehicle may determine that the steering assist unit 12 fails, and then apply corresponding target braking forces to the respective wheels by the target braking forces of the respective wheels determined by the state information of the vehicle, so that the vehicle travels as intended by the driver under the target braking forces of the respective wheels.

In one example, after the required target braking force is applied to each wheel, in order to detect whether the pressure value in the brake pipe of each wheel is consistent with the corresponding target braking force, a pressure sensor is correspondingly arranged in the brake pipe of each wheel, and the pressure sensor can detect the pressure value in the brake pipe. In this way, after the vehicle applies the corresponding target braking force to each wheel, the pressure value in the brake pipe of each wheel sent by the pressure sensor in the brake pipe of each wheel can be obtained; when the pressure value in the brake pipeline of the target wheel is determined to be inconsistent with the corresponding target braking force, the pressure value in the brake pipeline of the target wheel is adjusted to enable the pressure value in the brake pipeline of the target wheel to be consistent with the corresponding target braking pressure, wherein the target wheel is any one of the wheels.

The pressure value in the brake pipeline of the wheel is consistent with the target braking force of the wheel, namely, the pressure value in the brake pipeline of the wheel and the target braking force of the wheel meet the pre-stored proportional corresponding relation. The pressure value in the brake pipe of the wheel and the target braking force of the wheel are not consistent, that is, the pressure value in the brake pipe of the wheel and the target braking force of the wheel do not satisfy the proportional correspondence relationship stored in advance.

For example, if the vehicle determines that the pressure value in the brake line of the left front wheel is smaller than the pressure value corresponding to the required target brake pressure calculated from the current state information of the vehicle by the pressure sensor in the brake line of each wheel, the difference between the pressure value corresponding to the calculated target brake pressure and the detected pressure value may be used as a pressure adjustment value, and the line pressure of the pressure adjustment value may be applied to the brake of the left front wheel, so that the pressure value in the brake line of the left front wheel is in agreement with the calculated target brake pressure, that is, the pressure value in the brake line of the left front wheel is equal to the pressure value corresponding to the calculated target brake pressure.

As described above, the method may be executed by the vehicle control unit of the vehicle, may be executed by the steer-by-wire apparatus and the braking apparatus of the vehicle in cooperation, may be executed by the vehicle control unit and the braking apparatus of the vehicle in cooperation, and the like.

Correspondingly, the controller of the vehicle may be a steering controller of a steer-by-wire device, may also be a vehicle controller of the vehicle, may also be a brake controller of a brake device, and the controller may also be a brake steer controller integrating the steering controller and the brake controller, etc.

In one embodiment, the process of controlling the steering by the power steering unit may be performed by a steering controller, the process of calculating the target braking force of each wheel may be performed by the steering controller, the corresponding process of the vehicle in the steering may refer to a flow chart shown in fig. 3, and the vehicle configuration diagram may be shown in fig. 1, where in fig. 1, v represents a vehicle speed, ω represents a yaw rate, a represents a lateral acceleration, Φ represents position information of a brake pedal, Pm represents a pressure value of a brake master cylinder, and an arrow in fig. 1 represents a transmission direction of an electric signal or data.

In step 301, the steering controller reads the state information of the vehicle.

The state information may include a steering wheel angle and a torque output by the torque angle sensor, and is used for calculating a steering transmission ratio in steer-by-wire and for determining whether the power steering unit is disabled together with the rack position sensor. The state information may further include position information of a rack of a steering gear output from a rack position sensor for determining whether the steering assist unit is disabled together with a steering angle and a torque of the steering wheel. The state information may also include the vehicle speed of the vehicle for calculating the steering gear ratio and calculating the target braking force required to be applied by each wheel. The status information also includes a master cylinder pressure value output by a master cylinder pressure sensor for calculating a target braking force required to be applied by each wheel, for example, for determining a first braking force for each wheel. The state information may also include other parameters, which technicians may flexibly add as needed.

In step 302, when the steering controller determines a steering operation based on the steering angle of the steering wheel, it sends a steering electric signal to the power steering unit based on the steering angle and the torque of the steering wheel.

The steering electric signal carries rotation information of the steering drive motor, such as a rotation direction and a rotation amount, which can be determined by a rotation angle and a torque of the steering wheel.

In step 303, the steering assist unit performs a steering operation after receiving the steering electric signal.

In step 304, the steering controller determines whether the steering assist unit has failed based on the position information of the steering rack and the rotation angle of the steering wheel, which is also used to determine whether the steering assist unit has normally performed a steering operation in step 303.

And if the failure does not occur, ending the process of steering the vehicle. If the steering assist unit fails, the process proceeds to step 305.

In step 305, the steering controller acquires target braking forces for the respective wheels.

The braking force of each wheel is the braking force required to be applied to each wheel when the power steering unit fails to steer the vehicle.

In one example, the steering controller may calculate the target braking force for each wheel after reading in the state information of the vehicle and before determining that the steering assist unit is disabled. The steering controller may also recalculate the target braking force for each wheel upon receiving the failure signal. For safety, the steering controller may calculate the target braking force for each wheel after reading in the state information of the vehicle and before determining the fail signal. To save energy consumption, the steering controller may calculate the target braking force for each wheel upon receiving the fail signal. The embodiment does not limit the method, and technicians can flexibly set the method according to actual conditions.

In step 306, the steering controller sends the target braking force for each wheel to the brake controller of the brake device. The steering controller may also send a message to the brake controller that the steering assist feature is disabled.

After the brake controller receives the target braking force of each wheel sent by the steering controller in step 307, the required braking force may be applied to each wheel so that the vehicle is steered by the target braking force of each wheel, and then the process is terminated.

In another embodiment, the control process of steering by the steering assist unit may be performed by a steering controller, and the process of calculating the target braking force of each wheel may be integrated in a brake controller of the brake device. The corresponding process of vehicle steering may refer to the flow shown in fig. 4, wherein the vehicle structural diagram may be shown in fig. 5, wherein in fig. 5, v represents vehicle speed, ω represents yaw rate, a represents lateral acceleration, Φ represents position information, Pm represents pressure value of the master cylinder, and the arrow in fig. 5 represents transmission direction of electric signal or data.

In step 401, the steering controller reads the state information of the vehicle.

The state information may include a steering angle and a torque output by the torque steering angle sensor, and is used for calculating a steering transmission ratio in steer-by-wire and for judging whether the power steering unit is disabled together with the rack position sensor. The state information may further include position information of a rack of a steering gear output from a rack position sensor for determining whether the steering assist unit is disabled together with a steering angle and a torque of the steering wheel. The state information may also include the vehicle speed of the vehicle for calculating the steering gear ratio and calculating the target braking force required to be applied by each wheel. The state information also includes a pressure value in the master cylinder output by a pressure sensor in the master cylinder for calculating a target braking force required to be applied by each wheel, for example, for determining a first braking force of each wheel. The state information may also include other parameters, which technicians may flexibly add as needed.

In step 402, when the steering controller determines a steering operation based on the steering angle of the steering wheel, it sends a steering electric signal to the power steering unit based on the steering angle and the torque of the steering wheel.

In step 403, the steering assist unit performs a steering operation after receiving the steering electric signal.

In step 404, the steering controller determines whether the steering assist unit fails based on the position information of the steering rack and the rotation angle of the steering wheel, which may also be used to determine whether the steering assist unit performs the steering operation normally in step 403.

And if the failure does not occur, ending the process of steering the vehicle. If the steering assist feature fails, then the process goes to step 405.

In step 405, the steering controller sends a disable signal to the brake controller.

In step 406, the brake controller acquires target braking forces for the respective wheels.

In one example, to expedite the calculation of the target braking force for each wheel by the brake controller, the brake controller may read in state information of the vehicle prior to step 406, where the state information of the vehicle may be referred to above. The brake controller may also read in the vehicle's state information prior to step 405, or even as the steering controller reads in the vehicle's state information at step 401, the brake controller may also synchronously read in the vehicle's state information for later use.

After the brake controller reads the state information of the vehicle, the target braking force of each wheel may be directly calculated, or the target braking force of each wheel may be calculated again when the fail signal is received. For safety, the brake controller may calculate the target braking force for each wheel after reading in the state information of the vehicle and before receiving the fail signal. In order to save energy consumption, the brake controller may calculate a target braking force for each wheel upon receiving the fail signal. The embodiment does not limit the method, and technicians can flexibly set the method according to actual conditions.

In step 407, the brake controller applies the required target braking force to each wheel so that the vehicle is steered under the target braking force of each wheel, and then goes to the end.

In another embodiment, the process of controlling the power steering assist unit and the process of calculating the target braking force for each wheel may be integrated into a brake steering controller, i.e., the vehicle may integrate the brake controller and the steering controller into a single module, which may be referred to as a brake steering controller. Thus, the steering control process of the steer-by-wire apparatus is performed by the brake steering controller, and the braking process of the brake apparatus is also performed by the brake steering controller.

The corresponding process of vehicle steering may refer to the flow shown in fig. 6, wherein the vehicle structure diagram may be shown in fig. 7, v in fig. 7 represents vehicle speed, ω represents yaw rate, a represents lateral acceleration, Φ represents position information, Pm represents pressure value of the master cylinder, and the arrow in fig. 7 represents transmission direction of electric signal or data.

In step 601, the brake steering controller reads the status information of the vehicle.

In step 602, when the brake steering controller determines a steering operation based on the steering angle of the steering wheel, it sends a steering electric signal to the power steering unit based on the steering angle and the torque of the steering wheel.

In step 603, the steering assist unit performs a steering operation after receiving the steering electric signal.

In step 604, the brake steering controller determines whether the power steering unit is disabled based on the position information of the steering rack and the rotation angle of the steering wheel, which may also be used to determine whether the steering operation is normally performed in step 603.

And if the failure does not occur, ending the process of steering the vehicle. If the steering assist feature fails, then the process goes to step 605.

In step 605, the brake steering controller acquires target braking forces for the respective wheels.

The target braking force for each wheel is a braking force that needs to be applied to each wheel when the steering assist unit fails and the vehicle is steered.

In one example, the brake steering controller may calculate the target braking force for each wheel after reading in the state information of the vehicle and before determining that the power steering assist unit is disabled. The brake steering controller may also recalculate the target braking force for each wheel upon receiving the failure signal. For safety, the brake steering controller may calculate the target braking force for each wheel after reading in the status information of the vehicle and before determining the fail signal. In order to save energy consumption, the brake steering controller may calculate the target braking force for each wheel upon receiving the fail signal. The embodiment does not limit the method, and technicians can flexibly set the method according to actual conditions.

In step 606, the brake steering controller applies the required target braking force to each wheel so that the vehicle is steered by the braking force of each wheel, and then goes to the end.

In another embodiment, the control process of steering by the power steering component may be performed by a steering controller, and when the power steering component fails, the steering controller may send a failure electric signal to a brake controller through a Vehicle Control Unit (VCU) to enable the brake controller to start a brake steering operation mode, and the corresponding process of performing steering by the Vehicle may refer to a flow shown in fig. 8, where a schematic view of a Vehicle structure may be shown in fig. 9, v in fig. 9 represents a Vehicle speed, ω represents a yaw angular velocity, a represents a lateral acceleration, Φ represents position information, Pm represents a pressure value of a brake master cylinder, and an arrow in fig. 9 represents a transmission direction of the electric signal or data.

In step 801, the steering controller reads status information of the vehicle.

In step 802, when the steering controller determines a steering operation based on the steering angle of the steering wheel, it sends a steering electric signal to the power steering unit based on the steering angle and the torque of the steering wheel.

In step 803, the steering assist unit performs a steering operation after receiving the steering electric signal.

In step 804, the steering controller determines whether the steering assist unit is out of order based on the position information of the steering rack and the rotation angle of the steering wheel, which may also be used to determine whether the steering operation is normally performed in step 803.

And if the failure does not occur, ending the process of steering the vehicle. If the power steering component fails, the process proceeds to step 805.

In step 805, the steering controller sends a disable signal to the vehicle control unit.

After receiving the failure signal, the vehicle control unit may calculate the target braking force of each wheel, or may calculate the target braking force of each wheel through the brake controller. The present embodiment does not limit this, and the vehicle control unit may calculate the target braking force of each wheel through the brake controller.

In step 806, the hybrid controller sends a disable signal to the brake controller to cause the brake controller to initiate brake steering.

In step 807, the brake controller acquires target braking forces for the respective wheels.

In one example, to speed up the calculation of the target braking force for each wheel by the brake controller, the brake controller may read in the state information of the vehicle before step 807, wherein the state information of the vehicle may be referred to above. The brake controller may also read in the vehicle's status information prior to step 806, or even as the steering controller reads in the vehicle's status information at step 801, the brake controller may also synchronously read in the vehicle's status information for later use.

In step 808, the brake controller applies the required target braking force to each wheel so that the vehicle is steered under the target braking force of each wheel, and then goes to the end.

In the present embodiment, the execution main body for executing steer-by-wire and the execution main body for executing brake steering are not limited as long as the vehicle can be steered by the steer-by-wire mode when the power steering component is in a normal steering state, and the vehicle can be steered by the brake steering mode when the power steering component is in a failure state.

Based on the above, when the vehicle is steered by using the method, when the power steering component is in a normal state, the power steering component can be controlled to perform steering, so that the vehicle is steered, when the power steering component fails, the required target braking force can be applied to each wheel, so that the vehicle can be steered, and further, the vehicle can be prevented from being incapable of steering, so that the safety of the vehicle can be improved.

In addition, in the method, when the steering is performed and the power steering component is in a good state, the power steering component is controlled by an electric signal to drive the steering wheel to steer, so that the steer-by-wire of the vehicle is realized. When the steering is performed and the power steering unit is in a failure state, the electric signals control the wheels to brake with a target braking force for steering the vehicle, so that the traveling direction of the vehicle can be controlled. Therefore, the method can realize complete linear control in steering control, and the wire-controlled steering can save a steering intermediate transmission shaft, a steering gear input shaft and the like between a steering column and a steering power-assisted part, namely, a steering wheel controlled by a driver is not connected with the steering power-assisted part of a wire-controlled steering device through a mechanical transmission shaft, so that the arrangement space of a front cabin of a vehicle can be saved.

The embodiment of the application also provides a steer-by-wire device, the steer-by-wire device 1 comprises a control component and a power steering component 12, wherein, as shown in fig. 1, the power steering component 12 is connected with a steering wheel of a vehicle where the steer-by-wire device 1 is located. Wherein the steered wheels may be left and right front wheels of the vehicle.

Wherein the control means is configured to control the steering assist means 12 to drive the steered wheels to steer the vehicle when a steering operation is determined; control means for acquiring target braking forces required for the respective wheels of the vehicle when it is determined that the steering operation is performed and the steering assist means 12 is disabled, the target braking forces being determined from the state information of the vehicle; the corresponding target braking force is applied to each wheel to steer the vehicle.

For example, after the control unit determines that the steering assist unit 12 is disabled and obtains the target braking force required for each wheel of the vehicle, the corresponding target braking force may be directly applied to each wheel to steer the vehicle.

For another example, after the control unit determines that the power steering unit 12 is disabled and obtains the target braking force required for each wheel of the vehicle, the corresponding target braking force may be indirectly applied to each wheel to steer the vehicle. As an example, the control means may transmit the target braking force required for each wheel to the brake device 2 of the host vehicle to cause the brake device 2 to apply the corresponding target braking force to each wheel to steer the vehicle.

The control unit can determine whether or not the steering assist unit 12 is disabled by determining whether or not the yaw of the vehicle matches the turning angle of the steering wheel 13.

For example, a torque angle sensor 16 may be mounted on the steering column 14 of the steering wheel 13, the torque angle sensor 16 may output the angle and torque of the steering wheel 13, a yaw rate sensor may be mounted on the vehicle, and the yaw rate sensor may output the yaw rate and lateral acceleration of the vehicle, so that the control section may determine whether or not the steering assist section 12 is disabled by the yaw rate and lateral acceleration of the vehicle output from the yaw rate sensor, and the angle and torque of the steering wheel 13 output from the torque angle sensor 16.

The control unit may determine whether or not the steering assist unit 12 is out of order by determining whether or not the position information of the steering rack 123 of the steering assist unit 12 matches the steering angle of the steering wheel 13.

For example, as shown in fig. 1, the power steering unit 12 may include a steering rack 123 and a rack position sensor 126, the steering rack 123 being connected to the steering wheel through a tie rod, and the rack position sensor 126 being mounted on the housing 121 of the power steering unit 12 for detecting position information of the steering rack 123.

The number of the rack position sensors 126 may be one or more, and in the case of a plurality of rack position sensors 126, there may be a priority ranking, and the rack position sensor having a higher priority may be preferentially used by the vehicle. Alternatively, the vehicle may use data sent by any of the rack position sensors 126. This embodiment is not limited to this.

In one example, the rack position sensor 126 may monitor position information of the steering rack 123 that is movable left and right in the housing 121, so that the control unit may know the position information of the steering rack 123 in real time to compare with the rotation angle of the steering wheel 13 to determine whether the steering assist unit 12 performs a steering operation or not while the steering wheel 13 is rotating, so as to determine whether the steering assist unit 12 is out of order.

In this way, the control unit can determine that the steering assist unit 12 is disabled based on the fact that the position information of the steering rack 123 does not coincide with the rotation angle of the steering wheel 13 of the vehicle.

As shown in fig. 1, the steering assist unit 12 of the steer-by-wire apparatus 1 may further include a housing 121 and a steering drive motor 122, and the steering drive motor 122 may be mounted on the housing 121 for driving the steered wheels to steer in a normal condition of the steering assist unit 12. The steering gear rack 123 is in threaded connection with an output shaft of the steering drive motor 122, so that when the steering drive motor 122 rotates, the steering gear rack 123 can move leftwards or rightwards, and the purpose of driving the steering wheel to steer through the tie rod is achieved.

As shown in fig. 1, a first end of the steering rack 123 may pass through the housing 121 and the steer drive motor 122 to be mounted on the left front wheel via a left track rod 124, and a second end of the steering rack 123, the housing 121 and the steer drive motor 122, may be connected to the right front wheel via a right track rod 125. Wherein the left tie rod 124 may be rotatably connected to a first end of the steering rack 123, and the right tie rod 125 may be rotatably connected to a second end of the steering rack 123. The lengths of the left tie rod 124 and the right tie rod 125 can be flexibly selected by a technician according to actual requirements, which is not limited in this embodiment.

The steering driving motor 122 of the power steering unit 12 drives the steering wheel through the steering rack 123 and the tie rod. The power steering component 12 can also adopt a screw nut or a belt to drive the steering wheel to steer. The power steering assembly 12 can also be steered by directly driving the steering wheel with the steering drive motor 122. In the present embodiment, the specific manner in which the power steering assistance member 12 drives the steered wheels is not limited, and the power steering assistance member 12 may drive the steered wheels to steer after receiving the electric steering signal under normal conditions. For convenience of description, it is exemplified that the steering assist unit 12 drives the steered wheels to steer in the manner of the steering rack 123 and the tie rod.

In order to provide the driver with the feel of rotating the steering wheel 13, accordingly, as shown in fig. 1, the steer-by-wire apparatus 1 further includes a damper 15, and the steering wheel 13 and the damper 15 are connected by a steering column 14. As described above, the torque steering angle sensor 16 can output the steering angle and the torque, and accordingly, the control means can acquire the operation information of the steering wheel 13 by the driver through the torque steering angle sensor 16 so that the vehicle can perform the corresponding operation according to the intention of the driver.

In one example, the steer-by-wire apparatus further includes a sensor part for collecting and transmitting to the control part status information of the vehicle, the status information of the vehicle including position information of a brake pedal of the vehicle, a pressure value of a brake master cylinder of the vehicle, a vehicle speed of the vehicle, a steering angle of a steering wheel of the vehicle, and a torque. Thus, the control section can determine the steering operation based on the steering angle and torque of the steering wheel, and can also calculate the target braking force required for each wheel of the vehicle based on the position information of the brake pedal, the pressure value of the master cylinder, the vehicle speed of the vehicle, and the steering angle and torque of the steering wheel.

The sensor parts may include the various sensors described above, and may include, for example, a brake pedal position sensor, a master cylinder pressure sensor, a speed sensor, a rotational speed sensor, a torque angle sensor 16, and the like. The system comprises a control component, a brake pedal position sensor, a brake master cylinder pressure sensor, a speed sensor, a torque corner sensor 16 and a control component, wherein the brake pedal position sensor is used for acquiring and sending position information of a brake pedal to the control component, the brake master cylinder pressure sensor is used for acquiring and sending a pressure value of a brake master cylinder to the control component, the speed sensor is used for acquiring and sending vehicle speed to the control component, the rotation speed sensors at all wheels are used for acquiring and sending rotation speeds of all wheels to the control component, and the torque corner sensor 16 is used for acquiring and sending a corner.

The state information of the vehicle may further include a yaw rate and a lateral acceleration of the vehicle, and the corresponding sensor part may further include a yaw rate sensor for acquiring and transmitting the yaw rate and the lateral acceleration to the control part.

As can be seen from the above description, the steer-by-wire apparatus can control the power steering unit to perform a steering operation by an electric signal when the power steering unit is operating normally, and can control the vehicle traveling direction by controlling the braking force of each wheel by an electric signal when the power steering unit fails.

In the embodiment of the application, when the vehicle is steered by using the method, when the power steering component is in a normal state, the power steering component can be controlled to steer, so that the steering of the vehicle is realized, when the power steering component fails, the driving direction of the vehicle can be controlled by applying required target braking force to each wheel, and further the vehicle can be prevented from being out of control, so that the safety of the vehicle can be improved.

In one possible example, the control component is a steering controller, and the braking device of the vehicle includes a brake controller; and the steering controller is specifically used for acquiring target braking force required by each wheel of the vehicle when the steering operation is determined and the power steering assisting component fails, and sending the target braking force required by each wheel to the brake controller so that the brake controller applies the corresponding target braking force to each wheel to steer the vehicle, wherein the target braking force required by each wheel is calculated by the steering controller according to the state information of the vehicle.

In such a scenario, when the power steering component is normal, the steering controller may control the power steering component to perform a steering function. When the power steering component fails, the steering controller may be configured to determine a steering signal, a steering failure signal, and calculate a target braking force for each wheel, and applying the corresponding target braking force to each wheel may be performed by a brake controller of the brake device. The specific process can be described with reference to the flow of fig. 3, and is not described in detail here.

In another possible example, the control component is also a steering controller, the braking device of the vehicle comprising a brake controller; and the steering controller is specifically used for sending a steering failure signal to the brake controller when the steering operation is determined and the power steering assisting component fails so that the brake controller obtains target braking force required by each wheel of the vehicle and applies corresponding target braking force to each wheel to steer the vehicle, wherein the target braking force required by each wheel is calculated by the brake controller according to the state information of the vehicle.

In such a scenario, the steering controller may control the power steering component to perform the steering function when the power steering component is normal. The steering controller may be configured to determine a steering signal, a steering failure signal, and send the steering failure signal to the brake controller in the event of a failure of the power steering component. And calculating the target braking force for each wheel, and applying the corresponding target braking force to each wheel, may be performed by the brake controller. The specific implementation process can be described with reference to the flow of fig. 4, and is not described in detail here.

In another possible example, the control unit is a brake steering controller, and the target braking force required for each wheel is calculated by the brake steering controller based on the state information of the vehicle.

In this scenario, when the power steering component is normal, the brake steering controller may control the power steering component to perform a steering function. In the event of a failure of the power steering component, the brake steering controller may be configured to determine a steering signal, a steering failure signal, calculate a target braking force for each wheel, and apply a corresponding target braking force to each wheel. That is, the brake steering controller integrates the functions of the steering controller and the brake controller. The specific implementation process can be described with reference to the flow of fig. 6, and is not described in detail here.

In another possible example, the control component is a steering controller, the vehicle comprises a vehicle control unit, and the braking device of the vehicle comprises a braking controller; the steering controller is specifically used for sending a steering failure signal to the vehicle control unit when the steering operation is determined and the steering power-assisted part fails; when the vehicle control unit receives the steering failure signal, the vehicle control unit sends a command for starting a steering failure working mode to the brake controller, so that the brake controller obtains target braking force required by each wheel of the vehicle and applies corresponding target braking force to each wheel to steer the vehicle, and the target braking force required by each wheel is calculated by the brake controller according to the state information of the vehicle.

In this scenario, when the power steering component is normal, the steering controller may control the power steering component to perform a steering function. When the power steering component fails, the steering controller can be used for determining a steering signal and a steering failure signal and sending the steering failure signal to the vehicle control unit. The vehicle control unit may send a command to the brake controller to start the steering failure mode, and after receiving the command, the brake controller may calculate a target braking force for each wheel and apply a corresponding target braking force to each wheel. The specific implementation process can be described with reference to the flow of fig. 8, and is not described in detail here.

It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A control method of steering a vehicle, characterized by comprising:

2. The method according to claim 1, wherein before the target braking force required for each wheel of the vehicle is acquired when it is determined that the steering is operated and the steering assist unit is disabled, the method further comprises:

acquiring state information of the vehicle;

and calculating and storing target braking force required by each wheel according to the state information of the vehicle.

3. The method according to claim 1, wherein before the target braking force required for each wheel of the vehicle is acquired when it is determined that the steering is operated and the steering assist unit is disabled, the method further comprises:

acquiring state information of the vehicle;

when it is determined that the steering operation is performed and the steering assist member is disabled, target braking forces required for the respective wheels of the vehicle are calculated based on the state information of the vehicle.

4. The method according to claim 2 or 3, wherein the process of calculating the target braking force required for each wheel includes:

determining a first braking force generated by a brake pedal of the vehicle and a second braking force required by each wheel to steer according to the state information of the vehicle;

for each wheel, a target braking force required for the wheel is calculated from a sum of the first braking force and the corresponding second braking force of the wheel.

5. The method according to claim 4, characterized in that the state information of the vehicle includes position information of a brake pedal of the vehicle, a pressure value of a brake master cylinder of the vehicle, a vehicle speed of the vehicle, a steering angle and a torque of a steering wheel of the vehicle;

the determining a first braking force generated by a brake pedal of the vehicle and a second braking force required by each wheel to steer according to the state information of the vehicle comprises the following steps:

determining a first braking force of each wheel generated by a brake pedal of the vehicle according to the position information of the brake pedal and the pressure value of the brake master cylinder;

and determining second braking force required by steering of each wheel according to the vehicle speed of the vehicle, the turning angle of the steering wheel and the torque.

6. The method of claim 1, wherein the power steering component comprises a steering rack and a rack position sensor, the rack position sensor being configured to collect position information of the steering rack;

the method further comprises the following steps:

acquiring the position information of the steering gear rack acquired by the rack position sensor;

and determining that the power steering component is invalid according to the fact that the position information of the steering rack is not matched with the turning angle of the steering wheel of the vehicle.

7. The method of claim 1, wherein the vehicle comprises a yaw-rate sensor for acquiring a yaw-rate and a lateral acceleration of the vehicle;

the method further comprises the following steps:

acquiring the yaw velocity and the lateral acceleration of the vehicle, which are acquired by the yaw velocity sensor;

determining that the power steering component is disabled based on the yaw rate and the lateral acceleration of the vehicle not coinciding with the turning angle of the steering wheel of the vehicle.

8. The method according to claim 1, characterized in that the brake line of each wheel has a pressure sensor for acquiring the pressure value in the brake line;

the method further comprises the following steps:

acquiring pressure values in the brake pipelines of the wheels, which are acquired by pressure sensors in the brake pipelines of the wheels;

when it is determined that the pressure value in the brake pipeline of the target wheel is inconsistent with the corresponding target braking force, adjusting the pressure value in the brake pipeline of the target wheel so as to enable the pressure value in the brake pipeline of the target wheel to be consistent with the corresponding target braking force, wherein the target wheel is any one of the wheels.

9. A steer-by-wire apparatus of a vehicle, characterized in that the steer-by-wire apparatus comprises a control part and a steering assist part, wherein the steering assist part is connected to a steered wheel of the vehicle;

10. The steer-by-wire apparatus of claim 9, wherein the control component is a steering controller, and the vehicle braking device comprises a brake controller;

the steering controller is specifically configured to, when it is determined that a steering operation is performed and the power steering assist device is disabled, acquire a target braking force required for each wheel of the vehicle, and send the target braking force required for each wheel to the brake controller so that the brake controller applies a corresponding target braking force to each wheel to steer the vehicle, where the target braking force required for each wheel is calculated by the steering controller based on the state information of the vehicle.

11. The steer-by-wire apparatus of claim 9, wherein the control component is a steering controller, and the vehicle braking device comprises a brake controller;

the steering controller is specifically configured to send a steering failure signal to the brake controller when it is determined that the steering operation is performed and the power steering assist unit is failed, so that the brake controller obtains target braking forces required by respective wheels of the vehicle, and applies corresponding target braking forces to the respective wheels to steer the vehicle, where the target braking forces required by the respective wheels are calculated by the brake controller according to the state information of the vehicle.

12. The steer-by-wire apparatus according to claim 9, wherein the control means is a brake-steering controller, and the target braking force required for each wheel is calculated by the brake-steering controller based on the state information of the vehicle.

13. The steer-by-wire apparatus of claim 9, wherein the control component is a steering controller, the vehicle comprises a vehicle control unit, and the braking apparatus of the vehicle comprises a brake controller;

the steering controller is specifically used for sending a steering failure signal to the vehicle control unit when the steering operation is determined and the power steering component fails;

when the vehicle control unit receives the steering failure signal, sending a command for starting a steering failure working mode to the brake controller, so that the brake controller obtains target braking force required by each wheel of the vehicle, and applying corresponding target braking force to each wheel to steer the vehicle, wherein the target braking force required by each wheel is calculated by the brake controller according to the state information of the vehicle.

14. The steer-by-wire apparatus according to any one of claims 9 to 13, wherein the power steering assembly (12) comprises a steering rack (123) and a rack position sensor (126), wherein the steering rack (123) is connected to the steering wheel via a tie rod, and wherein the rack position sensor (126) is located on a housing (121) of the power steering assembly (12) for collecting and transmitting position information of the steering rack (123) to the control assembly;

and the control component is specifically used for determining that the power steering component (12) is failed according to the fact that the position information of the steering rack (123) is not matched with the rotating angle of a steering wheel (13) of the vehicle.

15. The steer-by-wire apparatus according to any one of claims 9 to 13, further comprising sensor means for acquiring and sending to the control means status information of the vehicle, the status information of the vehicle including position information of a brake pedal of the vehicle, a pressure value of a brake master cylinder of the vehicle, a vehicle speed of the vehicle, a steering angle and a torque of a steering wheel of the vehicle;

the control unit is specifically configured to determine a steering operation based on the steering angle and the torque of the steering wheel, and calculate a target braking force required for each wheel of the vehicle based on the position information of the brake pedal, the pressure value of the brake master cylinder, the vehicle speed of the vehicle, and the steering angle and the torque of the steering wheel.