Vehicle steering system and method for controlling vehicle steering

Abstract

To provide an automatic driving system and / or support drive system which is capable of not only achieving redundancy design for a steer-by-wire system but also capable of not only securing safety while the vehicle is in operation but also of effectively improving stability and comfort of steering of the vehicle.SOLUTION: An automatic driving system includes: a first control unit 11 configured to perform a steering function of a vehicle; a condition detection unit 12 configured to detect an operation state of the first control unit; and a second control unit 13 concerning control of a steering function of the vehicle when an abnormal operation state of the first control unit is detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to the field of vehicles, in particular vehicle steering systems, methods for controlling the steering of vehicles, and computer program products designed to assist in carrying out at least the steps of the methods according to the present disclosure. [Background technology]

[0002] In conventional vehicle steering systems, such as hydraulic steering systems or electric power steering (EPS) systems, the steering wheel is mechanically connected to the vehicle's front wheels at all times, allowing the driver to control the steering of the vehicle even in the event of a hydraulic or EPS failure.

[0003] With the development of vehicle technology, vehicle steering systems are gradually evolving into steer-by-wire systems, in which the transmission part of the steering column is removed, there is a complete separation between the input control signal from the steering wheel and the actuator of the front wheels, and the input control signal from the steering wheel needs to be transmitted to the actuator of the front wheels through a steer-by-wire signal transmission unit. However, even if the steer-by-wire system itself is installed for redundancy, some electronic components of the steer-by-wire system may still fail, and steering control failure may occur due to the failure of these electronic components while the vehicle is moving, thus affecting the driving safety of the vehicle.

[0004] Therefore, how to install a reliable vehicle steering system has become a current technical problem that needs to be addressed. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present disclosure to provide a vehicle steering system, a method for controlling the steering of a vehicle, and a computer program product for addressing problems in the prior art.

[0006] According to a first aspect of the present disclosure, a vehicle steering system is provided, comprising a first control unit configured to perform a steering function of the vehicle, a condition detection unit configured to detect an operating condition of the first control unit, and at least one second control unit configured to participate in controlling the steering function of the vehicle when an abnormal operating condition of the first control unit is detected.

[0007] The core idea of ​​the present disclosure is that when an abnormal operation state occurs in the primary steering system of the vehicle, a backup control unit, such as an electronic stability program system with steering control function, a rear wheel steering system, and / or a torque vectoring control system, can be activated to take part in controlling the steering function of the vehicle. According to the embodiments of the present disclosure, it is possible to provide redundancy of the steering system for a high level of autonomous driving system and / or assisted driving system, in particular, to achieve a redundancy design for the steer-by-wire system, and not only ensure safety when the vehicle is in a moving state, but also effectively improve the stability and comfort of the steering of the vehicle.

[0008] According to one optional embodiment of the present disclosure, the first control unit may comprise an EPS system or a steer-by-wire system. Optionally, the at least one second control unit comprises one or more of the following components: an electronic stability program system, a rear wheel steering system, and a torque vectoring control system.

[0009] According to another optional embodiment of the present disclosure, the electronic stability program system controls the braking torque of each wheel on a same side of the vehicle to steer the vehicle in a desired steering direction, and braking forces are applied separately to each wheel on the same side or to one wheel on the same side using a hydraulic braking mechanism and / or a friction-based electromechanical braking mechanism. Optionally, when oversteer is detected, the electronic stability program system applies braking forces to one or more wheels on a side of the vehicle on the desired steering direction to apply a lateral torque to the vehicle body toward the desired steering direction. Optionally, when oversteer is detected, the electronic stability program system applies braking forces to one or more wheels on an opposite side of the vehicle's desired steering direction to apply a lateral torque to the vehicle body in a direction opposite to the desired steering direction.

[0010] According to another optional embodiment of the present disclosure, the rear wheel steering system controls a rear wheel steering angle of the vehicle, such that the vehicle steers toward a desired steering direction, and the direction of the rear wheel steering angle is opposite to the desired steering direction.

[0011] According to another optional embodiment of the present disclosure, drive and / or braking parameters for each wheel on each side of the vehicle are controlled through a torque vectoring control system. For example, braking force is applied separately to each wheel on one side of the vehicle through either the torque vectoring control system or the braking system, while drive force is applied to each wheel on the other side of the vehicle through the torque vectoring control system, thereby steering the vehicle towards a desired steering direction.

[0012] According to another optional embodiment of the present disclosure, drive and / or braking parameters of each wheel on each side of the vehicle are synergistically controlled by a torque vectoring control system and an electronic stability program system, whereby the vehicle is steered toward a desired steering direction, the torque vectoring control system controls the drive and / or braking parameters of each wheel on each side of the vehicle, and the electronic stability program system is responsible for controlling the braking action of each wheel on at least one side of the vehicle.

[0013] According to another optional embodiment of the present disclosure, drive and / or braking parameters of each wheel on each side of the vehicle are synergistically controlled by an electronic stability program system and a rear wheel steering system, whereby the vehicle is steered toward a desired steering direction, with the electronic stability program system controlling the braking torque of each wheel on the same side of the vehicle, and the rear wheel steering system controlling the rear wheel steering angle of the vehicle.

[0014] According to another optional embodiment of the present disclosure, drive and / or braking parameters of each wheel on each side of the vehicle are synergistically controlled by a torque vectoring control system and a rear wheel steering system, whereby the vehicle steers toward a desired steering direction, the torque vectoring control system controls the drive and / or braking parameters of each wheel on each side of the vehicle, and the rear wheel steering system controls the rear wheel steering angle of the vehicle.

[0015] According to another optional embodiment of the present disclosure, the desired steering direction may be determined according to a driver's action command and / or may be determined according to an automated driving system and / or an assisted driving system based on a current driving scenario.

[0016] According to a second aspect of the present disclosure, there is provided a method for controlling steering of a vehicle, the method being performed using a vehicle steering system according to the present disclosure and comprising the following steps: detecting an operating state of a first control unit used to perform a steering function of the vehicle; determining whether there is an abnormal operating state of the first control unit; and activating at least one second control unit to participate in controlling the steering function of the vehicle if an abnormal operating state of the first control unit is detected.

[0017] According to a third aspect of the present disclosure, there is provided a computer program product, such as a computer readable program carrier, comprising computer program instructions, the execution of which by a processor at least assists in performing steps of a method according to the present disclosure. [Brief description of the drawings]

[0018] In the following, the present disclosure will be described in more detail with reference to the accompanying drawings, in order to provide a better understanding of its principles, features, and advantages. [Figure 1] FIG. 1 illustrates a structural block diagram of a vehicle steering system according to an exemplary embodiment of the present disclosure. [Diagram 2] 2 illustrates a flowchart of a method for controlling steering of a vehicle according to an exemplary embodiment of the present disclosure. [Diagram 3] 1 shows a schematic diagram of the principle involved in controlling the steering function of a vehicle by an electronic stability program system according to another exemplary embodiment of the present disclosure. [Figure 4] 1 shows a schematic diagram of the principle involved in controlling the steering function of a vehicle by an electronic stability program system according to another exemplary embodiment of the present disclosure. [Diagram 5] 2 shows a schematic diagram of the principles involved in the control of the steering function of a vehicle with a rear wheel steering system according to another exemplary embodiment of the present disclosure; [Figure 6] FIG. 2 shows a schematic diagram of the principle involved in the rear wheel steering system and electronic stability program system controlling the steering function of a vehicle according to another exemplary embodiment of the present disclosure. [Figure 7] 2 shows a schematic diagram of the principles involved in the control of the steering function of a vehicle with a rear wheel steering system according to another exemplary embodiment of the present disclosure; [Figure 8] 2 shows a schematic diagram of the principle involved in controlling the steering function of a vehicle with a torque vectoring control system according to another exemplary embodiment of the present disclosure; [Figure 9] 1 shows a schematic diagram of the principles involved in a torque vectoring control system and a rear wheel steering system in controlling the steering function of a vehicle according to another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In order to provide a clearer understanding of the technical problems, technical solutions, and beneficial technical effects to be addressed by the present disclosure, the following detailed description of the present disclosure will be provided with reference to the accompanying drawings and several exemplary embodiments. Of course, the specific embodiments described herein are provided only for the purpose of illustrating the present disclosure, and do not limit the scope of protection of the present disclosure.

[0020] It should be noted that in this document, terms such as "first", "second", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, such terms should not be understood as implying a particular quantity of the technical features depicted.

[0021] FIG. 1 shows a structural block diagram of a vehicle steering system according to an exemplary embodiment of the present disclosure.

[0022] 1, the vehicle steering system 1 may comprise a first control unit 11 configured to perform steering functions of the vehicle. In the present embodiment of the disclosure, the first control unit 11 may be understood as the primary steering system of the vehicle, which takes over control of the steering functions of the vehicle during normal operation of the vehicle.

[0023] The first control unit 11 may comprise, for example, an EPS system and its components, including, for example, a mechanical steering mechanism, a torque sensor, a vehicle speed sensor, an electronic control unit, and an electric motor. The working principle of the EPS system is described below. The steering wheel is connected to the front wheels through the mechanical steering mechanism. When the driver turns the steering wheel, the torque sensor detects the direction and magnitude of the steering force and converts it into an electric signal, which is then transmitted to the electronic control unit. The electronic control unit sends a control signal to the electric motor based on these electric signals and the vehicle speed signal detected by the vehicle speed sensor. This enables the electric motor to output a steering assist torque of appropriate magnitude and direction to the mechanical steering mechanism to provide a steering assist adapted to the current vehicle speed.

[0024] The first control unit 11 may also include, for example, a steer-by-wire system, which, unlike the traditional vehicle steering system, removes the mechanical connection mechanism between the steering wheel and the actuator, and the steering function of the vehicle is fully implemented by the electronic control system. The components of the steer-by-wire system include, for example, a steering wheel module, a steering actuator, and an electronic control unit, the operation principle of which is described below. The steering wheel module measures the steering wheel angle to obtain the driver's steering intention, converts it into a digital signal, and sends it to the electronic control unit. At the same time, the electronic control unit sends a corresponding torque control signal, and also generates a steering wheel positioning torque through a steering wheel positioning torque motor to provide the driver with corresponding road feedback information. The electronic control unit also outputs a control signal to the steering actuator based on the collected signal, thereby controlling the steering motor to output the torque required for steering, and realizing the driver's steering intention.

[0025] It is understood that in a steer-by-wire system, the steering wheel is separated from the actuator. If an electronic component in the steer-by-wire system that is not installed for redundancy fails, the steering operation cannot be realized. Therefore, a redundancy design is necessary in the steer-by-wire system.

[0026] The described vehicle steering system 1 may also comprise a state detection unit 12 and at least one second control unit 13, the state detection unit 12 being configured to detect an operating state of the first control unit 11, while the second control unit 13 is configured to take part in controlling the steering functions of the vehicle when an abnormal operating state of the first control unit 11 is detected.

[0027] The operating principle of the vehicle steering system 1 will be described in detail below in conjunction with a flowchart of a method for controlling steering of a vehicle according to an exemplary embodiment of the present disclosure as illustrated in FIG.

[0028] The method may include steps S1 to S3. In step S1, the operation state of the first control unit 11 for performing the steering function of the vehicle may be specifically detected by the state detection unit 12. In the context of the present disclosure, the operation state of the first control unit 11 may be divided into a normal operation state and an abnormal operation state, and when the first control unit 11 is in the normal operation state, it can steer the vehicle toward a desired direction based on the driver's steering intention, and the desired steering direction may be determined by the automatic driving system and / or the assisted driving system based on the driver's operation command or based on the current driving scenario. When the first control unit 11 is in the abnormal operation state, it may no longer be able to steer the vehicle toward a desired direction based on the driver's steering intention, i.e., it may only be able to participate partially in the steering control of the vehicle (e.g., when the output torque of the main steering system is smaller than the torque determined based on the driver's operation command), or it may not be able to participate at all in the steering control of the vehicle. This is particularly true when the first control unit 11 malfunctions (e.g. due to a sensor failure, an electronic control unit failure, a steering motor failure, power loss in the power supply unit, etc.) resulting in the first control unit 11 being unable to perform the steering functions of the vehicle.

[0029] In step S2, it is determined whether there is an abnormal operating state of the first control unit 11. If an abnormal operating state of the first control unit 11 is detected, in step S3, at least one second control unit 13 is activated to participate in controlling the steering function of the vehicle. Especially for high-level (e.g., SAE level 2 or higher) automated driving systems and / or assisted driving systems, redundancy of the steering system of the vehicle is mandatory to cover the backup time required to return the vehicle to a safe state in case of loss of control of the steering system itself. If the output parameters of the main steering system of the vehicle cannot meet the requirements of relevant laws / regulations regarding redundancy of the steering system, or if the output parameters of the main steering system of the vehicle cannot meet the requirements regarding driving comfort, at least one second control unit 13 may be activated to participate in controlling the steering function of the vehicle.

[0030] Here, when the first control unit 11 is unable to be fully involved in the steering control of the vehicle, the at least one second control unit 13 is able to fully take over the steering control of the vehicle, and when the first control unit 11 only has the ability to be partially involved in the steering control of the vehicle, the second control unit 13 and the first control unit 11 have the ability to perform synergistic control of the steering function of the vehicle.

[0031] In addition, it should be noted that the sequence numbers of the steps described herein do not necessarily represent a sequential order, but are merely reference numbers. Depending on the circumstances, the order may be changed as long as the technical objectives of the present disclosure are achieved.

[0032] Optionally, one second control unit 13 may comprise one or more of the following components: an electronic stability program system 131, a rear wheel steering system 132, and a torque vectoring control system 133. Depending on different second control units, the vehicle is equipped with a control process of the vehicle steering system 1, which will be described in detail below in conjunction with different embodiments.

[0033] In one optional embodiment of the present disclosure, the second control unit 13 may include an electronic stability program system 131. It is understood that most vehicles are now equipped with an electronic stability program system. The actuator of the electronic stability program system is a braking mechanism that has the ability to brake each wheel independently. This braking mechanism can apply appropriate braking force to each wheel as needed even when the driver does not engage the braking system. The braking mechanism may be a traditional hydraulic braking mechanism, or a friction-based electromechanical braking mechanism that does not require hydraulic lines but instead provides clamping force through motors located on the brake calipers on the side of all four wheels.

[0034] Under certain road surface and vehicle load conditions, the maximum adhesion that a wheel can provide is a constant value, i.e., under extreme conditions, there is a trade-off between the longitudinal force (along the direction of the wheel's rolling) and the lateral force (perpendicular to the direction of the wheel's rolling) exerted on the wheel. For example, when the longitudinal force exerted on the wheel reaches an extreme value (e.g., during tire lock-up), the lateral force is zero. At this point, the lateral movement of the vehicle becomes uncontrollable and it is unable to turn according to the driver's steering intention. However, through the electronic stability program system, longitudinal braking forces may be applied separately to each wheel. This affects the lateral force on the wheels, thereby generating a corresponding lateral torque on the vehicle and assisting the driver in moving in the desired direction.

[0035] In this case, the braking torque of each wheel on the same side of the vehicle may be controlled through the electronic stability program system 131 to steer the vehicle in a desired steering direction, and the braking force is applied separately to each wheel on the same side or to one wheel on the same side using a hydraulic braking mechanism and / or a friction-based electromechanical braking mechanism. FIG. 3 shows a schematic diagram of the principle in which the electronic stability program system is involved in controlling the steering function of the vehicle according to another exemplary embodiment of the present disclosure. When the driver steers the vehicle to the left, if the understeer of the vehicle is detected under the control of the first control unit 11, that is, if the actual steering angle of the vehicle in the turn is smaller than the desired steering angle determined based on the driver's operation command, the electronic stability program system 131 may apply longitudinal braking forces FBF and FBR separately to the two left wheels FL and RL. Specifically, the longitudinal braking force FBR is applied to the left rear wheel RL. Due to the increase in the fore-aft force on the left wheel, the ability of the left wheel to provide a lateral force is correspondingly reduced, thus creating a lateral torque TL on the vehicle toward the desired steering direction (left in this case) and assisting the vehicle to move in the desired steering direction. It is noted that "side" means the side of the vehicle along its direction of movement, which includes the left and right sides of the vehicle body along its direction of movement.

[0036] FIG. 4 shows a schematic diagram of the principle in which the electronic stability program system is involved in controlling the steering function of the vehicle according to another exemplary embodiment of the present disclosure. When the oversteer of the vehicle is detected under the control of the first control unit 11, i.e., when the actual steering angle of the vehicle in the turn is greater than the desired steering angle determined based on the driver's movement command, the electronic stability program system 131 may apply longitudinal braking forces FBF and FBR separately to the two right wheels FR and RR. Specifically, the longitudinal braking force FBF is applied to the right front wheel FR. Due to the increase in longitudinal force on the right wheel, the ability of the right wheel to provide lateral force is correspondingly reduced, thus generating a lateral torque TR on the vehicle opposite to the desired steering direction (right in this case) to counteract the oversteer of the vehicle.

[0037] In another optional embodiment of the present disclosure, the second control unit 13 may further include a rear wheel steering system 132. Currently, an increasing number of vehicles are equipped with a rear wheel steering system. Considering that a vehicle usually experiences oversteer at high speeds, i.e., the actual steering angle of the vehicle in a turn is larger than the steering angle of the front wheels, the rear wheels may be controlled through the rear wheel steering system 132 to turn in the same direction as the front wheels, thereby counteracting the oversteer tendency of the vehicle and enhancing driving stability and comfort.

[0038] FIG. 5 shows a schematic diagram of the principle that the rear wheel steering system is involved in controlling the steering function of the vehicle according to another exemplary embodiment of the present disclosure. Exemplarily, when the driver steers the vehicle to the left, as shown in FIG. 5, if it is detected that the first control unit 11 cannot control the steering function of the vehicle (e.g., due to the failure of the EPS system or the steer-by-wire system), and if the front wheels FL and FR cannot be turned to the left via the actuators, the rear wheels RL and RR of the vehicle may be controlled to turn to the right via the rear wheel steering system 132, i.e., the rear wheel steering angle is opposite to the desired steering direction. This generates a lateral torque TL on the vehicle toward the desired steering direction (left in this case), realizing the steering of the vehicle to the left, thus effectively preventing the loss of steering control caused by the failure of the front wheel actuators, and ensuring the redundancy of the steering system.

[0039] In another embodiment shown in Fig. 6, the driving and / or braking parameters of each wheel on each side of the vehicle may also be synergistically controlled by the electronic stability program 131 system and the rear wheel steering system 132, so that the vehicle is steered toward a desired steering direction, and the electronic stability program system 131 applies a braking force FBF to the left front wheel FL, and the rear wheel steering system 132 controls the rear wheels RL and RR of the vehicle to turn right, i.e., the direction of the rear wheel steering angle is opposite to the desired steering direction (left in this case), thereby generating a lateral torque TL on the vehicle toward the desired steering direction, and realizing the steering of the vehicle to the left. Through the synergistic control of the electronic stability program system 131 and the rear wheel steering system 132, not only can the loss of steering control caused by the failure of the front wheel actuator be effectively prevented and the redundancy of the steering system be ensured, but the driving stability and comfort of the vehicle may also be improved.

[0040] 7 shows a schematic diagram of the principle involved in the rear wheel steering system controlling the steering function of the vehicle according to another exemplary embodiment of the present disclosure. Exemplarily, when the driver steers the vehicle to the left, if it is detected that the steering angle of the front wheels FL and FR is smaller than the desired steering angle determined based on the driver's action command and cannot be further increased through the control of the first control unit 11, for example, when the vehicle deviates from the desired steering direction due to a large lateral wind force on the vehicle body, the rear wheels RL and RR may also be controlled to turn right via the rear wheel steering system 132, i.e., the direction of the rear wheel steering angle is opposite to the desired steering direction, thereby generating a lateral torque TL on the vehicle toward the desired steering direction (left in this case), so as to counterbalance the effect of the lateral wind on the steering direction of the vehicle and enable the vehicle to steer in the desired direction.

[0041] In another optional embodiment of the present disclosure, the second control unit 13 may further comprise a torque vectoring control system 133. Due to the electrification of vehicles, an increasing number of electric vehicles are equipped with torque vectoring control systems, which allow control of driving and / or braking parameters of each wheel, including torque, speed and / or rotation direction, e.g., via four electric motors arranged on the sides of the four wheels, thereby enhancing the operational performance of the vehicle, in particular its steering performance.

[0042] 8 shows a schematic diagram of the principle in which the torque vectoring control system is involved in controlling the steering function of the vehicle according to another exemplary embodiment of the present disclosure. Exemplarily, when the driver steers the vehicle to the left, if a fault (e.g., sensor failure, electronic control unit failure, steering motor failure, and / or power loss of the power supply unit) is detected in the first control unit 11, the driving and / or braking parameters of each wheel on each side of the vehicle may be controlled via the torque vectoring control system 133. For example, braking forces FBF and FBR may be applied separately to the two left wheels FL and RL through either the torque vectoring control system 133 or the braking system, and driving forces FAF and FAR may be applied to the two right wheels FR and RR through the torque vectoring control system 133, thereby generating a lateral torque TL on the vehicle toward the desired steering direction (left in this case) and enabling the vehicle to steer in the desired direction.

[0043] Exemplarily, it is also possible to have only three electric motors in the electric vehicle, one electric motor arranged on the front axle for simultaneous control of the two front wheels FL and FR, and two electric motors arranged on the rear axle for separate control of the two rear wheels RL and RR. In the example shown in Fig. 7, when it is detected that the steering angle of the front wheels FL and FR is smaller than the desired steering angle determined based on the driver's operation command, which may be due to insufficient power supply to the electric motor on the front axle, or a limitation of the driving force of the electric motor on the front axle, or may also be due to a large lateral wind force applied to the vehicle body, the driving and / or braking parameters of each wheel on each side of the vehicle may be synergistically controlled by the torque vectoring control system 133 and the electronic stability program system 131, where the torque vectoring control system 133 controls the driving and / or braking parameters of each wheel on each side of the vehicle, and the electronic stability program system 131 is involved in controlling the braking operation of the wheels of the vehicle on at least one side. In the example shown in FIG. 8, braking forces FBF and FBR may be applied separately to the left wheels FL and RL through the synergistic control of the torque vectoring control system 133 and the electronic stability program system 131, and driving forces FAF and FAR may be applied separately to the right wheels FR and RR via the torque vectoring control system 133, thereby generating a lateral torque TL on the vehicle toward the desired steering direction (left in this case), enabling the vehicle to steer in a desired direction, and therefore effectively improving the driving stability and safety of the vehicle.

[0044] Furthermore, in another example shown in FIG. 9 , when the driver steers the vehicle to the left, if it is detected that the first control unit 11 is unable to control the steering function of the vehicle (e.g., due to a failure of the power steering system or the steer-by-wire system), i.e., is unable to turn the front wheels FL and FR to the left via the actuators, the driving and / or braking parameters of each wheel on each side of the vehicle may also be synergistically controlled by the torque vectoring control system 133 and the rear wheel steering system 132. This allows the vehicle to steer towards a desired steering direction, where the torque vectoring control system 133 controls the driving and / or braking parameters of each wheel on each side of the vehicle (in this case applying braking forces FBF and FBR to the left wheels FL and FR, and applying driving forces FAF and FAR to the right wheels FR and RR), and the rear wheel steering system 132 controls the rear wheel steering angles of the rear wheels RL and RR of the vehicle (in this case turning right), thereby generating a lateral torque TL on the vehicle towards the desired steering direction (in this case left) and realizing steering of the vehicle to the left. This can more effectively prevent loss of steering control caused by failure of the front wheel actuator and achieve redundancy of the steering system.

[0045] It should be noted that in the above-described embodiment, the electronic stability program system 131, the rear wheel steering system 132, and the torque vectoring control system 133 may all participate in the control synergistically, thereby achieving a better control effect of the vehicle's steering function.

[0046] In addition, the second control unit 13 is any vehicle-mounted component that can be involved in controlling the steering functions of the vehicle, and is not limited to the listed electronic stability program system 131, rear wheel steering system 132, and torque vectoring control system 133.

[0047] According to an embodiment of the present disclosure, in the case of an abnormal operation state of the primary steering system of the vehicle, a backup control unit having a steering control function, such as an electronic stability program system, a rear wheel steering system, and / or a torque vectoring control system, may be activated to participate in controlling the steering function of the vehicle, which can provide a high level of redundancy for the automated driving system and / or assisted driving system, especially achieve redundancy in the steer-by-wire system, and not only ensure safety when the vehicle is moving, but also effectively enhance the stability and comfort of the vehicle steering.

[0048] Although certain embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even when described with respect to specific features of each embodiment. The examples of features provided in the present disclosure are intended to be illustrative and not limiting, unless otherwise specified. In a specific implementation, multiple features may be combined with each other according to practical requirements and where technically feasible. Various substitutions, changes, and modifications may be devised without departing from the spirit and scope of the present disclosure.

Claims

1. A vehicle steering system (1), comprising: a first control unit (11) configured to perform steering functions for the vehicle; a state detection unit (12) configured to detect an operating state of the first control unit (11); and at least one second control unit (13) configured to participate in controlling the steering function of the vehicle when an abnormal operating state of the first control unit (11) is detected.

2. 2. The vehicle steering system (1) according to claim 1, characterized in that the at least one second control unit (13) comprises one or more of the following components: an electronic stability program system (131), a rear wheel steering system (132), and a torque vectoring control system (133).

3. A vehicle steering system (1) according to any of claims 1 to 2, characterised in that the first control unit (11) comprises an electric power steering system or a steer-by-wire system.

4. The vehicle steering system (1) according to any one of claims 1 to 3, characterized in that the electronic stability program system (131) controls the braking torque of each wheel on a same side of the vehicle to steer the vehicle in a desired steering direction, and braking forces are applied separately to each wheel on the same side or to one wheel on the same side using a hydraulic braking mechanism and / or a friction-based electromechanical braking mechanism.

5. and / or when understeer is detected, the electronic stability program system (131) applies a braking force to one or more wheels of the vehicle on the side of the desired steering direction so as to apply a lateral torque to the vehicle body toward the desired steering direction; A vehicle steering system (1) according to any one of claims 1 to 4, characterized in that when oversteer is detected, the electronic stability program system (131) applies a braking force to one or more wheels of the vehicle opposite the desired steering direction so as to apply a lateral torque to the vehicle body in a direction opposite to the desired steering direction.

6. A vehicle steering system (1) according to any one of claims 1 to 5, characterized in that the rear wheel steering system (132) controls the rear wheel steering angle of the vehicle such that the vehicle is steered towards the desired steering direction, the direction of the rear wheel steering angle being opposite to the desired steering direction.

7. A vehicle steering system (1) as described in any one of claims 1 to 6, characterized in that the drive and / or braking parameters of each wheel on each side of the vehicle are controlled through the torque vectoring control system (133), e.g. braking forces are applied separately to each wheel on one side of the vehicle through either the torque vectoring control system (133) or a braking system, while drive forces are applied to each wheel on the other side of the vehicle through the torque vectoring control system (133), thereby steering the vehicle towards a desired steering direction.

8. 8. A vehicle steering system (1) according to any of claims 1 to 7, characterized in that the driving and / or braking parameters of each wheel on each side of the vehicle are synergistically controlled by the torque vectoring control system (133) and the electronic stability program system (131) to steer the vehicle towards the desired steering direction, the torque vectoring control system (133) controlling the driving and / or braking parameters of each wheel on each side of the vehicle, and the electronic stability program system (131) being involved in the control of the braking action of each wheel on at least one side of the vehicle.

9. A vehicle steering system (1) according to any one of claims 1 to 8, characterized in that the driving and / or braking parameters of each wheel on each side of the vehicle are synergistically controlled by the electronic stability program system (131) and a rear wheel steering system (132) to steer the vehicle towards the desired steering direction, the electronic stability program system (131) controlling the braking torque of each wheel on the same side of the vehicle and the rear wheel steering system (132) controlling the rear wheel steering angle of the vehicle.

10. 10. A vehicle steering system (1) according to any one of claims 1 to 9, characterized in that the driving and / or braking parameters of each wheel on each side of the vehicle are synergistically controlled by the torque vectoring control system (133) and the rear wheel steering system (132) to steer the vehicle towards the desired steering direction, the torque vectoring control system (133) controlling the driving and / or braking parameters of each wheel on each side of the vehicle and the rear wheel steering system (132) controlling the rear wheel steering angle of the vehicle.

11. A vehicle steering system (1) according to any one of claims 1 to 10, characterized in that the desired steering direction is determined according to an action command of the driver and / or based on a current driving scenario and according to an automated and / or assisted driving system.

12. A method for controlling the steering of a vehicle, said method being carried out using the vehicle steering system (1) according to any one of claims 1 to 11, said method comprising the following steps: detecting the operating state of the first control unit (11) used to implement the steering function of the vehicle; determining whether there is an abnormal operating condition of the first control unit (11); and activating at least one second control unit (13) to participate in controlling steering functions of the vehicle if an abnormal operating condition of the first control unit (11) is detected.

13. A computer program product, such as a computer readable program carrier, comprising computer program instructions, the execution of which by a processor at least assists in performing the steps of the method of any of claims 1 to 11.

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