Steering wheel control method applied to steer-by-wire system, and related apparatus

Abstract

A steering wheel control method applied to a steer-by-wire system. The method comprises: when it is detected that a vehicle satisfies a first preset condition, on the basis of the current angle and an initial angle of a steering wheel, acquiring an angle difference and an angular velocity; on the basis of the angle difference, acquiring a target angular velocity, wherein the target angular velocity is an angular velocity for counteracting a reverse acting force caused by the angle difference; on the basis of the target angular velocity and the angular velocity, acquiring a locking torque of the steering wheel, wherein the locking torque is used for preventing the steering wheel from further rotating, and the locking torque matches the reverse acting force; and on the basis of the locking torque, locking the steering wheel. In the control method, a locking torque of a steering wheel is determined on the basis of both an angle difference of the steering wheel and an angular velocity of the steering wheel. Compared with the prior art, the control method can improve the timeliness of locking the steering wheel, thereby preventing potential hazards.

Description

Steering wheel control methods and related devices applied to steer-by-wire systems Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a steering wheel control method and related device applied to a steer-by-wire system. Background Technology

[0002] With the development of the automotive industry and autonomous driving, the importance of steer-by-wire systems in the vehicle field is becoming increasingly apparent. Compared to traditional steering systems, there is no mechanical connection between the steering wheel and wheels in a steer-by-wire system, which can save interior space and make the vehicle design simpler.

[0003] In a steer-by-wire system, there is no mechanical connection between the steering wheel and the wheels. Because there is no resistance from the wheels, the steering wheel is in a free-moving state. To facilitate driver entry and exit, the steering wheel can be locked to prevent it from turning freely when the driver gets in or out of the vehicle. Currently, a mechanical locking structure can be added to the steer-by-wire system to lock the steering wheel when the driver gets in or out. However, this method of adding a mechanical locking structure is costly, and the structure occupies a significant amount of space inside the vehicle. Summary of the Invention

[0004] This application provides a steering wheel control method and related device for a steer-by-wire system, which can lock the steering wheel without occupying space inside the vehicle and is highly timely.

[0005] In a first aspect, embodiments of this application provide a steering wheel control method applied to a steer-by-wire system. The execution entity of this method is a controller or a chip within the controller; the following description uses a controller as an example. In this method, when a vehicle is detected to meet a first preset condition, the controller can obtain an angle difference and an angular velocity based on the current angle and initial angle of the steering wheel. The angle difference is the difference between the current angle and the initial angle of the steering wheel, which is generated by the driver rotating the steering wheel. The angular velocity is the angular velocity corresponding to the angle difference generated by rotating the steering wheel.

[0006] The controller can obtain the target angular velocity based on the angle difference. The target angular velocity is the angular velocity of the reaction force that overcomes the angle difference. In this application, the driver applies force to the steering wheel, causing it to rotate and generating an angle difference. To prevent the steering wheel from continuing to rotate, i.e., to overcome this angle difference, the controller can apply a reaction force. In other words, this reaction force is to overcome the force applied by the driver to the steering wheel. The angular velocity corresponding to this reaction force can be called the target angular velocity. The target angular velocity can also be referred to as the angular velocity that matches the reaction force.

[0007] In some embodiments, a mapping table may be pre-configured in the controller. This mapping table indicates the mapping relationship between the angle difference and the target angular velocity. In this example, the controller can query the mapping table to determine the target angular velocity mapped to the angle difference.

[0008] In some embodiments, the controller may also use a proportional-integral-derivative PID control algorithm to obtain the target angular velocity based on the angle difference.

[0009] After acquiring the target angular velocity, the controller can determine the locking torque of the steering wheel based on the target angular velocity and the angular velocity. The locking torque is used to prevent the steering wheel from continuing to rotate, and it matches the counterforce. For example, the magnitude of the locking torque can be equal to the counterforce, and the direction can be the same as the counterforce. After acquiring the locking torque, the controller can lock the steering wheel accordingly. Locking the steering wheel prevents it from continuing to rotate.

[0010] In this embodiment of the application, the vehicle includes a first motor linked to the steering wheel. After the controller obtains the locking torque of the steering wheel, the controller can control the first motor linked to the steering wheel to output the locking torque to lock the steering wheel.

[0011] In this application, the controller determines the locking torque of the steering wheel not only based on the angle difference of the steering wheel, but also on the angular velocity of the steering wheel. Compared with the prior art, this can improve the timeliness of locking the steering wheel and avoid danger.

[0012] In one possible implementation, after locking the steering wheel, the controller can also control the steering wheel angle to be the same as the wheel angle.

[0013] In this implementation, after locking the steering wheel, the controller can also control the steering wheel angle to be the same as the wheel angle, so that the steering wheel angle is aligned with the wheel angle, which facilitates subsequent driving and can improve driving safety.

[0014] The following describes how the controller obtains the steering wheel's locking torque:

[0015] In one possible implementation, the controller can obtain a first torque based on the target angular velocity and the angular velocity, and this first torque is matched with a counterforce. In some embodiments, the controller can use this first torque as the locking torque of the steering wheel. Here, the first torque can be used as the torque to overcome the force applied by the driver to the steering wheel; this first torque can be referred to as the feedback torque.

[0016] This section describes a method for the controller to obtain the first torque: the controller can obtain the first angular acceleration based on the target angular velocity and the angular velocity. The first angular acceleration refers to the angular acceleration that occurs when the angular velocity changes from the target angular velocity to the target angular velocity at a target time. In some embodiments, when the controller queries a mapping table to obtain the target angular velocity, the target time is the time corresponding to the target angular velocity. In some embodiments, when the controller uses a PID control algorithm to obtain the target angular velocity, the target time can be a preset time, which is less than the time it takes for the driver to rotate the steering wheel to generate the angular difference. The controller can obtain the first torque based on the first angular acceleration and the moment of inertia of the steering wheel.

[0017] In one possible implementation, in addition to the feedback torque, the controller can also perform feedforward locking based on the steering wheel rotation. Feedforward locking can be understood as adding a feedforward locking torque to the feedback locking torque to increase the torque output by the first motor and enhance the locking of the steering wheel. In some embodiments, the feedback locking torque can be simply referred to as the feedback torque, and the feedforward locking torque can be simply referred to as the feedforward torque. The feedforward torque can be used to compensate for the deformation caused by the torque generated by the steering wheel rotation. In other words, the feedforward torque is the torque applied to compensate for the deformation caused by the torque generated by the steering wheel rotation.

[0018] In this implementation, the controller can obtain a second torque based on the angular velocity and the torque generated by the steering wheel rotation. This second torque can be a feedforward torque. The controller can then use the sum of the first and second torques as the locking torque.

[0019] In this implementation, the controller can not only determine the feedback torque of the upper steering motor to the steering wheel based on the angle difference and angular velocity of the steering wheel, but also add feedforward torque on the basis of feedback torque to increase the torque output by the first motor, which can enhance the locking of the steering wheel and improve safety.

[0020] In one possible implementation, the controller can use the HWA dynamics model of the steering wheel-first motor to calculate the second torque. Specifically, the controller can obtain the first angular acceleration based on the target angular velocity and the angular velocity, and the controller can obtain the second angular acceleration of the first motor linked to the steering wheel based on the first angular acceleration and the speed ratio conversion relationship, where the speed ratio conversion relationship is the speed ratio conversion relationship between the first motor and the steering wheel. The controller can obtain the angular velocity of the first motor based on the angular velocity and the speed ratio conversion relationship.

[0021] The controller can obtain the second torque based on the angular velocity of the first motor, the second angular acceleration, the torque generated by the steering wheel rotation, the speed ratio conversion relationship, and the rotational inertia, damping parameters, and friction parameters of the first motor.

[0022] In this implementation, the controller can use the HWA dynamics model of the steering wheel-first motor to calculate the second torque, which is the deformation caused by the torque generated by the rotation of the steering wheel, to predict the torque that should be applied to the first motor to compensate for the deformation, thus accurately determining the second torque.

[0023] In one possible implementation, the controller can also obtain the current angle before obtaining the angle difference and angular velocity based on the current angle and the initial angle of the steering wheel.

[0024] For example, the vehicle includes a torque angle sensor for acquiring the current angle.

[0025] For example, the vehicle includes a first motor linked to the steering wheel. When the driver turns the steering wheel, causing the initial angle of the steering wheel to change to the current angle, the controller can obtain the output shaft angle of the first motor and obtain the current angle based on the output shaft angle and the speed ratio conversion relationship between the first motor and the steering wheel.

[0026] In this example, since the torque angle sensor obtains the current and initial angles of the steering wheel by detecting the deformation of the steering column, it is greatly affected by torque deformation. In some embodiments, in order to improve the accuracy of the current and initial angles of the steering wheel, the current and initial angles of the steering wheel can be determined by the angle output by the first motor. In this example, since the angle output by the upper steering motor is not affected by torque deformation, the accuracy of the current and initial angles of the steering wheel obtained by this method is high.

[0027] In one possible implementation, in response to a locking command, the controller can determine that the vehicle meets a first preset condition. The locking command can be triggered by the driver. For example, a locking button can be provided on the vehicle remote control. Before the driver gets out of the vehicle, pressing this button can trigger a locking command to be sent to the controller. In response to this locking command, the controller can determine that the vehicle meets the first preset condition and then perform the operation of locking the steering wheel as described in the above embodiment. Alternatively, a locking button can be provided on the vehicle remote control. Before the driver gets into the vehicle, or after the driver gets into the vehicle but before driving, pressing this button can trigger a locking command to be sent to the controller. In response to this locking command, the controller can determine that the vehicle meets the first preset condition and then perform the operation of locking the steering wheel as described in the above embodiment.

[0028] In one possible implementation, when the driver's driving action of getting in or getting out of the vehicle is detected, the controller can determine that the vehicle meets a first preset condition.

[0029] For example, when the vehicle is powered on and in driving mode, the controller can determine that the driver's driving action is getting into the vehicle.

[0030] For example, when the vehicle speed is less than or equal to a preset speed, the vehicle is in driving mode, and the driver's seat belt changes from a fastened state to an unfastened state, the controller can determine that the driver's driving action is to get out of the vehicle.

[0031] For example, when the vehicle speed is less than or equal to a preset speed, the vehicle is in driving mode, the driver's seat belt is switched from a fastened state to an unfastened state, and the vehicle is in park, the controller can determine that the driver's driving action is to get out of the vehicle.

[0032] In the above implementation, the driver can actively trigger the controller to lock the steering wheel, or the controller can actively detect and trigger the steering wheel lock, offering various flexible options and wide applicability. Furthermore, in this implementation, the controller can lock the steering wheel during driver entry and exit, facilitating driver assistance.

[0033] In one possible implementation, the method for locking the steering wheel provided in this application embodiment can also be applied to scenarios where the wheels are stuck. For example, when it is detected that the torque output by the second motor linked to the vehicle's wheels is greater than a preset torque and the wheel rotation angle is less than a preset angle, the controller can determine that the wheels are stuck, that is, the vehicle meets the first preset condition. In this case, the controller can also perform the operation of locking the steering wheel as described in the above embodiment.

[0034] In this implementation, in a scenario where the wheels are stuck, the wheels cannot turn. If the steering wheel is in a flexible state, the steering wheel angle will not be aligned with the wheel angle, affecting the driver's subsequent driving. Therefore, in a scenario where the wheels are stuck, the controller can lock the steering wheel to ensure the driver's safe driving.

[0035] The above describes a method for the controller to lock the steering wheel. In one possible implementation, when the vehicle is detected to meet a second preset condition, the controller can release the steering wheel lock so that the driver can continue driving the vehicle.

[0036] Specifically, when the driver's driving action is to get into the vehicle, the second preset condition includes: the steering wheel angle is the same as the wheel angle, and the vehicle is in an unlocked state. In other words, when the driver's driving action is to get into the vehicle, the controller locks the steering wheel. When it detects that the steering wheel angle is the same as the wheel angle and the vehicle is in an unlocked state, the controller can unlock the steering wheel.

[0037] In some embodiments, when the driver's driving action is to get into the vehicle, the second preset condition may further include at least one of the following:

[0038] The vehicle's speed is greater than the preset speed;

[0039] The vehicle is out of parking gear;

[0040] The vehicle's accelerator pedal was pressed.

[0041] In some embodiments, when the driver's driving action is to get into the vehicle, the second preset condition may further include the presence of a driver in the driver's seat of the vehicle.

[0042] Specifically, when the driver's driving action is to get out of the vehicle, the second preset condition includes: the steering wheel angle is the same as the wheel angle, and there is no driver in the driver's seat. In other words, when the driver's driving action is to get out of the vehicle, the controller locks the steering wheel. When it detects that the steering wheel angle is the same as the wheel angle and there is no driver in the driver's seat, the controller can release the steering wheel lock.

[0043] In some embodiments, when the driver's driving action is to get out of the vehicle, the second preset condition may further include: the steering wheel is not turned within a preset time period.

[0044] Specifically, when the controller detects a vehicle stall and locks the steering wheel, the second preset condition includes: the wheel rotation angle is positively correlated with the torque output of the second motor linked to the vehicle's wheels. In other words, when the controller detects a vehicle stall and locks the steering wheel, and detects that the wheel rotation angle is positively correlated with the torque output of the second motor linked to the vehicle's wheels (i.e., the vehicle changes from stalled to free-stalling), the controller can release the steering wheel lock.

[0045] This implementation also provides a method for the controller to unlock the steering wheel, ensuring the integrity of steering wheel control and facilitating smooth application in various scenarios.

[0046] Secondly, embodiments of this application provide a controller, which includes one or more processors and a memory. The memory is coupled to one or more processors and is used to store computer program code, which includes computer instructions. The one or more processors invoke the computer instructions to cause the controller to perform the methods described in the first aspect and various possible implementations above.

[0047] Thirdly, embodiments of this application provide a vehicle that includes a controller as described in the second aspect, and the vehicle can implement the methods described in the first aspect and various possible implementations above.

[0048] Fourthly, embodiments of this application provide a chip system applied to a controller. The chip system includes one or more processors, which are used to invoke computer instructions to cause the controller to execute the methods described in the first aspect and various possible implementations above.

[0049] In some alternative embodiments, the chip system further includes a memory connected to one or more processors via circuits or wires.

[0050] In some alternative embodiments, the chip system also includes a communication interface.

[0051] Fifthly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed in a controller, cause the controller to perform the methods described in the first aspect and various possible implementations above.

[0052] Sixthly, embodiments of this application provide a computer program product that, when run in a controller, causes the controller to execute the methods described in the first aspect and various possible implementations above.

[0053] It is understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0054] Figure 1 is a schematic diagram of a traditional steering system in a vehicle;

[0055] Figure 2 is a schematic diagram of a steer-by-wire system provided in an embodiment of this application;

[0056] Figure 3 is a schematic diagram of locking the steering wheel;

[0057] Figure 4 is a flowchart illustrating an embodiment of the steering wheel control method applied to a steer-by-wire system provided in this application.

[0058] Figure 5A is a comparative schematic diagram of the initial angle and current angle of the steering wheel provided in an embodiment of this application;

[0059] Figure 5B is another comparative schematic diagram of the initial angle and current angle of the steering wheel provided in the embodiment of this application;

[0060] Figure 6 is a schematic diagram of a locking steering wheel provided in an embodiment of this application;

[0061] Figure 7 is a flowchart illustrating another embodiment of the steering wheel control method applied to a steer-by-wire system provided in this application.

[0062] Figure 8 is a flowchart illustrating another embodiment of the steering wheel control method applied to a steer-by-wire system provided in this application.

[0063] Figure 9 is a flowchart illustrating another embodiment of the steering wheel control method applied to a steer-by-wire system provided in this application.

[0064] Figure 10 is a flowchart illustrating another embodiment of the steering wheel control method applied to a steer-by-wire system provided in this application.

[0065] Figure 11 is a schematic diagram of a driver getting out of the vehicle according to an embodiment of this application;

[0066] Figure 12 is a schematic diagram of a driver getting into the vehicle according to an embodiment of this application. Detailed Implementation

[0067] A vehicle's steering system is used to translate the driver's intention to operate the steering wheel into wheel steering actions. Figure 1 is a schematic diagram of a conventional steering system in a vehicle. Referring to Figure 1, a conventional steering system 10 may include: a steering wheel 11, a steering column 12, an intermediate shaft 13, a steering gear 14, a steering tie rod 15, and wheels 16.

[0068] The driver can input steering commands by turning the steering wheel 11.

[0069] The steering column 12 is responsible for transmitting the rotation of the steering wheel 11 to the intermediate shaft 13.

[0070] The intermediate shaft 13 is a key component in the conventional steering system 10, used to connect the steering wheel and the wheels. For example, the intermediate shaft 13 can be connected to the steering gear 14 via a connector such as a universal joint.

[0071] The steering gear 14 is responsible for converting the rotational motion transmitted from the steering column 12 into linear motion, thereby driving the steering tie rod 15 to steer the wheels 16. For example, the steering gear 14 may include various types such as rack and pinion type and recirculating ball type.

[0072] The steering tie rod 15 is an important component connecting the steering gear 14 and the wheel 16. It is responsible for converting the linear motion of the steering gear 14 into the steering action of the wheel 16. For example, the steering tie rod 15 typically includes two parts: an inner tie rod and an outer tie rod, which are connected to the wheel 16 via ball joint connectors.

[0073] In the conventional steering system 10, when the driver turns the steering wheel 11, the rotational motion of the steering wheel 11 is transmitted to the intermediate shaft 13 via the steering column 12. The intermediate shaft 13 then transmits this rotational motion to the steering gear 14. Inside the steering gear 14, the rotational motion is converted into linear motion via a transmission mechanism such as a rack and pinion or a recirculating ball, and this linear motion then drives the wheels 16 through the steering tie rod 15 to achieve steering.

[0074] Referring to Figure 1, the traditional steering system 10 has a complex structure and occupies a significant amount of space inside the vehicle. With the development of the automotive industry and autonomous driving, the importance of steer-by-wire systems in the vehicle field is becoming increasingly apparent. Steer-by-wire systems eliminate complex structures such as the intermediate shaft, reducing the space occupied inside the vehicle. Furthermore, there is no mechanical connection between the steering wheel and the wheels, making it easier for the driver to turn the steering wheel.

[0075] Figure 2 is a schematic diagram of a steer-by-wire system provided in an embodiment of this application. Referring to Figure 2, the steer-by-wire system 20 may include: a steering wheel 21, a steering column 22, a sensor 23, a reduction mechanism 24, an upper steering motor 25, a lower steering motor 26, wheels 27, and a communication device 28 for connecting the upper steering motor 25 and the lower steering motor 26.

[0076] When the driver turns the steering wheel 21, the steering column 22 rotates along with the steering wheel 21.

[0077] Sensor 23 is mounted on steering column 22 and is used to detect the angle of steering wheel 21. The angle of steering wheel 21 can be considered as the rotation angle of steering wheel 21. In addition, when steering column 22 rotates, sensor 23 can also detect the torque of steering column 22 by detecting the deformation of steering column 22.

[0078] In some embodiments, sensor 23 can be a torque and angle sensor (TAS). The TAS is used to detect the angle of the steering wheel 21 and the torque generated by the rotation of the steering wheel 21. This torque can be regarded as the torque of the steering column 22, or it can be called the TAS torque.

[0079] The upper steering motor 25 is the power source for the steer-by-wire system 10. The upper steering motor 25 can output torque of a specific direction and magnitude according to instructions from the controller in the vehicle. For example, the upper steering motor 25 can provide assist torque to the steering wheel 21, making it easier for the driver to steer the wheel 21. It should be understood that the controller in the vehicle is not shown in Figure 2.

[0080] In some embodiments, the controller in a vehicle may be an electronic control unit (ECU).

[0081] During the torque delivery process of the upper steering motor 25, the reduction mechanism 24 can be used to increase the torque transmitted from the upper steering motor 25 to the steering column 22. Specifically, when the power output from the upper steering motor 25 passes through the reduction mechanism 24, the gear ratio of the reduction mechanism 24 amplifies the torque output by the upper steering motor 25, thereby better driving the steering column 22 to assist the steering wheel 21 in completing steering actions. This design allows the steer-by-wire system 10 to maintain precise and rapid steering while possessing stronger driving force and stability.

[0082] In some embodiments, the upper steering motor 25 can be considered to be linked to the steering wheel 21, and the upper steering motor 25 can be referred to as the first motor. In some embodiments, the reduction mechanism 24 can be connected to the output shaft of the upper steering motor 25.

[0083] The controller in the vehicle can determine information such as the angle of the steering wheel 21 and the TAS torque based on the detection results of the sensor 23. The controller is used to control the lower steering motor 26 to drive the wheels 27 to rotate via the communication device 28 based on the information such as the angle of the steering wheel 21 and the TAS torque.

[0084] In some embodiments, the upper steering motor 25 and the lower steering motor 26 can be connected via wired or wireless means. For example, when the upper steering motor 25 and the lower steering motor 26 are wired, they can be connected via a controller area network (CAN) bus. For example, when the upper steering motor 25 and the lower steering motor 26 are wirelessly connected, they can be connected via means such as WiFi or Bluetooth. It should be understood that FIG2 illustrates the communication device 28 as a CAN bus.

[0085] The lower steering motor 26, in response to commands from the controller, can output torque of a specific direction and magnitude to drive the wheel 27 to rotate.

[0086] In the online steering system 20, when the driver turns the steering wheel 21, the steering wheel 21 drives the steering column 22 to rotate. The sensor 23 can collect information such as the angle and TAS torque of the steering wheel 21. Correspondingly, based on the information such as the angle and TAS torque of the steering wheel 21, the controller can control the lower steering motor 26 to output torque through the communication device 28 to drive the wheels 27 to rotate.

[0087] In some embodiments, the structure consisting of the steering wheel 21, steering column 22, sensor 23, reduction mechanism 24, and upper steering motor 25 can be called upper steering (handwheel actuator, HWA), and the structure consisting of the lower steering motor 26 and wheel 27 can be called lower steering (roadwheel actuator, RWA).

[0088] In traditional steering systems, there is a mechanical connection between the steering wheel and the wheels. The steering wheel is connected to the wheels via mechanical structures such as the steering column, intermediate shaft, steering gear, and steering tie rods. When the driver turns the steering wheel, they experience resistance from the wheels. However, in a steer-on-wire system, there is no mechanical connection between the steering wheel and the steering wheel (HWA and RWA). In other words, there is no mechanical connection between the steering wheel and the wheels, and the driver is not restricted by wheel resistance when turning the steering wheel. In other words, in a steer-on-wire system, the steering wheel is in a free-moving state.

[0089] When a driver gets out of the vehicle, they can use the steering wheel for support to stand up. However, in a steering-by-wire system, the steering wheel is in a free-moving state. When the driver grips the steering wheel, it will turn, providing no support and causing the driver's hand to move with it, potentially leading to a hazard. After the driver gets back in the vehicle, because the steering wheel is in a free-moving state, any random operation by the driver will turn the wheel, also causing safety issues. For example, if the driver rests their chin on their hand while the steering wheel rotates, their hand may move, creating a dangerous situation.

[0090] Therefore, to assist drivers in getting in and out of the vehicle, the steering wheel can be locked during this process. Once locked, the steering wheel remains stationary and will not rotate due to force from the driver, thus providing support.

[0091] The following describes the current methods for locking the steering wheel:

[0092] Method 1:

[0093] In this example, a mechanical locking mechanism and clutch are added to the linear steering system. The vehicle's operating status allows adjustment of the locking relationship between the locking mechanism and the clutch. For instance, when the vehicle is powered off and stopped, to facilitate driver entry and exit, the clutch is engaged, and the locking mechanism locks the steering wheel. With the steering wheel locked, the fixed steering wheel provides handhold support for the driver, making entry and exit easier.

[0094] While Method 1 can achieve the purpose of locking the steering wheel, adding a mechanical locking mechanism and clutch to the linear steering system will not only increase costs, but also take up space inside the vehicle.

[0095] Method 2:

[0096] A new algorithm module is added to the linear steering system. This module can lock the steering wheel by controlling the upper steering motor to output reverse torque. In Method 2, referring to Figure 3, assuming the initial steering wheel angle is 0°, when the driver gets in and out of the vehicle, the driver grips the steering wheel and rotates it clockwise, with the current steering wheel angle being α°. The algorithm module can calculate the steering wheel angle difference (α° - 0° = α°) based on the initial and current steering wheel angles. In this example, the algorithm module pre-stores a torque characteristic curve, which represents the mapping relationship between the steering wheel angle difference and torque. The algorithm module can determine the torque corresponding to the steering wheel angle difference by querying the torque characteristic curve and use this torque as the torque output by the upper steering motor. After determining the torque output by the upper steering motor, the controller can control the upper steering motor to output this torque. It should be understood that the direction of the torque output by the motor is opposite to the direction of steering wheel rotation, which is counterclockwise, thus enabling the steering wheel to be locked.

[0097] In method 2, the upper steering motor can be controlled to output a torque opposite to the driver's hand force to lock the steering wheel. This avoids the problems caused by adding mechanical structures (such as locking mechanisms and clutches) to the linear steering system. However, in method 2, the reverse torque is obtained by looking up the angle difference of the steering wheel in a table, without taking into account the angular velocity of the steering wheel, which may lead to problems with untimely control.

[0098] For example, when the driver applies a lot of force, the steering wheel can turn a lot in a very short time. If the steering torque is calculated based on the current and initial angles of the steering wheel and then locked, the driver's hand has already moved to a large angle following the rotation of the steering wheel. If the upper steering motor does not input the reverse torque in time to lock the steering wheel, it will cause a danger.

[0099] Furthermore, in Method 2, after the driver's hands leave the steering wheel, the steering wheel angle and the wheel angle cannot automatically align, which will affect the driver's next driving action. For example, if the steering wheel angle is 30° but the wheel direction is 0°, the driver may think that the steering wheel has been turned 30° by observing the steering wheel, but in reality, the wheels have not turned. Driving in this situation can lead to danger.

[0100] In summary, this application provides a steering wheel control method for a steer-by-wire system. In scenarios where the driver gets in and out of the vehicle, the vehicle determines the locking torque of the upper steering motor on the steering wheel not only based on the angle difference of the steering wheel but also on the angular velocity of the steering wheel. Compared with the prior art, this method can achieve timely control and avoid causing danger.

[0101] The steering wheel control method applied to a steer-by-wire system provided in this application will be described below with reference to specific embodiments. These embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0102] Figure 4 is a schematic flowchart of an embodiment of the steering wheel control method applied to a steer-by-wire system provided in this application. It should be understood that the executing entity of the steering wheel control method applied to the steer-by-wire system in Figure 4 can be a vehicle or a controller in a vehicle; Figure 4 uses a controller as an example for illustration.

[0103] Referring to Figure 4, the steering wheel control method for a steer-by-wire system provided in this application embodiment may include:

[0104] S401, when the vehicle is detected to meet the first preset condition, the angle difference and angular velocity are obtained based on the current angle and the initial angle of the steering wheel.

[0105] The vehicle meets the first preset condition, which triggers the controller to lock the steering wheel.

[0106] In some embodiments, the vehicle meeting a first preset condition can be used to instruct the driver to get in or out of the vehicle. In other words, in the scenario where the driver gets in or out of the vehicle, the controller can lock the steering wheel.

[0107] In some embodiments, the method for locking the steering wheel provided in this application can also be applied to scenarios where the wheels are stuck. For example, a vehicle's wheels hit a curb, preventing the vehicle from turning and causing the wheels to become stuck. In such a scenario, the wheels cannot turn, and if the steering wheel is in a flexible position, the steering wheel angle will not align with the wheel angle, affecting the driver's subsequent driving. Therefore, in a scenario where the wheels are stuck, the controller can lock the steering wheel.

[0108] The initial angle of the steering wheel can be understood as: the angle of the steering wheel when the vehicle is detected to meet a first preset condition, or the angle of the steering wheel before the driver turns the steering wheel when the vehicle is detected to meet the first preset condition. The current angle of the steering wheel can be understood as: the angle of the steering wheel when the driver turns the steering wheel.

[0109] In some embodiments, the initial angle and the current angle of the steering wheel are relative to a preset angle of the steering wheel. For example, referring to Figure 5A, assuming the preset angle of the steering wheel is 0°, such as the angle of the steering wheel when the driver is not turning the steering wheel. Assuming the initial angle of the steering wheel is 5° relative to the preset angle, then the initial angle of the steering wheel is 5°; assuming the current angle of the steering wheel is 10° relative to the preset angle, then the current angle of the steering wheel is 10°. For example, referring to Figure 5B, assuming the preset angle of the steering wheel is 0°, and the initial angle of the steering wheel is 0°, then the initial angle of the steering wheel is 0°; assuming the current angle of the steering wheel is 10° relative to the preset angle, then the current angle of the steering wheel is 10°.

[0110] It should be understood that in Figures 5A and 5B, the steering wheel in its initial position is represented by a solid line, and the steering wheel in its current position is represented by a dashed line. The initial position is the position before the driver turns the steering wheel, and the current position is the position after the driver turns the steering wheel. When the steering wheel is in its initial position, the steering wheel angle is the initial angle; when the driver turns the steering wheel to its current position, the steering wheel angle is the current angle.

[0111] This application does not limit the setting of the preset angle of the steering wheel in the embodiments, and does not affect the method in the embodiments of this application.

[0112] In some embodiments, the torque angle sensor can detect the current angle and initial angle of the steering wheel, and correspondingly, the controller can obtain the current angle and initial angle of the steering wheel from the torque angle sensor.

[0113] Because the torque angle sensor obtains the current and initial angles of the steering wheel by detecting the deformation of the steering column, it is greatly affected by torque deformation. In some embodiments, in order to improve the accuracy of the current and initial angles of the steering wheel, the current and initial angles of the steering wheel can be determined by the angle output by the first motor. In this example, since the angle output by the upper steering motor is not affected by torque deformation, the accuracy of the current and initial angles of the steering wheel obtained by this method is high.

[0114] In this embodiment, the first motor is linked to the steering wheel. Referring to the description of the linear rotation system in Figure 2, when the steering wheel rotates, the steering column drives the output shaft of the first motor to rotate as well, and there is a fixed speed ratio conversion relationship between the rotation angle of the steering wheel and the rotation angle of the output shaft of the first motor. Similarly, there is also a fixed speed ratio conversion relationship between the angular velocity of the steering wheel and the angular velocity of the output shaft of the first motor.

[0115] In this example, the controller can acquire the output shaft angle of the first motor and, based on the speed ratio conversion relationship between the first motor and the steering wheel, convert the output shaft angle of the first motor into the steering wheel angle. In some embodiments, an angle sensor can be installed on the output shaft of the first motor to detect the output shaft angle. Alternatively, the first motor can detect the rotation angle of its output shaft to acquire the output shaft angle.

[0116] The controller can pre-store the speed ratio conversion relationship between the first motor and the steering wheel. In this example, the controller can obtain the output shaft angle of the first motor through an angle sensor mounted on the first motor or the first motor itself. Based on the speed ratio conversion relationship between the first motor and the steering wheel, the controller can convert the output shaft angle of the first motor into the angle of the steering wheel. Specifically, the controller can convert the initial angle of the first motor's output shaft into the initial angle of the steering wheel, and the current angle of the first motor's output shaft into the current angle of the steering wheel, thereby obtaining the current and initial angles of the steering wheel.

[0117] In this embodiment, after the controller obtains the current angle and the initial angle of the steering wheel, it can use the difference between the current angle and the initial angle as the angle difference, and the ratio of the angle difference to time as the angular velocity of the steering wheel. Here, time is the time taken for the steering wheel to rotate from the initial angle to the current angle.

[0118] It should be understood that, in the embodiments of this application, as long as the controller detects a change in the angle of the steering wheel, the controller can perform the steps of obtaining the initial angle and current angle of the steering wheel, as well as obtaining the angle difference and angular velocity. In this way, the timeliness of steering wheel control can be improved.

[0119] S402, based on the angle difference, obtain the target angular velocity, which is the angular velocity that overcomes the reverse force of the angle difference.

[0120] When a driver grips the steering wheel and applies force, the steering wheel's angle changes. To prevent the steering wheel from continuing to turn, a counterforce can be applied. This counterforce is used to overcome the angle difference; that is, it overcomes the force that caused the angle difference.

[0121] In this embodiment, a target angular velocity can be preset. Unlike the angular velocity of the steering wheel, the target angular velocity can correspond to a shorter time, thereby improving the responsiveness of steering wheel control. The target angular velocity is the angular velocity that overcomes the reaction force of the angle difference.

[0122] In some embodiments, a mapping table can be pre-set to indicate the mapping relationship between angle differences and target angular velocities. For example, the mapping table includes multiple angle differences and the target angular velocities corresponding to each angle difference at different times. Here, time can be understood as the time required to eliminate the angle difference, and the target angular velocities corresponding to different times can be understood as the angular velocities at which the angle difference is eliminated at different times.

[0123] In this example, the controller can query a mapping table to determine the target angular velocity mapped by the angle difference. For example, the mapping table can refer to Table 1 below:

[0124] Table 1

[0125] Referring to Table 1, the controller can query the mapping table to determine the target angular velocity corresponding to the angle difference at different times, and use the target angular velocity corresponding to the target time as the target angular velocity mapped to the angle difference. The target time is less than the time taken to generate the angle difference. For example, if the steering wheel angle difference is 10° and this angle difference is generated within 3ms, the controller can use a time less than 3ms as the target time, and use the target angular velocity corresponding to the target time, such as A, as the target angular velocity corresponding to the angle difference.

[0126] In some embodiments, when there are multiple target times, the target angular velocity corresponding to the average of the multiple target times can be used as the target angular velocity corresponding to the angle difference. Alternatively, when there are multiple target times, the target angular velocity corresponding to the average of the smallest (or largest) target time can be used as the target angular velocity corresponding to the angle difference.

[0127] In this example, a mapping table can be pre-obtained and pre-installed in the vehicle (e.g., the controller) through testing or simulation. Taking simulation as an example, for each angle difference, different time intervals can be preset, and the angular velocities corresponding to eliminating the angle difference at different time intervals can be obtained. Based on the time, angle difference, and corresponding angular velocity, a mapping table is constructed.

[0128] In some embodiments, the controller can obtain the target angular velocity based on the angle difference using a proportional-integral-differential (PID) control algorithm.

[0129] In this example, since the target angular velocity is to eliminate the angular difference, the desired angular difference can be 0°. Knowing the desired angular difference, the controller can calculate the angular error, which can be "angular difference - 0°". Knowing the angular error, the controller can calculate the output of the proportional term (P) based on the angular error, integrate the angular error, and obtain the output of the integral term (I) based on the integration result. It can also calculate the output of the derivative term (D) based on the rate of change of the angular error. The controller can then add the outputs of the proportional term (P), the integral term (I), and the derivative term (D) to obtain the final output. The controller can convert the final output into the target angular velocity, a process involving scaling and / or limiting the control output to ensure the target angular velocity is within a reasonable range. Based on this, the controller can obtain the target angular velocity.

[0130] It should be understood that the PID control algorithm used in the embodiments of this application can refer to the description of existing PID control algorithms, and will not be repeated here.

[0131] S403 obtains the steering wheel locking torque based on the target angular velocity and angular velocity.

[0132] Torque is related to angular acceleration, which represents the rate of change of angular velocity. In this embodiment, to lock the steering wheel, the controller has acquired a target angular velocity. Since there is a certain difference between the steering wheel's angular velocity and the target angular velocity, to lock the steering wheel at the target angular velocity, the controller can acquire a first angular acceleration based on the target angular velocity and the target angular velocity. The first angular acceleration refers to the angular acceleration that changes from the angular velocity to the target angular velocity at a target time.

[0133] In some embodiments, when the controller queries the mapping table to obtain the target angular velocity, the target time is the time corresponding to the target angular velocity. In some embodiments, when the controller uses a PID control algorithm to obtain the target angular velocity, the target time can be a preset time, which is less than the time taken to generate the angle difference.

[0134] The controller can obtain the first torque based on the first angular acceleration and the moment of inertia. The moment of inertia can be the moment of inertia of the steering wheel. In this embodiment, the controller can obtain the first torque according to the following formula 1: T = I × a Formula 1

[0135] Where T represents the first torque, I represents the moment of inertia of the steering wheel, and a represents the first angular acceleration.

[0136] In some embodiments, the controller can use a first torque as the locking torque of the steering wheel. The locking torque is used to prevent the steering wheel from rotating further, and the locking torque is matched with a counterforce. The counterforce is used to prevent the steering wheel from rotating further; in other words, the counterforce is used to overcome the force that causes the angle difference in the steering wheel. In some embodiments, the locking torque matching the counterforce can be understood as the magnitude and direction of the locking torque being the same as the magnitude and direction of the counterforce.

[0137] S404, locks the steering wheel according to the locking torque.

[0138] The locking torque of the steering wheel is opposite to the direction of steering wheel rotation. In this embodiment, after the controller obtains the locking torque of the steering wheel, it can control the first motor linked to the steering wheel to output the locking torque to lock the steering wheel. The controller can send a first command to the first motor, which includes information such as the magnitude and direction of the locking torque. In response to the first command, the first motor can output the corresponding locking torque to lock the steering wheel.

[0139] Figure 6 is a schematic diagram of a locking steering wheel provided in an embodiment of this application. Referring to Figure 6, the solid line in Figure 6 represents the steering wheel in its initial position, which is the position before the driver turns the steering wheel. The dashed line in Figure 6 represents the steering wheel in its current position, which is the position after the driver turns the steering wheel. When the steering wheel is in its initial position, the angle of the steering wheel is the initial angle θ. raw When the driver turns the steering wheel clockwise, the steering wheel angle is θ when it is in its current position. offset The angle difference is α = θ. offset -θ raw The angular velocity of the steering wheel is ω = α / t. Here, t is the time it takes for the steering wheel to rotate from its initial position to its current position, which can also be called the time required to generate this angular difference.

[0140] The controller executes steps S402-S403 to obtain the locking torque of the steering wheel, and can control the first motor to output this locking torque to lock the steering wheel. The locking torque of the steering wheel is opposite to the direction of rotation of the steering wheel, i.e., counterclockwise.

[0141] In some embodiments, the steps in the embodiment shown in FIG4 can be simplified as shown in FIG7. Referring to FIG7, when it is determined that the vehicle meets the first preset condition (such as the driver getting in or out of the vehicle or wheel stall), the controller can activate the function of locking the steering wheel. Activating the function of locking the steering wheel can be understood as the controller starting to execute S401-S404 to lock the steering wheel. The steps of the controller executing S401-S403 can be simplified as shown in FIG7. After the controller obtains the locking torque, the controller can control the first motor to output the locking torque to lock the steering wheel.

[0142] In this embodiment, during the driver's entry and exit from the vehicle, the vehicle determines the locking torque of the steering wheel by the upper steering motor based not only on the steering wheel angle difference but also on the steering wheel angular velocity. Compared to existing technologies, this improves the timeliness of steering wheel locking and prevents accidents. Furthermore, this method of locking the steering wheel can also be applied to scenarios where wheels are stuck, enabling timely control and locking of the steering wheel to prevent accidents, thus demonstrating its wide applicability.

[0143] The above embodiments describe the process by which the controller determines the steering wheel locking torque by combining the steering wheel angle difference and the steering wheel angular velocity. In some embodiments, this process can be referred to as the process of obtaining feedback locking torque. The feedback locking torque is used to achieve timely feedback on steering wheel rotation. In some embodiments, the controller can also perform feedforward locking based on steering wheel rotation. Feedforward locking can be understood as adding a feedforward locking torque to the feedback locking torque to increase the torque output by the first motor and enhance the locking of the steering wheel.

[0144] In some embodiments, the feedback lock-up torque, which may be simply referred to as the feedback torque, is matched with a counterforce. This counterforce is used to prevent the steering wheel from continuing to turn; in other words, it is used to overcome the force that causes the angle difference in the steering wheel.

[0145] In this embodiment, referring to FIG8, the steering wheel control method applied to a steer-by-wire system provided in this application embodiment may include:

[0146] S801, when the vehicle is detected to meet the first preset condition, obtain the angle difference and angular velocity based on the current angle and initial angle of the steering wheel.

[0147] S802: Based on the angle difference, obtain the target angular velocity, which is the desired angular velocity to eliminate the angle difference.

[0148] S801-S802 can be referred to in the descriptions in S401-S402.

[0149] S803 obtains the first angular acceleration based on the target angular velocity and angular velocity.

[0150] S804 obtains the first torque based on the first angular acceleration and moment of inertia.

[0151] S803-S804 can be referred to in the description of S403. Among them, the first torque can be called the feedback torque.

[0152] S805 obtains the second torque based on the angular velocity and the torque generated by the steering wheel rotation.

[0153] It should be understood that the embodiments of this application do not limit the order of S803-S804 and S805. The second torque can be referred to as feedforward torque. The second torque is used to compensate for the deformation caused by the torque generated by the steering wheel rotation. In other words, the controller can predict the torque that should be applied to the first motor to compensate for the deformation based on the deformation caused by the torque generated by the steering wheel rotation.

[0154] The controller can calculate the second torque based on the angular velocity of the steering wheel and the torque generated by the steering wheel rotation, using the HWA dynamic model of the steering wheel-first motor. The HWA dynamic model of the steering wheel-first motor can be represented by the following formula:

[0155] Where T′ represents the second torque, J m θ represents the moment of inertia of the first motor. m This indicates the rotation angle of the first motor. This represents the angular velocity of the first motor. B represents the angular acceleration of the first motor. m T represents the damping parameter of the first motor. s G represents the torque generated by turning the steering wheel. m This indicates the speed ratio conversion relationship, f m This represents the friction parameters of the first motor. The damping parameter of the first motor can be the damping coefficient, and the friction parameter can be the friction coefficient.

[0156] In this embodiment, the controller can obtain a first angular acceleration based on the target angular velocity and the steering wheel angular velocity, as described in S803. This first angular acceleration is the angular acceleration of the steering wheel.

[0157] Because there is a fixed speed ratio between the steering wheel's rotation angle and the rotation angle of the first motor's output shaft, and also a fixed speed ratio between the steering wheel's angular velocity and the first motor's output shaft's angular velocity, correspondingly, there is also a fixed speed ratio between the steering wheel's angular acceleration and the first motor's output shaft's angular acceleration. Therefore, the controller can convert the steering wheel's angular velocity into the first motor's angular velocity based on the speed ratio conversion relationship; this speed ratio conversion relationship represents the speed ratio between the first motor and the steering wheel. Similarly, the controller can convert the first angular acceleration of the steering wheel into the second angular acceleration of the first motor based on the speed ratio conversion relationship; this speed ratio conversion relationship represents the speed ratio between the first motor and the steering wheel.

[0158] In addition, the torque angle sensor can obtain the torque generated by the steering wheel, and correspondingly, the controller can obtain the torque generated by the steering wheel through the torque angle sensor.

[0159] After acquiring the angular velocity and second angular acceleration of the first motor, the controller can substitute these parameters—including the angular velocity, second angular acceleration, torque generated by the steering wheel rotation, speed ratio conversion relationship, and the first motor's moment of inertia, damping parameters, and friction parameters—into Formula 2 above to obtain the second torque. The torque generated by the steering wheel can be detected by a torque angle sensor; correspondingly, this second torque is the feedforward lock-up torque. The speed ratio conversion relationship, as well as the first motor's moment of inertia, damping parameters, and friction parameters, can be pre-stored in the controller.

[0160] S806 uses the sum of the first torque and the second torque as the lock-up torque.

[0161] The first torque and the second torque are in the same direction, that is, both are opposite to the direction of steering wheel rotation. In this embodiment, a second torque (feedback locking torque) can be added to the first torque (feedback locking torque) to enhance the locking of the steering wheel and increase safety.

[0162] In this embodiment of the application, the controller can use the sum of the first torque and the second torque as the locking torque of the steering wheel.

[0163] S807, locks the steering wheel according to the locking torque.

[0164] S807 can be found in the description in S404.

[0165] In some embodiments, the steps in the embodiment shown in FIG8 can be simplified as shown in FIG9. Referring to FIG9, when it is determined that the vehicle meets the first preset condition (such as the driver getting in or out of the vehicle or wheel stall), the controller can activate the function of locking the steering wheel. Specifically, the controller can execute S801-S804 to obtain the feedback locking torque, and the controller can execute S805 to obtain the feedforward locking torque. The controller can use the sum of the first torque and the second torque as the locking torque to lock the steering wheel.

[0166] In this embodiment of the application, when it is determined that the vehicle meets the first preset condition (such as the driver getting in or out of the vehicle or the wheels being stuck), the controller can not only determine the feedback locking torque of the upper steering motor on the steering wheel based on the angle difference and angular velocity of the steering wheel, but also add a feedforward locking torque on the basis of the feedback locking torque to increase the torque output by the first motor, which can enhance the locking of the steering wheel and improve safety.

[0167] Referring to the description of the above embodiments, the controller can accurately obtain the steering wheel rotation angle (such as angle difference) during the process of locking the steering wheel. In some embodiments, in order to facilitate the driver's subsequent driving, the controller can control the steering wheel angle to be the same as the wheel angle. This ensures that the steering wheel angle is consistent with the wheel angle, and the driver can accurately obtain the position of the steering wheel and the position of the wheels when driving again, which helps to ensure safe driving.

[0168] Taking the embodiment shown in Figure 8 as an example, and referring to Figure 10, the following may be included after S807:

[0169] S808, the steering wheel angle is the same as the wheel angle.

[0170] In this embodiment, when the vehicle meets a first preset condition (such as the driver getting in or out of the vehicle or wheel stall), the driver will turn the steering wheel, causing the steering wheel angle to be inconsistent with the wheel angle. In other words, the steering wheel angle and wheel angle are not aligned, which will affect the driver's subsequent driving. Therefore, to improve driving safety, when the steering wheel angle changes, the controller can control the steering wheel angle to be the same as the wheel angle, ensuring alignment between them.

[0171] Angle sensors can be installed on the wheels. For example, an angle sensor can be installed on the wheel's rotating bearing to detect the wheel's angle. The controller can obtain the wheel's angle through the angle sensor and control the steering wheel angle to be the same as the wheel's angle. Specifically, the controller can output corresponding torque through a first motor to control the steering wheel angle to be the same as the wheel's angle.

[0172] It should be understood that, taking the embodiment shown in Figure 4 as an example, after S404, it may also include: controlling the angle of the steering wheel to be the same as the angle of the wheel. This step is not shown in Figure 4, but can be referred to the description in S808.

[0173] In this embodiment, after locking the steering wheel, the controller can also control the steering wheel angle to be the same as the wheel angle, so that the steering wheel angle is aligned with the wheel angle, which facilitates subsequent driving by the driver and can improve driving safety.

[0174] The following explains the process of "the controller detecting that the vehicle meets the first preset condition":

[0175] Scenario 1: The vehicle meets a first preset condition to instruct the driver to get out of the vehicle. In other words, when the controller detects that the driver's driving action is to get out of the vehicle, it determines that the vehicle meets the first preset condition.

[0176] Scenario 1 depicts the driver exiting the vehicle. In this scenario, the driver can use the steering wheel for support while standing up, or stand up while using the steering wheel to exit the vehicle. To assist the driver in exiting, the controller can lock the steering wheel. The first preset condition in Scenario 1 is described below with reference to Figure 11:

[0177] The vehicle's speed is less than or equal to the preset speed, the vehicle is in a non-preset function mode, and the driver's seat belt has switched from a fastened state to an unfastened state.

[0178] In some embodiments, the preset speed can be 3 kph. When the vehicle speed is less than or equal to the preset speed, it indicates that the vehicle speed is very low. At this time, the controller can predict that the vehicle is about to stop. When the vehicle is about to stop, the driver needs to get out of the vehicle, and the controller can lock the steering wheel.

[0179] As vehicle functions become increasingly sophisticated, vehicle function modes may include, but are not limited to, game mode, bracket mode, and normal mode. In some embodiments, normal mode may also be driving mode, and game mode and bracket mode may be non-driving modes.

[0180] In the vehicle's game mode, the driver can operate the steering wheel to experience different types of games, such as racing games and driving simulation games. In game mode, the driver needs to operate the steering wheel, so the controller does not need to lock it. In stand mode, the vehicle provides a stand configuration for simulating driving. In this mode, the driver needs to operate the steering wheel, so the controller does not need to lock it. In normal mode, the vehicle provides normal driving functions such as driving and parking. When the driver exits the vehicle, they do not need to operate the steering wheel, so the controller can lock it.

[0181] The game mode and bracket mode can both be considered preset function modes. When the vehicle is in a preset function mode, if the driver needs to operate the steering wheel, the controller will not lock the steering wheel. The normal mode can be considered a non-preset function mode. When the vehicle is in a non-preset function mode, if the driver needs to get out of the vehicle, the controller can lock the steering wheel.

[0182] It should be understood that the embodiments of this application illustrate several vehicle function modes, and the embodiments of this application do not limit the vehicle function modes. In summary, when the vehicle is in the preset function mode, the vehicle does not need to lock the steering wheel; when the vehicle is in a non-preset function mode, the vehicle needs to lock the steering wheel.

[0183] When the driver's seatbelt changes from fastened to unfastened, it indicates that the driver has unfastened the seatbelt. The controller can then determine that the driver needs to get out of the vehicle and can lock the steering wheel.

[0184] In summary, referring to Figure 11, when the controller detects that the vehicle's speed is less than or equal to a preset speed, the vehicle is in a non-preset function mode, and the driver's seatbelt has switched from a fastened state to an unfastened state—that is, when the vehicle meets the first preset condition in the exit scenario—the controller can determine that the driver needs to exit the vehicle. To facilitate the driver's exit, the controller can activate the steering wheel locking function to lock the steering wheel, and control the steering wheel angle to be the same as the wheel angle. This alignment of the steering wheel angle with the wheel angle can also be referred to as vertical angle alignment. Here, "up" represents upward steering, and "down" represents downward steering. Vertical angle alignment can be understood as the upward steering angle and the downward steering angle being aligned (the same).

[0185] In some embodiments, the first preset condition may further include: the vehicle is in parking gear. When the vehicle is in parking gear, it indicates that the vehicle has stopped and the driver needs to get out of the vehicle. Moreover, "the vehicle is in parking gear" is a stronger indicator of the driver's need to get out of the vehicle than the condition "the vehicle speed is less than or equal to a preset speed". Therefore, adding the condition "the vehicle is in parking gear" to the first preset condition can improve the accuracy of the controller in detecting the driver getting out of the vehicle, thereby improving the driving experience. It should be understood that the dashed box in Figure 11 indicates the optional condition "the vehicle is in parking gear" in the first preset condition.

[0186] In this embodiment of the application, in scenario 1, when the controller detects that the vehicle meets the second preset condition, the controller can release the lock on the steering wheel, allowing the steering wheel to move freely. The second preset condition indicates that the driver has completed disembarking; once the driver has disembarked, the controller can release the lock on the steering wheel.

[0187] In scenario 1, the second preset condition may include: the angle of the steering wheel is the same as the angle of the wheel, there is no driver in the driver's seat of the vehicle, and the steering wheel has not been turned within a preset time period.

[0188] In particular, because the controller can control the steering wheel angle to be the same as the wheel angle when the driver gets out of the car, the steering wheel angle is the same as the wheel angle when the steering wheel locking function is active.

[0189] If there is no driver in the driver's seat, it means the driver has exited the vehicle, and the controller no longer needs to lock the steering wheel; the steering wheel can be released. For example, a pressure sensor can be installed on the driver's seat to collect the pressure value exerted by the driver. The controller can determine whether a driver is present in the driver's seat based on the pressure value collected by the sensor. Specifically, when the pressure value is less than or equal to a preset pressure value, the controller can determine that there is no driver in the driver's seat; when the pressure value is greater than the preset pressure value, the controller can determine that a driver is present in the driver's seat.

[0190] If the steering wheel does not turn within a preset time, this condition can also indicate that the driver has finished getting out of the vehicle, and the controller no longer needs to lock the steering wheel and can release the lock. For example, if the controller detects that the torque generated by steering wheel rotation is less than 0.3 Nm and the duration of this torque is less than 1 second, the controller can determine that the driver has finished getting out of the vehicle. The torque generated by steering wheel rotation can be obtained from a torque angle sensor.

[0191] In summary, referring to Figure 11, when the controller detects that the steering wheel angle is the same as the wheel angle, there is no driver in the driver's seat of the vehicle, and the steering wheel has not been turned within a preset time period, that is, when the vehicle meets the second preset condition in the driver getting off the vehicle scenario, the controller can determine that the driver has finished getting off the vehicle, and the controller can turn off the steering wheel locking function to release the steering wheel lock.

[0192] Scenario 2: The vehicle meets the first preset condition to instruct the driver to get in. In other words, when the controller detects that the driver's driving action is to get in, it determines that the vehicle meets the first preset condition.

[0193] Scenario 2 depicts the driver getting into the vehicle. In this scenario, if the steering wheel is freely movable, any random action by the driver will cause it to turn, potentially leading to safety issues. For example, if the driver rests their chin on their hand while the steering wheel is turned arbitrarily, the driver's hand could move, causing a hazard. The first precondition in Scenario 2 is explained below with reference to Figure 12:

[0194] The vehicle is powered on, and the vehicle is in a non-preset function mode.

[0195] Understandably, after the driver gets in the car, they can start the vehicle. The vehicle switches from an off-power state to a powered-on state. When the vehicle is powered on, it means that the driver has entered the car. At this time, the controller needs to lock the steering wheel to avoid danger.

[0196] The vehicle's functional modes can be referred to in Scenario 1. When the vehicle is in a non-preset functional mode, there is a need to lock the steering wheel.

[0197] In summary, referring to Figure 12, when the controller detects that the vehicle is powered on and is in a non-preset function mode, that is, when the vehicle meets the first preset condition in the driver getting in scenario, the controller can determine that the driver has gotten in the vehicle. In order to avoid the danger caused by the driver turning the steering wheel flexibly after getting in the vehicle, the controller can activate the function of locking the steering wheel to lock the steering wheel and control the steering wheel angle to be the same as the wheel angle.

[0198] In this embodiment of the application, in scenario 2, when the controller detects that the vehicle meets the second preset condition, the controller can release the lock on the steering wheel, allowing the steering wheel to move freely. The second preset condition indicates that the vehicle is starting to move; at this time, the driver no longer needs to lock the steering wheel but can operate it to drive the vehicle normally.

[0199] In scenario 2, the second preset condition may include any of the following:

[0200] The vehicle's speed is greater than the preset speed;

[0201] The vehicle is out of parking gear;

[0202] The vehicle's accelerator pedal was pressed.

[0203] When the vehicle's speed exceeds the preset speed, it indicates that the vehicle's speed has increased. At this point, the controller can predict that the vehicle will start moving. Once the vehicle starts moving, the controller can release the lock on the steering wheel so that the driver can operate the steering wheel freely.

[0204] When the vehicle is out of parking gear, it indicates that the driver intends to drive. The controller can then release the lock on the steering wheel so that the driver can operate the steering wheel freely.

[0205] When the accelerator pedal is pressed, it indicates that the driver is driving the vehicle. The controller can then release the lock on the steering wheel, allowing the driver to operate the steering wheel freely.

[0206] In summary, if the controller detects that the vehicle meets any of the above conditions, it means that the vehicle meets the second preset condition in the driver getting in scenario, and the controller can release the lock on the steering wheel.

[0207] To improve the accuracy of the controller's judgment on the start of vehicle movement, in some embodiments, the second preset condition may further include: the angle of the steering wheel is the same as the angle of the wheels, and the vehicle is in an unlocked anti-theft state.

[0208] In scenario 2, when the controller detects that the vehicle meets the first preset condition in the driver getting in scenario, the controller can lock the steering wheel and control the steering wheel angle to be the same as the wheel angle. Therefore, when the steering wheel locking function is active, the steering wheel angle is the same as the wheel angle.

[0209] Additionally, normally, after the driver exits the vehicle, the driver can control the vehicle to enter anti-theft mode, or the vehicle will automatically enter anti-theft mode. When the driver gets back into the vehicle, the driver can control the vehicle to deactivate the anti-theft mode, or the vehicle will automatically deactivate the anti-theft mode, such as in response to the driver opening the driver's door. When the vehicle is in deactivated mode, the controller can predict that the driver has entered the vehicle and has a need to drive, therefore it can release the steering wheel lock.

[0210] In some embodiments, the second preset condition may further include: a driver is present in the driver's seat of the vehicle. The presence of a driver in the driver's seat indicates that the driver has completed the action of getting into the vehicle and has a need to drive, therefore the steering wheel lock can be released.

[0211] In summary, referring to Figure 12, when the controller detects that the vehicle meets the second preset condition in the driver getting in scenario, the controller can determine that the vehicle has started to drive or there is a driving need. The controller can then disable the steering wheel locking function to release the steering wheel lock so that the driver can drive the vehicle.

[0212] Scenario 3: The vehicle meets a first preset condition to indicate wheel stall. In other words, when wheel stall is detected, the controller determines that the vehicle meets the first preset condition.

[0213] The second motor is linked to the wheel, and can drive the wheel to rotate.

[0214] It should be understood that when the wheels are not stalled, the wheel rotation angle is positively correlated with the torque output by the second motor; that is, the greater the torque output by the second motor, the greater the wheel rotation angle. Scenario 3 is a scenario where the wheels are stalled. When the wheels are stalled, no matter how much torque the second motor outputs, the wheels cannot rotate or the wheel rotation angle is very small.

[0215] In scenario 3, the first preset condition may include: the torque output by the second motor linked to the vehicle's wheels is greater than a preset torque, and the wheel rotation angle is less than a preset angle. In other words, if the controller detects that the torque output by the second motor is large, but the wheel rotation angle remains unchanged or is small, the controller can determine that the wheel is stalled.

[0216] In the event of wheel spin jamming, to facilitate safe driving for the driver, the controller can activate the steering wheel locking function to lock the steering wheel and control the steering wheel angle to be the same as the wheel angle.

[0217] In this embodiment of the application, in scenario 3, when the controller detects that the vehicle meets the second preset condition, the controller can release the lock on the steering wheel, allowing the steering wheel to move freely. The second preset condition indicates that wheel jamming has been resolved, meaning the wheels are no longer jammed.

[0218] It should be understood that when the wheel is not stalled, the wheel's rotation angle is positively correlated with the torque output by the second motor. Therefore, in scenario 3, the second preset condition may include: the wheel's rotation angle is positively correlated with the torque output by the second motor that links the vehicle's wheels. For example, the greater the torque output by the second motor, the greater the wheel's rotation angle, indicating that the wheel is no longer stalled.

[0219] When the wheels are no longer locked, the controller can disable the steering wheel locking function to facilitate driver operation, thereby releasing the steering wheel lock.

[0220] In summary, referring to the descriptions in scenarios 1 to 3, the embodiments of this application provide an accurate and comprehensive condition detection mechanism in different application scenarios, which provides a foundation for the controller to accurately control the steering wheel and can improve the driving experience.

[0221] As described in scenarios 1 to 3 above, the method of the controller actively detecting and triggering the locking of the steering wheel and unlocking the steering wheel is introduced. In some embodiments, in response to the locking command, the controller can also perform the operation of locking the steering wheel in the above embodiments.

[0222] In some embodiments, the locking command can be triggered by the driver. For example, the driver can trigger the locking command to the controller by pressing a button or using voice interaction.

[0223] For example, a locking button can be installed on the vehicle or on the vehicle remote control. Taking a locking button on the vehicle remote control as an example, before the driver gets out of the vehicle, the driver can press the locking button to trigger a locking command to be sent to the controller. In response to the locking command, the controller can determine that the vehicle meets a first preset condition and then perform the steering wheel locking operation as described in the above embodiment. For example, before the driver gets into the vehicle, or after the driver gets into the vehicle but before driving, the driver can press the locking button to trigger a locking command to be sent to the controller. In response to the locking command, the controller can determine that the vehicle meets a first preset condition and then perform the steering wheel locking operation as described in the above embodiment. Similarly, for example, when the wheels are stuck, the driver can press the locking button to trigger the controller to perform the steering wheel locking operation as described in the above embodiment.

[0224] In some embodiments, the controller can unlock the steering wheel in response to an unlock command. In this example, after the controller locks the steering wheel, the driver can trigger an unlock command to the controller by pressing buttons or using voice interaction.

[0225] For example, after the driver gets into the vehicle but before driving, the driver can press the lock button to trigger a lock command sent to the controller, which can then lock the steering wheel. The driver can press the lock button again to trigger an unlock command sent to the controller, which can then release the steering wheel lock.

[0226] It should be understood that the embodiments of this application do not limit the way the driver triggers the locking command and the unlocking command, as illustrated above.

[0227] It should be noted that all data involved in this application (including but not limited to data used for analysis, stored data, and displayed data) is information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use, and processing of this data must comply with the relevant laws, regulations, and standards of the relevant countries and regions, and corresponding access points are provided for users to choose to authorize or refuse. The user can be a driver.

[0228] This application provides a controller, which may include a processor and a memory; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory, causing the controller to perform the methods described in the above embodiments.

[0229] This application provides a steer-by-wire system, which may include a processor, wherein the processor is used to execute the methods described in the above embodiments.

[0230] Additionally, referring to the description in Figure 2, the steer-by-wire system may also include a steering wheel, steering column, sensors, reduction gear, upper steering motor, lower steering motor, wheels, and a communication device for connecting the upper steering motor and the lower steering motor.

[0231] In some embodiments, the controller can control the components in the upward steering and the components in the downward steering.

[0232] In some embodiments, the steer-by-wire system may include a first controller and a second controller, the first controller corresponding to upward steering and the second controller corresponding to downward steering. The first controller and the second controller communicate via a communication device, wherein the first controller is used to control the components in upward steering, and the second controller is used to control the components in downward steering. It is understood that the controller performing the method in the above embodiments may be the first controller.

[0233] In this example, when the first controller controls the steering wheel angle to be the same as the wheel angle, the second controller can obtain the wheel angle through the angle sensor on the wheel. The second controller can send the wheel angle to the first controller through a communication device. In this way, the first controller can control the steering wheel angle to be the same as the wheel angle based on the wheel angle.

[0234] This application provides a vehicle that may include a controller as described above, or a steer-by-wire system as described above. The vehicle can implement the steering wheel control method described above.

[0235] This application provides a chip. The chip includes a processor, which is used to call a computer program in memory to execute the technical solutions in the above embodiments. Its implementation principle and technical effects are similar to those in the related embodiments described above, and will not be repeated here.

[0236] This application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, it implements the methods described in the above embodiments. The methods described in the above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any combination thereof. If implemented in software, the functionality can be stored as one or more instructions or code on or transmitted over the computer-readable medium. The computer-readable medium can include computer storage media and communication media, and can also include any medium that can transfer a computer program from one place to another. The storage medium can be any target medium accessible by a computer.

[0237] In one possible implementation, a computer-readable medium may include random access memory (RAM), read-only memory (ROM), compact disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other medium intended to carry or store required program code in the form of instructions or data structures, and accessible by a computer. Furthermore, any connection is appropriately referred to as a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. As used herein, disks and optical discs include optical discs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically, while optical discs optically reproduce data using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0238] This application provides a computer program product, which includes a computer program that, when run, causes a computer to perform the above-described method.

[0239] It should be noted that the modules or components described in the above embodiments can be one or more integrated circuits configured to implement the above methods, such as one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), etc. Furthermore, when a module is implemented through processing element scheduler code, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processors capable of calling program code, such as a controller. Additionally, these modules can be integrated together to implement a system-on-a-chip (SOC).

[0240] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., a solid-state disk (SSD)).

[0241] The term "multiple" in this document refers to two or more. The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the preceding and following related objects; in formulas, " / " indicates a "division" relationship. Additionally, it should be understood that in the description of this application, words such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0242] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application.

[0243] It is understood that, in the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A steering wheel control method applied to a steer-by-wire system, characterized in that, include: When the vehicle is detected to meet the first preset condition, the angle difference and angular velocity are obtained based on the current angle and the initial angle of the steering wheel; Based on the angle difference, the target angular velocity is obtained, whereby the target angular velocity is the angular velocity that overcomes the opposing force of the angle difference. Based on the target angular velocity and the angular velocity, the locking torque of the steering wheel is obtained. The locking torque is used to prevent the steering wheel from continuing to rotate, and the locking torque is matched with the counterforce. The steering wheel is locked according to the locking torque.

2. The method according to claim 1, characterized in that, After locking the steering wheel, the method further includes: The angle of the steering wheel is controlled to be the same as the angle of the wheels.

3. The method according to claim 1 or 2, characterized in that, The step of obtaining the locking torque of the steering wheel based on the target angular velocity and the angular velocity includes: Based on the target angular velocity and the angular velocity, a first torque is obtained, and the first torque is matched with the reaction force; Based on the angular velocity and the torque generated by the rotation of the steering wheel, a second torque is obtained, which is used to compensate for the deformation caused by the torque generated by the rotation of the steering wheel. The sum of the first torque and the second torque is taken as the locking torque.

4. The method according to claim 3, characterized in that, The step of obtaining the first torque based on the target angular velocity and the angular velocity includes: Based on the target angular velocity and the angular velocity, obtain the first angular acceleration; The first torque is obtained based on the first angular acceleration and the moment of inertia of the steering wheel.

5. The method according to claim 3 or 4, characterized in that, The step of obtaining the second torque based on the angular velocity and the torque generated by the steering wheel rotation includes: Based on the target angular velocity and the angular velocity, obtain the first angular acceleration; Based on the first angular acceleration and the speed ratio conversion relationship, the second angular acceleration of the first motor linked to the steering wheel is obtained, wherein the speed ratio conversion relationship is the speed ratio conversion relationship between the first motor and the steering wheel; The angular velocity of the first motor is obtained based on the angular velocity and the speed ratio conversion relationship; The second torque is obtained based on the angular velocity of the first motor, the second angular acceleration, the torque generated by the rotation of the steering wheel, the speed ratio conversion relationship, and the moment of inertia, damping parameters, and friction parameters of the first motor.

6. The method according to any one of claims 1-5, characterized in that, The vehicle includes a first motor linked to the steering wheel. Before obtaining the angle difference and angular velocity based on the current and initial angles of the steering wheel, the method further includes: Obtain the output shaft angle of the first motor; The current angle is obtained based on the output shaft angle and the speed ratio conversion relationship between the first motor and the steering wheel.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: In response to the locking command, it is determined that the vehicle meets the first preset condition.

8. The method according to any one of claims 1-6, characterized in that, The method further includes: When the driver's driving action of getting on or off the vehicle is detected, it is determined that the vehicle meets the first preset condition.

9. The method according to claim 8, characterized in that, The method further includes: When the vehicle is powered on and in driving mode, the driver's driving action is determined to be getting into the vehicle.

10. The method according to claim 8, characterized in that, The method further includes: When the vehicle's speed is less than or equal to a preset speed, the vehicle is in driving mode, and the driver's seatbelt changes from fastened to unfastened, the driver's driving action is determined to be getting out of the vehicle.

11. The method according to claim 9 or 10, characterized in that, The method further includes: When the vehicle is detected to meet the second preset condition, the steering wheel is unlocked.

12. The method according to claim 11, characterized in that, When the driver's driving action is to get into the vehicle, the second preset condition includes: the angle of the steering wheel is the same as the angle of the wheels, and the vehicle is in an unlocked anti-theft state.

13. The method according to claim 11, characterized in that, When the driver's driving action is to get out of the vehicle, the second preset condition includes: the angle of the steering wheel is the same as the angle of the wheels, and there is no driver in the driver's seat of the vehicle.

14. A controller, characterized in that, include: One or more processors and memory; The memory is coupled to the one or more processors, the memory being used to store computer program code, the computer program code including computer instructions, the one or more processors invoking the computer instructions to cause the controller to perform the method as described in any one of claims 1-13.

15. A vehicle, characterized in that, include: The controller as described in claim 14.

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