Vehicle steering wheel return method, device, computer equipment and storage medium

Abstract

The present disclosure relates to the technical field of automatic parking, and particularly relates to a vehicle steering wheel return-to-center method and device, a computer device and a storage medium, which comprises the following steps: when a steering wheel return-to-center instruction is received, a first angle of the steering wheel of a vehicle at a first time is acquired; a first error between the first angle and a target request angle is acquired, and whether the steering wheel is located in a return-to-center position interval is determined by analyzing the first error, wherein the target request angle is an angle of the steering wheel at a return-to-center position, and the return-to-center position interval is determined according to the return-to-center position of the steering wheel and a preset threshold; if the steering wheel is located in the return-to-center position interval, a real-time torque of the vehicle is acquired; a comparison result between the real-time torque and a torque threshold is acquired, and if the comparison result does not satisfy a preset condition, a target rotation angle is obtained based on the real-time torque, and the steering wheel is controlled to rotate reversely by using the target rotation angle until the steering wheel is at the return-to-center position. The present disclosure can improve the accuracy of steering wheel return-to-center and reduce the number of adjustments.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of automatic parking, in particular to a method and device for returning a steering wheel of a vehicle to a neutral position, a computer device and a storage medium. BACKGROUND

[0002] With the rapid development of automobile technology, automatic driving assistance technology is increasingly popular, including functions such as assisted cruise, assisted braking and assisted parking. Among them, the automatic parking assistance system helps the vehicle enter the target parking space by controlling the rotation of the steering wheel. However, after the vehicle enters the target parking space, the automatic parking assistance system exits the control, at this time, due to the incomplete release of tire stress, the steering wheel may be deflected, resulting in poor vehicle stability and poor user experience.

[0003] The existing steering wheel return control scheme relies on preset values (i.e. auxiliary parameters for the vehicle to complete the steering wheel return), but the numerical setting of these preset values may not be suitable for all vehicles and road types, because different tires will have different deformation degrees on the same road type, and the same wheel will also have different deformation degrees on different road types. Fixed increase in a certain value may cause the steering wheel to be adjusted too much or not enough, resulting in inaccurate adjustment, and even more adjustment times, thereby affecting efficiency and effectiveness. Therefore, how to improve the accuracy of the steering wheel return has become a problem to be solved. SUMMARY

[0004] Therefore, the present disclosure provides a method and device for returning a steering wheel of a vehicle to a neutral position, a computer device and a storage medium to solve the problem that the steering wheel return cannot be accurately implemented at present.

[0005] In a first aspect, the present disclosure provides a method for returning a steering wheel of a vehicle to a neutral position, the method comprising:

[0006] receiving a steering wheel return instruction, and obtaining a first angle of the steering wheel of the vehicle at a first time point;

[0007] obtaining a first error between the first angle and a target request angle, and analyzing the first error to determine whether the steering wheel is located in a return position interval, wherein the target request angle is an angle of the steering wheel at a return position, and the return position interval is determined according to the return position of the steering wheel and a preset threshold;

[0008] if the steering wheel is located in the return position interval, obtaining a real-time torque of the vehicle;

[0009] The comparison result between the real-time torque and the torque threshold is obtained, and in a case where the comparison result does not satisfy a preset condition, a target rotation angle is obtained based on the real-time torque, and the steering wheel is controlled to rotate reversely by using the target rotation angle until the steering wheel is in a return position, wherein the preset condition is that the real-time torque is less than the torque threshold.

[0010] Further, the first error is analyzed to determine whether the steering wheel is in a return position interval, comprising:

[0011] If the first error falls within a numerical range corresponding to the return position interval, it is determined that the steering wheel is in the return position interval.

[0012] If the first error does not fall within the numerical range corresponding to the return position interval, it is determined that the steering wheel is not in the return position interval.

[0013] Further, if the steering wheel is in the return position interval, the real-time torque of the vehicle is obtained, comprising:

[0014] When the steering wheel is in the return position interval, vehicle driving condition data of the vehicle is obtained.

[0015] A preset time length is determined based on the vehicle driving condition data, wherein the preset time length is a time length from a first time to a time when the real-time torque of the steering assist motor of the vehicle needs to be waited for.

[0016] After waiting for the preset time length, the real-time torque of the vehicle is obtained.

[0017] Further, the preset time length is determined based on the vehicle driving condition data, comprising:

[0018] Based on the vehicle driving condition data and a real-time model of the steering system, a first change curve of the steering assist motor torque of the vehicle moving backward with time and a second change curve of the steering wheel angle moving backward with time are obtained, wherein the real-time model of the steering system is used to evaluate the steering fluctuation state of the vehicle.

[0019] The preset time length is determined based on the first change curve and the second change curve.

[0020] Further, the preset time length is determined based on the first change curve and the second change curve, comprising:

[0021] A first change rate is obtained based on the first change curve, and a second change rate is obtained based on the second change curve.

[0022] The first change rate is compared with a corresponding first change rate threshold, and the second change rate is compared with a corresponding second change rate threshold.

[0023] In a case where the first change rate is less than the first change rate threshold and the second change rate is less than the second change rate threshold, a current second time is obtained.

[0024] Based on the first time and the second time, a preset time length is obtained.

[0025] Further, the method further comprises:

[0026] After determining that the steering wheel is not located in the return position interval, a steering wheel return instruction is sent, and a preset rotation parameter corresponding to the steering wheel is obtained, wherein the preset rotation parameter is used to gradually return the steering wheel from the current position to the return position;

[0027] The steering wheel is controlled to perform angle adjustment based on the preset rotation parameter until the steering wheel is located in the return position interval.

[0028] Further, based on the real-time torque, a target rotation angle is obtained, and the steering wheel is controlled to reverse rotation by using the target rotation angle until the steering wheel is in the return position, comprising:

[0029] Based on the real-time torque, a target rotation angle is obtained, and the steering wheel is controlled to reverse rotation by using the target rotation angle, to obtain a second angle of the steering wheel, and the second angle is taken as the first angle, starting from a first error between the first angle and a target request angle to perform a loop execution until a comparison result meets a preset condition, to determine that the steering wheel is in the return position.

[0030] In a second aspect, the present disclosure provides a device for returning a steering wheel of a vehicle to a position, comprising:

[0031] A first obtaining module is configured to obtain a first angle of a steering wheel of a vehicle at a first time when a steering wheel return instruction is received;

[0032] A second obtaining module is configured to obtain a first error between the first angle and a target request angle, and analyze the first error to determine whether the steering wheel is located in a return position interval, wherein the target request angle is an angle at which the steering wheel is in the return position, and the return position interval is determined according to the return position of the steering wheel and a preset threshold;

[0033] A third obtaining module is configured to obtain a real-time torque of the vehicle if the steering wheel is located in the return position interval;

[0034] A control module is configured to obtain a comparison result between the real-time torque and a torque threshold, and based on the real-time torque, obtain a target rotation angle if the comparison result does not meet a preset condition, and control the steering wheel to reverse rotation by using the target rotation angle until the steering wheel is in the return position, wherein the preset condition is that the real-time torque is less than the torque threshold.

[0035] In a third aspect, the present disclosure provides a computer device, comprising a memory and a processor, which are communicatively connected with each other, and the memory stores computer instructions, and the processor executes the computer instructions to perform the method for returning the steering wheel of the vehicle according to the first aspect or any one of the corresponding embodiments thereof.

[0036] In a fourth aspect, the present disclosure provides a computer readable storage medium, which stores computer instructions for causing a computer to perform the method for returning the steering wheel of the vehicle according to the first aspect or any one of the corresponding embodiments thereof.

[0037] The method provided by the embodiments of the present application, when receiving the steering wheel returning instruction, acquires the first angle of the steering wheel of the vehicle at the first time, then compares the first angle with the target request angle of the steering wheel at the returning position, obtains the first error, then determines whether the steering wheel is located in the returning position interval based on the first error, further obtains the real-time torque of the vehicle, and obtains the target rotation angle based on the comparison result between the real-time torque and the torque threshold, controls the steering wheel to rotate reversely by using the target rotation angle, and until the steering wheel is located at the returning position. Since the real-time torque can reflect the road type and the rebound angle of the steering wheel after the control, the target rotation angle of the steering wheel is dynamically calculated by using this algorithm, the steering wheel is controlled to rotate reversely by using the target rotation angle, the accuracy of the steering wheel returning can be improved, the number of adjustments can be reduced, the system can be prevented from entering the dead loop or being unable to complete the returning, and the returning accuracy and the user experience are improved. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the specific embodiments of the present disclosure or the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0039] Figure 1 is a flowchart of the method for returning the steering wheel of the vehicle according to the embodiments of the present application;

[0040] Figure 2 is a schematic diagram of the returning position interval of the method for returning the steering wheel of the vehicle according to the embodiments of the present application;

[0041] Figure 3 is a schematic diagram of the change of the target rotation angle according to the embodiments of the present application;

[0042] Figure 4 is a complete flowchart of the method for returning the steering wheel of the vehicle according to the embodiments of the present application;

[0043] Figure 5is a structural block diagram of an apparatus of a vehicle steering wheel return-to-center method according to an embodiment of the present application;

[0044] Figure 6 is a hardware structure schematic diagram of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, any other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0046] According to the embodiments of the present application, a vehicle steering wheel return-to-center method, apparatus, computer device, and storage medium are provided. It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0047] In the present embodiment, a vehicle steering wheel return-to-center method is provided, Figure 1 is a flowchart of a vehicle steering wheel return-to-center method according to an embodiment of the present application, as Figure 1 shown, the method can be applied to a steering system, and the method flow includes the following steps:

[0048] Step S101, upon receiving a steering wheel return-to-center instruction, obtaining a first angle of a steering wheel of a vehicle at a first time.

[0049] In the present embodiment, the automatic parking system of the vehicle sends a steering wheel return-to-center request to the steering system through a CAN (Controller Area Network) or other vehicle-mounted communication interface, and a highly integrated electronic control unit (ECU) is constructed inside the steering system of the vehicle, which is like the "intelligent brain" of the entire steering system. Once the steering wheel return-to-center instruction is generated, the instruction signal will be transmitted to this electronic control unit at an extremely fast speed through the vehicle-mounted network.

[0050] The electronic control unit then obtains the first angle of the steering wheel at the first time instant in real time. The first time instant refers to the time instant at which the electronic control unit of the vehicle receives the steering wheel return instruction. Specifically, the steering system is equipped with high-precision angle sensors for the steering wheel, which are closely connected to the rotating shaft of the steering wheel. When the steering wheel is in a rotating state, the sensors convert the rotating angle of the steering wheel into corresponding electrical signals or digital signals according to their unique working principle, and then convert the corresponding angle signals based on the electrical signals or digital signals to obtain the first angle of the steering wheel at the first time instant.

[0051] In step S102, a first error between the first angle and a target request angle is obtained, and the first error is analyzed to determine whether the steering wheel is located in a return position interval. The target request angle is an angle at which the steering wheel is in a return position, and the return position interval is determined according to the return position of the steering wheel and a preset threshold.

[0052] In the embodiment of the present application, the target request angle A is set to 0°, which is an angle at which the steering wheel is returned to the return position. At this time, whether the steering wheel is located in the return position interval can be determined based on the first error (i.e., the difference between the first angle and the target request angle A) between the first angle and the target request angle A. It should be noted that the return position interval is determined according to the return position of the steering wheel and a preset threshold, wherein the return position of the steering wheel (see Figure 2 ) is known, that is, during the production and manufacturing process of the vehicle, engineers will accurately design and debug the steering system to determine the return position of the steering wheel. This position is determined based on the overall layout of the vehicle, the geometric parameters of the steering mechanism, and four-wheel positioning, etc., to ensure that the steering wheel is in a specific intermediate position when the vehicle is driving in a straight line, so that the vehicle can maintain a stable straight driving state.

[0053] In addition, in order to determine whether the steering wheel is close to or close to the return position at the first time instant, a certain interval is obtained based on the preset threshold, as shown in Figure 2 , an offset angle is set on the left and right of the return position, and this angle is the preset threshold, for example, 3°, so the return position interval is [-3°, 3°].

[0054] It should be noted that the return position interval is an angle range for measuring whether the steering wheel is in a reasonable intermediate position, and the return position of the steering wheel determined by accurate design and debugging in the vehicle production process is the core reference. The position comprehensively considers factors such as vehicle overall layout, steering mechanism geometric parameters, four-wheel positioning, and is the key setting to ensure the stability of vehicle straight driving. On this basis, a certain angle is extended to the left and right sides around the return position, and the angle is the preset threshold. For example, the return position is taken as the origin, and each side is extended by 3°, forming the interval [-3°, 3°], which is a typical return position interval. When the first error between the first angle of the steering wheel and the target request angle A (0°, that is, the ideal angle of the steering wheel returning to the return position) falls within the interval, it is determined that the steering wheel is in the return position interval in the current state, indicating that the angle is close to or in the ideal return state, which helps to maintain the stability of vehicle straight driving; otherwise, it indicates that the steering wheel deviates.

[0055] In the embodiment of the present application, the analysis of the first error to determine whether the steering wheel is located in the return position interval includes steps A1-A2:

[0056] Step A1, if the first error falls within the numerical range corresponding to the return position interval, it is determined that the steering wheel is located in the return position interval.

[0057] Specifically, in the embodiment of the present application, the return position interval corresponds to a numerical range, such as [-3°, 3°] described above. When the first error falls within the numerical range, it is considered that the steering wheel is located in the return position interval, that is, it is considered that the steering wheel is close to the return position and has approached the return position.

[0058] Step A2, if the first error does not fall within the numerical range corresponding to the return position interval, it is determined that the steering wheel is not located in the return position interval.

[0059] Specifically, in the embodiment of the present application, the return position interval corresponds to a numerical range, such as [-3°, 3°] described above. When the first error does not fall within the numerical range, it is considered that the steering wheel is not located in the return position interval, that is, it is considered that the steering wheel is far from the return position, and at this time the steering wheel needs to be close to the return position before proceeding to the next step.

[0060] In the embodiment of the present application, after it is determined that the steering wheel is not located in the return position interval, the following steps A3-A4 are further included:

[0061] Step A3, receiving a steering wheel return instruction and obtaining a preset rotation parameter corresponding to the steering wheel, wherein the preset rotation parameter is used to gradually return the steering wheel from the current position to the return position.

[0062] Specifically, when the automatic parking system detects that the steering wheel deviates from the return position interval and is far away from the return position, the steering wheel return instruction is immediately issued. The steering system receives the instruction through a special communication interface, which can transmit the instruction from the automatic parking system to the steering system.

[0063] After receiving the instruction, the steering system starts the parameter acquisition process. It accesses the vehicle's on-board database, which stores a large number of pre-set steering parameters for different initial positions of the steering wheel and different driving states of the vehicle. The steering system first reads the actual position information of the current steering wheel. Then, according to the position information and the current driving speed, direction and other state data of the vehicle, it filters out the pre-set steering parameters that match from the database. The parameters include the rotation direction (clockwise or counterclockwise) and the rotation angle required for the steering wheel to gradually return to the return position from the current position.

[0064] Step A4, control the steering wheel to adjust the angle based on the pre-set steering parameters until the steering wheel is in the return position interval.

[0065] Specifically, after successfully acquiring the pre-set steering parameters, the steering system adjusts the angle of the steering wheel. First, it controls the rotation direction of the steering motor according to the parameter of the rotation direction. If the rotation direction is clockwise, the steering system sends a clockwise rotation control signal to the motor, and the motor starts to drive the steering wheel to rotate clockwise; if it is counterclockwise, it sends a counterclockwise rotation signal.

[0066] During the rotation process, the steering system continuously receives real-time angle information feedback from the steering wheel angle sensor. At the same time, the current actual rotation angle is compared with the pre-set rotation angle in real time. As the steering wheel rotates, when the actual rotation angle gradually approaches the pre-set rotation angle, the steering system gradually reduces the rotation speed of the motor to achieve accurate angle adjustment. Once the actual rotation angle reaches the pre-set rotation angle and the steering wheel position is detected to be in the return position interval, the steering system immediately stops sending the driving signal to the motor, and the motor stops running, thereby completing the angle adjustment of the steering wheel and making it stable in the return position interval.

[0067] Step S103, if the steering wheel is in the return position interval, acquire the real-time torque of the vehicle.

[0068] In the embodiments of the present application, if the steering wheel is in the return position interval, the real-time torque of the vehicle is acquired, including the following steps B1-B3:

[0069] Step B1, when the steering wheel is in the return position interval, acquire the vehicle driving condition data of the vehicle.

[0070] Specifically, if the steering wheel is located in the return position interval, it is considered that the steering wheel has approached the return position, at which time the current real-time torque of the vehicle can be obtained after waiting for a period of time, or the current real-time torque of the vehicle can be directly obtained.

[0071] The embodiments of the present application take the example of obtaining the real-time torque of the vehicle after waiting for a preset time period. Specifically, various sensors deployed on the vehicle, such as a vehicle speed sensor, an acceleration sensor, a steering wheel angle sensor, etc., collect vehicle driving condition data in real time through the sensors, and the driving condition data includes vehicle speed, acceleration, vehicle body attitude, initial angle of the steering wheel, etc.

[0072] Step B2, determining a preset time period based on the vehicle driving condition data, wherein the preset time period is the time period that needs to be waited for from the first time to obtain the real-time torque of the steering assist motor of the vehicle.

[0073] In the embodiments of the present application, the preset time period is determined based on the vehicle driving condition data, including the following steps B21-step B22:

[0074] Step B21, based on the vehicle driving condition data and the real-time model of the steering system, obtaining a first change curve of the steering assist motor torque of the vehicle with time shift and a second change curve of the steering wheel angle with time shift, wherein the real-time model of the steering system is used to evaluate the steering fluctuation state of the vehicle.

[0075] Specifically, the real-time model of the steering system runs in the ECU, and the model is constructed based on the mechanical structure characteristics of the vehicle steering system, the dynamics principle and a large amount of actual test data, and can accurately evaluate the steering fluctuation state of the vehicle under different conditions.

[0076] When calculating the first change curve of the steering assist motor torque with time shift, first, the collected driving condition data is input into the real-time model of the steering system. The model will calculate according to these data, combined with the mechanical transmission relationship of the steering system, the characteristic curve of the assist motor and other parameters. For example, when the vehicle is driving at low speed, the model will calculate the larger assist motor torque required to provide appropriate steering feel according to the vehicle speed and the steering wheel angle; while driving at high speed, the assist motor torque will be correspondingly reduced. With the passage of time, the model will continuously receive new condition data and continuously update the calculation, thereby obtaining a series of steering assist motor torque values corresponding to different times, arranging these values in time sequence to form the first change curve of the steering assist motor torque with time shift.

[0077] For the second change curve of the steering wheel angle with time, the collected vehicle driving condition data is also used as the basis. The steering wheel angle sensor detects the steering wheel rotation angle in real time and transmits the angle data to the ECU. The ECU records these real-time angle data in chronological order, and at the same time, combines the evaluation results of the steering system real-time model on the vehicle steering fluctuation state to correct and optimize the angle data. For example, when the model detects that the vehicle has a slight steering fluctuation during driving, the steering wheel angle data will be adjusted appropriately to more accurately reflect the actual effective rotation angle of the steering wheel. As time goes on, the ECU continuously collects and processes new steering wheel angle data, and eventually forms the second change curve of the steering wheel angle with time, thus presenting the changes of the steering wheel angle at different times.

[0078] Step B22, determining the preset time length based on the first change curve and the second change curve.

[0079] In the embodiments of the present application, determining the preset time length based on the first change curve and the second change curve includes the following steps B221-B224:

[0080] Step B221, obtaining a first change rate based on the first change curve and a second change rate based on the second change curve.

[0081] Step B222, comparing the first change rate with a corresponding first change rate threshold value and comparing the second change rate with a corresponding second change rate threshold value.

[0082] Step B223, in the case that the first change rate is less than the first change rate threshold value and the second change rate is less than the second change rate threshold value, obtaining a current second time.

[0083] Step B224, obtaining the preset time length based on the first time and the second time.

[0084] In the embodiments of the present application, if the first change curve and the second change curve can be represented by a mathematical function y=f(x), then the change rate of these curves at a certain point is the derivative f'(x) of the function. According to the derivative formula and rules, the derivative of the function can be obtained, and the corresponding curve change rate can be obtained.

[0085] Then the first change rate is compared with the corresponding first change rate threshold value, and the second change rate is compared with the corresponding second change rate threshold value. For example, the first change rate threshold value is 0.1 N·m / s, and the second change rate threshold value is 0.5° / s. If the first change rate is less than 0.1 N·m / s and the second change rate is less than 0.5° / s, it is considered that the steering system reaches a stable state. According to the simulation process, the time required from the current time (i.e. the first time) to the time under the stable state (i.e. the second time) is determined, and the preset time length is obtained.

[0086] Example: the vehicle speed is stable at 20km / h, and the vehicle is driving along the left-turn path with an acceleration of 0.5m / s 2 , the steering wheel uniformly rotates from 0° to 90° in 3 seconds, i.e. the steering angle change rate is 30° / s. At the same time, based on historical data and system identification algorithm, a real-time model of the steering system is built.

[0087] The collected vehicle speed, acceleration, steering angle change rate and other data are input into the real-time model of the steering system for numerical simulation. During the simulation process, the model calculates and outputs the change of steering assist motor torque and steering wheel angle with time according to its own model parameters and input data.

[0088] According to the model output results, the change curves of steering assist motor torque and steering wheel angle are constructed. When the simulation is carried out to the 5th second, it is calculated that the torque change rate decreases to 0.08N·m / s, which is less than the first change rate threshold 0.1N·m / s; the steering wheel angle change rate decreases to 0.3° / s, which is less than the second change rate threshold 0.5° / s. Therefore, it can be judged that the steering system reaches a stable state at this time.

[0089] Through the simulation process, it is known that from the start of the left-turn operation of the vehicle (0th second) to the stable state of the steering system, a total of 5 seconds is needed. This result provides an important basis for the vehicle control system, and the steering system can wait for 5 seconds accordingly.

[0090] On the one hand, the curve constructed by the real-time model and multi-dimensional data can accurately capture the dynamic changes of the steering system, providing a data basis for analyzing the performance of the steering system; on the other hand, by setting the change rate threshold and comparing, the abnormal fluctuation state of the steering system can be accurately identified, and when the first change rate and the second change rate are less than the threshold, it indicates that the steering system is in a stable operating state, and the preset time obtained at this time can be used to quantitatively evaluate the stability of the steering system, which provides a basis for subsequent optimization of the control strategy of the steering system and improvement of the smoothness of vehicle steering.

[0091] Step B3, after waiting for the preset time, obtaining the real-time torque of the vehicle.

[0092] Specifically, after the steering system waits for a preset time length, such as 5 seconds, the current real-time torque of the vehicle can be obtained by installing torque sensors in the transmission system of the vehicle, for example, at the positions of the drive shaft, the transmission output shaft, or the engine crankshaft. These sensors convert the torque signal into an electrical signal by using the principle of strain gauges, magneto-electric effect, photoelectric effect, and the like, thereby measuring the size of the transmitted torque in real time. The engine output torque can also be calculated by a pre-set engine torque model. For example, the electronic control unit determines the basic torque according to the throttle opening and the engine speed, and then corrects it according to the intake air volume, water temperature, and other parameters, thereby obtaining the real-time engine torque value.

[0093] In step S104, a comparison result between the real-time torque and the torque threshold value is obtained, and in a case where the comparison result does not satisfy a preset condition, a target rotation angle is obtained based on the real-time torque, and the steering wheel is controlled to reverse rotation by using the target rotation angle until the steering wheel is in a return-to-center position, wherein the preset condition is that the real-time torque is less than the torque threshold value.

[0094] In the embodiments of the present application, the target rotation angle is obtained based on the real-time torque, and the steering wheel is controlled to reverse rotation by using the target rotation angle until the steering wheel is in a return-to-center position, including step C1:

[0095] Step C1: the target rotation angle is obtained based on the real-time torque, and the steering wheel is controlled to reverse rotation by using the target rotation angle, to obtain a second angle of the steering wheel, and the second angle is taken as the first angle, and the first error between the first angle and the target request angle is obtained, and the cycle is executed until the comparison result satisfies the preset condition, to determine that the steering wheel is in the return-to-center position.

[0096] Specifically, in the embodiments of the present application, a preset condition for the vehicle to complete the return-to-center of the steering wheel is that the real-time torque is less than a torque threshold value (such as 0.3 N·m), and only when the calculated real-time torque of the vehicle satisfies the preset condition, the automatic parking system exits the control. Otherwise, the target rotation angle B n :

[0097]

[0098] In the formula, T m is the real-time torque of the n-th sampling, k eps is the stiffness of the steering system.

[0099] Meanwhile, the steering system controls the steering wheel to reverse rotation by using the target rotation angle, to compensate for the steering wheel deflection problem caused by tire deformation, excessive rotation of the steering wheel, or other factors, so that the steering wheel gradually returns to the center. In addition, when the steering wheel reverses rotation based on the target rotation angle, the real-time torque obtained by each sampling is constantly changing, so the target rotation angle obtained will also change. For example, Figure 3As shown, the target rotation angle calculated based on the first sampled real-time torque is B1, and then the steering wheel is directed to rotate to the middle, close to the target request angle A (0°).

[0100] After the rotation, the steering wheel has not completely returned to the middle, and another target rotation angle B2 is calculated according to the new real-time torque (i.e., the real-time torque obtained by the second sampling), the previous B1 and the current B2 are added together, and then the steering wheel is adjusted in the opposite direction, and then close to the target request angle A (0°).

[0101] In this process, as time goes on, the target rotation angle will fluctuate as shown in Figure 3 During the continuous adjustment of the steering wheel based on the target rotation angle, the second angle of the steering wheel will be obtained multiple times. Then the second angle is taken as the first angle, and the cycle is executed from the first error between the first angle and the target request angle, until the real-time torque is less than the torque threshold, and it is determined that the vehicle completes the steering wheel return, and the automatic parking system exits the control.

[0102] The method provided by the embodiment of the application receives the steering wheel return instruction, obtains the first angle of the vehicle steering wheel at the first time, then compares the first angle with the target request angle of the steering wheel in the return position, obtains the first error, then determines whether the steering wheel is located in the return position interval based on the first error, and further obtains the real-time torque of the vehicle, and obtains the target rotation angle based on the comparison result between the real-time torque and the torque threshold, and controls the steering wheel to rotate in the opposite direction by using the target rotation angle until the steering wheel is in the return position. Since the real-time torque can reflect the road type and the rebound angle of the steering wheel after the control is released, the target rotation angle of the steering wheel is dynamically calculated by using this algorithm, the steering wheel is controlled to rotate in the opposite direction by using the target rotation angle, the accuracy of the steering wheel return can be improved, the number of adjustments can be reduced, the system can be prevented from entering a dead loop or being unable to complete the return, and the return accuracy and user experience are improved.

[0103] Figure 4 is a complete flow diagram of the method for returning the steering wheel of the vehicle according to the embodiment of the application, and the specific process is as follows:

[0104] Step S1. The automatic parking system sends a steering wheel return request to the steering system, and sets the target request angle to 0° to ensure that the steering wheel returns to the return position.

[0105] Step S2. The automatic parking system monitors the current angle of the steering wheel in real time through the steering wheel angle sensor, and calculates the error between the current angle and the target request angle (0°).

[0106] Step S3. Determine whether the error is less than a preset threshold (e.g., 3°). If the error is less than the preset threshold, execute step S4, the system confirms that the steering wheel has approached the return-to-center position, and proceed to step S5. Otherwise, the automatic parking system continues to send the steering wheel return-to-center request until the error is less than the preset threshold.

[0107] Step S5. Start timing, and after waiting for a preset time, obtain the real-time torque of the steering assist motor.

[0108] Step S6. Determine whether the real-time torque is less than a torque threshold. If the real-time torque is less than the torque threshold, proceed to step S7 to determine that the vehicle has completed the steering wheel return-to-center, and the automatic parking system exits the control. If the condition is not met, proceed to step S8.

[0109] Step S8. Calculate a target steering angle based on the real-time torque.

[0110] Step S9. The automatic parking system sends a target steering angle request to the steering system based on the calculated target steering angle, controls the steering wheel to rotate in the opposite direction of the current deflection direction, so as to compensate for the steering wheel deflection problem caused by tire deformation or other factors.

[0111] Step S10. Calculate the error between the current angle of the steering wheel and the target request angle, and repeat steps S3 to S10 until the real-time torque is less than the torque threshold, execute step S7, the vehicle has completed the steering wheel return-to-center, and the automatic parking system exits the control.

[0112] The vehicle steering wheel return-to-center method provided in the embodiments of the present application calculates the target steering angle of the steering wheel based on the real-time torque of the steering wheel. Since the real-time torque can reflect the road type and the rebound angle of the steering wheel after the control is released, the reverse rotation of the steering wheel based on the target steering angle can improve the accuracy of the steering wheel return-to-center, reduce the number of adjustments, and prevent the system from entering a dead loop or failing to complete the return-to-center.

[0113] In the embodiments, a vehicle steering wheel return-to-center device is also provided, which is used to implement the above-described embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and contemplated.

[0114] The embodiments provide a vehicle steering wheel return-to-center device, as shown in Figure 5 , comprising:

[0115] A first acquisition module 501 is configured to acquire a first angle of a steering wheel of a vehicle at a first time when a steering wheel return-to-center instruction is received.

[0116] The second acquisition module 502 is configured to acquire a first error between the first angle and a target request angle, and analyze the first error to determine whether the steering wheel is located in a return-to-zero position interval, wherein the target request angle is an angle of the steering wheel in a return-to-zero position, and the return-to-zero position interval is determined according to the return-to-zero position of the steering wheel and a preset threshold.

[0117] The third acquisition module 503 is configured to acquire a real-time torque of the vehicle if the steering wheel is located in the return-to-zero position interval.

[0118] The control module 504 is configured to acquire a comparison result between the real-time torque and a torque threshold, and obtain a target rotation angle based on the real-time torque and control the steering wheel to rotate reversely by using the target rotation angle until the steering wheel is located in the return-to-zero position, if the comparison result does not satisfy a preset condition, wherein the preset condition is that the real-time torque is less than the torque threshold.

[0119] In the embodiment of the present application, the second acquisition module 502 is configured to determine that the steering wheel is located in the return-to-zero position interval if the first error falls within a numerical range corresponding to the return-to-zero position interval, and determine that the steering wheel is not located in the return-to-zero position interval if the first error does not fall within the numerical range corresponding to the return-to-zero position interval.

[0120] In the embodiment of the present application, the third acquisition module 503 is configured to acquire vehicle driving condition data of the vehicle when the steering wheel is located in the return-to-zero position interval, determine a preset time length based on the vehicle driving condition data, wherein the preset time length is a time length from a first time to a time when the real-time torque of the steering assist motor of the vehicle needs to be waited for, and acquire the real-time torque of the vehicle after waiting for the preset time length.

[0121] In the embodiment of the present application, the third acquisition module 503 is configured to obtain a first change curve of a steering assist motor torque of the vehicle moving backward with time and a second change curve of a steering wheel angle moving backward with time based on the vehicle driving condition data and a real-time model of a steering system, wherein the real-time model of the steering system is used to evaluate a steering fluctuation state of the vehicle, and determine the preset time length based on the first change curve and the second change curve.

[0122] In the embodiment of the present application, the third acquisition module 503 is configured to obtain a first change rate based on the first change curve, obtain a second change rate based on the second change curve, compare the first change rate with a corresponding first change rate threshold, compare the second change rate with a corresponding second change rate threshold, and acquire a second time in a case that the first change rate is less than the first change rate threshold and the second change rate is less than the second change rate threshold, and obtain the preset time length based on the first time and the second time.

[0123] In this embodiment of the application, the device further includes: after determining that the steering wheel is not in the return-to-center position range, receiving a steering wheel return-to-center command and obtaining a preset rotation parameter corresponding to the steering wheel, wherein the preset rotation parameter is used to provide information for gradually returning the steering wheel from the current position to the return-to-center position; controlling the steering wheel to adjust the angle based on the preset rotation parameter until the steering wheel is in the return-to-center position range.

[0124] In this embodiment of the application, the control module 504 is used to obtain the target steering angle based on the real-time torque, and use the target steering angle to control the steering wheel to rotate in the opposite direction to obtain the second angle of the steering wheel, and use the second angle as the first angle. The module is executed cyclically from the first error between the first angle and the target requested angle until the comparison result meets the preset conditions, and the steering wheel is determined to be in the straight position.

[0125] In this embodiment, the vehicle steering wheel return device is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0126] This application also provides a computer device having the above-described features. Figure 5 The device shown is for returning the vehicle's steering wheel to center.

[0127] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of a computer device provided in an optional embodiment of this disclosure, such as... Figure 6 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 6 Take a processor 10 as an example.

[0128] The processor 10 can be a central processor, a network processor, or a combination thereof. The processor 10 can further include hardware chips. The hardware chips can be application specific integrated circuits, programmable logic devices, or a combination thereof. The programmable logic devices can be complex programmable logic devices, field programmable logic gate arrays, general array logic, or any combination thereof.

[0129] The memory 20 stores instructions executable by the at least one processor 10 to cause the at least one processor 10 to perform the methods illustrated by the above embodiments.

[0130] The memory 20 can include a program storage area and a data storage area. The program storage area can store an operating system, application programs required by at least one function, and the like. The data storage area can store data created according to the use of the computer device, and the like. In addition, the memory 20 can include a high-speed random access memory, and can further include a non-transitory memory such as at least one disk storage device, a flash memory device, or other non-transitory solid state memory device. In some alternative embodiments, the memory 20 can optionally include a memory disposed remotely from the processor 10, which can be connected to the computer device through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0131] The memory 20 can include a volatile memory such as a random access memory, and can also include a non-volatile memory such as a flash memory, a hard disk, or a solid state disk. The memory 20 can further include a combination of the above-mentioned types of memories.

[0132] The electronic device further includes a communication interface 30 for communication of the electronic device with other devices or communication networks.

[0133] The embodiments of the present application also provide a computer readable storage medium. The above-mentioned methods according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or stored in a remote storage medium or a non-transitory machine readable storage medium originally through network downloading and then stored in a local storage medium, so that the methods described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid state disk, etc. Further, the storage medium can further include a combination of the above-mentioned types of memories. It can be understood that the computer, the processor, the microprocessor controller, or the programmable hardware includes a storage component that can store or receive software or computer code, which, when accessed and executed by the computer, the processor, or the hardware, implements the methods illustrated by the above embodiments.

[0134] While embodiments of the present application have been described in conjunction with the appended drawings, various modifications and changes can be suggested by persons skilled in the art, and all such modifications and changes are believed to fall within the scope of the present application as defined by the appended claims.

Claims

1. A method for straightening a vehicle steering wheel, characterized in that, The method includes: Upon receiving a steering wheel return command, the first angle of the vehicle's steering wheel at the first moment is obtained, where the first moment refers to the moment when the vehicle's electronic control unit receives the steering wheel return command; The first error between the first angle and the target requested angle is obtained, and the first error is analyzed to determine whether the steering wheel is in the return-to-center position range, wherein the target requested angle is the angle at which the steering wheel is in the return-to-center position, and the return-to-center position range is determined based on the return-to-center position of the steering wheel and a preset threshold. If the steering wheel is in the center position range, the real-time torque of the vehicle is obtained; The comparison result between the real-time torque and the torque threshold is obtained. If the comparison result does not meet the preset condition, the target steering angle is obtained based on the real-time torque. The target steering angle is used to control the steering wheel to rotate in the opposite direction until the steering wheel is in the straight position. The preset condition is that the real-time torque is less than the torque threshold.

2. The method according to claim 1, characterized in that, The analysis of the first error to determine whether the steering wheel is in the centering position range includes: If the first error falls within the numerical range corresponding to the return-to-center position interval, then the steering wheel is determined to be in the return-to-center position interval. If the first error does not fall within the numerical range corresponding to the return-to-center position interval, then it is determined that the steering wheel is not located in the return-to-center position interval.

3. The method according to claim 1, characterized in that, If the steering wheel is in the centering position range, then the real-time torque of the vehicle is obtained, including: When the steering wheel is in the centering position range, vehicle driving condition data is acquired; A preset time is determined based on the vehicle driving condition data, wherein the preset time is the time required to wait from the first moment until the real-time torque of the vehicle's power steering motor is obtained; After waiting for the preset time, the real-time torque of the vehicle is obtained.

4. The method according to claim 3, characterized in that, Determining the preset duration based on the vehicle driving condition data includes: Based on the vehicle driving condition data and the real-time steering system model, a first curve showing the change of the vehicle's steering assist motor torque over time and a second curve showing the change of the steering wheel angle over time are obtained. The real-time steering system model is used to evaluate the vehicle's steering fluctuation state. The preset duration is determined based on the first change curve and the second change curve.

5. The method according to claim 4, characterized in that, Determining the preset duration based on the first change curve and the second change curve includes: A first rate of change is obtained based on the first change curve, and a second rate of change is obtained based on the second change curve. Compare the first rate of change with the corresponding first rate of change threshold, and compare the second rate of change with the corresponding second rate of change threshold; If the first rate of change is less than the first rate of change threshold and the second rate of change is less than the second rate of change threshold, obtain the current second moment. The preset duration is obtained based on the first time point and the second time point.

6. The method according to claim 2, characterized in that, After determining that the steering wheel is not in the centering position range, the method further includes: Receive the steering wheel return command and obtain the preset rotation parameters corresponding to the steering wheel, wherein the preset rotation parameters are used to gradually return the steering wheel from the current position to the return position; The steering wheel is controlled to adjust its angle based on the preset rotation parameters until it is in the centering position range.

7. The method according to claim 1, characterized in that, The step of obtaining the target steering angle based on the real-time torque and using the target steering angle to control the steering wheel to rotate in the opposite direction until the steering wheel is in the straight position includes: The target steering angle is obtained based on the real-time torque, and the steering wheel is controlled to rotate in the opposite direction using the target steering angle to obtain the second angle of the steering wheel. The second angle is used as the first angle. The process is repeated from the first error between the first angle and the target requested angle until the comparison result meets the preset condition, and the steering wheel is determined to be in the centering position.

8. A device for centering a vehicle steering wheel, characterized in that, The device includes: The first acquisition module is used to acquire the first angle of the vehicle's steering wheel at a first moment when a steering wheel return command is received, wherein the first moment refers to the moment when the vehicle's electronic control unit receives the steering wheel return command; The second acquisition module is used to acquire the first error between the first angle and the target requested angle, and analyze the first error to determine whether the steering wheel is in the return-to-center position range, wherein the target requested angle is the angle at which the steering wheel is in the return-to-center position, and the return-to-center position range is determined based on the return-to-center position of the steering wheel and a preset threshold. The third acquisition module is used to acquire the real-time torque of the vehicle if the steering wheel is in the centering position range; The control module is used to obtain the comparison result between the real-time torque and the torque threshold, and if the comparison result does not meet the preset condition, to obtain the target steering angle based on the real-time torque, and to use the target steering angle to control the steering wheel to rotate in the opposite direction until the steering wheel is in the straight position, wherein the preset condition is that the real-time torque is less than the torque threshold.

9. A computer device, characterized in that, include: A memory and a processor are communicatively connected, the memory storing computer instructions, and the processor executing the computer instructions to perform the method for returning the vehicle steering wheel to center as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method of returning the vehicle steering wheel to center as described in any one of claims 1 to 7.

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