Steering wheel angle zero point calibration method and related products
By calibrating the initial steering wheel angle value after four-wheel alignment and receiving the zero-point calibration command, the problem of inaccurate steering wheel angle zero point in the electric power steering system is solved, thereby improving the vehicle's straight-line driving and steering smoothness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BYD CO LTD
- Filing Date
- 2024-04-28
- Publication Date
- 2026-07-14
Smart Images
Figure CN118372885B_ABST
Abstract
Description
Technical Field
[0001] This application relates to automotive steering technology, and more particularly to a method for zero-point calibration of steering wheel angle and related products. Background Technology
[0002] The car's steering wheel is rigidly connected to the rack of the Electric Power Steering (EPS) system via a mechanical structure. To ensure the symmetry of left and right steering, when the car body and wheels are in a straight line, the connection point between the steering wheel and the rack should be located at the center of the rack's effective length, and the steering wheel angle should be 0°. However, because the sensor that collects the steering wheel angle signal is not installed with a precise or fixed mechanical zero point position and limiting mechanism, the steering wheel angle value determined by the EPS system based on the angle signal when the car body and wheels are in a straight line will vary depending on the sensor's installation position and the rack length. In other words, the determined steering wheel angle value may not be 0°. Therefore, it is necessary to recalibrate the steering wheel's zero point. Summary of the Invention
[0003] Therefore, it is necessary to provide a steering wheel angle zero-point calibration method and related products that can recalibrate the steering wheel angle zero point to address the above-mentioned technical problems.
[0004] In a first aspect, this application provides a method for calibrating the zero point of a steering wheel angle, the method comprising:
[0005] With the vehicle's four-wheel alignment completed, determine the initial steering angle value when the steering wheel is in the center position;
[0006] Receive zero-point calibration command;
[0007] In response to the zero-point calibration command, the angle position corresponding to the initial angle value is calibrated as the zero point of the steering wheel.
[0008] In one embodiment, the step of calibrating the angle position corresponding to the initial angle value as the zero point of the steering wheel in response to the zero-point calibration command includes:
[0009] When the zero-point calibration conditions are met, in response to the zero-point calibration command, the angle position corresponding to the initial angle value is calibrated as the zero point of the steering wheel. The zero-point calibration conditions include at least one of the following: the power supply voltage of the vehicle to the electric power steering system EPS is within a preset range, the controller local area network communication is normal, the wiring harness connection of the device used to collect the angle signal is normal, the EPS has no operational fault, and the vehicle speed is lower than a threshold speed.
[0010] In one embodiment, the method is applied to EPS; determining the initial steering angle value when the steering wheel is in the center position after the vehicle has completed four-wheel alignment includes:
[0011] With the vehicle having completed four-wheel alignment and the EPS powered on, determine the initial steering angle value when the steering wheel is in the center position;
[0012] The method further includes:
[0013] When the EPS is powered off, the initial angle value corresponding to the zero point of the angle is written into the non-volatile memory NVM of the EPS.
[0014] In one embodiment, the method further includes:
[0015] When the EPS is powered on again, the rotation angle value when the steering wheel is turned to the target position is determined, and the rotation angle value is the rotation angle value corresponding to the collected rotation angle signal;
[0016] Read the initial rotation value stored in the NVM;
[0017] Based on the difference between the rotation angle value and the initial rotation angle value, the actual rotation angle value when the steering wheel is rotated to the target position is determined. The actual rotation angle value refers to the actual rotation angle value when the steering wheel is rotated to the target position compared to when the steering wheel is in the center position.
[0018] In one embodiment, the method further includes:
[0019] Based on the actual turning angle value, the assist torque that the EPS needs to provide is determined. The assist torque is used to assist the vehicle in steering when the steering wheel is turned.
[0020] In one embodiment, determining the actual steering angle when the steering wheel is turned to the target position based on the difference between the rotation angle value and the initial steering angle value includes:
[0021] The initial rotation angle value is corrected based on the difference between the rotation angle value and the initial rotation angle value.
[0022] The actual steering angle value when the steering wheel is turned to the target position is determined based on the difference between the rotation angle value and the corrected initial steering angle value.
[0023] In one embodiment, correcting the initial rotation angle value based on the difference between the rotation angle value and the initial rotation angle value includes:
[0024] If the difference between the rotation angle value and the initial rotation angle value is greater than the maximum rotation angle value, then the sum of the initial rotation angle value and the preset value is used as the corrected initial rotation angle value; or
[0025] If the difference between the rotation angle value and the initial rotation angle value is less than the minimum rotation angle value, then the difference between the initial rotation angle value and the preset value is used as the corrected initial rotation angle value; or
[0026] If the difference between the rotation angle value and the initial rotation angle value is greater than or equal to the minimum rotation angle value and less than or equal to the maximum rotation angle value, then the initial rotation angle value is used as the corrected initial rotation angle value.
[0027] Secondly, this application also provides a steering wheel angle zero-point calibration device, the device comprising:
[0028] The first determining module is used to determine the initial steering angle value when the steering wheel is in the center position after the vehicle has completed four-wheel alignment;
[0029] The instruction receiving module is used to receive zero-point calibration instructions;
[0030] The zero-point calibration module is used to calibrate the angle position corresponding to the initial angle value as the zero point of the steering wheel in response to the zero-point calibration command.
[0031] Thirdly, this application also provides a vehicle including an electric power steering system for performing the steps of the method as shown in the first aspect or any embodiment of the first aspect.
[0032] Fourthly, this application also provides a computer device, including: a memory and a processor, wherein the memory stores program instructions; when the program instructions are executed by the processor, the processor performs the method as shown in the first aspect or any embodiment of the first aspect.
[0033] Fifthly, this application also provides a computer-readable storage medium storing a computer program; when the computer program is run on one or more processors, it performs the method as shown in the first aspect or any embodiment of the first aspect.
[0034] The first aspect provides a steering wheel angle zero-point calibration method. With the vehicle's four-wheel alignment completed, the steering wheel is centered, the vehicle body and wheels are in a straight line, and the front left and right wheels are symmetrical. Under these conditions, zero-point calibration ensures that when the steering wheel is at its zero point, the front left and right wheels are symmetrical, and the vehicle maintains a straight-line driving state, preventing deviation. Furthermore, the EPS determines the initial steering angle value when the steering wheel is in the centered position based on the steering angle signals collected by the sensors. Since the steering angle value corresponding to any position of the steering wheel within its effective travel range remains constant after the sensor is installed in the EPS system, this angle value is fixed with respect to the sensor's installation position. When the steering wheel rotates left and right within its effective travel range, symmetrical to the centered position, the steering wheel angle value determined by the EPS based on the steering angle signals is also symmetrical about the steering wheel angle position corresponding to this initial angle value. Therefore, the steering wheel angle position corresponding to the initial angle value can be taken as the steering wheel angle zero point. Furthermore, the EPS receives a zero-point calibration command and, in response, calibrates the angle position corresponding to the initial angle value as the steering wheel's zero-point. Based on this zero-point position, the EPS adjusts the angle value when the steering wheel is in the centered position, resulting in an adjusted angle value of 0°. This steering wheel angle zero-point calibration method achieves the recalibration of the steering wheel's zero point, ensuring that the angle value determined by the EPS during steering wheel rotation is accurate and symmetrical about the zero-point position.
[0035] Understandably, the steering wheel angle zero-point calibration device provided in the second aspect, the vehicle provided in the third aspect, the computer equipment provided in the fourth aspect, and the computer-readable storage medium provided in the fifth aspect are all used to perform the method shown in the first aspect or any embodiment of the first aspect of this application. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects in the corresponding methods, and will not be repeated here. Attached Figure Description
[0036] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below.
[0037] Figure 1 One of the flowcharts for the steering wheel angle zero-point calibration method provided in the embodiments of this application;
[0038] Figure 2 A second schematic flowchart illustrating the steering wheel angle zero-point calibration method provided in this application embodiment;
[0039] Figure 3 The third flowchart illustrating the steering wheel angle zero-point calibration method provided in this application embodiment;
[0040] Figure 4 The fourth flowchart illustrating the steering wheel angle zero-point calibration method provided in this application embodiment;
[0041] Figure 5 This is a flowchart illustrating how to determine the actual steering angle when the steering wheel is rotated to the target position based on the difference between the rotation angle value and the initial steering angle value, as provided in an embodiment of this application.
[0042] Figure 6 This is a flowchart illustrating the process of determining the actual steering angle value when the steering wheel is turned to the target position, as provided in an embodiment of this application.
[0043] Figure 7 Fifth flowchart illustrating the steering wheel angle zero-point calibration method provided in this application embodiment;
[0044] Figure 8 This is a schematic diagram of the steering wheel angle zero-point calibration device provided in the embodiments of this application;
[0045] Figure 9 This is a schematic diagram of the vehicle structure provided in an embodiment of this application;
[0046] Figure 10 A schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation
[0047] To facilitate understanding of the embodiments of this application, a more comprehensive description of the embodiments of this application will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the embodiments of this application. However, the embodiments of this application can be implemented in many different forms and are not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the embodiments of this application more thorough and complete.
[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of this application belong. The terminology used herein in the description of embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of this application.
[0049] The terms "first," "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. For example, "first determining module" can also be described as "second determining module," and "second determining module" can also be described as "first determining module." When used, the singular expressions "a," "an," "the," "the," "this," and "this" are intended to also include the plural expressions, unless the context clearly indicates otherwise. It should also be understood that the term "comprising / including" specifies the presence of the stated features, wholes, steps, operations, parts, or combinations thereof, but does not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, parts, or combinations thereof.
[0050] With the rapid development of automotive technology, people's demands for driving experience are also increasing. Vehicle ride comfort and handling stability, as characteristics directly affecting the sensory experience and personal safety of drivers and passengers, have received increasing attention. The vehicle's steering system, as a key component for driver control, determines the overall safety and handling of the vehicle; smooth and comfortable steering is crucial for overall vehicle safety. EPS (Electric Power Steering) is a power steering system that relies on an electric motor to provide assistance. It is currently the mainstream steering system for passenger cars, mainly composed of a torque / angle sensor, an electronic control unit, a motor, a reduction mechanism, and a steering actuator. EPS uses the steering wheel torque detected by the torque / angle sensor and the current steering wheel angle as system inputs. After a series of algorithms, it calculates the required assist torque to assist vehicle steering, which is then output by the motor. Therefore, ensuring the accuracy and symmetry of the current steering wheel angle is crucial for the smooth and comfortable steering of the electric power steering system.
[0051] The car's steering wheel is rigidly connected to the EPS rack via a mechanical structure. To ensure the symmetry of left and right steering, when the vehicle body and wheels are in a straight line, the connection point between the steering wheel and the rack should be located at the center of the rack's effective length, and the steering wheel angle should be 0°. The EPS's torque / angle sensor collects the steering wheel's angle signal. Based on the raw angle signal, the EPS calculates the steering wheel angle value, which changes cyclically within a certain range as the steering wheel rotates. Because the torque / angle sensor is not installed with a precise or fixed mechanical zero point position and limiting mechanism when mounted on the EPS, the steering wheel angle value determined by the EPS based on the angle signal will vary depending on the installation position of the torque / angle sensor and the rack length when the vehicle body and wheels are in a straight line. In other words, the determined steering wheel angle value may not necessarily be 0°. Therefore, it is necessary to recalibrate the zero point of the steering wheel angle so that when the vehicle body and wheels are in a straight line, the steering wheel angle value input by the EPS system is 0°, so that when the steering wheel is turned, the steering wheel angle value input by the EPS system is accurate and symmetrical about the zero point position, thereby enabling the EPS to provide accurate assist torque to assist the vehicle steering.
[0052] like Figure 1 As shown in the figure, this application provides a method for calibrating the zero point of the steering wheel angle. The method for calibrating the zero point of the steering wheel angle includes the following steps S101 to S103.
[0053] S101, after the vehicle has completed four-wheel alignment, determines the initial steering angle value when the steering wheel is in the center position.
[0054] The steering wheel angle value determined by the EPS based on the angle signal will vary depending on the installation position of the torque / angle sensor and the rack length. However, once the torque / angle sensor is installed, the angle value corresponding to any position of the steering wheel within its effective travel range remains constant as long as the installation position of the torque / angle sensor is fixed. Therefore, when the vehicle body and wheels are in a straight line after the torque / angle sensor is installed, the steering wheel is in the centered position, and the steering wheel angle value determined by the EPS based on the angle signal remains constant. Let the angle value determined at this centered position be the initial angle value. It can be understood that when the steering wheel is turned left or right within its effective travel range, symmetrical about the centered position, the steering wheel angle value determined by the EPS based on the angle signal is symmetrical about the steering wheel angle position corresponding to this initial angle value. Therefore, the steering wheel angle position corresponding to the initial angle value can be taken as the zero point of the steering wheel angle. Adjusting the steering wheel angle value determined by the EPS at the centered position based on this zero point will result in an adjusted angle value of 0°.
[0055] Specifically, after the torque / steering angle sensor is installed in the EPS system, the vehicle undergoes a four-wheel alignment to ensure the steering wheel is centered and the vehicle body and wheels are in a straight line, guaranteeing symmetry between the front left and right wheels. After the four-wheel alignment is completed, the steering angle zero-point calibration ensures that when the steering wheel is at the zero-point, the front left and right wheels are symmetrical and the vehicle maintains a straight-line driving state, preventing deviation. Then, the torque / steering angle sensor and other devices collect the steering angle signal when the steering wheel is centered. Based on the original steering angle signal, the EPS calculates and processes the initial steering angle value when the steering wheel is centered. It is important to note that after the four-wheel alignment, the steering wheel position cannot be adjusted, otherwise the initial steering angle value will be incorrect. If the steering wheel position has been adjusted, the vehicle must undergo a new four-wheel alignment, and the EPS must redetermine the initial steering angle value.
[0056] S102 receives zero-point calibration instructions.
[0057] Among them, the zero-point calibration command is a control command that instructs the zero-point calibration of the turning angle.
[0058] S103, in response to the zero-point calibration command, calibrates the angle position corresponding to the initial angle value as the zero point of the steering wheel.
[0059] The sender of the zero-point calibration command can be an external device other than the vehicle, or it can be a module inside the vehicle. As long as it can send a valid zero-point calibration command, this application embodiment does not limit the sender of the zero-point calibration command.
[0060] For example, a zero-point calibration command can be sent from an external diagnostic instrument. The diagnostic instrument connects to the vehicle's onboard automatic diagnostic system (OBS) via an interface, establishing normal communication between the instrument and the vehicle. The diagnostic instrument performs diagnostic and routine control services for the vehicle, sending a zero-point calibration function routine control command—that is, sending a zero-point calibration command—to the vehicle's EPS (Electrical Power Control) system, which then enables the EPS to perform the zero-point calibration function. By sending the zero-point calibration command through the diagnostic instrument to instruct the calibration of the steering angle zero point, the EPS receives the command and, in response, calibrates the steering angle position corresponding to the initial steering angle value as the steering wheel's zero point. The operation is simple and convenient. For example, after completing the zero-point calibration, the EPS sends a response message to the diagnostic instrument indicating that the zero-point calibration is complete.
[0061] For example, the torque / angle sensor in this embodiment can be a high-precision non-contact electromagnetic induction position sensor with high low-temperature sensitivity, electromagnetic compatibility, and robustness. Furthermore, the torque / angle sensor acquires the original angle signal in real time based on the principle of electromagnetic induction, achieving non-contact linear and angular position measurement, and transmits the angle signal to the EPS. The EPS uses a vernier algorithm to calculate the angle value, ensuring the accuracy of the calculated angle value, which in turn facilitates the output of precise steering torque to assist vehicle steering.
[0062] In this embodiment, with the vehicle's four-wheel alignment completed, the steering wheel is in the centered position, and the vehicle body and wheels maintain a straight line. The front left and right wheels are symmetrical. Under these conditions, zero-point calibration of the steering angle ensures that when the steering wheel is at the zero-point, the front left and right wheels are symmetrical, and the vehicle maintains a straight-line driving state, avoiding deviation. Furthermore, the EPS determines the initial steering angle value when the steering wheel is in the centered position based on the steering angle signal collected by the torque / steering angle sensor. When the steering wheel rotates left and right within its effective travel range, symmetrical to the centered position, the steering wheel angle value determined by the EPS based on the steering angle signal is also symmetrical about the steering wheel angle position corresponding to this initial angle value. Therefore, the steering wheel angle position corresponding to the initial angle value can be taken as the zero-point of the steering wheel. Further, the EPS receives a zero-point calibration command and, in response, calibrates the angle position corresponding to the initial angle value as the zero-point of the steering wheel. Based on this zero-point position, the steering angle value determined by the EPS when the steering wheel is in the centered position is adjusted. The adjusted steering angle value is 0°, ensuring that the steering wheel angle input by the EPS system is 0°, which helps the vehicle maintain straight-line driving when the steering wheel is in the centered position. Using the steering wheel angle zero-point calibration method in this embodiment, the zero-point of the steering angle is recalibrated, which helps ensure that the steering wheel angle value input by the EPS system is accurate and symmetrical about the zero-point position when the steering wheel is turned. This, in turn, helps the EPS provide accurate assist torque to assist vehicle steering.
[0063] Secondly, current automotive steering technology employs a scheme to calibrate the zero point using two separate power steering systems, each equipped with sensors. However, this scheme is costly and impractical, making it difficult to implement in practice. In this embodiment, the EPS calculates the initial steering angle value based on the steering angle signal collected by the torque / steering angle sensor mounted on the EPS. Upon receiving a zero-point calibration command, the steering angle zero point can be calibrated without incurring additional costs, thus demonstrating high feasibility. The sender of the zero-point calibration command, such as a diagnostic instrument like the VDS2000, is already a standard tool in vehicle assembly lines. Therefore, sending the zero-point calibration command from the diagnostic instrument to the vehicle's EPS also requires no additional cost.
[0064] In one embodiment, step S103, which calibrates the angle position corresponding to the initial angle value as the zero point of the steering wheel in response to the zero point calibration command, includes the following steps: when the zero point calibration conditions are determined to be met, the angle position corresponding to the initial angle value is calibrated as the zero point of the steering wheel in response to the zero point calibration command. The zero point calibration conditions include at least one of the following: the power supply voltage of the vehicle to the electric power steering system EPS is within a preset range, the controller local area network communication is normal, the wiring harness connection of the device used to collect the angle signal is normal, the EPS has no operational faults, and the vehicle speed is lower than a threshold speed.
[0065] After the EPS is powered on, the EPS continuously and repeatedly checks whether the power supply voltage to the electric power steering system EPS is within the preset range, whether the controller local area network communication is normal, whether the wiring harness connection of the device used to collect the steering angle signal is normal, whether the EPS has no operational faults, and whether the vehicle speed is lower than the threshold speed, so as to ensure that the steering wheel angle calibration is carried out when the vehicle is in normal condition and the vehicle is stationary. The preset range of the power supply voltage is generally 6.5 volts to 18 volts. In this embodiment, the device for acquiring the steering angle signal is a torque / steering angle sensor. Whether its wiring harness connection is normal will directly determine whether the steering angle signal and steering angle value are valid. Therefore, in order to acquire a valid steering angle signal in real time and obtain a valid steering wheel angle value, it is necessary to ensure that the wiring harness connection between the torque / steering angle sensor and the EPS, as well as inside the torque / steering angle sensor, is normal. The operating faults of the EPS include internal faults of the microcontroller unit, faults of the torque / steering angle sensor, and other faults that cannot be recovered in the current ignition cycle. The steering wheel angle calibration must be performed under the premise that there are no operating faults of the EPS. The vehicle speed is preferably 0, that is, the zero-point calibration of the steering angle is performed when the vehicle is completely stationary, so as to ensure the accuracy of the zero-point calibration and the safety of the calibration environment. However, in cases where special circumstances are allowed, such as the vehicle slowly rolling, the threshold speed of the vehicle speed can be set to 3 kilometers per hour. It should be noted that the steering wheel angle calibration function is not applicable during vehicle movement.
[0066] For example, the conditions for determining the zero-point calibration of the EPS are met when the power supply voltage to the electric power steering system (EPS) is within a preset range, the controller local area network communication is normal, the wiring harness connection of the device used to collect the steering angle signal is normal, the EPS has no operational faults, and the vehicle speed is lower than the threshold speed.
[0067] Specifically, after the vehicle completes four-wheel alignment, the EPS is powered on, determines the initial steering angle value when the steering wheel is in the center position, and continuously and repeatedly checks whether the zero-point calibration condition is met. Then, it receives the zero-point calibration command, and if the zero-point calibration condition is met, it calibrates the steering angle position corresponding to the initial steering angle value as the steering wheel's zero point in response to the zero-point calibration command, ensuring that the steering wheel angle calibration is performed when the vehicle is in normal condition and stationary.
[0068] For example, if a diagnostic instrument outside the vehicle sends a steering angle zero-point calibration function routine control command, i.e., sends a zero-point calibration instruction to the vehicle's EPS, the EPS, upon receiving the zero-point calibration instruction and determining that the zero-point calibration conditions are met, calibrates the steering angle position corresponding to the initial steering angle value as the steering wheel's zero point in response to the zero-point calibration instruction. After completing the steering angle zero-point calibration, it sends a response message to the diagnostic instrument indicating that the zero-point calibration is complete. If the zero-point calibration conditions are not met, the EPS, upon receiving the zero-point calibration instruction, sends a response message to the diagnostic instrument indicating that the zero-point calibration conditions are not met and terminates the zero-point calibration routine.
[0069] In this embodiment, the zero-point calibration of the steering angle is performed after the vehicle has completed four-wheel alignment. This ensures that when the steering wheel is placed at the zero-point, the left and right front wheels of the vehicle are symmetrical and the vehicle can maintain a straight-line driving state, avoiding deviation. Furthermore, the EPS determines the initial steering angle value when the steering wheel is in the center position based on the steering angle signal collected by the torque / steering angle sensor, and continuously and repeatedly checks whether the zero-point calibration condition is met. Further, the EPS receives the zero-point calibration command, and when it is determined that the zero-point calibration condition is met, it calibrates the steering angle position corresponding to the initial steering angle value as the steering wheel's zero-point, thereby achieving recalibration of the zero-point and ensuring that the steering wheel angle calibration is performed when the vehicle is in a normal state and stationary.
[0070] like Figure 2 As shown, in one embodiment, the steering wheel angle zero-point calibration method is applied to EPS. The steering wheel angle zero-point calibration method includes the following steps S201 to S204. Among them, steps S202 to S203 correspond one-to-one with steps S102 to S103 in the previous embodiment. The discussion of steps S202 to S203 in this embodiment can be referred to the previous embodiment, and will not be repeated in this embodiment.
[0071] S201, with the vehicle having completed four-wheel alignment and the EPS powered on, determines the initial steering angle value when the steering wheel is in the center position.
[0072] Specifically, after the vehicle completes its four-wheel alignment, the vehicle is switched to the ON position to provide power to all electronic devices inside the vehicle, including the EPS. After the EPS is powered on, the initial steering angle value is determined when the steering wheel is in the center position at the moment of power-on.
[0073] S202 receives zero-point calibration commands.
[0074] S203, in response to the zero-point calibration command, calibrates the angle position corresponding to the initial angle value as the zero point of the steering wheel.
[0075] For example, when the zero-point calibration conditions are met, the steering angle position corresponding to the initial steering angle value is calibrated as the steering wheel's zero-point in response to the zero-point calibration command. The zero-point calibration conditions include at least one of the following: the power supply voltage of the vehicle to the electric power steering system EPS is within a preset range, the controller local area network communication is normal, the wiring harness connection of the device used to collect the steering angle signal is normal, the EPS has no operational faults, and the vehicle speed is lower than a threshold speed.
[0076] S204 writes the initial angle value corresponding to the zero point of the angle to the non-volatile memory NVM of the EPS when the EPS is powered off.
[0077] The NVM is a standard memory in the EPS. When the EPS is powered off, the data stored in the NVM will not be lost. Based on this, the data stored in the NVM can be read or retrieved by the EPS after it is powered on again.
[0078] Specifically, after receiving the power-down hibernation command, the EPS writes the initial angle value corresponding to the zero point of the angle into the NVM so that it can be directly read and called after power-on.
[0079] For example, Figure 3 This is a flowchart illustrating the steering wheel angle zero-point calibration method provided in an embodiment of this application. Figure 3 As shown, after the vehicle completes its four-wheel alignment, the vehicle is put in the ON position to power on the EPS (Electric Power Steering). When powered on, devices on the EPS, such as the torque / angle sensor, collect the initial steering angle signal when the steering wheel is in the centered position and transmit it to the EPS. The EPS determines the initial steering angle value based on this signal. Furthermore, the EPS continuously and repeatedly checks whether the zero-point calibration conditions are met. Then, the external diagnostic instrument VDS2000 sends a zero-point calibration command to the vehicle's EPS. Upon receiving the command and confirming that the zero-point calibration conditions are met, the EPS calibrates the steering angle position corresponding to the initial steering angle value as the steering wheel's zero-point. After completing the zero-point calibration, it sends a response message to the VDS2000 indicating that the zero-point calibration is complete. Finally, when the EPS is powered off, it writes the initial steering angle value corresponding to the zero-point to the NVM (Neural Machine Virtual Machine) for easy retrieval upon power-up. If the zero-point calibration conditions are not met, EPS will send a response message to the diagnostic instrument VDS2000 after receiving the zero-point calibration command, indicating that the zero-point calibration conditions are not met, and then terminate the zero-point calibration routine.
[0080] In this embodiment, the zero-point calibration of the steering angle is performed after the vehicle has completed four-wheel alignment. This ensures that when the steering wheel is at the zero-point, the left and right front wheels of the vehicle are symmetrical and the vehicle can maintain a straight driving state, avoiding deviation. Furthermore, the EPS determines the initial steering angle value when the steering wheel is in the center position based on the steering angle signal collected by the torque / steering angle sensor, and continuously and repeatedly checks whether the zero-point calibration condition is met. Further, the EPS receives a zero-point calibration command, and when the zero-point calibration condition is determined to be met, it calibrates the steering angle position corresponding to the initial steering angle value as the steering wheel's zero-point, thereby achieving recalibration of the zero-point and ensuring that the steering wheel angle calibration is performed when the vehicle is in a normal state and stationary. Finally, when the EPS is powered off, the initial steering angle value corresponding to the zero-point is written to the NVM for easy retrieval upon power-up. The initial steering angle value is then used to adjust the steering angle value corresponding to the steering angle signal, ensuring that the adjusted steering wheel angle value input by the EPS system when the steering wheel is turned is accurate and symmetrical about the zero-point position.
[0081] like Figure 4 As shown, in one embodiment, the steering wheel angle zero-point calibration method includes the following steps S401 to S407. Steps S401 to S404 correspond one-to-one with steps S201 to S204 in the previous embodiments. The discussion of steps S401 to S404 in this embodiment can be found in the previous embodiments, and will not be repeated here.
[0082] S401 determines the initial steering angle value when the steering wheel is in the center position after the vehicle has completed four-wheel alignment and the EPS is powered on.
[0083] S402 receives zero-point calibration commands.
[0084] S403, in response to the zero-point calibration command, calibrates the angle position corresponding to the initial angle value as the zero point of the steering wheel.
[0085] S404 writes the initial angle value corresponding to the zero point of the angle to the non-volatile memory NVM of the EPS when the EPS is powered off.
[0086] S405, when the EPS is powered on again, determines the steering angle value when the steering wheel is turned to the target position. The steering angle value is the angle value corresponding to the collected steering angle signal.
[0087] The target position can be any position of the steering wheel within its effective travel range, determined by the driver turning the steering wheel according to driving needs.
[0088] Specifically, when the EPS is powered on again, the torque / angle sensor collects the angle signal when the steering wheel is turned to the target position. The EPS determines the rotation angle value when the steering wheel is turned to the target position based on the angle signal collected by the torque / angle sensor. This rotation angle value is the angle value determined by the EPS for system input to calculate the assist torque without zero-point calibration.
[0089] S406, read the initial angle value stored in NVM.
[0090] Specifically, when the EPS is powered on, it automatically reads the initial angle value corresponding to the calibrated zero position, and this initial angle value can be read and used in the current ignition cycle.
[0091] S407, determine the actual steering angle value when the steering wheel is turned to the target position based on the difference between the rotation angle value and the initial steering angle value. The actual steering angle value refers to the actual steering angle value when the steering wheel is turned to the target position compared to when the steering wheel is in the center position.
[0092] Specifically, when the steering wheel is in the center position, the EPS determines the initial steering angle based on the steering angle signal. When the steering wheel is turned to the target position, the EPS determines the final steering angle based on the steering angle signal. Therefore, by calculating the difference between the final steering angle and the initial steering angle, the actual steering angle value when the steering wheel is turned from the center position to the target position can be determined. This actual steering angle value is the accurate steering angle value determined by the EPS for system input to calculate the power assist torque, assuming zero-point calibration has been performed.
[0093] In this embodiment, the steering wheel rotation angle is adjusted by using the initial angle value corresponding to the zero point position to obtain the actual angle value. This ensures that the steering wheel angle value input by the EPS system is accurate and symmetrical about the zero point position when the steering wheel is turned. After calibrating the zero point, the initial angle value corresponding to the zero point position can be directly read whenever the EPS is powered on, allowing for accurate adjustment of the steering wheel angle value input to the EPS system, making operation convenient. Each power-on cycle of the EPS calculates the rotation angle value of the steering wheel position at the moment of power-on and compares it with the initial angle value at the zero point position to obtain the actual angle value relative to the zero point position, which serves as the angle offset for the current ignition cycle. Once the torque / angle sensor is installed, the angle value corresponding to any position of the steering wheel within its effective travel range remains constant as the installation position of the torque / angle sensor is fixed. Therefore, after the steering wheel angle zero point is calibrated, the actual steering angle value is determined based on the fixed initial steering angle value, which can ensure the consistency of the steering wheel angle value input by the EPS system when the steering wheel is turned to the same position in any ignition cycle.
[0094] In one embodiment, the steering wheel angle zero-point calibration method, in addition to steps S401 to S407, further includes the step of: determining the assist torque that the EPS needs to provide based on the actual angle value, wherein the assist torque is used to assist the vehicle steering when the steering wheel is turned.
[0095] Specifically, EPS adjusts the steering angle value when the steering wheel is turned by using the initial steering angle value corresponding to the zero point position. The actual steering angle value obtained is the system input. After a series of algorithm calculations, the system obtains the assist torque that needs to be provided to assist the vehicle in steering when the steering wheel is turned, and the motor executes the output.
[0096] In this embodiment, based on the actual steering angle value symmetrical about the zero point position when the steering wheel is turned, the assist torque that the EPS needs to provide can be determined more accurately, so as to assist the vehicle steering more accurately and achieve smooth and comfortable steering.
[0097] like Figure 5 As shown, in one embodiment, step S407, which determines the actual steering angle value when the steering wheel is turned to the target position based on the difference between the rotation angle value and the initial steering angle value, includes the following steps S501 to S502.
[0098] S501, correct the initial rotation angle value based on the difference between the rotation angle value and the initial rotation angle value.
[0099] Because the steering wheel's turning angle ranges from -740° to 740°, and this turning angle is cyclical (if the turning angle exceeds 740° in the current cycle, it will enter the next cycle at -740°), any difference between the current turning angle and the initial turning angle exceeding the -740° to 740° range cannot be directly used as the actual turning angle. For example, if the initial turning angle is -10°, and the turning angle when the steering wheel reaches the target position is 735°, the difference between the current turning angle and the initial turning angle is 745°. Since 745° exceeds the -740° to 740° range, it is not a valid actual turning angle. In this example, the actual turning angle should be 745 - 1480 = -735°. Therefore, it is necessary to first correct the initial turning angle based on the difference between the current turning angle and the initial turning angle to obtain a valid actual turning angle within the range.
[0100] In one embodiment, step S501 above, correcting the initial rotation angle value based on the difference between the rotation angle value and the initial rotation angle value, includes the following steps:
[0101] If the difference between the rotation angle value and the initial rotation angle value is greater than the maximum rotation angle value, then the sum of the initial rotation angle value and the preset value is used as the corrected initial rotation angle value; or
[0102] If the difference between the rotation angle value and the initial rotation angle value is less than the minimum rotation angle value, then the difference between the initial rotation angle value and the preset value is used as the corrected initial rotation angle value; or
[0103] If the difference between the rotation angle value and the initial rotation angle value is greater than or equal to the minimum rotation angle value and less than or equal to the maximum rotation angle value, then the initial rotation angle value is used as the corrected initial rotation angle value.
[0104] Based on the actual range of steering wheel angle values in vehicles, the maximum steering angle is set to 740°, the minimum steering angle to -740°, and the preset value to 1480°. Specifically, if the difference between the steering angle value and the initial steering angle value is greater than 740°, the corrected initial steering angle value is the sum of the initial steering angle value and 1480°; if the difference between the steering angle value and the initial steering angle value is less than -740°, the corrected initial steering angle value is the difference between the initial steering angle value and 1480°; if the difference between the steering angle value and the initial steering angle value is within the range of -740° to 740° of the vehicle's steering wheel angle value, the corrected initial steering angle value is the initial steering angle value, in other words, no adjustment or correction is needed to the initial steering angle value.
[0105] S502, determine the actual steering angle value when the steering wheel is turned to the target position based on the difference between the rotation angle value and the corrected initial steering angle value.
[0106] Specifically, based on the difference between the rotation angle value and the corrected initial rotation angle value, the effective actual rotation angle value within the rotation angle value range when the steering wheel is turned to the target position is determined.
[0107] For example, Figure 6 This is a flowchart illustrating the process of determining the actual steering angle value when the steering wheel is turned to the target position, as provided in an embodiment of this application. When the EPS is powered on, the EPS determines the steering angle value when the steering wheel is turned to the target position based on the steering angle signal collected by the torque / steering angle sensor, and directly and automatically reads the initial steering angle value corresponding to the calibrated zero point position stored in the NVM. Then, it determines whether the difference between the steering angle value and the initial steering angle value is greater than 740°. If it is determined to be greater than 740°, the corrected initial steering angle value is set to the initial steering angle value + 1480°. If it is determined to be less than 740°, it continues to determine whether the difference between the steering angle value and the initial steering angle value is less than -740°. If it is determined to be less than -740°, the corrected initial steering angle value is set to the initial value - 1480°. If it is determined to be neither less than -740°, the corrected initial steering angle value is set to the initial steering angle value. Further, the actual steering angle value when the steering wheel is turned to the target position is determined; the actual steering angle value is the difference between the steering angle value and the corrected initial steering angle value.
[0108] For example, if the difference between the rotation angle value and the initial rotation angle value is within the range of the vehicle steering wheel angle value from -740° to 740°, that is, not greater than 740° and not less than -740°, then there is no need to adjust and correct the initial rotation angle value, and the difference between the rotation angle value and the initial rotation angle value is directly output. This difference is the valid actual rotation angle value within the rotation angle value range.
[0109] In this embodiment, the steering wheel angle range and the calculation rules of the cyclical formula of the steering wheel value are combined in actual situations. The initial steering angle value is corrected according to the difference between the rotation angle value and the initial steering angle value to obtain an effective actual steering angle value within the steering angle range. This ensures that when the steering wheel is rotated, the steering wheel angle value input by the EPS system is accurate and symmetrical about the zero point position.
[0110] like Figure 7 As shown, in one embodiment, the steering wheel angle zero-point calibration method is applied to EPS. The steering wheel angle zero-point calibration method includes the following steps S701 to S711.
[0111] S701 determines the initial steering angle value when the steering wheel is in the center position after the vehicle has completed four-wheel alignment and the EPS is powered on.
[0112] S702 receives zero-point calibration commands.
[0113] S703, upon determining that the zero-point calibration conditions are met, responds to the zero-point calibration command by calibrating the angle position corresponding to the initial angle value as the zero point of the steering wheel angle. The zero-point calibration conditions include at least one of the following: the power supply voltage to the electric power steering system (EPS) is within a preset range; the controller local area network communication is normal; the wiring harness connection of the device used to collect the angle signal is normal; the EPS has no operational faults; and the vehicle speed is below a threshold speed.
[0114] S704 writes the initial angle value corresponding to the zero point of the angle to the non-volatile memory NVM of the EPS when the EPS is powered off.
[0115] S705, when the EPS is powered on again, determines the steering angle value when the steering wheel is turned to the target position. The steering angle value is the angle value corresponding to the collected steering angle signal.
[0116] S706 reads the initial rotation value stored in NVM.
[0117] S707, if the difference between the rotation angle value and the initial rotation angle value is greater than the maximum rotation angle value, then the sum of the initial rotation angle value and the preset value is used as the corrected initial rotation angle value.
[0118] Alternatively, in S708, if the difference between the rotation angle value and the initial rotation angle value is less than the minimum rotation angle value, then the difference between the initial rotation angle value and the preset value is used as the corrected initial rotation angle value.
[0119] Or S709, if the difference between the rotation angle value and the initial rotation angle value is greater than or equal to the minimum rotation angle value and less than or equal to the maximum rotation angle value, then the initial rotation angle value is used as the corrected initial rotation angle value.
[0120] S710 determines the actual steering angle when the steering wheel is turned to the target position based on the difference between the actual steering angle and the corrected initial steering angle. The actual steering angle refers to the actual steering angle when the steering wheel is turned to the target position compared to when the steering wheel is in the center position.
[0121] S711 determines the power assist torque that the EPS needs to provide based on the actual steering angle value. The power assist torque is used to assist the vehicle's steering when the steering wheel is turned.
[0122] In this embodiment, with the vehicle's four-wheel alignment completed, the steering wheel is in the centered position, and the vehicle body and wheels maintain a straight line. The front left and right wheels are symmetrical. Under these conditions, zero-point calibration of the steering angle ensures that when the steering wheel is at the zero-point, the front left and right wheels are symmetrical, and the vehicle maintains a straight-line driving state, avoiding deviation. Furthermore, the EPS determines the initial steering angle value when the steering wheel is in the centered position based on the steering angle signal collected by the torque / steering angle sensor, and continuously and repeatedly checks whether the zero-point calibration condition is met. When the steering wheel rotates left and right within its effective travel range, symmetrical to the centered position, the steering wheel angle value determined by the EPS based on the steering angle signal is also symmetrical about the steering wheel angle position corresponding to this initial angle value. Therefore, the steering wheel angle position corresponding to the initial angle value can be taken as the zero-point of the steering wheel. Furthermore, the EPS receives a zero-point calibration command and, upon confirming that the zero-point calibration conditions are met, calibrates the angle position corresponding to the initial angle value as the steering wheel's zero-point angle in response to the command. This achieves recalibration of the zero-point angle and ensures that the steering wheel angle calibration is performed when the vehicle is in a normal state and stationary. Based on this zero-point position, the EPS adjusts the angle value when the steering wheel is in the centered position, resulting in an adjusted angle value of 0°. This ensures that the steering wheel angle value input by the EPS system is 0°, which helps the vehicle maintain straight-line driving when the steering wheel is in the centered position. Finally, when the EPS is powered off, the initial angle value corresponding to the zero-point angle is written to the NVM for easy retrieval upon power-up. When the EPS is powered on again, it determines the steering angle value when the steering wheel is turned to the target position and automatically reads the initial steering angle value stored in the NVM. Then, it combines the actual steering wheel angle value range of the vehicle and the cyclical calculation rules of the steering angle value to correct the initial steering angle value. The EPS adjusts the steering angle value corresponding to the steering angle signal when the steering wheel is turned with the corrected initial steering angle value to obtain an effective actual steering angle value within the steering angle value range. This makes the adjusted steering wheel angle value input by the EPS system accurate and symmetrical about the zero point position when the steering wheel is turned. This helps the EPS to provide accurate assist torque according to the actual steering angle value to assist the vehicle steering, achieving smooth and comfortable steering.
[0123] like Figure 8 As shown in the illustration, this application also provides a steering wheel angle zero-point calibration device 800. The steering wheel angle zero-point calibration device 800 includes a first determining module 801, an instruction receiving module 802, and a zero-point calibration module 803. The first determining module 801 is used to determine the initial steering angle value when the steering wheel is in the centered position after the vehicle has completed four-wheel alignment. The instruction receiving module 802 is used to receive a zero-point calibration instruction. The zero-point calibration module 803 is used to calibrate the steering angle position corresponding to the initial steering angle value as the steering wheel's zero-point in response to the zero-point calibration instruction.
[0124] In one embodiment, the zero-point calibration module 803 is further configured to, in response to a zero-point calibration command, calibrate the angle position corresponding to the initial angle value as the zero point of the steering wheel when the zero-point calibration conditions are met. The zero-point calibration conditions include at least one of the following: the power supply voltage of the vehicle to the electric power steering system EPS is within a preset range; the controller local area network communication is normal; the wiring harness connection of the device used to collect the angle signal is normal; the EPS has no operational faults; and the vehicle speed is lower than a threshold speed.
[0125] In one embodiment, the steering wheel angle zero-point calibration device 800 is applied to the EPS; the aforementioned first determining module 801 is further configured to determine the initial steering angle value when the steering wheel is in the centered position after the vehicle has completed four-wheel alignment and the EPS is powered on. The aforementioned steering wheel angle zero-point calibration device 800 also includes an angle writing module, configured to write the initial steering angle value corresponding to the zero point of the steering angle into the non-volatile memory NVM of the EPS when the EPS is powered off.
[0126] In one embodiment, the steering wheel angle zero-point calibration device 800 further includes a second determining module, an angle reading module, and a third determining module. The second determining module is used to determine the rotation angle value when the steering wheel is turned to the target position when the EPS is powered on again; the rotation angle value is the angle value corresponding to the collected angle signal. The angle reading module is used to read the initial angle value stored in the NVM. The third determining module is used to determine the actual angle value when the steering wheel is turned to the target position based on the difference between the rotation angle value and the initial angle value; the actual angle value refers to the angle value actually rotated when the steering wheel is turned to the target position compared to when the steering wheel is in the centered position.
[0127] In one embodiment, the steering wheel angle zero-point calibration device 800 further includes a fourth determining module, used to determine the assist torque that the EPS needs to provide based on the actual angle value. The assist torque is used to assist the vehicle in steering when the steering wheel is turned.
[0128] In one embodiment, the third determining module includes a correction unit and a determining unit. The correction unit is used to correct the initial steering angle value based on the difference between the rotation angle value and the initial steering angle value. The determining unit is used to determine the actual steering angle value when the steering wheel is rotated to the target position based on the difference between the rotation angle value and the corrected initial steering angle value.
[0129] In one embodiment, the correction unit is further configured to: if the difference between the rotation angle value and the initial rotation angle value is greater than the maximum rotation angle value, then use the sum of the initial rotation angle value and a preset value as the corrected initial rotation angle value; or if the difference between the rotation angle value and the initial rotation angle value is less than the minimum rotation angle value, then use the difference between the initial rotation angle value and the preset value as the corrected initial rotation angle value; or if the difference between the rotation angle value and the initial rotation angle value is greater than or equal to the minimum rotation angle value and less than or equal to the maximum rotation angle value, then use the initial rotation angle value as the corrected initial rotation angle value.
[0130] For explanations of the terms, please refer to the relevant descriptions in the foregoing method embodiments; they will not be elaborated upon here.
[0131] It should be noted that the specific execution process of the aforementioned steering wheel angle zero-point calibration device 800 can be found in [reference needed]. Figures 1 to 7 The specific details of the embodiments shown are not elaborated here.
[0132] Each module in the aforementioned steering wheel angle zero-point calibration device 800 can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.
[0133] like Figure 9 As shown in the illustration, this application also provides a vehicle 900. The vehicle 900 includes an electric power steering system 901, which is used to perform the above-described... Figures 1 to 7 The method steps of the illustrated embodiment can be found in the detailed execution process. Figures 1 to 7 The specific details of the embodiments shown are not elaborated here.
[0134] With the vehicle 900 having completed its four-wheel alignment, the electric power steering system 901 determines the initial steering angle value when the steering wheel is in the centered position. Then, the electric power steering system 901 receives a zero-point calibration command and, in response, calibrates the steering angle position corresponding to the initial steering angle value as the zero point of the steering wheel's angle.
[0135] In this embodiment, after the vehicle 900 completes four-wheel alignment, the steering wheel is in the centered position, and the vehicle body and wheels maintain a straight line. The front left and right wheels of the vehicle 900 are symmetrical. Under these conditions, zero-point calibration of the steering angle ensures that when the steering wheel is at the zero-point, the front left and right wheels of the vehicle 900 are symmetrical, and the vehicle 900 can maintain a straight driving state, avoiding deviation. Furthermore, the electric power steering system 901 determines the initial steering angle value when the steering wheel is in the centered position. When the steering wheel rotates left and right within its effective travel range, symmetrical about the centered position, the steering wheel angle value determined by the electric power steering system 901 is also symmetrical about the steering wheel angle position corresponding to this initial angle value. Therefore, the steering wheel angle position corresponding to the initial angle value can be taken as the zero point of the steering wheel. Further, the electric power steering system 901 receives a zero-point calibration command and, in response to the zero-point calibration command, calibrates the angle position corresponding to the initial angle value as the zero point of the steering wheel. Based on this zero-point position, the electric power steering system 901 adjusts the steering angle value when the steering wheel is in the centered position. The adjusted steering angle value is 0°, ensuring that the steering wheel angle value input by the electric power steering system 901 is 0°. This helps the vehicle 900 maintain straight-line driving when the steering wheel is in the centered position. Using the vehicle 900 in this embodiment, the zero-point of the steering angle is recalibrated, which helps ensure that the steering wheel angle value input by the electric power steering system 901 is accurate and symmetrical about the zero-point position when the steering wheel is turned. This, in turn, helps the electric power steering system 901 provide accurate assist torque to assist the vehicle 900 in steering.
[0136] like Figure 10 As shown in the illustration, this application also provides a computer device 1000. Exemplarily, the computer device 1000 may include a processor 1001, a communication interface 1002, a communication bus 1003, and a memory 1004. Specifically, the computer device 1000 may include:
[0137] The system includes at least one processor 1001, such as a CPU, at least one communication interface 1002, a memory 1004, and at least one communication bus 1003. The communication bus 1003 is used to enable communication between these components. The communication interface 1002 may optionally include a standard wired interface, a wireless interface (such as a Wi-Fi interface or a Bluetooth interface), etc. The memory 1004 may be high-speed RAM or non-volatile memory, such as at least one disk storage device. Optionally, the memory 1004 may also be at least one storage device located remotely from the aforementioned processor 1001. Figure 10 As shown, the memory 1004, which serves as a computer storage medium, may include an operating system and program instructions.
[0138] For example, processor 1001 can be used to implement the above. Figure 8 The steps or methods executed by the first determining module 801, the instruction receiving module 802, and the zero-point calibration module 803.
[0139] Understandably, the above method is merely an example, and the above can also be executed by the processor 1001 and other modules in the aforementioned computer device 1000. Figure 8 The steps or methods executed by the first determining module 801, the instruction receiving module 802, and the zero-point calibration module 803 are not limited in this document.
[0140] exist Figure 10 In the computer device 1000 shown, the processor 1001 can be used to load program instructions stored in the memory 1004 and specifically perform the following operations:
[0141] With the vehicle's four-wheel alignment completed, determine the initial steering angle value when the steering wheel is in the center position;
[0142] Receive zero-point calibration command;
[0143] In response to the zero-point calibration command, the steering angle position corresponding to the initial steering angle value is calibrated as the steering wheel's zero-point.
[0144] For explanations of the terms, please refer to the relevant descriptions in the foregoing method embodiments; they will not be elaborated upon here.
[0145] It should be noted that the specific execution process can be found in [link to relevant documentation]. Figures 1 to 7 The specific details of the embodiments shown are not elaborated here.
[0146] This application also provides a computer-readable storage medium that can store multiple instructions adapted to be loaded and executed by a processor as described above. Figures 1 to 7 The method steps of the illustrated embodiment can be found in the detailed execution process. Figures 1 to 7 The specific details of the embodiments shown are not elaborated here.
[0147] As used in the above embodiments, depending on the context, the term "when..." can be interpreted as meaning "if...", "after...", "in response to determining...", or "in response to detecting...". Similarly, depending on the context, the phrase "when determining..." or "if (the stated condition or event) is detected" can be interpreted as meaning "if determining...", "in response to determining...", "when (the stated condition or event) is detected", or "in response to detecting (the stated condition or event)".
[0148] 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. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are 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, the 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) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer 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., solid-state drive), etc.
[0149] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.
[0150] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0151] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method for calibrating the zero point of a steering wheel angle, characterized in that, The method is applied to EPS; the method includes: With the vehicle's four-wheel alignment completed, determine the initial steering angle value when the steering wheel is in the center position; Receive zero-point calibration command; In response to the zero-point calibration command, the angle position corresponding to the initial angle value is calibrated as the zero point of the steering wheel angle; When the EPS is powered off, the initial angle value corresponding to the zero point of the angle is written into the non-volatile memory NVM of the EPS; When the EPS is powered on again, the rotation angle value when the steering wheel is turned to the target position is determined, and the rotation angle value is the rotation angle value corresponding to the collected rotation angle signal; Read the initial rotation value stored in the NVM; Based on the difference between the rotation angle value and the initial rotation angle value, the actual rotation angle value when the steering wheel is rotated to the target position is determined. The actual rotation angle value refers to the actual rotation angle value when the steering wheel is rotated to the target position compared to when the steering wheel is in the center position. The determination of the initial steering angle value when the steering wheel is in the center position after the vehicle has completed four-wheel alignment includes: With the vehicle having completed four-wheel alignment and the EPS powered on, determine the initial steering angle value when the steering wheel is in the center position; The step of determining the actual steering angle value when the steering wheel is rotated to the target position based on the difference between the rotation angle value and the initial steering angle value includes: The initial angle value is corrected based on the difference between the rotation angle value and the initial angle value, the range of steering wheel angle values, and the calculation rules of the cyclic formula of the angle value. The actual steering angle value when the steering wheel is turned to the target position is determined based on the difference between the rotation angle value and the corrected initial steering angle value.
2. The method according to claim 1, characterized in that, The step of calibrating the steering wheel's zero-angle position corresponding to the initial steering angle value as the zero-angle position in response to the zero-point calibration command includes: When the zero-point calibration conditions are met, in response to the zero-point calibration command, the angle position corresponding to the initial angle value is calibrated as the zero point of the steering wheel. The zero-point calibration conditions include at least one of the following: the power supply voltage of the vehicle to the electric power steering system EPS is within a preset range, the controller local area network communication is normal, the wiring harness connection of the device used to collect the angle signal is normal, the EPS has no operational fault, and the vehicle speed is lower than a threshold speed.
3. The method according to claim 1, characterized in that, The method further includes: Based on the actual turning angle value, the assist torque that the EPS needs to provide is determined. The assist torque is used to assist the vehicle in steering when the steering wheel is turned.
4. The method according to claim 1, characterized in that, The step of correcting the initial steering angle value based on the difference between the rotation angle value and the initial steering angle value, the steering wheel's steering angle value range, and the calculation rules of the steering angle value cycle includes: If the difference between the rotation angle value and the initial rotation angle value is greater than the maximum rotation angle value within the steering wheel's rotation angle range, then the sum of the initial rotation angle value and the preset value is used as the corrected initial rotation angle value; or If the difference between the rotation angle value and the initial rotation angle value is less than the minimum rotation angle value within the range of steering wheel rotation angle values, then the difference between the initial rotation angle value and the preset value is used as the corrected initial rotation angle value; or If the difference between the rotation angle value and the initial rotation angle value is greater than or equal to the minimum rotation angle value and less than or equal to the maximum rotation angle value, then the initial rotation angle value is used as the corrected initial rotation angle value.
5. A vehicle, characterized in that, The vehicle includes an electric power steering system for performing the steps of the method as described in any one of claims 1 to 4.
6. A computer device, characterized in that, include: A memory and a processor, wherein the memory stores program instructions; when the program instructions are executed by the processor, the processor performs the method as described in any one of claims 1 to 4.
7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program; when the computer program is run on one or more processors, it performs the method as described in any one of claims 1 to 4.