A method and apparatus for calibrating the soft limit range of vehicle steering.

Abstract

This disclosure relates to a method and apparatus for calibrating a soft limit range for vehicle steering. The method includes: starting the vehicle and, while the vehicle is stationary, rotating the steering wheel to its leftmost position and holding it there; if the steering wheel input torque is greater than a steering wheel input torque determination value and the steering wheel rotation angle is greater than a steering wheel rotation angle determination value, starting a timer; if the continuous duration of the timer exceeds a first preset duration, entering a soft limit range calibration state; in the soft limit range calibration state, the steering controller calibrates the soft limit range for the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ. This disclosure solves the problem that the theoretical turning angle is smaller than the actual turning angle and the turning radius is larger due to the soft limit angle limit range caused by the steering linkage. It achieves adaptive calibration of the soft limit range through self-learning while ensuring the universality of the steering gear platform configuration.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle steering assist control, and more specifically, to a method and apparatus for calibrating a soft limit range for vehicle steering. Background Technology

[0002] With the continuous upgrading of vehicle emissions and increasingly stringent fuel consumption restrictions, in order to meet the Stage IV fuel consumption requirements, improving the power economy of fuel-powered commercial vehicles while also focusing on energy conservation and consumption reduction in various systems is a crucial measure. Therefore, lightweight, low-energy-consumption, and high-performance electronic power steering systems are gradually being promoted and applied in commercial vehicles. The current mainstream technology is to use an electric recirculating ball steering gear to replace the traditional hydraulic steering gear, integrating the power steering motor, steering controller (ECU), torque / angle sensor, and worm gear reduction mechanism into one unit, achieving electronic power steering in commercial vehicles through vehicle CAN information interaction. However, due to the special characteristics of commercial vehicles—large cargo capacity and harsh operating conditions—the required output torque of the electronic power steering system is higher than that of ordinary passenger cars. When the vehicle frequently makes U-turns or turns at large angles while stationary, the large torque impact of the motor will severely shorten the service life of the worm gear reduction pair in the electric steering gear, thus affecting the safety of the entire vehicle's steering system. To address this issue, most steering gear manufacturers currently employ a software-programmed method that rapidly reduces motor power assist and increases steering effort when the steering angle is close to its limit (approximately 30°-50° before the limit). This allows customers to perceive the steering as reaching its limit, thus protecting the worm gear pair from direct impact. This method is commonly known as "soft steering limit."

[0003] However, in the existing technology's "soft limit" limit angle range setting, if the limit angle range is set unreasonably, it may lead to a large turning radius and poor maneuverability when driving the vehicle. Additionally, the steering wheel may feel heavy before reaching the end of the steering angle range, causing inconvenience for users. Furthermore, existing technology theoretically verifies the steering angle by assuming the steering linkage is rigid and deformation-free. However, in actual vehicle operation, the steering linkage deforms under high torque output, resulting in a smaller theoretically verified angle than the actual angle. This leads to a heavy steering wheel before reaching the limit, resulting in a larger turning radius and poorer maneuverability; it also hinders platform-based deployment. During the development of electric steering systems, the soft limit angle range is limited by the front axle angle, the steering system's bending angle, and the rocker arm ratio coefficient. When these parameters change, the soft limit angle range will be adjusted accordingly, and the software version number will change.

[0004] Therefore, one or more methods are needed to solve the above problems.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this disclosure is to provide a method and apparatus for calibrating the soft limit range of vehicle steering, thereby overcoming, at least to some extent, one or more problems caused by the limitations and defects of related technologies.

[0007] According to one aspect of this disclosure, a method for calibrating a soft limit range for vehicle steering is provided, comprising:

[0008] Start the vehicle, and with the vehicle stationary, turn the steering wheel to the left to its maximum position and hold it there;

[0009] The system receives the steering wheel input torque from the vehicle torque sensor and the steering wheel rotation angle from the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state.

[0010] In the soft limit range calibration state, the steering controller calibrates the soft limit range of the left side of the vehicle as [γ-30°,γ] based on the current steering wheel rotation angle γ of the vehicle.

[0011] In one exemplary embodiment of this disclosure, the method further includes:

[0012] Start the vehicle, and with the vehicle stationary, turn the steering wheel to the right to its limit and hold.

[0013] The system receives the steering wheel input torque from the vehicle torque sensor and the steering wheel rotation angle from the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state.

[0014] In the soft limit range calibration state, the steering controller calibrates the soft limit range of the right side of the vehicle as [β-30°,β] based on the current steering wheel rotation angle β of the vehicle.

[0015] In one exemplary embodiment of this disclosure, the method further includes:

[0016] The system receives the steering wheel input torque from the vehicle torque sensor and the steering wheel rotation angle from the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state.

[0017] When the steering wheel experiences greater resistance than the preset value and there is a pull-back state, it indicates that the soft limit range of the left / right limit of the vehicle has been successfully calibrated.

[0018] In one exemplary embodiment of this disclosure, the method further includes:

[0019] After the soft limit range of the left side limit and the soft limit range of the right side limit of the vehicle are successfully calibrated, the EPS status indicator light in the vehicle instrument panel will turn off.

[0020] If the soft limit range of the left or right limit of the vehicle is not successfully calibrated, the EPS status indicator light in the vehicle instrument panel will flash, indicating that the soft limit range of the left or right limit of the vehicle needs to be recalibrated.

[0021] In one exemplary embodiment of this disclosure, the method further includes:

[0022] After the soft limit ranges of the left and right sides of the vehicle are successfully calibrated, the vehicle is powered off.

[0023] After maintaining the vehicle in the power-off and engine-off state for a second preset time, start the vehicle. If the EPS status indicator light in the vehicle's instrument panel goes out, it is determined that the vehicle's steering controller soft limit range calibration self-learning is complete.

[0024] In one exemplary embodiment of this disclosure, the method further includes:

[0025] After the vehicle's steering controller has completed its soft limit range calibration self-learning, if the vehicle's steering wheel is rotated left or right into the soft limit range, the vehicle's steering controller will reduce the power assist motor current by a preset amplitude so that the vehicle's steering operation is in the soft limit state.

[0026] In one aspect of this disclosure, a soft limit range calibration device for vehicle steering is provided, comprising:

[0027] The steering module is used to start the vehicle and, when the vehicle is stationary, to rotate the steering wheel of the vehicle to the left to its extreme position and hold it there.

[0028] The determination module is used to receive the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor, and compare the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque determination value and the steering wheel rotation angle determination value, respectively. If the steering wheel input torque is greater than the steering wheel input torque determination value and the steering wheel rotation angle is greater than the steering wheel rotation angle determination value, the timer is started. If the continuous duration of the timer exceeds the first preset duration, the module enters the soft limit interval calibration state.

[0029] The calibration module is used to calibrate the soft limit range of the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ of the vehicle in the soft limit range calibration state.

[0030] An exemplary embodiment of this disclosure provides a method for calibrating a soft limit range for vehicle steering. The method includes: starting the vehicle and, while the vehicle is stationary, rotating the steering wheel to the left to its extreme position and holding it there. If the steering wheel input torque is greater than a steering wheel input torque determination value and the steering wheel rotation angle is greater than a steering wheel rotation angle determination value, a timer is started. If the continuous duration of the timer exceeds a first preset duration, a soft limit range calibration state is entered. In the soft limit range calibration state, the steering controller calibrates the soft limit range for the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ. This disclosure solves the problem of steering angle error caused by the soft limit angle limit range due to the steering linkage, while ensuring the platform versatility of the steering system.

[0031] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0032] The above and other features and advantages of this disclosure will become more apparent from the detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0033] Figure 1 A flowchart is shown for a soft limit range calibration method for vehicle steering according to an exemplary embodiment of the present disclosure;

[0034] Figure 2 A schematic block diagram of a soft limit range calibration device for vehicle steering according to an exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0035] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0036] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of the specific details described, or other methods, components, materials, apparatuses, steps, etc., can be employed. In other instances, well-known structures, methods, apparatuses, implementations, materials, or operations are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0037] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, or in one or more software-hardened modules, or in different network and / or processor devices and / or microcontroller devices.

[0038] In this example embodiment, a method for calibrating the soft limit range of vehicle steering is first provided; refer to Figure 1 As shown, the method for calibrating a soft limit range for vehicle steering may include the following steps:

[0039] Step S110: Start the vehicle, and while the vehicle is stationary, rotate the steering wheel of the vehicle to the left to its extreme position and hold it there;

[0040] Step S120: Receive the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor, and compare the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, start the timer. If the continuous duration of the timer exceeds the first preset duration, enter the soft limit interval calibration state.

[0041] In step S130, under the soft limit interval calibration state, the steering controller calibrates the soft limit interval of the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ of the vehicle.

[0042] An exemplary embodiment of this disclosure provides a method for calibrating a soft limit range for vehicle steering. The method includes: starting the vehicle and, while the vehicle is stationary, rotating the steering wheel to the left to its extreme position and holding it there. If the steering wheel input torque is greater than a steering wheel input torque determination value and the steering wheel rotation angle is greater than a steering wheel rotation angle determination value, a timer is started. If the continuous duration of the timer exceeds a first preset duration, a soft limit range calibration state is entered. In the soft limit range calibration state, the steering controller calibrates the soft limit range for the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ. This disclosure solves the problem of steering angle error caused by the soft limit angle limit range due to the steering linkage, while ensuring the platform versatility of the steering system.

[0043] The following will further explain a method for calibrating a soft limit range for vehicle steering in this example embodiment.

[0044] Example 1:

[0045] In step S110, the vehicle can be started, and while the vehicle is stationary, the steering wheel of the vehicle is rotated to the left to its extreme position and held.

[0046] In step S120, the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor can be received. The steering wheel input torque and steering wheel rotation angle are compared with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value and the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state.

[0047] In step S130, under the soft limit interval calibration state, the steering controller can calibrate the soft limit interval of the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ of the vehicle.

[0048] In this example embodiment, the method further includes:

[0049] Start the vehicle, and with the vehicle stationary, turn the steering wheel to the right to its limit and hold.

[0050] The system receives the steering wheel input torque from the vehicle torque sensor and the steering wheel rotation angle from the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state.

[0051] In the soft limit range calibration state, the steering controller calibrates the soft limit range of the right side of the vehicle as [β-30°,β] based on the current steering wheel rotation angle β of the vehicle.

[0052] In this example embodiment, the method further includes:

[0053] The system receives the steering wheel input torque from the vehicle torque sensor and the steering wheel rotation angle from the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state.

[0054] When the steering wheel experiences greater resistance than the preset value and there is a pull-back state, it indicates that the soft limit range of the left / right limit of the vehicle has been successfully calibrated.

[0055] In this example embodiment, the method further includes:

[0056] After the soft limit range of the left side limit and the soft limit range of the right side limit of the vehicle are successfully calibrated, the EPS status indicator light in the vehicle instrument panel will turn off.

[0057] If the soft limit range of the left or right limit of the vehicle is not successfully calibrated, the EPS status indicator light in the vehicle instrument panel will flash, indicating that the soft limit range of the left or right limit of the vehicle needs to be recalibrated.

[0058] In this example embodiment, the method further includes:

[0059] After the soft limit ranges of the left and right sides of the vehicle are successfully calibrated, the vehicle is powered off.

[0060] After maintaining the vehicle in the power-off and engine-off state for a second preset time, start the vehicle. If the EPS status indicator light in the vehicle's instrument panel goes out, it is determined that the vehicle's steering controller soft limit range calibration self-learning is complete.

[0061] In this example embodiment, the method further includes:

[0062] After the vehicle's steering controller has completed its soft limit range calibration self-learning, if the vehicle's steering wheel is rotated left or right into the soft limit range, the vehicle's steering controller will reduce the power assist motor current by a preset amplitude so that the vehicle's steering operation is in the soft limit state.

[0063] Example 2:

[0064] In this example embodiment, the calibration logic of the soft limit of the electronic power steering is optimized, and the steering controller is operated in a "self-learning" mode to perform individual calibration for each vehicle.

[0065] The "self-learning" work method is as follows:

[0066] 1. The steering controller receives the vehicle start command and begins operation.

[0067] 2. After the steering controller completes the steering center position calibration (steering center position calibration: the initial zero point position calibration of the steering controller when the vehicle is traveling in a straight line), the soft limit calibration begins. The calibration process is as follows:

[0068] With the vehicle stationary, turn the steering wheel to the left to its extreme position and hold it there for more than 5 seconds. When the steering wheel feels heavier and pulls back, it indicates that the left limit of the "soft limit" has been successfully calibrated.

[0069] Turn the steering wheel to the right to its limit and hold it there for more than 5 seconds. When the steering wheel feels heavier and there is a pulling sensation, it means that the right limit of the "soft limit" has been successfully calibrated. When both the left and right "soft limits" are successfully calibrated, the EPS status indicator on the instrument panel will turn off. If the calibration is not successful, the indicator will be flashing. You need to repeat steps ① and ② until the indicator turns off.

[0070] After turning off the engine for 10 seconds, restart the vehicle and check the status of the EPS status indicator light on the instrument panel again to determine whether the controller's "soft limit" self-learning was successful.

[0071] Example 3:

[0072] In this example embodiment, the steering controller operates according to the following logic during the calibration process of the soft limit of this disclosure:

[0073] 1. Has the controller completed "soft limit"? If it has, the soft limit self-learning function is turned off and is not triggered by calibration conditions. The corresponding bit of the EPS status indication message sent by the controller is 1, and the EPS status indicator on the instrument is off. If not, the controller will be in self-learning state and will trigger the self-learning function according to the corresponding calibration conditions. The corresponding bit of the EPS status indication message sent by the controller will be 0, and the EPS status indicator on the instrument will flash.

[0074] 2. Self-learning trigger conditions:

[0075] ① Steering wheel input torque ≥ 6 Nm (the steering wheel input torque signal is provided by the torque sensor);

[0076] ② Steering wheel rotation angle ≥ 360° (the steering wheel rotation angle signal is provided by the steering angle sensor);

[0077] ③ This state must be maintained for more than 5 seconds (the steering controller determines this by counting the torque / angle signal message cycle and number of times);

[0078] 3. When the above conditions are triggered, the steering controller determines that the current angle position γ is the actual limit angle position of the steering system. At this time, the controller sets the angle range [γ-30°, γ] as the "soft limit" range. When the current angle signal emitted by the angle sensor is within this range, the controller will reduce the power assist motor current (the current value decreases by approximately 90%). At this time, the steering wheel will become heavy, and the hand force will increase sharply, giving the driver the feeling that "the steering wheel has been turned all the way," thereby reducing the risk of damage to the internal screws of the steering gear due to mechanical shock. When the current angle signal leaves this range, the power assist motor current value returns to normal, and the steering controller's "soft limit" calibration is successful.

[0079] The above is just one new type of steering soft limit calibration logic, which involves specific "self-calibration" calibration conditions and vehicle settings and adjustments such as the specific state of the steering controller, instrument or host computer representation methods.

[0080] It should be noted that although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0081] Furthermore, in this example embodiment, a soft limit range calibration device for vehicle steering is also provided. (Refer to...) Figure 2As shown, the soft limit range calibration device 200 for vehicle steering may include: a steering module 210, a determination module 220, and a calibration module 230. Wherein:

[0082] Steering module 210 is used to start the vehicle and, when the vehicle is stationary, to rotate the steering wheel of the vehicle to the left to its extreme position and hold it there;

[0083] The determination module 220 is used to receive the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor, and compare the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque determination value and the steering wheel rotation angle determination value, respectively. If the steering wheel input torque is greater than the steering wheel input torque determination value and the steering wheel rotation angle is greater than the steering wheel rotation angle determination value, the timer is started. If the continuous duration of the timer exceeds the first preset duration, the soft limit interval calibration state is entered.

[0084] The calibration module 230 is used to calibrate the soft limit range of the left side of the vehicle as [γ-30°, γ] based on the current steering wheel rotation angle γ of the vehicle in the soft limit range calibration state.

[0085] The specific details of the soft limit interval calibration device module for each of the above-mentioned vehicle steering methods have been described in detail in the corresponding soft limit interval calibration method for vehicle steering, so they will not be repeated here.

[0086] It should be noted that although several modules or units of a soft limit range calibration device 200 for vehicle steering have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0087] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0088] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0089] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for calibrating a soft limit interval for vehicle steering, characterized in that, The method includes: Start the vehicle, and with the vehicle stationary, turn the steering wheel to the left to its maximum position and hold it there; The system receives the steering wheel input torque from the vehicle torque sensor and the steering wheel rotation angle from the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state. In the soft limit interval calibration state, the steering controller calibrates the soft limit interval of the left side of the vehicle as [γ-30°,γ] based on the current steering wheel rotation angle γ of the vehicle. After the soft limit range of the left side limit and the soft limit range of the right side limit of the vehicle are successfully calibrated, the EPS status indicator light in the vehicle instrument panel will turn off. If the soft limit range of the left side limit or the soft limit range of the right side limit of the vehicle is not successfully calibrated, the EPS status indicator light in the vehicle instrument will flash, and the soft limit range of the left side limit / right side limit of the vehicle needs to be recalibrated. After the soft limit ranges of the left and right sides of the vehicle are successfully calibrated, the vehicle is powered off. After maintaining the vehicle in the power-off and engine-off state for a second preset time, start the vehicle. If the EPS status indicator light in the vehicle's instrument panel is off, it is determined that the vehicle's steering controller soft limit range calibration self-learning is complete. During the calibration process of the soft limit, the steering controller operates as follows: Determine whether the steering controller has completed "soft limit". If it has, the soft limit self-learning function is turned off and is not triggered by calibration conditions. If not, the steering controller will be in self-learning state and the self-learning function will be triggered according to the corresponding calibration conditions.

2. The method as described in claim 1, characterized in that, The method further includes: Start the vehicle, and with the vehicle stationary, turn the steering wheel to the right to its limit and hold. The system receives the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state. In the soft limit range calibration state, the steering controller calibrates the soft limit range of the right side of the vehicle as [β-30°,β] based on the current steering wheel rotation angle β of the vehicle.

3. The method as described in claim 2, characterized in that, The method further includes: The system receives the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor, and compares the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque judgment value and the steering wheel rotation angle judgment value, respectively. If the steering wheel input torque is greater than the steering wheel input torque judgment value or the steering wheel rotation angle is greater than the steering wheel rotation angle judgment value, a timer is started. If the continuous duration of the timer exceeds the first preset duration, the system enters the soft limit interval calibration state. When the steering wheel experiences greater resistance than the preset value and there is a pull-back state, it indicates that the soft limit range of the left / right limit of the vehicle has been successfully calibrated.

4. The method as described in claim 3, characterized in that, The method further includes: After the vehicle's steering controller has completed its soft limit range calibration self-learning, if the vehicle's steering wheel is rotated left or right into the soft limit range, the vehicle's steering controller will reduce the power assist motor current by a preset amplitude so that the vehicle's steering operation is in the soft limit state.

5. A soft limit range calibration device for vehicle steering, characterized in that, The device includes: The steering module is used to start the vehicle and, when the vehicle is stationary, to rotate the steering wheel of the vehicle to the left to its extreme position and hold it there. The determination module is used to receive the steering wheel input torque sent by the vehicle torque sensor and the steering wheel rotation angle sent by the steering angle sensor, and compare the steering wheel input torque and steering wheel rotation angle with the steering wheel input torque determination value and the steering wheel rotation angle determination value, respectively. If the steering wheel input torque is greater than the steering wheel input torque determination value and the steering wheel rotation angle is greater than the steering wheel rotation angle determination value, the timer is started. If the continuous duration of the timer exceeds the first preset duration, the module enters the soft limit interval calibration state. The calibration module is used to calibrate the soft limit range of the left side of the vehicle as [γ-30°,γ] based on the current steering wheel rotation angle γ of the vehicle in the soft limit range calibration state. After the soft limit range of the left side limit and the soft limit range of the right side limit of the vehicle are successfully calibrated, the EPS status indicator light in the vehicle instrument panel will turn off. If the soft limit range of the left side limit or the soft limit range of the right side limit of the vehicle is not successfully calibrated, the EPS status indicator light in the vehicle instrument will flash, and the soft limit range of the left side limit / right side limit of the vehicle needs to be recalibrated. After the soft limit ranges of the left and right sides of the vehicle are successfully calibrated, the vehicle is powered off. After maintaining the vehicle in the power-off and engine-off state for a second preset time, start the vehicle. If the EPS status indicator light in the vehicle's instrument panel is off, it is determined that the vehicle's steering controller soft limit range calibration self-learning is complete. During the calibration process of the soft limit, the steering controller operates as follows: Determine whether the steering controller has completed "soft limit". If it has, the soft limit self-learning function is turned off and is not triggered by calibration conditions. If not, the steering controller will be in self-learning state and the self-learning function will be triggered according to the corresponding calibration conditions.

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