Steer-by-wire safety corner calibration method

Abstract

The invention belongs to the field of automobile safety, and particularly relates to a steer-by-wire safety turning angle calibration method, which comprises a test vehicle inspection module, an equipment installation module, a vehicle limit state data acquisition module, a data analysis module and a safety turning angle determination module, the equipment installation module is used for installing steering engine position reading equipment on a test vehicle, a force measuring device is installed on a rear suspension of the test vehicle and used for measuring the transverse force of the rear suspension and indirectly representing the lateral force of tires, and the vehicle limit state data acquisition module is used for conducting constant-speed steering at different vehicle speeds in an automatic driving or machine driving mode. And collecting and recording the position of the steering engine in the test process until the vehicle is unstable. According to the steer-by-wire safety corner calibration method, limit stable corners of a vehicle at different vehicle speeds are obtained in an actual measurement mode, a limit stable corner curve is formed, and the performance of a vehicle chassis is conveniently and fully utilized.

Description

Technical Field

[0001] The invention relates to the technical field of automobile safety, and in particular to a method for calibrating a safe turning angle of a wire-controlled steering system. Background Art

[0002] As the development direction of automobile steering systems, steer-by-wire is mainly characterized by the fact that the steering wheel and steering gear are no longer mechanically connected, that is, the driver's operation and wheel-end steering are mechanically decoupled, which can expand the safe steering function. When the car is driving at high speed, large-angle steering may cause dangerous conditions such as tail-spinning and sideslipping. The safe steering function adds different turning angle limits (i.e., safe turning angles) for the car at various speeds. It detects the current position of the steering gear and steering requests from all parties in real time while driving, effectively preventing excessive wheel turning angles caused by driver misoperation, excessive steering requests for automatic driving, etc., thereby avoiding vehicle instability.

[0003] At present, the existing safety steering function usually sets the safety turning angle at various vehicle speeds based on experience, and then conducts relevant vehicle evaluation tests. If there is no instability such as skidding, the safety steering setting is considered reasonable. In order to ensure driving safety, this method usually calibrates the safety turning angle too conservatively, cannot fully utilize the vehicle chassis performance, affects the driving experience, and cannot distinguish the styles according to the vehicle model positioning. In view of this, we propose a wire-controlled steering safety angle calibration method. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for calibrating a safe turning angle of a steer-by-wire system, which can solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides a method for calibrating a safe turning angle of a steer-by-wire system, comprising:

[0006] A test vehicle inspection module, which is used to confirm that the state of the test vehicle meets the test requirements;

[0007] An equipment installation module, wherein the equipment installation module is used to install a steering gear position reading device on the test vehicle, and to install a force measuring device on the rear suspension of the test vehicle to measure the lateral force of the rear suspension, thereby indirectly representing the lateral force of the tire;

[0008] A vehicle limit state data acquisition module, which is used to perform constant speed steering at different vehicle speeds by automatic driving or machine driving until the vehicle becomes unstable, and to collect and record the steering gear position and suspension lateral force during the test;

[0009] A data analysis module, the data analysis module is used to identify and determine the wheel angle when the vehicle skids at different vehicle speeds, and obtain a vehicle limit stability angle curve;

[0010] A safety turning angle determination module is used to determine a safety turning angle curve according to the vehicle limit stability turning angle curve and vehicle model positioning.

[0011] Preferably, the test vehicle inspection module includes a vehicle weight inspection unit, a weight distribution inspection unit, a power characteristic inspection unit, a suspension characteristic inspection unit, a tire characteristic inspection unit, and a steering symmetry inspection unit.

[0012] Preferably, the vehicle weight inspection unit is used to confirm that the vehicle weight meets the design requirements, check the vehicle weight, and ensure that it meets the design requirements; the weight distribution inspection unit is used to confirm that the weight distribution meets the design requirements, check the weight distribution, and ensure that the weight ratio of the front and rear axles is reasonable; the power characteristic inspection unit is used to confirm that the power characteristics meet the design requirements, and test the power characteristics, including engine power, torque output, etc.; the suspension characteristic inspection unit is used to confirm that the suspension characteristics meet the design requirements, and check the suspension characteristics, such as suspension stiffness, damping, etc.; the tire characteristic inspection unit is used to confirm that the tire characteristics meet the design requirements, and check the tire characteristics, including tire model, tire pressure, etc.; the steering symmetry inspection unit is used to confirm that the steering symmetry meets the design requirements, check the steering symmetry, and ensure that the performance of the left and right sides of the steering system is consistent.

[0013] Preferably, the equipment installation module includes a force sensor installation unit, a steering gear position reading device installation unit, and an equipment docking unit. The force sensor installation unit is used to install a force sensor on the rear suspension of the test vehicle that meets the test requirements, connect it to the force measuring system, measure and record the force of the control arm in the lateral direction of the whole vehicle, so as to characterize the change trend of the tire lateral force, wherein pressure is positive and tension is negative. The force measuring device is installed at a suitable position of the rear suspension of the test vehicle, such as installing a force sensor on the wheel camber control arm, symmetrically installed on the left and right sides, connecting the force sensor to the data acquisition system, and measuring and recording the lateral force of the rear suspension in real time. The steering gear position reading device installation unit is used to connect the vehicle's wire control system to the calibration tool, read the steering gear position data, right turn is positive, left turn is negative, install the steering gear position reading device, such as an angle sensor, connected to the steering gear, accurately read the position information of the steering gear, connect the angle sensor to the data acquisition system, and ensure the accurate transmission of the steering gear position data. The equipment docking unit is used to dock the force measuring system with the calibration tool, perform clock synchronization, calibrate and debug the installed equipment, and ensure its normal operation.

[0014] Preferably, the vehicle limit state data acquisition module includes an automatic driving control unit, a vehicle speed control unit, and a steering operation unit. The automatic driving control unit is used to control the vehicle to travel in a closed and safe test site in the form of automatic driving. A closed and safe test site is selected and the vehicle is controlled to travel in the form of automatic driving. The vehicle speed control unit is used to control the vehicle to travel at a constant speed at different speeds. Different speeds are set, starting from 10 km / h, and the speed is gradually increased at intervals of 10 km / h until the maximum allowable speed of the vehicle is reached. The steering operation unit is used to slowly steer from the middle position at each speed until the vehicle loses stability or reaches the maximum travel of the steering gear. A steering test is performed on the left and right sides respectively. At each speed, the test vehicle is driven at a constant speed, and slowly steers from the middle position, gradually increasing the steering angle until the vehicle loses stability or reaches the maximum travel of the steering gear. During the test, data such as the steering gear position, suspension lateral force, vehicle speed, and time are recorded at the same time. For each speed, a steering test is performed on the left and right sides, each once.

[0015] Preferably, the data analysis module includes a steering gear position data extraction unit, a data validity confirmation unit, and a limit stability angle curve establishment unit.

[0016] Preferably, the steering gear position data extraction unit is used to extract the steering gear position data when the vehicle loses stability and skids, and the "suspension lateral force-time" data measured by the force measuring device is time-aligned with the "steering gear position-time" data measured by the steering gear position reading device. By analyzing the "suspension lateral force-steering gear position" data curve, the corresponding data point when the vehicle loses stability and skids is found. When the rolling between the tire and the ground turns into skidding, the lateral force will suddenly change, which corresponds to the lower inflection point on the data curve. By finding these lower inflection points, the steering gear position when the vehicle loses stability and skids can be determined. The steering gear position data is marked according to the steering direction and vehicle speed during the test, such as AL10 represents the steering gear position when turning left at a speed of 10 km / h, and AR10 represents the steering gear position when turning right at a speed of 10 km / h. If a "control arm lateral force-steering gear position" data curve has no lower inflection point, it means that at this speed, even if the steering is turned to the maximum angle, it will not cause the vehicle to skid, and the vehicle will be marked. The ALX / ARX at the same speed is recorded as the maximum travel of the steering gear. The data validity confirmation unit is used to obtain the steering gear position ALX and ARX at the same vehicle speed. The absolute values ​​should be close when the steering gear position is obtained for left turn and right turn. The steering gear position ALX during left turn should be uniformly negative and increase with the increase of speed. The steering gear position data ARX during right turn should be uniformly positive and decrease with the increase of vehicle speed. If the data does not meet the requirements, it is necessary to find out the cause of the data deviation, re-test or data processing. The limit stable turning angle curve establishment unit is used to take the minimum value of the absolute values ​​of ALX and ARX at the same vehicle speed, which are recorded as A10min, A20min, A30min, A40min, A50min, A60min..., respectively. According to the valid data, the minimum value of the absolute value of the steering gear position of left turn and right turn is taken at the same vehicle speed. For example, A10min represents the limit stable turning angle at a vehicle speed of 10km / h. In this way, the vehicle speed-limit stable turning angle limit curve can be obtained.

[0017] Preferably, the safety turning angle determination module includes a vehicle type positioning analysis unit, a safety turning angle curve determination unit, and an accuracy verification unit.

[0018] Preferably, the vehicle type positioning analysis unit is responsible for analyzing and determining the need for a safety turning angle curve based on the vehicle's extreme stability turning angle curve and vehicle type positioning; the safety turning angle curve determination unit is responsible for determining one or more safety turning angle curves as calibration data based on the vehicle type positioning analysis results; for example, when the mode style is positioned as extreme control, the extreme stability turning angle curve can be directly used as the safety turning angle curve; when the mode style tends to be safety and comfort, the extreme stability turning angle curve can be lowered by a certain proportion as the safety turning angle curve; different safety turning angle curve styles can also be set on the same vehicle type for user selection; the accuracy verification unit is responsible for verifying the accuracy of the safety turning angle curve by comparing the actual vehicle driving data with the calibrated safety turning angle curve, and adjusting and optimizing according to the verification results.

[0019] Preferably, the automatic driving control unit also includes a safety monitoring subunit for monitoring the vehicle's driving status in real time to ensure the safety of the test process. The data validity confirmation unit also includes a data deviation investigation subunit for investigating the cause of data deviation when the data does not meet the requirements and taking corresponding treatment measures, such as re-conducting the test or data processing.

[0020] The present invention provides a method for calibrating a safe turning angle of a wire-controlled steering system. It has the following beneficial effects:

[0021] (1) The steer-by-wire safety turning angle calibration method uses actual measurement to obtain the vehicle's ultimate stable turning angle at different speeds, forming an ultimate stable turning angle curve, which provides an accurate basis for the calibration of the safety turning angle, facilitates full utilization of the vehicle chassis performance, and improves the driving experience.

[0022] (2) The safe turning angle calibration method of the wire control steering determines the safe turning angle curve according to the vehicle positioning and user needs, which can give full play to the performance of the vehicle while ensuring driving safety.

[0023] (3) The safe turning angle calibration method of the wire-controlled steering adopts the method of automatic driving or machine driving to collect data, which greatly improves the safety and reliability of the test and reduces the influence of human factors on the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 is a block diagram of the method of the present invention;

[0026] Figure 2 This is a block diagram of the test vehicle inspection module of the present invention;

[0027] Figure 3 It is a block diagram of the module for installing the device of the present invention;

[0028] Figure 4 This is a block diagram of a vehicle limit state data acquisition module of the present invention;

[0029] Figure 5 This is a block diagram of the data analysis module of the present invention;

[0030] Figure 6 This is a block diagram of a safe turning angle determination module of the present invention;

[0031] Figure 7 It is a comparison curve diagram of the lateral force of the control arm-steering gear position for left turn and right turn of the present invention;

[0032] Figure 8 It is a curve diagram of the lateral force of the control arm-steering gear position of the present invention;

[0033] Fig. 9 The vehicle speed-limit stability turning angle limit curve diagram of the present invention;

[0034] Fig.10 It is a curve diagram of safe turning angles in different modes of the present invention;

[0035] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] See also Figure 1 - Fig.10The present invention proposes a method for calibrating a safe turning angle of a controlled steering system, comprising a test vehicle inspection module, an equipment installation module, a vehicle limit state data acquisition module, a data analysis module, and a safe turning angle determination module. The test vehicle inspection module is used to confirm that the state of the test vehicle meets the test requirements. The equipment installation module is used to install a steering gear position reading device on the test vehicle. A force measuring device is installed on the rear suspension of the test vehicle to measure the lateral force of the rear suspension, and indirectly characterize the lateral force of the tire. The vehicle limit state data acquisition module is used to perform constant-speed steering at different vehicle speeds by automatic driving or machine driving until the vehicle becomes unstable, and collect and record the steering gear position and the lateral force of the suspension during the test. The data analysis module is used to identify and determine the wheel turning angle when the vehicle skids at different vehicle speeds, and obtain the vehicle limit stability turning angle curve. The safe turning angle determination module determines the safe turning angle curve according to the vehicle limit stability turning angle curve and the vehicle model positioning.

[0038] In an embodiment of the present invention, the test vehicle inspection module includes a vehicle weight inspection unit, a weight distribution inspection unit, a power characteristic inspection unit, a suspension characteristic inspection unit, a tire characteristic inspection unit, and a steering symmetry inspection unit. The vehicle weight inspection unit is used to confirm that the weight of the vehicle meets the design requirements, inspect the weight of the vehicle, and ensure that it meets the design requirements. The weight distribution inspection unit is used to confirm that the weight distribution meets the design requirements, inspect the weight distribution, and ensure that the weight ratio of the front and rear axles is reasonable. The power characteristic inspection unit is used to confirm that the power characteristics meet the design requirements and test the power characteristics, including engine power, torque output, etc. The suspension characteristic inspection unit is used to confirm that the suspension characteristics meet the design requirements and inspect the suspension characteristics, such as suspension stiffness, damping, etc. The tire characteristic inspection unit is used to confirm that the tire characteristics meet the design requirements and inspect the tire characteristics, including tire model, tire pressure, etc. The steering symmetry inspection unit is used to confirm that the steering symmetry meets the design requirements, inspect the steering symmetry, and ensure that the performance of the left and right sides of the steering system is consistent.

[0039] Furthermore, the equipment installation module includes a force sensor installation unit, a steering gear position reading device installation unit, and an equipment docking unit. The force sensor installation unit is used to install a force sensor on the rear suspension of the test vehicle that meets the test requirements, connect it to the force measuring system, measure and record the force on the control arm in the lateral direction of the whole vehicle, so as to characterize the change trend of the tire lateral force, where pressure is positive and tension is negative. The force measuring device is installed at a suitable position on the rear suspension of the test vehicle, such as installing a force sensor on the wheel camber control arm, symmetrically installing it on the left and right sides, connecting the force sensor to the data acquisition system, and measuring and recording the lateral force of the rear suspension in real time. The steering gear position reading device installation unit is used to connect the vehicle's wire-controlled steering system to the calibration tool, read the steering gear position data, right turn is positive, and left turn is negative, install a steering gear position reading device, such as an angle sensor, connected to the steering gear, accurately read the position information of the steering gear, connect the angle sensor to the data acquisition system, and ensure the accurate transmission of the steering gear position data. The equipment docking unit is used to dock the force measuring system with the calibration tool, synchronize the clock, calibrate and debug the installed equipment, and ensure its normal operation.

[0040] Furthermore, the vehicle limit state data acquisition module includes an automatic driving control unit, a speed control unit, and a steering operation unit. The automatic driving control unit is used to control the vehicle to drive in a closed and safe test site in the form of automatic driving. A closed and safe test site is selected and the vehicle is controlled to drive in the form of automatic driving. The speed control unit is used to control the vehicle to drive at a constant speed at different speeds. Different speeds are set, starting from 10km / h, and the speed is gradually increased at intervals of 10km / h until the maximum allowable speed of the vehicle is reached. The steering operation unit is used to slowly steer from the middle position at each speed until the vehicle becomes unstable or reaches the maximum travel of the steering gear. A steering test is performed on the left and right sides respectively. At each speed, the test vehicle is driven at a constant speed, and slowly steers from the middle position, gradually increasing the steering angle until the vehicle becomes unstable or reaches the maximum travel of the steering gear. During the test, data such as the steering gear position, suspension lateral force, vehicle speed, and time are recorded at the same time. For each speed, a steering test is performed on the left and right sides, once each.

[0041] Furthermore, the data analysis module includes a steering gear position data extraction unit, a data validity confirmation unit, and a limit stability angle curve establishment unit. The steering gear position data extraction unit is used to extract the steering gear position data when the vehicle is unstable and skidding, and the "suspension lateral force-time" data measured by the force measuring device is aligned with the "steering gear position-time" data measured by the steering gear position reading device. By analyzing the "suspension lateral force-steering gear position" data curve, the corresponding data point when the vehicle is unstable and skidding is found. When the rolling between the tire and the ground turns into skidding, the lateral force will suddenly change, which corresponds to the lower inflection point on the data curve. By finding these lower inflection points, the steering gear position when the vehicle is unstable and skidding can be determined. According to the steering direction and vehicle speed during the test, the steering gear position data is marked, such as AL10 represents the steering gear position when turning left at a speed of 10km / h, and AR10 represents the steering gear position when turning right at a speed of 10km / h. If a "control arm lateral force-steering gear position" data curve has no lower inflection point, it means that at this speed, If the vehicle will not skid even when turning to the maximum angle, ALX / ARX at that speed is recorded as the maximum travel of the steering gear. The data validity confirmation unit is used to obtain the steering gear position ALX and ARX at the same speed. The absolute values ​​should be close when turning left and right. The steering gear position ALX should be uniformly negative and increase with the increase of speed. The steering gear position data ARX should be uniformly positive when turning right and decrease with the increase of speed. If the data does not meet the requirements, it is necessary to find out the cause of the data deviation, re-test or data processing. The limit stable turning angle curve establishment unit is used to take the minimum value of the absolute values ​​of ALX and ARX at the same speed, which are recorded as A10min, A20min, A30min, A40min, A50min, A60min... According to the valid data, the minimum value of the absolute value of the steering gear position of left turn and right turn at the same speed is taken. For example, A10min represents the limit stable turning angle at a speed of 10km / h. In this way, the vehicle speed-limit stable turning angle limit curve can be obtained.

[0042] Furthermore, the safety turning angle determination module includes a vehicle model positioning analysis unit, a safety turning angle curve determination unit, and an accuracy verification unit. The vehicle model positioning analysis unit is responsible for analyzing and determining the requirements for the safety turning angle curve according to the vehicle's extreme stability turning angle curve and vehicle model positioning. The safety turning angle curve determination unit is responsible for determining one or more safety turning angle curves as calibration data based on the vehicle model positioning analysis results. For example, when the mode style is positioned as extreme control, the extreme stability turning angle curve can be directly used as the safety turning angle curve; when the mode style tends to be safe and comfortable, the extreme stability turning angle curve can be lowered by a certain proportion as the safety turning angle curve; different safety turning angle curve styles can also be set on the same vehicle model for user selection. The accuracy verification unit is responsible for verifying the accuracy of the safety turning angle curve by comparing the actual vehicle driving data with the calibrated safety turning angle curve, and adjusting and optimizing it according to the verification results. The automatic driving control unit also includes a safety monitoring subunit for real-time monitoring of the vehicle driving status to ensure the safety of the test process. The data validity confirmation unit also includes a data deviation investigation subunit for investigating the cause of data deviation when the data does not meet the requirements, and taking corresponding processing measures, such as re-testing or data processing.

[0043] Embodiment 1

[0044] See also Figure 1 - Fig.10 , a certain brand of car is selected, and a test car inspection is carried out on the car. All performance indicators meet the requirements. A force measuring device and a steering gear position reading device are installed and calibrated. The vehicle limit state data is collected at the test site with a speed range of 10km / h to 120km / h. The collected data is analyzed to obtain the vehicle's limit stability turning angle curve. According to the vehicle model positioning as a sports type, the limit stability turning angle curve is used as the safety turning angle curve.

[0045] Embodiment 1

[0046] See also Figure 1 - Fig.10 , a certain SUV model was selected, and the test vehicle was inspected to ensure that the vehicle was in good condition. Relevant equipment was installed and debugged. Data was collected at the test site with a speed range of 10km / h to 100km / h. The data was analyzed to obtain the limit stable turning angle curve. Considering that this model is positioned for family use and focuses on safety and comfort, the limit stable turning angle curve was lowered by 20% as the safe turning angle curve.

[0047] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for calibrating a safe turning angle of a wire-controlled steering system, characterized in that: include: A test vehicle inspection module, which is used to confirm that the state of the test vehicle meets the test requirements; An equipment installation module, wherein the equipment installation module is used to install a steering gear position reading device on the test vehicle, and to install a force measuring device on the rear suspension of the test vehicle to measure the lateral force of the rear suspension, thereby indirectly representing the lateral force of the tire; A vehicle limit state data acquisition module, which is used to perform constant speed steering at different vehicle speeds by automatic driving or machine driving until the vehicle becomes unstable, and to collect and record the steering gear position and suspension lateral force during the test; A data analysis module, the data analysis module is used to identify and determine the wheel angle when the vehicle skids at different vehicle speeds, and obtain a vehicle limit stability angle curve; A safety turning angle determination module is used to determine a safety turning angle curve according to the vehicle limit stability turning angle curve and vehicle model positioning.

2. The method for calibrating safe turning angle of steer-by-wire according to claim 1, characterized in that: The test vehicle inspection module includes a vehicle weight inspection unit, a weight distribution inspection unit, a power characteristic inspection unit, a suspension characteristic inspection unit, a tire characteristic inspection unit, and a steering symmetry inspection unit.

3. The method for calibrating safe turning angle of steer-by-wire according to claim 2, characterized in that: The vehicle weight inspection unit is used to confirm that the vehicle weight meets the design requirements, the weight distribution inspection unit is used to confirm that the weight distribution meets the design requirements, the power characteristics inspection unit is used to confirm that the power characteristics meet the design requirements, the suspension characteristics inspection unit is used to confirm that the suspension characteristics meet the design requirements, the tire characteristics inspection unit is used to confirm that the tire characteristics meet the design requirements, and the steering symmetry inspection unit is used to confirm that the steering symmetry meets the design requirements.

4. The method for calibrating safe turning angle of steer-by-wire according to claim 1, characterized in that: The equipment installation module includes a force sensor installation unit, a steering gear position reading device installation unit, and an equipment docking unit. The force sensor installation unit is used to install the force sensor on the rear suspension of the test vehicle that meets the test requirements, connect it to the force measuring system, measure and record the force of the control arm in the lateral direction of the whole vehicle, so as to characterize the change trend of the tire lateral force, where pressure is positive and tension is negative. The steering gear position reading device installation unit is used to connect the vehicle's wire-controlled steering system to the calibration tool and read the steering gear position data, where right turn is positive and left turn is negative. The equipment docking unit is used to dock the force measuring system with the calibration tool for clock synchronization.

5. The method for calibrating safe turning angle of steer-by-wire according to claim 1, characterized in that: The vehicle limit state data acquisition module includes an automatic driving control unit, a vehicle speed control unit, and a steering operation unit. The automatic driving control unit is used to control the vehicle's driving in the form of automatic driving in a closed and safe test field. The vehicle speed control unit is used to control the vehicle to travel at a constant speed at different speeds. The steering operation unit is used to slowly turn from the neutral position at each speed until the vehicle becomes unstable or reaches the maximum travel of the steering gear, and a steering test is performed on each side.

6. A method for calibrating safe turning angle of steer-by-wire according to claim 5, characterized in that: The data analysis module includes a steering gear position data extraction unit, a data validity confirmation unit, and a limit stability angle curve establishment unit.

7. The method for calibrating safe turning angle of steer-by-wire according to claim 6, characterized in that: The steering gear position data extraction unit is used to extract the steering gear position data when the vehicle becomes unstable and skids, so that the vehicle will not skid even when the steering is turned to the maximum angle, and the ALX / ARX at the vehicle speed is recorded as the maximum steering gear stroke. The data validity confirmation unit is used to obtain the steering gear position ALX and ARX absolute values ​​when turning left and right at the same vehicle speed, which should be close. If the data does not meet the requirements, it is necessary to find out the cause of the data deviation, re-test or data processing. The limit stable turning angle curve establishment unit is used to take the minimum value of the absolute values ​​of ALX and ARX at the same vehicle speed, which are recorded as A10min, A20min, A30min, A40min, A50min, A60min..., and the vehicle speed-limit stable turning angle limit curve can be obtained.

8. The method for calibrating safe turning angle of steer-by-wire according to claim 1, characterized in that: The safety turning angle determination module includes a vehicle type positioning analysis unit, a safety turning angle curve determination unit, and an accuracy verification unit.

9. The method for calibrating safe turning angle of steer-by-wire according to claim 8, characterized in that: The vehicle type positioning analysis unit is responsible for analyzing and determining the requirements for the safety turning angle curve based on the vehicle's ultimate stability turning angle curve and vehicle type positioning; the safety turning angle curve determination unit is responsible for determining one or more safety turning angle curves as calibration data based on the vehicle type positioning analysis results; the accuracy verification unit is responsible for verifying the accuracy of the safety turning angle curve by comparing actual vehicle driving data with the calibrated safety turning angle curve, and adjusting and optimizing according to the verification results.

10. The method for calibrating safe turning angle of steer-by-wire according to claim 6, characterized in that: The automatic driving control unit also includes a safety monitoring subunit for monitoring the vehicle's driving status in real time to ensure the safety of the test process. The data validity confirmation unit also includes a data deviation investigation subunit for investigating the cause of data deviation when the data does not meet the requirements and taking corresponding treatment measures, such as re-conducting the test or data processing.

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