Corner module steering performance test method

Abstract

The application relates to the field of automobile intelligent chassis testing, in particular to a kind of angle module steering performance test method.The test method comprises: according to preset speed, preset steering angle, preset vertical wheel load, preset road adhesion coefficient, determine steering basic response and control precision comprehensive test condition, control test bench to execute steering basic response and control precision comprehensive test;Steering basic response and control precision comprehensive test condition includes step input response test condition, hysteresis and non-linear characteristic evaluation condition, dynamic response characteristic evaluation condition, return torque and residual angle test condition, steering angle precision and tracking error test condition;According to preset speed and preset vertical wheel load, determine steering-wheel load coupling performance test condition, control test bench to execute steering-wheel load coupling performance test.The application can standardize the steering performance of angle module, test each condition in full dimension, and accurately present the comprehensive steering performance of angle module in actual vehicle operating condition.

Description

Technical Field

[0001] This application relates to the field of automotive intelligent chassis testing, and more specifically, to a method for testing the corner module steering performance. Background Technology

[0002] The steering performance of the corner module plays a crucial role in vehicle operation, directly affecting the agility of steering response, the precision of handling, the self-centering efficiency, and the stability of steering in complex scenarios. Therefore, conducting comprehensive and high-precision testing on the corner module has become the core support for the corner module from research and development, parameter calibration, quality acceptance, to achieving precise matching with the vehicle chassis.

[0003] Currently, most vehicle steering performance testing methods rely on traditional mechanical steering or integrated electric power steering systems, which suffer from limitations such as limited testing scenarios and insufficient coverage. These testing methods fail to leverage the independent control and multi-scenario adaptability of modular steering to create a dedicated testing environment, making it difficult to accurately capture the real-world steering performance of the modular steering system under diverse conditions, including different vehicle speeds, steering commands, and dynamic wheel load changes. Furthermore, traditional testing procedures lack specific verification of the coupling characteristics between steering and wheel load; the accompanying testing equipment struggles to accurately reproduce the actual force and motion states at the wheel ends; and there is a lack of unified testing specifications, quantitative evaluation standards, and unified judgment criteria, resulting in poor repeatability of test results. This hinders the optimization of control strategies for modular steering systems, the calibration of actuator performance, and the matching optimization of the entire vehicle steering system.

[0004] Furthermore, in actual vehicle operation, corner modules need to handle complex steering scenarios such as low-speed, large-angle steering, high-speed, small-angle fine-tuning, emergency obstacle avoidance, and dynamic wheel load adjustment. Existing testing methods fail to fully simulate these complex conditions, making it impossible to accurately assess the robustness, control precision, and coupling adaptability of the corner module steering system. Therefore, there is an urgent need to develop a standardized steering performance testing method that closely aligns with the technical characteristics of corner module steering and comprehensively covers various operating conditions. This would fill the technological gap in specialized corner module steering testing and lay a solid technical foundation for the performance verification of core components of intelligent chassis.

[0005] In view of the above, this application is hereby submitted. Summary of the Invention

[0006] The purpose of this application is to provide a method for testing the steering performance of corner modules, so as to solve the problems of inconsistent testing standards and the inability to simulate complex working conditions in all dimensions in the existing technology.

[0007] To achieve the above objectives, this application adopts the following technical solution: This application provides a method for testing the steering performance of a corner module, including: Based on preset vehicle speed, preset steering angle, preset vertical wheel load, and preset road surface adhesion coefficient, the comprehensive test conditions for steering basic response and control accuracy are determined, and the test bench is controlled to perform the comprehensive test of steering basic response and control accuracy. The comprehensive test conditions for steering basic response and control accuracy include step input response test condition, hysteresis and nonlinear characteristic evaluation condition, dynamic response characteristic evaluation condition, self-aligning torque and residual angle test condition, and steering angle accuracy and tracking error test condition. Based on the preset vehicle speed and preset vertical wheel load, the test conditions for steering-wheel load coupling performance are determined, and the test bench is controlled to perform the steering-wheel load coupling performance test.

[0008] In some technical solutions, the step input response test conditions include: Three vehicle speeds of 10km / h, 60km / h, and 100km / h were selected from the preset speeds as the first type of setting values. The step steering command was set as follows: the preset steering angles for 10km / h and 60km / h were ±15° and ±30°, respectively, and the preset steering angle for 100km / h was ±8°.

[0009] In some technical solutions, the control test bench performs comprehensive testing of steering basic response and control accuracy, including: The corner module is placed in a straight-line driving state, and the test bench is controlled to stabilize the vehicle speed to the first type of set value. A step steering command with a rise time of ≤50ms is sent, and the steering command signal, actual steering angle, motor current and torque are collected simultaneously. Each working condition is tested ≥3 times, and the average response time is calculated after removing abnormal data.

[0010] In some technical solutions, the evaluation conditions for hysteresis and nonlinear characteristics include: Select three speeds from the preset speeds: 0km / h, 10km / h, and 60km / h, as the second type of setting value, with a steering angle of ±30°.

[0011] In some technical solutions, the control test bench performs comprehensive testing of steering basic response and control accuracy, including: The control test bench stabilizes the vehicle speed to the second type of set value, turns back to the center position and completes zero-point calibration, and performs full-range cyclic steering from 0° to +30° to 0° to -30° to 0°. At the same time, it performs step-by-step steering angle input within a range of ±30°. After each gear stabilizes for 3 seconds, the data is recorded. Each vehicle speed is tested ≥3 times and the average value is taken.

[0012] In some technical solutions, dynamic response characteristic evaluation includes: Large-angle emergency obstacle avoidance: Apply ±30° step steering command at a vehicle speed of 60km / h, complete the obstacle avoidance action of 0°→+30°→return to center→0°→-30°→return to center, and repeat the cycle ≥3 times, collecting response delay, corner following error, and peak steering torque data; Continuous large-angle serpentine driving: Apply ±30° continuous sinusoidal steering commands at a vehicle speed of 60km / h, run continuously for ≥10 cycles, and collect data on steering angle following consistency and command and execution phase lag. High-speed small-angle obstacle avoidance: Apply a small-angle rapid step steering command of ±8° at a vehicle speed of 100km / h, and complete the action of 0°→+8°→return to center→-8°→return to center. Repeat each set 3 times.

[0013] In some technical solutions, the testing of the aligning torque and residual angle includes: Tests were conducted using a vehicle speed-steering angle matrix. The low-speed range of 10km / h corresponded to ±15°, the medium-speed range of 40km / h and 60km / h corresponded to ±15°, and the high-speed range of 80km / h and 100km / h corresponded to ±5° and ±8°, respectively. Stabilize the vehicle speed to the target speed, apply the corresponding steering angle and run stably for 2 seconds, then instantly cut off the steering control command, and collect the return torque, return time and steady-state residual angle. Repeat the test ≥3 times for each working condition and take the average value.

[0014] In some technical solutions, the test conditions for rotational accuracy and tracking error include: With a preset vehicle speed of 60km / h, the system sets preset vertical loads of 1000N, 2500N, and 5000N, and preset road surface adhesion coefficients of μ=0.1, 0.3, 0.5, and 0.8 for coupled conditions. The steering command input consists of triangular wave, sawtooth wave, and multi-frequency composite signal, with each waveform running for ≥10 cycles. The triangular wave is -25° to +25°, 10° / s; the sawtooth wave is 0° to +20°, rising 5° / s / falling 40° / s; the multi-frequency composite signal is -15° to +15° superimposed with ±2° / 3Hz.

[0015] In some technical solutions, determining the steering-wheel load coupling performance test conditions based on a preset vehicle speed and a preset vertical wheel load includes: With a preset vehicle speed of 60km / h, the system sets a preset dynamic continuous cycle of vertical wheel load change from 1000N to 5000N and a tire lateral deformation of ±5mm. The steering input is divided into two types: ① Step command ±10°, held for 3s and completing the cycle of 0°→10°→0°→-10°→0°; ② Sine command ±15°, 0.2Hz, continuously running for ≥10 cycles.

[0016] In some technical solutions, the control test bench performs steering-wheel load coupling performance testing, including: The control test bench loading mechanism applies the preset vertical wheel load, achieving continuous and stable cyclic changes within the range of 1000N to 5000N. Simultaneously, the drum lateral movement mechanism is activated to induce a continuously adjustable lateral elastic deformation of the tire from 0 to ±5mm. Under the condition of synchronous coupling changes between the preset vertical wheel load and the tire lateral deformation, a steering step command and a sinusoidal steering command are input sequentially, and the angle module maintains closed-loop control. The vertical wheel load, tire lateral deformation, target steering angle, actual steering angle, and steering torque are collected synchronously throughout the process.

[0017] Compared with the prior art, the beneficial effects of this application are as follows: The corner module steering performance testing method provided in this application establishes a standardized testing environment system and establishes consistent testing condition standards. This method fully utilizes the precise control and simulation capabilities of a test bench (e.g., a wheel-coupled five-degree-of-freedom test bench) to systematically plan a multi-dimensional testing condition system covering basic steering response characteristics, control accuracy levels, and steering-wheel load coupling efficiency. Simultaneously, it precisely defines a quantitative evaluation index system and universal judgment criteria to achieve the testing objective of high precision and high repeatability for the corner module steering system, thereby objectively and accurately presenting the system's comprehensive steering performance under actual vehicle operating conditions. Based on the testing results of this application, it can provide solid technical support for the structural improvement design of the corner module steering system, precise calibration of control strategies, and vehicle steering adaptation. Furthermore, this solution establishes a standardized testing process and specification model for industry acceptance of corner module steering performance. Detailed Implementation

[0018] The following description provides exemplary embodiments of this application, including various details to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0019] As mentioned in the background section, existing technologies suffer from the lack of a standardized testing method for steering performance of the corner module and the inability to perform full-dimensional simulation of complex working conditions. To address this, this application employs a method based on preset vehicle speed, preset steering angle, preset vertical wheel load, and preset road surface adhesion coefficient to determine specific testing conditions, and then conducts tests based on these conditions. The following detailed description, in conjunction with embodiments, further illustrates this application.

[0020] Example 1 This embodiment provides a method for testing the steering performance of a corner module, including the following steps: S110. Based on the preset vehicle speed, preset steering angle, preset vertical wheel load, and preset road surface adhesion coefficient, determine the comprehensive test conditions for steering basic response and control accuracy, and control the test bench to perform the comprehensive test for steering basic response and control accuracy; the comprehensive test conditions for steering basic response and control accuracy include step input response test conditions, hysteresis and nonlinear characteristic evaluation conditions, dynamic response characteristic evaluation conditions, self-aligning torque and residual angle test conditions, and steering angle accuracy and tracking error test conditions.

[0021] Optionally, the step input response test conditions include: Three vehicle speeds of 10km / h, 60km / h, and 100km / h were selected from the preset speeds as the first type of setting values. The step steering command was set as follows: the preset steering angles for 10km / h and 60km / h were ±15° and ±30°, respectively, and the preset steering angle for 100km / h was ±8°.

[0022] Optionally, the step input response test includes: The corner module is placed in a straight-line driving state, and the test bench is controlled to stabilize the vehicle speed to the first type of set value. A step steering command with a rise time of ≤50ms is sent, and the steering command signal, actual steering angle, motor current and torque are collected simultaneously. Each working condition is tested ≥3 times, and the average response time is calculated after removing abnormal data.

[0023] The evaluation criteria for this test are as follows: the dynamic response time from steering command to actual turning angle is ≤80ms, the turning angle following accuracy meets the steady-state error requirements, the response consistency is good at different vehicle speeds, and there is no obvious overshoot, oscillation, or lag.

[0024] Optionally, the evaluation conditions for hysteresis and nonlinear characteristics include: Select three speeds from the preset speeds: 0km / h, 10km / h, and 60km / h, as the second type of setting value, with a steering angle of ±30°.

[0025] Optionally, hysteresis and nonlinearity characteristic evaluation tests include: The control test bench stabilizes the vehicle speed to the second type of set value, turns back to the center position and completes zero-point calibration, and performs full-range cyclic steering from 0° to +30° to 0° to -30° to 0°. At the same time, it performs step-by-step steering angle input within a range of ±30°. After each gear stabilizes for 3 seconds, the data is recorded. Each vehicle speed is tested ≥3 times and the average value is taken.

[0026] The evaluation criteria for this test are as follows: the steering angle / torque hysteresis meets the design requirements, the nonlinearity of the steering angle-torque characteristic meets the standard, there is no obvious steering dead zone, and the steering execution repeatability is good.

[0027] Optionally, the dynamic response characteristic evaluation includes: Large-angle emergency obstacle avoidance: Apply ±30° step steering command at a vehicle speed of 60km / h, complete the obstacle avoidance action of 0°→+30°→return to center→0°→-30°→return to center, and repeat the cycle ≥3 times, collecting response delay, corner following error, and peak steering torque data; Continuous large-angle serpentine driving: Apply ±30° continuous sinusoidal steering commands at a vehicle speed of 60km / h, run continuously for ≥10 cycles, and collect data on steering angle following consistency and command and execution phase lag. High-speed small-angle obstacle avoidance: Apply a small-angle rapid step steering command of ±8° at a vehicle speed of 100km / h, and complete the action of 0°→+8°→return to center→-8°→return to center. Repeat each set 3 times.

[0028] Optionally, the return torque and residual angle tests include: Tests were conducted using a vehicle speed-steering angle matrix. The low-speed range of 10km / h corresponded to ±15°, the medium-speed range of 40km / h and 60km / h corresponded to ±15°, and the high-speed range of 80km / h and 100km / h corresponded to ±5° and ±8°, respectively. Stabilize the vehicle speed to the target speed, apply the corresponding steering angle and run stably for 2 seconds, then instantly cut off the steering control command, and collect the return torque, return time and steady-state residual angle. Repeat the test ≥3 times for each working condition and take the average value.

[0029] The target vehicle speeds mentioned above refer to the various vehicle speeds in the vehicle speed-steering angle matrix, including 10km / h, 40km / h, 60km / h, 80km / h, and 100km / h.

[0030] The evaluation criteria for this test are as follows: return time ≤ 1.5s, steady-state residual angle ≤ 0.5°, smooth return torque curve without oscillation, and good consistency of return performance under different vehicle speeds and angles.

[0031] Optionally, the test conditions for rotation accuracy and tracking error include: With a preset vehicle speed of 60km / h, the system sets preset vertical loads of 1000N, 2500N, and 5000N, and preset road surface adhesion coefficients of μ=0.1, 0.3, 0.5, and 0.8 for coupled conditions. The steering command input consists of triangular wave, sawtooth wave, and multi-frequency composite signal, with each waveform running for ≥10 cycles. The triangular wave is -25° to +25°, 10° / s; the sawtooth wave is 0° to +20°, rising 5° / s / falling 40° / s; the multi-frequency composite signal is -15° to +15° superimposed with ±2° / 3Hz.

[0032] Optionally, the turning accuracy and tracking error test includes: setting the working conditions in sequence according to the preset vertical load-preset road surface adhesion coefficient combination, inputting various types of steering commands after the system stabilizes, and synchronously collecting the target turning angle and the actual turning angle. Each combination completes three waveform tests.

[0033] The evaluation criteria for this test are: root mean square error (RMSE) of steering angle tracking ≤ 0.3°, and maximum tracking error ≤ 0.8°.

[0034] S120. Based on the preset vehicle speed and preset vertical wheel load, determine the test conditions for steering-wheel load coupling performance and control the test bench to perform the steering-wheel load coupling performance test.

[0035] Optionally, determining the steering-wheel load coupling performance test conditions based on a preset vehicle speed and a preset vertical wheel load includes: With a preset vehicle speed of 60km / h, the system sets a preset dynamic continuous cycle of vertical wheel load change from 1000N to 5000N and a tire lateral deformation of ±5mm. The steering input is divided into two types: ① Step command ±10°, held for 3s and completing the cycle of 0°→10°→0°→-10°→0°; ② Sine command ±15°, 0.2Hz, continuously running for ≥10 cycles.

[0036] Optionally, the control test bench performs steering-wheel load coupling performance testing, including: The control test bench loading mechanism applies the preset vertical wheel load, achieving continuous and stable cyclic changes within the range of 1000N to 5000N. Simultaneously, the drum lateral movement mechanism is activated to induce a continuously adjustable lateral elastic deformation of the tire from 0 to ±5mm. Under the condition of synchronous coupling changes between the preset vertical wheel load and the tire lateral deformation, a steering step command and a sinusoidal steering command are input sequentially, and the angle module maintains closed-loop control. The vertical wheel load, tire lateral deformation, target steering angle, actual steering angle, and steering torque are collected synchronously throughout the process.

[0037] The evaluation criteria for this test are as follows: root mean square error (RMSE) of steering angle tracking ≤ 0.3°, maximum tracking error ≤ 0.8°; steering torque changes smoothly and continuously with wheel load and lateral deformation without abrupt changes; steering angle control has no obvious drift or shaking, and steering action is smooth without jamming, abnormal noise, out-of-tolerance or loss of control.

[0038] If all dimensions of the comprehensive test of steering basic response and control accuracy in step S110 and all evaluation indicators of the steering-wheel load coupling performance test in step S120 meet the quantitative requirements set in this embodiment, and there are no sensor drift, drum abnormalities, steering overtravel, equipment alarms, etc. during the test, the steering performance of the corner module is deemed qualified; if any evaluation indicator of any test dimension / item does not meet the requirements, or if the above-mentioned abnormalities occur during the test, the steering performance of the corner module is deemed unqualified, and the hardware structure or control strategy problem needs to be investigated and the full process test is re-executed.

[0039] Optionally, the process before S110 also includes pre-test preparation, including: mechanically assembling the corner module onto the wheel-coupled five-degree-of-freedom test bench; completing the debugging of the steering system and lubrication system to ensure that the steering mechanism has no mechanical interference, jamming, or looseness within a ±30° range; calibrating all test sensors such as the high-precision corner encoder, steering angle sensor, steering torque sensor, and wheel speed sensor; setting the sampling frequency of the CANoe data acquisition system to no less than 1kHz; controlling the test environment temperature to 20±5℃; ensuring that tire pressure and axle load meet standard operating conditions; starting the test bench for pre-running to a thermally stable state; completing the steering center zero-point calibration; eliminating initial system disturbances; and confirming that the corner module and test bench have no fault alarms.

[0040] The testing method in this embodiment has at least the following advantages: (1) Strong test bench adaptability: This embodiment can be carried out based on a wheel coupling five-degree-of-freedom test bench. This bench can accurately realize multi-dimensional collaborative control and simulation of wheel end vehicle speed, vertical wheel load and tire lateral deformation. It can reproduce the real steering force and motion state when the corner module is running on the actual vehicle, especially the coupled working condition of dynamic wheel load change, which meets the high precision and multi-working condition requirements of corner module steering performance test. The authenticity and reference value of the test data are significantly improved.

[0041] (2) Full coverage of test dimensions: This invention designs two core test items: basic steering response and control accuracy, and steering-wheel load coupling performance. It covers the full-dimensional performance indicators of the corner module steering system, including step response, hysteresis nonlinearity, dynamic steering, self-centering performance, tracking accuracy, and wheel load coupling adaptation. It accurately matches complex working conditions such as low-speed large-angle steering, high-speed fine adjustment, emergency obstacle avoidance, and dynamic wheel load changes of real vehicles. The test results can truly reflect the actual steering performance of the corner module.

[0042] (3) High degree of standardization in testing: This embodiment sets unified test environment conditions, sensor calibration requirements, and data acquisition standards. It designs standardized working condition parameters and test steps for each test dimension / item, clarifies quantitative evaluation indicators and general judgment criteria, effectively solves the problems of poor repeatability and lack of unified standards in traditional test methods, and establishes a standardized paradigm for industry acceptance of corner module steering performance.

[0043] (4) Test conditions closely match the actual vehicle: This embodiment relies on the simulation capability of the test bench to reproduce typical steering scenarios of the actual vehicle, such as emergency obstacle avoidance and high-speed fine adjustment, in the dynamic response test. In the coupling performance test, it restores the actual working conditions of wheel load dynamic change and tire lateral deformation during vehicle driving, so that the test conditions are highly consistent with the actual use scenario of the corner module, and the test data is more valuable for engineering applications.

[0044] (5) The test results are highly instructive: This embodiment collects data such as steering response time, hysteresis characteristics, return torque, tracking error, torque and angle changes under coupled conditions. It can not only determine the qualification of the corner module steering performance, but also accurately identify key issues such as system steering response defects, control accuracy shortcomings, and insufficient coupling adaptation. It provides core data support for the structural optimization, control strategy calibration, and steer-by-wire algorithm optimization of the corner module steering system, and helps improve the efficiency of corner module R&D.

[0045] Example 2 This embodiment provides a method for testing the steering performance of a corner module, including the following steps: 1. Precise preparation of test bench and supporting equipment A wheel-coupled five-degree-of-freedom test bench was selected, capable of precise control of wheel-end speed, vertical wheel load, and tire lateral deformation, and supporting synchronous triggering of steering commands and multi-condition coupled simulation. The bench must meet the requirements of multi-parameter collaborative closed-loop control, with core control accuracy reaching: equivalent vehicle speed ±0.5km / h, vertical wheel load ±10N, tire lateral deformation ±0.1mm, steering angle control ±0.01°, and steering command linkage response delay ≤10ms. High-precision test sensors and high-frequency data acquisition equipment were provided. All sensors were professionally calibrated and within their validity period. Specific configuration requirements are as follows: Angle encoder: accuracy ±0.01°, sampling frequency 1kHz, directly connected to the output of the steering actuator to achieve accurate acquisition of actual steering angle; Steering angle sensor: accuracy ±0.01°, sampling frequency 1kHz, collects the target angle of the steering command and compares it with the actual steering angle; Steering torque sensor: accuracy ±0.1N m, sampling frequency 1kHz, real-time acquisition of torque output and feedback during steering execution; Wheel speed sensor: 0.1 rpm resolution, 1 kHz sampling frequency, no pulse loss, accurately captures the wheel end motion state at different vehicle speeds; Load cell: accuracy ±5N, sampling frequency 1kHz, placed at the loading end of the test bench to realize dynamic acquisition of vertical wheel load; Displacement sensor: accuracy ±0.01mm, sampling frequency 1kHz, detects tire lateral deformation to ensure accurate simulation of coupled working conditions; CANoe High-Frequency Data Acquisition System: The sampling frequency can be set to ≥2kHz, supporting multi-channel synchronous data acquisition, real-time storage and offline analysis, compatible with steering controller data interaction, and realizing synchronous capture of command and feedback data; the test bench is debugged to achieve precise control of each degree of freedom with no linkage error, completes the bench's own zero-point calibration and accuracy verification, the steering control module, load loading module and lateral deformation simulation module function normally, the communication of each system controller is normal, the baud rate is ≥500kbps, the data interaction has no delay, and the bench self-test program has a 100% pass rate.

[0046] 2. Integrated installation of corner modules and full system debugging The corner module to be tested is fixed to the wheel end mounting position of the test bench using a custom-made high-strength aluminum alloy fixture. The fixture uses a double fixing method of positioning pins and high-strength bolts to ensure that the coaxiality error of the corner module installation is ≤0.02mm and the perpendicularity error is ≤0.01°. 50 Shore A hardness damping pads are added to the contact points between the fixture and the corner module to avoid vibration interference with steering accuracy and data acquisition accuracy during testing. After completing the mechanical connection between the corner module and the test bench, the wiring and piping connections of the steering controller, drive-by-wire actuator, and lubrication system are completed sequentially: the wiring uses shielded cables and is reliably grounded to avoid electromagnetic interference in steering command transmission; the lubrication system is filled to the calibrated scale, and the pipeline pressure is adjusted to 0.2MPa±0.02MPa to ensure smooth steering mechanism movement and no leakage at any pipeline joints; the steering actuator is connected to the wheel end in place, with no mechanical interference, jamming, or looseness within a ±30° steering range. The diagonal module underwent integrated system-wide debugging: First, the steering mechanism was manually rotated to check the smoothness of movement within a ±30° range, ensuring there was no jamming, abnormal noise, or looseness. Then, the steering system was powered on to trigger single-action steering commands at different angles, confirming that the target turning angle and the actual turning angle response were synchronized, and that the torque output was stable without abnormal fluctuations. The bench idle program was started to simulate typical vehicle speeds such as 10km / h, 60km / h, and 100km / h, triggering step and continuous steering commands at different angles to confirm that the diagonal module's steering response, torque output, and return-to-center function were all normal, the controller had no fault codes, and the data acquisition from each sensor was free of packet loss and garbled codes. Finally, the steering center zero point was precisely calibrated to ensure that the initial steering position was without deviation, laying the foundation for subsequent testing.

[0047] 3. Precise control of standardized testing conditions The testing laboratory was controlled by a constant temperature and humidity air conditioner at 24℃±1℃ and 55%RH±5%RH. During the testing process, frequent personnel entry and exit were minimized to avoid the impact of environmental temperature and humidity fluctuations on sensor accuracy and steering component motion performance. The tire pressure of the corner module was adjusted to the manufacturer's recommended standard value and precisely calibrated using a tire pressure monitoring system, with the error controlled within ±0.05 bar. Axle loads were set according to standard operating conditions, with load control accuracy of ±10N, to ensure that the initial test conditions met the actual vehicle standards. The test bench was pre-run, running at a constant speed of 30 km / h (equivalent to a vehicle speed) for 10 minutes to ensure the core components, including the steering module controller, drive-by-wire actuator, and transmission mechanism, reached thermal stability. The thermal stability criterion was a temperature fluctuation of ≤2℃ for the core components over 10 consecutive minutes, with the final temperature of the steering system core components stabilizing at 42℃±2℃. Zero-point calibration of all test systems, including steering angle, torque, wheel speed, load, and displacement, was completed. A multi-point calibration method was used to improve calibration accuracy and eliminate initial system disturbances. The steering center zero-point calibration was repeated three times to ensure a calibration error ≤0.01°. The CANoe data acquisition system sampling frequency was set to 2kHz (higher than the basic requirement of 1kHz). All acquisition channels were debugged and calibrated, and data storage paths and formats were set to ensure synchronous acquisition of multi-channel data (synchronization error ≤1ms) without packet loss, achieving synchronous capture of steering commands, actual steering angle, torque, vehicle speed, and load data.

[0048] 4. Refined Implementation of Core Testing Items 4.1 Comprehensive Test of Steering Basic Response and Control Accuracy This test is performed sequentially according to five dimensions: step input response, hysteresis and nonlinear characteristics, dynamic response characteristics, self-aligning torque and residual angle, and angular accuracy and tracking error. The data acquisition interval for all working conditions is 1ms. Each dimension test is repeated a specified number of times. After removing abnormal data with a deviation exceeding ±8%, the arithmetic mean is taken to ensure the accuracy and repeatability of the test results.

[0049] Step input response test: The test bench drives the corner module to set speeds of 10km / h, 60km / h, and 100km / h ±0.5km / h through closed-loop control, maintaining stable straight-line operation for more than 3 seconds, with speed fluctuation ≤ ±0.5km / h. Step steering commands of corresponding angles are sent according to the working conditions, with the command rise time precisely controlled within 40ms (better than the 50ms requirement). Steering command signals, actual steering angle, motor current, and torque are collected synchronously. At low speed of 10km / h, ±15° and ±30° angles are tested; at medium speed of 60km / h, ±15° and ±30° angles are tested; and at high speed of 100km / h, ±8° angles are tested. Each working condition is repeated 3 times, and the average response time is calculated. The dynamic steering response time is verified to be ≤80ms, and the steering angle following accuracy meets the steady-state error requirements, with no obvious overshoot, oscillation, or lag.

[0050] Hysteresis and nonlinearity evaluation: The test bench was set to 0km / h, 10km / h, and 60km / h±0.5km / h respectively. The steering wheel was returned to the center position and zero-point calibration was completed. The full-range cyclic steering was performed from 0°→+30°→0°→-30°→0°. At the same time, the steering angle was stepped into a step of 5° within the ±30° range. After each angle stabilized for 3 seconds, the steering angle and torque data were recorded. The test was repeated 3 times at each vehicle speed. The average value was used to plot the steering angle-torque characteristic curve to verify that the steering angle / torque hysteresis meets the design requirements, the nonlinearity meets the standard, there is no obvious steering dead zone, and the steering execution repeatability is good.

[0051] Dynamic response characteristics evaluation: Tested sequentially under three typical dynamic operating conditions, maintaining stable vehicle speed throughout, and ensuring accurate command execution: Large-angle emergency obstacle avoidance: At a vehicle speed of 60km / h±0.5km / h, a ±30° step steering command is applied to complete the obstacle avoidance action of 0°→+30°→return to center→0°→-30°→return to center. This is repeated 3 times. Data such as response delay, corner following error, and peak steering torque are collected to verify that there is no obvious lag or overshoot, and the torque output has no violent impact. Continuous large-angle serpentine maneuver: At a vehicle speed of 60km / h±0.5km / h, a continuous sinusoidal steering command of ±30° and frequency of 0.5Hz is applied and run continuously for 10 cycles. Data such as steering angle following consistency and command and execution phase lag are collected to verify that there is no deviation in continuous steering following and no performance degradation. High-speed small-angle obstacle avoidance: At a vehicle speed of 100km / h±0.5km / h, apply a small-angle rapid step steering command of ±8° to complete the action of 0°→+8°→return to center→-8°→return to center. Repeat each set 3 times to verify high corner following accuracy and no shaking or drifting at high speed.

[0052] Return torque and residual angle tests: Tests were conducted according to the vehicle speed-steering angle matrix. Low speed (10km / h) corresponded to ±15°, medium speed (40km / h, 60km / h) corresponded to ±15°, and high speed (80km / h, 100km / h) corresponded to ±5° and ±8°, respectively. The control accuracy for each vehicle speed was ±0.5km / h, and the control accuracy for the angle was ±0.01°. The vehicle speed was stabilized to the set value, the corresponding steering angle was applied and the vehicle was allowed to run stably for 2 seconds. The steering control command was then cut off instantaneously, and the return torque, return time, and steady-state residual angle were collected simultaneously. Each test condition was repeated 3 times, and the effective average value was taken to verify that the return time was ≤1.5s, the steady-state residual angle was ≤0.5°, the return torque curve was smooth without oscillation, and the return performance was consistent under different vehicle speeds and angles.

[0053] Turning angle accuracy and tracking error test: The test bench was set to a simulated vehicle speed of 60km / h±0.5km / h. Vertical loads of 1000N, 2500N, and 5000N (accuracy ±10N) and road adhesion coefficients μ=0.1, 0.3, 0.5, and 0.8 were set sequentially. Steering commands were input in the following conditions: triangular wave (-25°~+25°, 10° / s), sawtooth wave (0°~+20°, rise 5° / s / fall 40° / s), and multi-frequency composite signal (-15°~+15° superimposed ±2° / 3Hz). Each waveform was run for 10 cycles. The test conditions were set sequentially according to the load-adhesion coefficient combination. After the system stabilized, various types of steering commands were input, and the target turning angle and actual turning angle data were collected synchronously. The root mean square error (RMSE) of the steering angle tracking was verified to be ≤0.3°, and the maximum tracking error was ≤0.8°.

[0054] 4.2 Steering-Wheel Load Coupling Performance Test The test bench was set to a simulated vehicle speed of 60km / h ± 0.5km / h. Dynamic vertical wheel load was applied through the bench loading mechanism, achieving continuous and stable cyclic changes within the range of 1000N to 5000N, with a load change rate of 50N / s and a control accuracy of ±10N. Simultaneously, the drum lateral movement mechanism was activated to induce a continuously adjustable lateral elastic deformation of the tire from 0 to ±5mm, with a deformation control accuracy of ±0.1mm, thus achieving synchronous coupling simulation of wheel load and lateral deformation. Under the condition of synchronous dynamic changes in wheel load and lateral deformation, two types of steering commands are input sequentially, and the angle module maintains closed-loop control: ① Step command ±10°, held for 3s and completing the cycle of 0°→10°→0°→-10°→0°, executed 5 times; ② Sine command ±15°, 0.2Hz, continuously running for 10 cycles; key data such as vertical wheel load, tire lateral deformation, target steering angle, actual steering angle, and steering torque are collected synchronously throughout the process, with a collection interval of 1ms. After the system stabilizes, the middle 80% of the effective data segment is selected for analysis. Based on the collected data, the steering angle tracking error is calculated, and the characteristic curve of steering torque changing with wheel load and lateral deformation is plotted. It is verified that the root mean square error (RMSE) of steering angle tracking is ≤0.3°, and the maximum tracking error is ≤0.8°; the steering torque changes smoothly and continuously with wheel load and lateral deformation without abrupt changes; the steering angle control has no obvious drift or jitter, and the steering action is smooth without jamming, abnormal noise, out-of-tolerance, or loss of control.

[0055] 5. Professional data processing and accurate assessment of overall eligibility The collected raw data was filtered, denoised, and synchronized using professional data processing software such as Matlab / Simulink and Origin to remove outlier data points. Following the formulas and requirements of this invention, the core evaluation indicators for each test dimension / item were precisely calculated, including steering response time, return-to-center time, steady-state residual angle, root mean square error of tracking, and maximum tracking error. Simultaneously, steering command-actual angle response curves, angle-torque hysteresis characteristic curves, return-to-center torque variation curves, and angle-torque / wheel load characteristic curves under coupled conditions were plotted to visually demonstrate the steering performance characteristics of the angle module. Strictly adhering to the comprehensive pass / fail criteria, each of the five dimensions of basic steering response and control accuracy, and all evaluation indicators of steering-wheel load coupling performance, was checked to ensure they met the quantitative requirements set by this invention. Furthermore, the test bench fault log and data acquisition log were reviewed to confirm that there were no sensor drift, drum abnormalities, steering overtravel, equipment alarms, or data acquisition interruptions during the test. If all indicators meet the requirements, a formal corner module steering performance qualification test report will be issued. The report will include complete content such as basic test information, bench and corner module parameters, raw test data, data processing results, calculated values ​​of core indicators, performance characteristic curves, and judgment conclusions. If any indicator fails to meet the requirements, the root cause of the problem will be located through fault tracing analysis. If it is a control strategy problem, the steering control algorithm, command tracking strategy, and coupling adaptation logic will be optimized. If it is a hardware structure problem, the steering actuator, transmission components, and drive-by-wire module will be rectified. After rectification, a full-process test will be carried out again on the wheel coupling five-degree-of-freedom test bench.

[0056] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0057] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for testing the steering performance of a corner module, characterized in that, include: Based on preset vehicle speed, preset steering angle, preset vertical wheel load, and preset road surface adhesion coefficient, the comprehensive test conditions for steering basic response and control accuracy are determined, and the test bench is controlled to perform the comprehensive test of steering basic response and control accuracy. The comprehensive test conditions for steering basic response and control accuracy include step input response test condition, hysteresis and nonlinear characteristic evaluation condition, dynamic response characteristic evaluation condition, self-aligning torque and residual angle test condition, and steering angle accuracy and tracking error test condition. Based on the preset vehicle speed and preset vertical wheel load, the test conditions for steering-wheel load coupling performance are determined, and the test bench is controlled to perform the steering-wheel load coupling performance test.

2. The corner module steering performance testing method according to claim 1, characterized in that, The step input response test conditions include: Three vehicle speeds of 10km / h, 60km / h, and 100km / h were selected from the preset speeds as the first type of setting values. The step steering command was set as follows: the preset steering angles for 10km / h and 60km / h were ±15° and ±30°, respectively, and the preset steering angle for 100km / h was ±8°.

3. The corner module steering performance testing method according to claim 2, characterized in that, The control test bench performs comprehensive tests on steering basic response and control accuracy, including: The corner module is placed in a straight-line driving state, and the test bench is controlled to stabilize the vehicle speed to the first type of set value. A step steering command with a rise time of ≤50ms is sent, and the steering command signal, actual steering angle, motor current and torque are collected simultaneously. Each working condition is tested ≥3 times, and the average response time is calculated after removing abnormal data.

4. The corner module steering performance testing method according to claim 1, characterized in that, The evaluation conditions for hysteresis and nonlinear characteristics include: Select three speeds from the preset speeds: 0km / h, 10km / h, and 60km / h, as the second type of setting value, with a steering angle of ±30°.

5. The corner module steering performance testing method according to claim 4, characterized in that, The control test bench performs comprehensive tests on steering basic response and control accuracy, including: The control test bench stabilizes the vehicle speed to the second type of set value, turns back to the center position and completes zero-point calibration, and performs full-range cyclic steering from 0° to +30° to 0° to -30° to 0°. At the same time, it performs step-by-step steering angle input within a range of ±30°. After each gear stabilizes for 3 seconds, the data is recorded. Each vehicle speed is tested ≥3 times and the average value is taken.

6. The corner module steering performance testing method according to claim 1, characterized in that, Dynamic response characteristic evaluation includes: Large-angle emergency obstacle avoidance: Apply ±30° step steering command at a vehicle speed of 60km / h, complete the obstacle avoidance action of 0°→+30°→return to center→0°→-30°→return to center, and repeat the cycle ≥3 times, collecting response delay, corner following error, and peak steering torque data; Continuous large-angle serpentine driving: Apply ±30° continuous sinusoidal steering commands at a vehicle speed of 60km / h, run continuously for ≥10 cycles, and collect data on steering angle following consistency and command and execution phase lag. High-speed small-angle obstacle avoidance: Apply a small-angle rapid step steering command of ±8° at a vehicle speed of 100km / h, and complete the action of 0°→+8°→return to center→-8°→return to center. Repeat each set 3 times.

7. The corner module steering performance testing method according to claim 1, characterized in that, The return torque and residual angle tests include: Tests were conducted using a vehicle speed-steering angle matrix. The low-speed range of 10km / h corresponded to ±15°, the medium-speed range of 40km / h and 60km / h corresponded to ±15°, and the high-speed range of 80km / h and 100km / h corresponded to ±5° and ±8°, respectively. Stabilize the vehicle speed to the target speed, apply the corresponding steering angle and run stably for 2 seconds, then instantly cut off the steering control command, and collect the return torque, return time and steady-state residual angle. Repeat the test ≥3 times for each working condition and take the average value.

8. The corner module steering performance testing method according to claim 1, characterized in that, The test conditions for rotation accuracy and tracking error include: With a preset vehicle speed of 60km / h, the system sets preset vertical loads of 1000N, 2500N, and 5000N, and preset road surface adhesion coefficients of μ=0.1, 0.3, 0.5, and 0.8 for coupled conditions. The steering command input consists of triangular wave, sawtooth wave, and multi-frequency composite signal, with each waveform running for ≥10 cycles. The triangular wave is -25° to +25°, 10° / s; the sawtooth wave is 0° to +20°, rising 5° / s / falling 40° / s; the multi-frequency composite signal is -15° to +15° superimposed with ±2° / 3Hz.

9. The corner module steering performance testing method according to claim 1, characterized in that, The test conditions for determining the steering-wheel load coupling performance based on the preset vehicle speed and preset vertical wheel load include: With a preset vehicle speed of 60km / h, the system sets a preset dynamic continuous cycle of vertical wheel load change from 1000N to 5000N and a tire lateral deformation of ±5mm. The steering input is divided into two types: ① Step command ±10°, held for 3s and completing the cycle of 0°→10°→0°→-10°→0°; ② Sine command ±15°, 0.2Hz, continuously running for ≥10 cycles.

10. The corner module steering performance testing method according to claim 9, characterized in that, The control test bench performs steering-wheel load coupling performance tests, including: The control test bench loading mechanism applies the preset vertical wheel load, achieving continuous and stable cyclic changes within the range of 1000N to 5000N. Simultaneously, the drum lateral movement mechanism is activated to induce a continuously adjustable lateral elastic deformation of the tire from 0 to ±5mm. Under the condition of synchronous coupling changes between the preset vertical wheel load and the tire lateral deformation, a steering step command and a sinusoidal steering command are input sequentially, and the angle module maintains closed-loop control. The vertical wheel load, tire lateral deformation, target steering angle, actual steering angle, and steering torque are collected synchronously throughout the process.