| The control accuracy of the intelligent vehicle’s motion trajectory is determined by the stability and reliability of the steering system directly.Aiming at the imperfect measurement equipment and standards of intelligent vehicle steering system,the research on the static steering measurement and control system of intelligent vehicle is carried out based on the sub-project of the National Key Research and Development Program"Holographic Traffic State Reconfiguration and Vehicle Population Cooperative Control Test Validation"（2018YFB1600605）,using the method of CAN communication control steering and laser sensor measurement to measure the front wheel deflection angle.The intelligent vehicle steering system is analyzed,and the scheme formulation,hardware selection,software programming and test verification of the measurement and control system are completed.Firstly,the research method and functional requirements of steering measurement and control are analyzed,and the measurement system and control system are developed as subsystems respectively,and the specific implementation plan is proposed.Secondly,the direct-fire triangulation is used as the distance measurement method,the spatial position of the laser sensor is determined,and the construction and commissioning of the test equipment of the measurement and control system is completed.Thirdly,the recursive averaging filtering algorithm is improved and the filtering effect is verified using the actual laser sensor measurement data.The steering wheel angle and front wheel deflection angle are measured in real time by combining with the producer-consumer model.The upper computer programming is completed by Lab VIEW to realize the steering command sending,and the control,signal acquisition and algorithm implementation of the measurement equipment.The sending of steering commands,the control,signal acquisition and algorithm development of the laser sensor and steering wheel angle-torque measuring instrument are realized.Finally,real vehicle tests are carried out on the control system and measurement system respectively.The feasibility of the theoretical laser sensor spacing is verified by comparing the calibration results of different laser sensor distances.The left and right front wheels are measured separately as the target wheels for the test,and the versatility of the system is verified.The collected discrete data are fitted to a function curve to evaluate the effectiveness of this calibration method.The three-order Fourier fit is determined to fit the relationship between the steering wheel and the front wheel in terms of turning angle.By analyzing the fitting results,the reasonableness of the Fourier fitting is verified.The test results show that when the control step size of the intelligent vehicle static steering measurement and control system is 5°,the maximum tracking error is 3.2°,the average relative error is 0.0082,and the average response time is 0.24s,which can quickly and accurately send steering instructions.The repeatability error of calibrated steering extrema is within±0.5°and the maximum variance of the repeatability test is 0.147.When the kingpin offset is input,the steering measurement error is within±0.5°.When the kingpin offset is used as the default value,the non-target wheel error is within 1°,combined with the effect of Ackerman’s understeering.The2 and2(（6（95）0）（9） curves of the steering relationship fitting are above 99.90%,which can meet the requirements of steering measurement and control and Angle calibration. |
