| The automotive testing industry has long been limited by the degree of automation of test equipment and has not been able to automate or semi-automate testing,and has always used human drivers for testing.The human driver has the disadvantages of imprecise control,poor repeatability and fatigue,which can directly affect the test progress and even the accuracy of the test data.In order to improve the current state of automotive testing dilemmas,a steering robot was designed to control the lateral displacement of the vehicle and to realise the automatic testing function for the Automotive Handling Stability Test Method.The main research includes the following.1.The steering robot is driven by a DC servo motor,which is decelerated by a primary reducer to increase the output torque to drive the steering wheel.The steering robot is designed for versatility and the sliding base is designed to ensure that the steering robot conforms to different steering wheel diameters.ANSYS software was used to analyse the steering robot support structure and gear pair.2.According to the national standard test "Vehicle Handling and Stability Test Method",the data acquisition system is designed for the data required by the test,and then the hardware circuit and software program are designed.In view of man-machine interaction,the upper computer interface is designed to facilitate man-machine interaction,and the measured experimental data is displayed on the user interface in real-time.3.The path tracking algorithm of the vehicle under the control of the steering robot is studied.The vehicle dynamics model was studied,the state space equation and the lateral error equation were established,and the linear quadratic optimal controller(LQR)was designed.Based on the existing shortcomings of LQR,genetic algorithm was used to optimize it.In addition,the mathematical model of steering robot is established and PID control method is used to control steering robot.Finally,the effectiveness of the linear quadratic controller optimized by genetic algorithm for vehicle path tracking is verified by co-simulation with Carsim-Simulink.4.The steering robot was installed on the vehicle to carry out the steering lightness test.The data required for the test was collected and plotted against the steering wheel angle,trajectory tracking,torque-steering wheel angle and lateral displacement error.The analysis shows that the steering robot designed in this project can meet the test requirements in practical applications. |
