Research On Path Planning And Tracking Control Of Semi-mounted Vehicle Vertical Parking System

Semitrailer vehicles have become the backbone of the transportation industry because of their advantages of large transport volume,low transport cost and high transport efficiency.However,when semi-mounted vehicles parking,the visual field blind area is large,the driving operation is opposite to daily driving,and the folding instability phenomenon directly increases the difficulty of semi-mounted vehicles parking.Therefore,the function of automatic parking system of semi-mounted vehicle has important research significance and commercial value.This paper studies the path planning and path tracking control of semi-mounted vehicle automatic parking system.The main contents are as follows.Firstly,the kinematic analysis and scene construction of parking system are carried out,and the kinematic model of semi-mounted vehicle is established and the accuracy of the model is verified.Truck Sim software was used to build a vertical parking scene for semi-mounted vehicles.By analyzing the turning process of semi-articulated vehicle parking and warehousing,the changing rule of turning instantaneous center of vehicle is obtained,the minimum turning radius of semi-articulated vehicle is deduced,and the calculation method of turning passing width of vehicle is established.Secondly,the path planning of semi-mounted vehicle automatic parking system is studied.The hinge Angle and collision constraints of the path planning algorithm are obtained.Based on the B-spline parking path curve control point optimization mathematical model to solve the control points,and then complete the semi-attached vehicle system parking path planning.A steering controller model of semi-mounted vehicle based on front wheel feedback control was built,and the numerical boundary of input and state quantity in the path optimization algorithm was established to realize the purpose of tracking and optimizing the parking planning path of the trailer.Thirdly,the path tracking control strategy of semi-mounted vehicle automatic parking system is studied.The sliding mode control method is used to control the longitudinal driving speed of semi-mounted vehicle.The simulation results show that the designed sliding mode controller can effectively stabilize the parking speed.The inverse kinematics model of semi-mounted vehicle was established,and the state space equation of the kinematics model was linearly discretized.The optimal control linear quadratic regulator was used to solve the control gain coefficient.A feedforward and feedback input controller for lateral front wheel Angle based on LQR was established and the accuracy of the path tracking controller was verified.Finally,Truck Sim software was used to build the vehicle dynamics model,and Matlab/Simulink software was used to build the path planning model and path tracking controller model.The co-simulation test of the two software verified the effectiveness of the path planning algorithm and the accuracy of the path tracking control strategy.