Research On Trajectory Control Of Unmanned Vehicle Based On GPS/INS Integrated Navigation

With the development of the automobile industry,the application scenarios of unmanned vehicles tracking paths along fixed routes at low speed have gradually increased.Therefore,the problem of path tracking of unmanned vehicles at low speed has become particularly siganificant.Taking the path tracking control problem of unmanned vehicles at low speed as the research object,and sets up the unmanned logistics vehicle as an experimental platform to carry out the following research work:First,considering the application scenario and the cost,the whole scheme of the trajectory control system based on GPS and INS is constructed.By analyzing the structure of chassis platform,the communication protocol between the top layer and bottom layer is designed.The RTK DGPS is selected and on the basis of the selectedd GPS,the data output format and coordinate conversion is designed.Against the selected low-cost INS,a discrete Kalman filtering algorithm is proposed to decrease its positoning error.Secondly,a path tracking algorithm based on heading estimation is proposed to solve the problems of low tracking accuracy and low longitudinal speed adaptability at low speed.A desired road model is established and a forward point search algorithm on any road is proposed.Combining it with the vehicle model,additional heading model,and heading estimation model,a fuzzy PID control algorithm based on heading estimation in multiple paths is proposed.A joint simulation platform of MATLAB and Car Sim is established to verify the effectiveness of the algorithm.Then,a Dead Reckoning algorithm based on low-cost sensors is proposed to solve the problem of the GPS signal lost under the occlusion of buildings or trees.According to the two-degree-of-freedom model of the vehicle,a yaw rate estimation method that meets the actual motion of the vehicle is proposed,and the lateral acceleration is estimated.Based on it,a data fusion algorithm consisting of vehicle position and velocity model is proposed.A semi-physical offline simulation platform is established to verify the effectiveness of the positioning algorithm.Finally,the software for tracking and controlling the path of unmanned vehicles is written,and the functions and procedures of the program are performed.Then the vehicle experiments for Dead Reckoning postionging algorithm,path tracking based on GPS and Dead Reckoning positionging are performed.The experiment results show that The proposed path tracking control algorithm can effectively implement path tracking,and the positioning algorithm can effectively make up for the problem of lost GPS signals.