Simulation Research On Path Planning And Tracking Control For Intelligent Vehicles

As an important development direction of the automobile industry in the future,the intelligent vehicle and its related technologies have been attracting worldwide attention and becoming the research focus of universities and enterprises.Path planning and tracking control technology plays a decisive role in the entire intelligent driving system.In-depth and systematic research on it will help to build and perfect the intelligent vehicle technology system,so as to better promote the development of intelligent vehicles in our country.Considering that the path planning algorithms in structured environments are relatively mature,the research on path planning in this paper focuses on partially-known unstructured environments.According to the characteristics of the environments,a path planning strategy based on the combination of global and local path planning is adopted.The global planning is based on the D* Lite algorithm.The path planning process and the heuristic value of D* Lite are improved in order to better cooperate with the local planning and improve planning efficiency.The local planning is based on the HCAA*(Hybrid-State Convergence-Accelerated A*)algorithm.The discrete path set and its selection method of HCAA* are improved to meet the driving requirements of different speed.In addition,the value system of HCAA* is also improved by introducing steering angle coefficient to better evaluate the expected path.The effectiveness of the improved algorithms is verified by MATLAB simulation.Considering that the local path planning algorithm has the characteristics of "path changed with vehicle speed",a longitudinal velocity planning strategy and its software are designed.The application of the speed planning method can extend the application range of HCAA* algorithm from "constant speed" to "variable speed".After formulating the strategy of the longitudinal speed planning,a speed tracking controller based on the incremental PID control algorithm is designed.In the aspect of path tracking control,the pure pursuit algorithm and fuzzy control algorithm are studied in this paper.The pure pursuit controller and fuzzy controller are designed based on their principles.The tracking effect of them is verified by using straight path and sinusoidal path.Based on the simulation analysis of the advantages and disadvantages of two controllers,a composite controller consisted of pure pursuit controller and fuzzy controller is designed to satisfy the tracking requirements of intelligent vehicles for different expected paths.Finally,a simulation platform is built by using MATLAB/Simulink,Car Sim and AMESim software.The joint simulation of path planning and tracking control algorithm is realized by using the platform,and the comprehensive effect of them is verified.