Research On Local Path Planning And Tracking Control Algorithm For Unmanned Vehicles

With the development of 5G technology and V2 x,driverless technology has gradually entered people’s horizons.At present,many domestic and foreign technology companies,vehicle manufacturers and research institutes are increasing their efforts on driverless technology.Many car manufacturers have deployed L2 assisted driving system on commercial vehicles.Even some companies such as Dongfeng Motor and Audi Automobile have begun to deploy L3 autonomous driving technology system on vehicles recently.At present,the main application scenario of commercialization of driverless technology is still the highway scenario.Considering that the next urban scenario to be applied first is the urban expressway,this article designs a local driverless path planning and tracking control system around the urban expressway scenario,the specific research content is as follows:1)First,it analyzes the current situation of the development of driverless technology at home and abroad,and focuses on comparing the gaps between domestic and foreign auto companies,technology companies and universities and research institutes.At the same time,it analyzes the research status of decision-making,path planning and tracking control of driverless vehicles in detail,analyzes the advantages and disadvantages of each algorithm by referring to the data,and proposes suitable algorithms for the urban expressway scenario in this paper.2)With the help of the test vehicle in this paper,the unmanned architecture is analyzed,the problems that unmanned vehicles will face in the urban expressway scenario are proposed,and the design criteria for unmanned vehicle decision-making layers are proposed.The machine design decision module,and designed the local path target planner.3)An improved RRT-Connect algorithm is proposed.Vehicle shape constraints are added to the algorithm,which improves the passability of unmanned vehicles during local path planning.Aiming at the problem that the planned path is not suitable for vehicle driving,this paper proposes to increase the pruning of path points and optimize the path points based on the quadratic B-spline curve.In addition,this paper also improves the dynamic planning of the vehicle.4)The tracking controller is designed.This article is based on the model prediction algorithm.Therefore,before this,the vehicle dynamic model and tire model are first established.The model is linearly simplified according to the needs of the design prediction model and the dynamic constraints are increased with the objective function design,the completed tracking controller can accurately track the expected trajectory and meet the design requirements of urban expressway scenarios.5)For the improved RRT algorithm,a simulation experiment was performed in MATLAB.The results show that the improved algorithm has advantages in planning time and number of iterations.In this paper,the simulation verification was carried out through a joint simulator of Prescan and Simulink.Finally it was found that the MPC tracking controller has a good tracking effect in the double-shift line condition and the continuous curve condition.