Research On Obstacle Avoidance Control System For Unmanned Vehicle Formatio

With the development of artificial intelligence and autonomous driving technology,the formation of unmanned ground vehicles(UGV)has broad application prospects in industrial production,disaster search and rescue,park inspection and other fields.When UGV formation performs specific tasks in an obstacle environment,it not only needs to maintain the desired formation movement,but also needs to avoid obstacles reasonably and efficiently.This requires UGV formation to have stable formation structure and formation retention capabilities,and to make optimal obstacle avoidance strategies according to the actual environment.Therefore,this paper mainly studies the formation control and obstacle avoidance strategies of differential wheeled UGVs.The main work contents and innovation points are as follows:The overall scheme of the system is designed,the functional requirements of the unmanned vehicle are analyzed,and the experimental platform of the UGV is built.Lidar is used to obtain surrounding environment information,and communication between UGV formations is realized based on the WIFI and ROS distributed node mechanism,which provides a physical experimental platform basis for the subsequent experimental verification of UGV formation control algorithms and obstacle avoidance strategies.Aiming at the formation and maintenance of the UGV formation,a Separation-Bearing based Leader-follower UGV formation model is established,and the formation control problem is transformed into the trajectory tracking problem of UGV.A fixed-time sliding mode controller is designed so that the trajectory tracking error of the system can converge to zero along the proposed fixed-time sliding mode surface,independent of the initial value of the system.The system has good stability and timing convergence,the formation control performance of UGV is improved by improving the formation generation and maintenance ability.Aiming at the obstacle avoidance problem of UGV formation in obstacle environment,the overall obstacle avoidance method of formation is adopted,and an obstacle avoidance strategy of dynamic change of UGV formation considering environmental constraints is proposed.Introduce the concept of safety potential field inside and outside the UGV,introduce the concept of safety potential field inside and outside the UGV,there are three formation obstacle avoidance modes: zero switching,isomorphic shrinkage switching and isomeric switching.Designing the formation change performance evaluation index,and a decision-making mechanism for formation change is established,so that the UGV formation can make the optimal formation change selection under different obstacle environments.Completed real-environment experiments.Firstly,the UGV formation experiment is carried out in an unobstructed environment to verify the effectiveness of the fixed-time sliding mode controller designed in this paper.Secondly,the experiment of isomorphic formation shrinkage obstacle avoidance and the isomeric formation transformation experiment are carried out in the environment with obstacles,which verifies the efficiency of the formation obstacle avoidance strategy proposed in this paper.