Research On Formation Control Method Of Large Number Of Unmanned Ground Vehicles Under Complex Road Conditions

The rapid development of robotics and communication technologies has led to the gradual move from theoretical research to practical applications of multi-manned vehicle systems.However,the real-world driving environment is more complex and the situation is more volatile.In practice,especially in military applications,the number of unmanned vehicles within a multi-unmanned vehicle system is also more enormous,which also leads to a high risk of workshop collisions in the initial assembly phase and during the travel of the convoy.The existing theoretical algorithms are also insufficient to effectively deal with the complex road conditions that arise during the travel of large numbers of multi-unmanned vehicle systems.In order to solve the adverse effects of large number of vehicles and complex road conditions on the multi unmanned vehicle system,this paper conducts in-depth formation method research for large number of unmanned vehicle formations under complex road conditions from three aspects respectively.First,in order to improve the traditional formation control methods that cannot effectively deal with the collisions between vehicles caused by the huge number of vehicles,this paper proposes a dual RRT optimization algorithm to solve the formation shape generation problem of the large number of unmanned vehicle fleet.After transforming the obstacle avoidance problem of unmanned vehicles into a path planning problem,two different RRT algorithms are used for global planning and local optimization,and an evaluation function is introduced for overall path finding.While completing the formation shape generation,the algorithms also significantly improve the RRT algorithm’s own defects and obtain more stable path results.After that,this paper adopts the leader-follower method to design the formation controller to solve the formation tracking problem for a large number of unmanned vehicle fleet.The distributed control of the leader-follower method is more flexible than other formation control methods,and it is also easier to realize the formation change in the subsequent geometric relationship.In this way,control laws that stabilize the formation system are derived to ensure that the unmanned vehicle fleet maintains the preset formation in motion.Since the communication between vehicles under this approach is concentrated between the leader and the follower,this makes the leader’s decision crucial for the whole fleet.Therefore,this also facilitates the subsequent design of the decision layer of the leader in the formation reconfiguration problem.Finally,this paper proposes a large number of unmanned vehicle formation reconfiguration methods based on formation change library and formation change influence factors to help multi-unmanned vehicles cope with the complex road conditions that arise during the travel.By combining the two reconfiguration methods of geometric configuration change and dynamic adjustment of unmanned vehicle formations,this paper establishes a formation change library that is suitable for coping with complex road conditions.At the same time,this paper proposes a formation change influence factor and applies it to the formation change library.Through the formation change influence factor,the unmanned vehicle system can drive the unmanned fleet to choose the appropriate formation change strategy to reconfigure the formation according to the road environment ahead,so as to ensure the fleet can pass the complex road conditions safely.The experimental results show that with the above method,the multi-unmanned vehicle system consisting of a large number of unmanned vehicles can safely and rapidly generate the expected formation shape,avoid workshop collisions,and steadily maintain that formation forward;in the face of complex road conditions encountered during the movement,the multi-unmanned vehicle system can autonomously discriminate the road conditions ahead and make adaptive formation reconfiguration to flexibly and effectively cope with various complex terrains while maintain the stability within the fleet.Finally,the unmanned vehicle formation control and normal operation can still be effectively carried out by a large number of unmanned vehicle systems under complex road conditions.