Research On Distributed Formation Keeping And Reconfiguration Control For Multiple Unmanned Aerial Vehicles

With the development of navigation technology,control technology,communication technology and microelectronics,unmanned aerial vehicle(UAV)autonomous tracking control has become an important research direction in the aviation field.The formation of multiple UAVs can accomplish large and complex tasks that a single UAV cannot accomplish.Even in complex environments,when UAVs can not obtain absolute information or can not communicate,UAVs can still acquire relative state information through sensing devices,thus completing complex tasks.The main contents of this thesis are as follows.Firstly,considering the influence of external disturbances and uncertainties of model parameters,the problem of distributed formation keeping control for multiple UAVs is studied.Then a finite-time distributed formation control strategy based on neural network disturbance observer is proposed.In detail,a control-oriented model of unmanned helicopter is established based on Newton's Euler's law.Based on non-singular fast terminal sliding mode method,distributed formation controller is designed.Next,attitude tracking controller is designed using adaptive non-singular fast terminal sliding mode method.The closed-loop system of unmanned helicopter is proved to be finite-time stable.At last,the simulation results show that the distributed formation keeping control strategy is effective.Furthermore,in order not to rely on global information such as communication topology and Leader state,the fully distributed formation keeping control of multiple UAVs is studied,and then a finite-time fully distributed formation control strategy based on adaptive disturbance observer is proposed.An adaptive disturbance observer is designed by the sliding mode method.Based on the adaptive terminal sliding mode method,the fully distributed formation controller and attitude tracking controller are designed.It is proved that the closed-loop system of unmanned helicopter is finite-time stable.The simulation results show that the fully distributed formation maintenance control strategy is effective.Thirdly,considering the requirement of collision avoidance task in formation reconfiguration,the problem of fully distributed formation reconfiguration control for multiple UAVs is investigated,and then a finite-time fully distributed formation reconfiguration control strategy is proposed.A novel fully distributed formation reconfiguration controller is designed by using the potential function and terminal sliding mode method.The finite-time stability of the closed-loop of the unmanned helicopter is proved.The simulation results show that the proposed finite-time fully distributed formation reconfiguration control strategy is effective.Finally,considering the situation of no absolute state information and no communication,the problem of distributed formation keeping control for multiple UAVs based on relative measurement is studied,and a distributed formation control strategy is proposed.Based on the impulsive sliding mode method and relative measurement information,a distributed formation controller is designed to complete the stability analysis of the closed-loop system of unmanned helicopter.The simulation results show that the designed distributed formation keeping control strategy is effective.