Consensus Fault-Tolerant Controller Design For Multi-Agent Systems Based On Adaptive Technique

In recent years,research on cooperative control of multi-agent systems(MAS)has received considerable attention from various scientific fields.It has potential applications in both military and civilian areas including the formation of flight of satellites,sensor networks,mobile robots and unmanned vehicles.Compared with a single agent,increasing demands for safety and reliability in MAS with huge and complicated construction have motivated a great of researchers.And the time-varying parameter uncertainties or actuator faults of a single agent can cause unsatisfactory performances or even system instability leading to catastrophic accidents,meanwhile,the coupling of information communication exists between the agents.All the factors mentioned have brought great challenges to the model confirming and control system designing of MAS.In this thesis,based on the linearized reduced-order aircraft model of F18 developed by NASA,the related researches are carried out to design tracking controllers for both of the linear and nonlinear time-varying uncertainties and external disturbance of linear aircraft model.The main work is as follows:Firstly,considering the agents'models in MAS subject to mismatched parameters,external disturbances and actuator faults including time-varying loss of effectiveness,outage and stuck.It is assumed that the actuator efficiency factors,the upper bounds of the unparameterisable time-varying stuck faults and disturbance are unknown Based on the local state information of neighboring agents,a novel distributed fault-tolerant tracking control scheme by using adaptive mechanism without the eigenvalue of Laplacian matrix of the global communication information is proposed.The method presented has better capability to deal with the problems of unknown global communication information and enhance the safety and reliability of MAS.It is not only to guarantee the stability of MAS,but also realizing the objection of followers can consensus tracking leader.Secondly,there have different dynamics between leader and followers in MAS,and researched multiple delay state perturbations of followers further which is unknown but knowing the upper bounds.Based on presented controller,by using only relative state information to multiple delay state perturbations and controller parameters online,a novel distributed fault compensation controller against the actuator faults in individual node is designed,and using the adaptive mechanism to compensate the influence of presented factors automatically,guaranteeing the stability of MAS.Thirdly,considering the actual complicacy of external disturbance in MAS,the designed controller can be separated for interference rejection controller and compensation controller of nonlinear parameter uncertainties respectively according to the matching degree between disturbance and parameter of input with knowing the eigenvalue of Laplacian matrix of the global communication information.The controller for disturbance is designed by using robust H_? control,to ensure the systems stable with unmatched disturbances.The compensation controller is used the relative state information to design distributed fault-tolerant controller,and using adaptive mechanism to estimate the controller parameter online,compensating the influence of nonlinear parameter uncertainties and actuator faults for MAS.The simulation results show that the accurate tracking control between followers and leader of MAS can be reaized by using the proposed approach.Concluding remarks are presented at the end of this thesis.Some open problems are also pointed out,which deserve further study.