Research On Fault-tolerant Control Technology For Multiple UAVs System Based On Distributed Observers

In the past two or three decades,unmanned aerial vehicles(UAVs)have been playing more and more roles in civil and military fields,such as intelligence reconnaissance,material transportation,agriculture,forestry and plant protection.With the development of integrated chips,artificial intelligence,information and communication technologies,the development of UAVs is becoming more autonomous,intelligent and clustered.Because of its potential military and commercial value,the collaborative control technology of UAVs has become a research hotspot in many countries.Therefore,the research on fault diagnosis and fault-tolerant control technology of multiple UAVs cooperative system(MUAVS)has attracted great attention from scholars,but at the same time,the complexity of communication network and structure brings challenges to the realization of diagnosis and fault-tolerant technology.In this paper,based on distributed observer method,fault diagnosis and fault-tolerant control technology of MUAVS are studied,and a semi-physical simulation experimental platform is built to verify the effectiveness of the proposed method.Firstly,the research background and significance of the subject is described,and the research status of fault diagnosis and fault-tolerant control technology of MUAVS at home and abroad are summarized.Then,the graph theory method is used to model the communication relationship between UAVs in the MUAVS,and the nonlinear model and linear model of the UAV flight control system are established.Secondly,for a class of MUAVS under disturbance and sensor fault,a fault estimation algorithm based on distributed descriptor observer is studied to solve the bound of the fault derivate and unknown needed to be known.The UAV control system is transform into descriptor system by matrix transformation,and this paper designed the distributed descriptor observer for fault estimation,meeting the global error of system stability,and the effectiveness of the algorithm is verified by simulation.Then,considering the reliability and security of the MUAVS,the whole system needs to be fault-tolerant.In this paper,an active fault-tolerant control method based on distributed fault estimation observer is proposed,the stability of the global tracking error system is proved,and sufficient conditions are given for the collaborative fault-tolerant consistency of the MUAVS.The simulation results show that the proposed fault tolerant control algorithm is effective.Finally,in order to verify the engineering practicability of the algorithm designed in this paper,a fault tolerant control semi-physical simulation experiment platform of the multi-UAV system was built,and the injection methods of actuator fault,sensor fault and communication fault were designed,and the specific engineering implementation method of communication topology network of the MUAVS was designed.Through interpolation gain scheduling PID fault-tolerant actuator fault injection experiment verified the effectiveness of fault-tolerant control method,and use a quadrotor UAV and two ground robots for semi-physical simulation experiment,proves the quadrotor UAV sensor fault cases designed by MUAVS based on distributed observer applicability of fault-tolerant control method.