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Research On Fault-tolerant Cooperative Control Method For Multi-UAV System

Posted on:2020-07-21Degree:MasterType:Thesis
Country:ChinaCandidate:Z H ZhaoFull Text:PDF
GTID:2392330602461501Subject:Control Science and Engineering
Abstract/Summary:PDF Full Text Request
Due to the characteristic of small size,simple mechanical structure,flexible flight and hovering,quadrotor UAV has received great attention in recent years.Sensors and actuators may fail during the flight of the quadrotor UAV.In order to ensure that the quadrotor UAV can still fly stably after failure,the UAV fault-tolerant control technology has become one of the important research directions.Compared with a single quadrotor UAV,the multi-UAV cooperative control system can complete complex tasks more efficiently,stronger robustness and fault tolerance,so it has become a research hotspot.In this paper,the mathematical model of the quadrotor UAV and the mathematical model of the multi-UAV cooperative system are established according to the strong coupling,nonlinear and underactuated of the quadrotor UAV systems.We focus on the tracking trajectory problem of the quadrotor UAV,the fault-tolerant control problem of partial failure of the actuator and the formation shape maintenance problem of the multi-UAV cooperative system.The fault tolerant controller is designed for the single quadrotor UAV and cooperative controller is designed for the cooperative system.Firstly,the flight principle of the quadrotor UAV is analyzed,and the mathematical model of the quadrotor UAV is established.Secondly,NFTSM fault-tolerant controller is designed for quadrotor UAV under the actuator partial loss-of-effectiveness(LOE)fault,stability is proved by Lyapunov function.Simulation results verify that the quadrotor UAV converges to equilibrium states in finite time after failure.Then,the formation controller based on the Leader-Follower method is designed for the multi-UAV cooperative system under the fixed communication topology,and the communication structure is layered.The trajectory of the Leader is predefined,then the desired trajectory of each UAV is calculated by the cooperative controller.Each quadrotor UAV tracks the desired trajectory by the onboard NFTSM controller in finite time to keep the stability of the formation shape.Simulation results show the effectiveness of the Leader-follower method.Finally,a double-layer controller is designed for multi-UAV cooperative system with repetitive tasks and a variable communication topology,graph theory is used to construct the information topology among multi-UAV.The reference trajectory is generated by a virtual leader,and each quadrotor UAV keeps a desired deviation from the reference trajectory.In the upper cooperative controller,ILC controller is designed to keep the formation shape and generate the desired trajectory for individual UAV in the lower layer.In the lower-layer,the trajectory of each quadrotor UAV is tracked by the onboard PD controller.The validity of the controller is proved by the simulation of the cooperative system composed of six UAVs.
Keywords/Search Tags:quadrotor UAV, fault tolerant control, cooperative control, finite-time convergence, iterative learning control, graph theory
PDF Full Text Request
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