Fault-Tolerant Controller Design For Unmanned Surface Vehicles In Network Environments

Unmanned surface vehicle(USV)is a high-precision surface motion platform with fast and flexible response.With ships as the supporting platform,USV is an unmanned intelligent device capable of autonomous long-distance navigation for a long time.Because of the fully autonomous operation mode,it is relatively easy to generate faults and requires a high degree of intelligence.Therefore,higher requirements are put forward for fault-tolerant control technology.In this thesis,an unmanned surface vehicles in network environment is taken as the research object.Fault diagnosis observer and fault-tolerant controller are designed for compensating the actuator faults and sensor faults of unmanned surface vehicles.The main contents of this paper are as follows:(1)According to the characteristics of communication network,some event-trigger rules are designed for feedback scheme of observer,control input of unmanned vehicle,and input of observer.As a result,the delay times of time-delay terms formed by the two-channel network fluctuation are consistent,which leads to the same control input for the unmanned surface vehicle and the observer,so the design complexity is reduced.(2)Concerning the actuator faults in the heading control system of unmanned surface vehicle,a state and fault estimation observer is designed in the network environment,and then the fault estimation is used to construct a fault-tolerant controller.The system uniformly ultimately bounded condition of the system state is given by theoretical analysis.(3)Through analyzing the motion equation of the dynamic positioning system of unmanned surface vehicle and the event-driven rules designed in this thesis,a network-based T-S fuzzy model is established for the dynamic positioning system of unmanned surface vehicle.Concerning the sensor faults and actuator faults,a state and fault estimation observer and fault-tolerant controller are designed for the dynamic positioning system.Under the designed fault-tolerant control,the dynamic positioning control system of unmanned surface vehicle can still hold proper function,even when actuator faults and sensor faults occur.