Fault-tolerant Control Of Interconnected Systems Based On Fault Estimation

Complex interconnected systems are more and more likely to be encountered in engineering applications,with the controlled system becomes more and more complex and larger,and the control requirements are getting higher and higher.Therefore,this topic focuses on two major categories of interconnected systems: mechanical interconnection and network interconnection,respectively,to discuss fault estimation and fault-tolerant control when encountering actuator fault or sensor fault.Make them proactively fault-tolerant when encountering a fault,compensate for the impact of the fault on the system as a whole,and complete the tasks to be completed by the system.The main contributions of this paper are as follows:(1)Aiming at a linear mechanical interconnection system with actuator fault and sensor fault,an augmented unknown input observer and adaptive technology are proposed to estimate actuator fault and sensor fault respectively,and the estimated two fault values are used for dynamic compensate the sliding mode control scheme to compensate the impact of faults on the system.The augmented unknown input observer and the dynamic compensation sliding mode controller solve the fault-tolerant control problem of the linear mechanical interconnection system.Finally,simulation is used to verify that the control strategy can ensure the stability of the system.(2)Aiming at a type of spacecraft formation flight system with external interference,actuator fault and saturation,which is mainly a network interconnection system,a distributed attitude fault-tolerant tracking control scheme is proposed for this.The spacecraft formation flight system is established with a directional communication topology based on the leader spacecraft.The decentralized unknown input observer is designed to estimate the unknown actuator fault factor,which will affect the flight performance of the spacecraft formation,and the obtained fault estimation is used as the design of the distributed fault-tolerant formation controller.At the same time,a distributed fault-tolerant formation control algorithm using an adaptive TSM control method is proposed,so that each follower spacecraft can follow the leader spacecraft in the presence of actuator fault and saturation.(3)For a type of spacecraft formation flight system with external interference and sensor fault,based on a distributed fault-tolerant attitude tracking control scheme in Chapter 4,an event trigger mechanism is introduced to reduce the frequency of actuator update.Event triggering can greatly reduce the communication pressure.Only when the system error value is higher than a certain time-varying signal,each subsystem will have a communication to transfer their respective status.A decentralized unknown input observer is proposed to estimate the unknown sensor fault factor,which will affect the flight performance of spacecraft formation and the communication between spacecraft.The estimated sensor faults are used in the designed adaptive TSM control scheme to compensate for the effects of sensor faults and solve the problem of the following spacecraft following the leader spacecraft’s decline in the presence of sensor faults.