Research On Fault-tolerant Tracking Control Technology For Interconnected Nonlinear Systems With Output Time Delay

With the continuous development of science and technology,the expansion of production scale and the improvement of product quality,a single system will not be able to meet some specific needs.This makes more and more systems have the characteristics of interconnection,which needs to be modeled as an interconnected systems for research.For example: chemical production system,large-scale power system,computer network communication system and intelligent transportation system.Because decentralized control can design the controller according to local state information,it can effectively reduce the burden of the system and increase the reliability and flexibility of the system.Which makes it a popular method to study interconnected systems.In this paper,several types of interconnected nonlinear time delay systems are studied.According to the system characteristics,the corresponding decentralized adaptive fault-tolerant control algorithms are designed for stability analysis.At the same time,numerical simulation is used to verify the effectiveness of the algorithm.The main research and work are as follows:(1)The interconnected nonlinear systems with input saturation,actuator failure and output time delay are studied,and a decentralized adaptive fault-tolerant tracking control scheme is designed.In the process of backstepping design,extreme learning machine(ELM)is used to approximate the unknown nonlinear function,and Nussbaum function is introduced to deal with the impact of input saturation and actuator failure on system performance.Through Lyapunov theory,it is proved that the proposed control scheme can ensure the stability of the closed-loop system.Finally,the corresponding simulation examples and simulation results are given to illustrate the effectiveness of the proposed control scheme.(2)The interconnected nonlinear time delay systems with input saturation and actuator failure are further studied,and an effective prescribed performance decentralized adaptive fault-tolerant control scheme is proposed.In order to achieve the prescribed performance,the error constraint function is introduced.According to Lyapunov theory,it is proved that the proposed control scheme can ensure the stability of the closed-loop system,and the tracking error of each subsystem can be constrained within the preset range.Finally,a simulation example is given to illustrate the effectiveness of the proposed control scheme.(3)The interconnected nonlinear time delay systems with input saturation,actuator failure and full state constraints are studied.In order to realize the full state constraint,a nonlinear transformation function related to the system state is introduced,and the state constraint problem is transformed into the stability problem of the transformed unconstrained system.In the backstepping method,adaptive technology is used to design a decentralized adaptive fault-tolerant control scheme with full state constraints.Through Lyapunov theory,it is proved that under the action of the control algorithm,all signals of the closed-loop system are uniformly ultimately bounded,and all states of the system can be kept within the specified range.Finally,a simulation example is given to illustrate the effectiveness of the proposed control scheme.