Adaptive Fault Tolerant Control For Switched Nonlinear Systems With Actuator Failures

With the increasing innovation and development of science and technology,the scale and complexity of the controller studied are also increasing.Many new problems need new theories and methods to deal with.Switched system is a kind of complex and important hybrid dynamic system studied from the perspective of control science,which has important theoretical research value and extensive engineering background.The interaction between continuous dynamics and switching signals makes the dynamic behavior of the system more flexible.In order to ensure the safety of personnel and property and avoid accidents,adaptive fault tolerant control is widely studied as an important means to ensure the stability of control system.Switching adaptive fault tolerant control has certain advantages in improving the stability and reliability of the system.In this paper,based on the nonlinear switching system,combined with adaptive control,backstepping and Tuning Function,the fault-tolerant control problem of nonlinear switching system is discussed.For uncertain nonlinear switched systems with unknown parameters and actuator failures,an adaptive fault-tolerant control mechanism based on Lyapunov function switching method is designed.Firstly,based on the multi-Lyapunov function method and the backstepping method,the state feedback controllers are constructed for each subsystem.Secondly,unknown parameters are estimated by tuning function method and adaptive update law.Then,the switched adaptive fault-tolerant control mechanism is designed to compensate the fault.Finally,the theoretical analysis proves that the designed switching rules guarantee the stability of the system,and the effectiveness of the proposed control scheme is verified by simulation.Considering uncertain nonlinear switched systems with unknown control directions and full-state constraints,a switched adaptive fault-tolerant control mechanism is designed for actuator faults.Firstly,the barrier Lyapunov function is constructed according to the full-state constraint of the system,and the virtual controller is constructed by using the backstepping method.Secondly,by introducing the lower bound of the unknown control coefficient into the barrier Lyapunov function,the constraint on the unknown control coefficient is realized.Finally,a switched adaptive fault-tolerant control mechanism is designed to ensure that the tracking error converges asymptotically without violating the complete state constraint,and the simulation results show that the proposed control scheme is effective.