Decentralised fault compensation of time-delayed interactions and dead-zone actuators for a class of large-scale non-linear systems

An approximation-based decentralised adaptive fault compensation (FC) problem is addressed for large-scale non-linear time-delay systems with unknown faults in both time-delayed C¹ non-linear interconnections and non-symmetric dead-zone actuators. Error surfaces constrained by prescribed performance bounds, which characterise the convergence rate and maximum overshoot of control errors, are presented to provide predefined bounds of control errors. Then, we design a memoryless decentralised FC control system using the constrained-surfaces-based dynamic surface design methodology, without constructing a dead-zone inverse and requiring the information about dead-zone parameters and time-delayed interactions. For the compensator design, the function approximation technique using neural networks is applied to adaptively estimate unknown non-linear effects and changes in model dynamics because of time-delayed interaction and dead-zone actuator faults. It is shown from Lyapunov stability theorem that all the error surfaces are preserved within the prescribed performance bounds and finally converge to an adjustable neighbourhood of the origin. Therefore guaranteed transient performance is achieved at the moment the faults occur.