Robust Fault Diagnosis and Fault‐Tolerant Control for Heterogeneous Nonlinear Multi‐Agent Systems

ABSTRACT A robust fault diagnosis (FD) and fault‐tolerant control (FTC) scheme for heterogeneous nonlinear multi‐agent systems (MASs), which are affected by actuator fault and sensor fault simultaneously, is proposed in this paper. First, to eliminate the coupling between actuator fault and sensor fault and to facilitate the design of distributed observer and controller, the heterogeneous nonlinear MAS is decoupled into independent subsystems by the given coordinate transformation. Later on, a robust distributed unknown input observer is designed for the purpose of FD. Besides, to estimate the nonlinear term more accurately and loosen the limitations on the nonlinear part in previous literature, a neural network method is employed to deal with the nonlinear parts in decoupled subsystems. When the fault estimation is obtained based on the relative output information, which is easier to acquire than state data, an active FTC strategy is executed to ensure the output trajectories of the follower systems are consistent with the expected trajectory. Finally, to demonstrate the effectiveness of the proposed strategy, a heterogeneous nonlinear MAS consisting of manipulators is adopted.