Observer-Based Fuzzy Adaptive Formation FTC for Nonlinear MASs Against Communication Link and Sensor Faults

This article investigates the adaptive fuzzy formation fault-tolerant control (FTC) issue for nonlinear multi-agent systems (MASs) with intermittent communication link faults and sensor faults. The proposed formation FTC method is composed of a fault-estimation-based fuzzy state observer, a distributed observer, and a formation fault-tolerant controller. In the control design, fuzzy logic systems (FLSs) are utilized to model uncertain agents, and a fault-estimation-based fuzzy state observer is designed to estimate the unknown system states and sensor fault factors. A distributed observer is constructed to avoid that the discontinuous communication signals caused by intermittent communication link faults repeatedly differentiate in the backstepping procedure. Based on the fault-estimation-based fuzzy state observer and distributed observer, a formation fault-tolerant controller is constructed by backstepping control design theory. It is proved that all the variables of the controlled nonlinear MASs are bounded, and the outputs of the followers can track the leader under sensor faults and intermittent communication link faults. Finally, two simulation examples and comparison results are given to show the effectiveness of the proposed formation FTC algorithm.