Adaptive Cooperative Fault-Tolerant Control for Output-Constrained Nonlinear Multi-Agent Systems Under Stochastic FDI Attacks
Guangliang Liu, Qiuye Sun, Hanguang Su, Mengxin Wang
Abstract
The primary objective of this article is to construct a distributed adaptive cooperative fault-tolerant control (FTC) protocol for dynamic output-constrained nonlinear multi-agent systems (MASs) subject to actuator fault and unknown output dead zone (UODZ) in the presence of stochastic false data injection (SFDI) attacks. By establishing a unified universal barrier function (UUBF) upon output, the original constrained system is transformed into a fully equivalent non-constrained system, which not only eliminates the restrictive condition of the constraint boundaries/functions but also solves the output constraints problem without changing the control structure. To circumvent the effects of unknown time-varying output coefficient derived from UODZ, we introduce the Nussbaum function in backstepping design. An adaptive FTC strategy based on the parameter adaptive law compensation approach that does not require the lower and upper bounds of the unknown fault coefficient is developed, and it can tolerate SFDI attacks. The result shows that the derived adaptive backstepping FTC protocol can not only achieve the cooperative control for MASs subject to UODZ under SFDI attacks, but also guarantee that all signals are bounded in the closed-loop system and the output constraints are not violated. Finally, simulation examples validate the validity of the developed schemes.