Predesignated fault-tolerant formation tracking quality for networked uncertain nonholonomic mobile robots in the presence of multiple faults

This paper presents a fault-tolerant formation tracking (FTFT) scheme ensuring predesignated bounds of overshoot, convergence rate, and steady-state values of distributed formation errors for networked nonholonomic mobile robots in the presence of unexpected multiple actuator and system faults. It is assumed that (i) nonlinearities and multiple faults of follower models and their bounds are unknown, and (ii) the time-varying posture information of the leader robot is accessible to only a small fraction of follower robots under directed networks. A continuous local controller for each follower is designed without utilizing any adaptive and function approximation mechanism to compensate for unexpected actuator and nonlinear system faults and computing repeated time derivatives of certain signals. Compared with the related results in the literature, this feature enables the proposed FTFT scheme to be implementable with remarkably low complexity. Theoretical and simulation verifications of our control strategy guaranteeing that the distributed FTFT errors remain within preassigned bounds regardless of the occurrence of unexpected faults are studied in a rigorous manner.