Distributed Adaptive Fault-tolerant Formation Control of Uncertain Nonholonomic Mobile Robots

In this paper, the distributed adaptive fault-tolerant formation control problem is investigated for a group of nonholonomic mobile robots(NMRs). The communication flow is described by a digraph and it is supposed that only a subset of the NMRs has direct access to the common desired trajectory. Besides, the actuators of each NMR may suffer from intermittent type of actuator faults. To estimate the unknown trajectory information and topology parameters, distributed estimators are proposed based on the neighboring available information. In addition, estimators are also introduced to estimate the lower bounds of the actuator fault coefficients. Based on the estimation values and Young's inequality, nonlinear damping terms are designed. Then, a novel fault-tolerant control scheme is proposed by applying the adaptive backstepping technique. It is guaranteed that the formation errors will converge to an adjustable compact set and the control inputs are globally uniformly bounded. Simulation results validate the effectiveness of the proposed control scheme.