Fault-Tolerant Cooperative Control of WMRs under Actuator Faults Based on Particle Swarm Optimization

This paper investigates fault-tolerant cooperative control (FTCC) of multiple wheeled mobile robots (WMRs) in the presence of severe actuator faults. Initially, a team of robots is moving in pre-defined formation configuration. When actuator faults occur in one or more robots, and the faulty robot(s) cannot complete the mission, the rest of robots start reconfiguring the formation to compensate the fault effect on the whole mission. First, the new formation reconfiguration is generated by solving an optimal assignment problem where each healthy robot should be assigned to a unique place. Then, the new formation can be reconfigured by recasting the reconfiguration problem as an optimization problem, while the objective is to minimize the time to achieve the new formation reconfiguration within the constraints of the robots' dynamics and collision avoidance. A hybrid approach of control parametrization and time discretization (CPTD) and particle swarm optimization (PSO) is proposed to solve the optimization problem. The results of the numerical simulations demonstrate the effectiveness of the proposed algorithm.