Fault-tolerant cooperative control of multiple wheeled mobile robots under actuator faults

This paper investigates fault-tolerant cooperative control (FTCC) strategies for multiple autonomous differentially-driven wheeled mobile robots (WMRs) in the presence of actuator faults during formation operation. Initially, an integrated approach with a decentralized linear model predictive control (MPC) and an input-output feedback linearization is designed and implemented on a team of WMRs in order to accomplish a formation task under normal conditions (i.e., fault-free cases). The linear model of each robot with nonlinear dynamics is found through feedback linearization, while MPC is subsequently applied to the linear model of each robot to perform the formation control. When actuator faults occur in one of the robots of the team, the faulty robot is not able to complete its assigned task anymore due to the fault, and the faulty robot has to get out from the formation mission. An FTCC strategy is designed with the tasks of the WMRs team are re-assigned to the remaining healthy vehicles to still complete the mission but with graceful performance degradation. Formation operation of the robot team is based on a leader-follower approach, while the control algorithm is implemented in a decentralized manner. Simulation results are presented to demonstrate the performance of the designed algorithm in several fault scenarios.