Reconfiguration Strategy for a Heavy Mobile Robot with Multiple Steering Configurations

A redundant robot can complete a given task even in a faulty situation using its alternative configurations. This paper presents a reconfiguration strategy for a redundant heavy mobile robot called Robutainer. It is a four wheeled mobile robot, which is used to transport 40 feet container in port terminals. Robutainer has redundant steering actuations for the front and rear sides, due to this redundancy, it shows four steering configurations namely, dual, front, rear, and skid. Thus, Robutainer can reconfigure between its four steering configurations when subjected to a fault in the steering system. But, it is necessary to detect and isolate a fault in the steering system; subsequently, the robot can be reconfigured according to the available steering configurations. The steering system of Robutainer is a complex multi-domain system with hybrid dynamics. In this work, a graphical modeling approach Bond Graph (BG) is used to develop the fault detection and isolation (FDI) model of the steering system considering its multi-domain components including electric motor, pump, accumulator, hydraulic motor, and transmission; moreover, discrete dynamics of distributor valves are included. Finally, a reconfiguration strategy is developed in order to reconfigure the system according to faults in the components of the steering system. The developed algorithm is verified through simulation in Matlab/Simulink with different components faults, and the experimental data of the robot tracking with four steering configurations is used to develop the reconfiguration strategy. Copyright (C) 2020 The Authors.