Reconfiguration of four-legged walking robot for actuator faults

This paper presents fault accommodation through the reconfiguration of a four legged (quadruped) walking robot. It is assumed that the walking robot is moving using a bounding gait. A bond graph model to represent the robot’s locomotion in the sagittal plane is developed. A novel and simple attitude control device based on a moving appendage is proposed. This appendage device serves as redundant hardware and is activated only when the robot experiences a locked joint failure. The bond graph model of the system is used to generate the analytical redundancy relations which are then evaluated with actual measurements to generate residuals. These residuals are used to perform structural fault isolation. Once the fault list is updated in the equipment availability database, an automaton selects the best option to reconfigure the system such that the given control objectives are achieved. The developed methodology is validated by considering the failure of a joint’s actuator.