Fault-tolerant gait for Hexapod Robots with partial active joints locked

Abstract

The fault-tolerant gait for legged robots can improve the reliability and prolong the service time. However, few fault-tolerant gaits are available for hexapod robots with parallel leg mechanisms to realize the walkability and adapt to rough terrains when several active joints locked. This paper proposes a fault-tolerant gait for hexapod robots based on the non-fault gait without changing its gait sequence. First, a hexapod robot with serial-parallel leg mechanism is introduced. Then, the fault-tolerant gait with partial active joints locked based on typical walking gait is proposed. The gait planning algorithm selects the minimum square sum of the displacements of the active joints as the objective function to improve the walking ability of the robot. Further, two examples are chosen to analyze the walking ability on ground and rough terrain. Finally, experiments are carried out to validate the fault-tolerant gait and its performances. The results show that the fault-tolerant gait can effectively solve the walking of hexapod robots with partial active joints locked and it can also walk in different directions and traverse rough terrains such as steps.