Control algorithms for multi-legged robots in fault conditions using fuzzy logic

Fault tolerance is an important design criterion for robotic systems operating in hazardous or remote environments. This paper addresses the issue of tolerating a locked joint failure in gait planning for hexapod walking machines which have symmetric structures and legs in the form of an articulated arm with two revolute joints. A locked joint failure is one for which a joint cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but hexapod walking machines have the ability to continue static walking. A fault tolerant fuzzy control algorithms using dynamics of leg is proposed. Also, problem of kinematics constraints of the failed leg in fault-tolerant gaits for a locked joint failure is presented.