Fault-tolerant gait design for quadruped robots with one locked leg using the GF set theory

Abstract

The fault-tolerant gait plays an important role in improving the reliability and prolonging the service life of legged robots. However, few fault-tolerant gaits are available for quadruped robots and the static stability margin in some gaits cannot avoid being zero. This paper designs a novel fault-tolerant gait for quadruped robots with one locked leg using the GF set theory. First, a quadruped robot with serial-parallel leg mechanism and its typical static gait are introduced. Then, the mobility of the robot with one locked leg in different stages is addressed using the GF set theory. The fault-tolerant gait pattern is developed by taking full advantage of the mobility. Further, the performances of the fault-tolerant gaits are analyzed to demonstrate its capability. Finally, simulations are conducted to validate the fault-tolerant gait and its performance. The results show that the fault-tolerant gait has the capability of omnidirectional walking and adapting to rough terrains while maintaining a nonzero static stability margin.