Nonsingular fast terminal sliding mode posture control for six-legged walking robots with redundant actuation

The posture changing ability of multi-legged walking robots is significant for walking in rough terrains. Six-legged walking robots are nonlinear and redundant systems with uncertainties and disturbances. The rabidity, accuracy, and robustness of posture control are important for enhancing the posture changing ability. In this study, a new nonsingular fast terminal sliding mode (NFTSM) is proposed for the posture control of six-legged walking robots. The NFTSM controller is designed with a nonsingular terminal sliding manifold and a fast terminal sliding-type reaching law based on the posture control model of six-legged walking robots. The stability, rapidity, and robustness of the controller are analyzed. Simulation and experiment results show that fast, accurate, and robust performance is obtained for the posture control of six-legged walking robots using the NFTSM controller.