Novel adaptive fuzzy control for pendubot with actuator faults and uncertainties: Design and experiments

Pendubot has been widely applied as a benchmark platform for control research and education. In this paper, a novel adaptive fuzzy hierarchical sliding mode controller (AFHSMC) is proposed for the pendubot under actuator faults and uncertainties. The proposed controller is designed by combining hierarchical sliding mode control (HSMC), fuzzy logic control (FLC), and balancing composite motion optimization. The proposed controller preserves many advantages such as having a straightforward structure, simple implementation, chattering reduction, and high precision and robustness. The stability of the proposed controller is ensured by using the Lyapunov approach. To verify the control performance, various numerical simulations and experiments are conducted on a pendubot under conditions that involve actuator faults and uncertainties. Compared to the conventional HSMC and FHSMC controllers, the proposed AFHSMC improves by 0.43% and 0.38% for tracking precision of the first link's angle estimate, 3.26% and 0.08% for the second link's angle estimate when influenced by uncertainties, as well as 65.23% and 12.24% for the first link, 83.95% and 16.15% for the second link when influenced by faults. • The proposed approach integrates HSMC and FLCs to tune the sliding gain and approximate uncertainties. • The BCMO method is proposed for optimizing the proposed controller, hence it is simple and easy to implement. • The proposed AHSMC controller offers advantages like simplicity, chatter-free operation, and high precision. • The proposed controller outperforms both HSMC and FHSMC in simulations and experiments on the pendubot.