Hölder Condition Based Design of Finite-Time Control Scheme for Underactuated Robotic System Under Time-Varying Disturbance

Abstract

Controlling an underactuated robot is an attractive research issue as some of the robot joints cannot be controlled directly. Besides, facing the unknown time-varying disturbance, the nature of the plant makes the stability of such uncertain nonlinear system more challenging. This work presents a robust finitetime control scheme that combines Hölder condition based extended state observer and sliding mode control approach to cope with the mentioned issues. The unknown time-varying disturbance and other uncertainties can be well recognized and actively compensated under the proposed scheme. Besides, this control scheme is easy to be implemented due to the small amount of information required. Simulation results demonstrate the performance of the proposed scheme and validate its better robustness and convergent speed compared with other schemes. INDEX TERMS Sliding-mode control, finite-time control, robot control, extended state observer.