Experimental implementation of a novel model-free adaptive fractional-order sliding mode controller for a flexible-link manipulator

摘要

This paper presents an experimental study of a robust control scheme for a single flexible-link manipulator. Regarding the nonlinear dynamics of flexible manipulators and vibration problems associated with these robots, this study aims to propose a novel fractional-order controller for efficient reference tracking, even in the presence of noise and total disturbances. In this regard, the control term is formulated by adopting the intelligent proportional-integral-derivative (PID) (iPID) technique and sliding mode control. As for estimating unknown states of the system, and ensuring that time-variable disturbances are well-handled and they do not excite vibrating modes, the generalized proportional integral (GPI) observer is utilized. Then, the adaptive reaching laws are derived along with the Lyapunov stability analysis, and finite-time convergence of the sliding surface is proven. Finally, well-trajectory tracking and robustness of the system are illustrated by the experimental results. The effectiveness of the fractional calculus in terms of accuracy, control effort, and vibration suppression is depicted as well.