Robust Fractional-Order Control of Manipulators Based on SMC-ADRC Dynamic Coordination and Intelligent Optimization

Abstract

To address the limitations posed by model uncertainties and the constraints of single control methods in high-precision trajectory tracking of manipulators, this paper proposes a novel dynamic coordination strategy integrating fractional-order sliding mode control (FOSMC) and fractional-order active disturbance rejection control (FOADRC). A super-twisting algorithm-based FOSMC is designed to ensure robustness and suppress chattering, while a FOADRC is developed to estimate and compensate for disturbances. Key parameters of the FOADRC are systematically tuned using a particle swarm optimization algorithm. An adaptive S-function-based dynamic weighting mechanism is introduced to smoothly adjust the outputs of the two controllers according to real-time tracking error, thereby achieving effective fusion of rapid convergence under large errors and high steadystate accuracy under small errors. Simulation results on a two-degree-of-freedom manipulator demonstrate that, compared to using FOSMC or FOADRC alone, the proposed collaborative strategy significantly improves tracking performance: the root mean square error is reduced by over 52%, the convergence rate is increased by approximately 23.5%, and the smoothness of the control input is enhanced with a variance reduction exceeding 53%. This study validates the effectiveness of the dynamic collaborative mechanism in realizing high precision, rapid response, and strong robustness in complex manipulator control.