Disturbance-Rejection-Based Adaptive RISE Control for an n-DOF Electro-Hydraulic Manipulators With Structural Nonlinearity

This article focuses on an n-degree-of-freedom (DOF) hydraulic manipulator operating in three-dimensional (3-D) space. Given that inaccurate modeling and disturbances pose difficulties for system control performance, a controller is designed based on the robust integral of sign error (RISE) approach with its parameters tuned using an adaptive method. A novel dual extended state observer (DESO) is employed to estimate and compensate for disturbances arising from both matched and mismatched uncertainties. Experiments are conducted on a multi-DOF experimental platform. The experimental findings demonstrate that the proposed controller effectively enhances joint tracking performance of the multi-DOF hydraulic manipulator. Specifically, on average, the control system's tracking accuracy for command signals is 47.02% higher than that achieved with RISE, 51.51% higher than that achieved with feedback linearization controller (FLC), and 69.66% higher than that achieved with proportional-integral (PI) control.