Research on Control Strategy of 3-DOF Electro-Hydraulic Servo Manipulator Based on Active Disturbance Rejection Controller

To address the high-precision control requirements of a three-degree-of-freedom (3-DOF) electro-hydraulic servo robotic arm, this paper innovatively integrates the funnel control (FC) concept into the compensation structure of an active disturbance rejection controller (ADRC), designing a triple-parallel decoupled active disturbance rejection controller (TPDADRC). By establishing a precise global dynamic model of the electro-hydraulic servo system and the 3-DOF robotic arm, complex factors such as unmodeled dynamics, external disturbances, and nonlinear characteristics are elegantly unified and represented as a total disturbance term. An extended state observer (ESO) is employed for real-time precise estimation. The TPDADRC constrains the transient behavior of the error through performance funnel constraints, not only enhancing the estimation and compensation capabilities for the total disturbance but also significantly improving control performance. Based on Lyapunov stability theory and linear matrix inequalities (LMI), the Lurie system is constructed to rigorously prove the stability of TPDADRC. Comparison of simulation results shows that compared to sliding mode funnel control (SMC-FC), TPDADRC significantly improves trajectory and velocity tracking accuracy through a synergistic mechanism of dynamic compensation and decoupling, while achieving fast response and demonstrating robust robustness under disturbance conditions. This method provides an innovative new approach to addressing the multi-degree-of-freedom coupled control problem in hydraulic robotic arms. The integration of FC and ADRC effectively optimizes error dynamics, improves disturbance estimation accuracy, and enhances interference resistance, thereby advancing the development of robotic arm control technology.