Constraint control of electro-hydraulic position servo system based on command filter

To address the dynamic constraints and disturbance suppression issues in high-precision position tracking of electro-hydraulic servo systems, a prescribed performance control strategy based on a filter compensator is proposed. First, a nonlinear model with compound disturbances is established, and a novel prescribed performance function is designed to transform the error surface. By incorporating a barrier Lyapunov function, the tracking error is rigorously confined within predefined bounds in finite time. To alleviate the differential explosion inherent in conventional backstepping, a finite-time stable command filter is developed, while a filter error compensation mechanism is introduced to improve transient performance. Furthermore, an extended state observer is introduced to estimate unknown disturbances within the system, enhancing the robustness and disturbance rejection capability of the control system. Experimental results show that compared to the backstepping controller combined with a disturbance observer, the proposed control strategy achieves a 35.7% reduction in maximum steady-state tracking error performance, a 62.2% reduction in average steady-state tracking error performance, and a 52.7% reduction in maximum tracking error performance. These results validate the efficacy of the proposed control strategy in enhancing dynamic response, control precision, and disturbance suppression.