Lift-Type Power Catwalk System Based on Dual Closed-Loop Error-Driven Active Disturbance Rejection Control

To mitigate the flutter instability observed during lift-type power catwalk operations, a Dual-Loop Error-Driven Adaptive Disturbance Rejection Control (EDDL-ADRC) strategy is proposed. This approach enhances the tracking accuracy and robustness of the electro-hydraulic servo system under variable load and large inertia conditions, effectively alleviating flutter induced by fluctuations in driving speed. Under low-frequency small load conditions, the EDDL-ADRC overcomes the limitations of traditional Active Disturbance Rejection Control (ADRC), particularly those related to system order, and demonstrates superior control performance compared to conventional ADRC. The dual-loop error-driven controller consists of two identical second-order ADRC modules. The primary controller operates in a conventional driving mode, while the error-driven controller utilizes both the system's output error and control input as driving signals. This error-driven controller effectively compensates for phase lag in the main controller and the limited observation accuracy of the Extended State Observer (ESO), thereby improving overall system performance. The proposed control strategy's effectiveness is validated via a joint simulation platform that integrates both the electro-hydraulic and mechanical systems of the catwalk mechanism.