Controller Design for Autonomous Excavators

Autonomous excavators are pivotal to modern construction machinery. Enhancing their operational precision and safety necessitates advanced control strategies that address inherent challenges like strong nonlinearities, time-varying parameters, and external disturbances. This paper proposes a novel hybrid control strategy that integrates a dual-loop switching PID controller with a feedback-type Disturbance Observer (DOB). The switching PID structure is specifically engineered to mitigate bidirectional motion asymmetry in hydraulic systems, while the DOB is designed to compensate for load fluctuations and model uncertainties. Experimental results demonstrate quantitatively that the integrated PID+DOB controller significantly outperforms the baseline PID alone. Specifically, it reduces oscillation amplitude by 60-80% (e.g., from 0.08 to 0.02 for the boom) and cuts overshoot by 70-90% (e.g., from 10% to 2% for the boom) across various joints under disruptive conditions. This research establishes a robust theoretical foundation and a practical, scalable technical framework (implemented via a Qt-based architecture) for next-generation autonomous excavator control systems, markedly improving tracking accuracy and robustness.