Observer based adaptive discrete hierarchical sliding mode control for industrial overhead crane with input saturation

This paper presents an adaptive discrete hierarchical sliding-mode controller (AHSMC) based on a cascaded state observer (ALKF) to address inaccurate state estimation and control performance degradation caused by input saturation in industrial overhead crane anti-sway control. First, a cascaded observer integrating a Luenberger observer and an adaptive Kalman filter with an adaptive weighting mechanism is constructed to enhance the robustness and accuracy of state estimation. Subsequently, an adaptive discrete hierarchical sliding-mode controller featuring an input saturation compensation mechanism is designed. This controller suppresses the effects of input saturation and improves system robustness by dynamically adjusting the parameters of the sliding-mode reaching law, without introducing additional system complexity. The stability of the proposed control scheme is theoretically analyzed and proven. Finally, comparative experiments conducted on a 0.5-ton industrial overhead crane demonstrate superior performance in swing suppression.