Disturbance Suppression Strategy for Six-DOF Magnetic Levitation Micro-Motion Stage Based on Adaptive Cascade Linear Extended State Observer

To effectively suppress the composite disturbances in a six-degree-of-freedom magnetic levitation micro-motion stage, this paper proposes a disturbance compensation strategy based on a bandwidth-adaptive cascade linear extended state observer. First, a static decoupling algorithm is employed to establish independently controllable state-space equations for each degree of freedom, and the components of the composite disturbances in each axis are analyzed. Subsequently, to achieve higher-order disturbance compensation, a cascade linear extended state observer is designed to estimate and compensate for the lumped disturbances in each degree of freedom. Moreover, to balance dynamic disturbance rejection with static noise sensitivity, a bandwidth-adaptive mechanism is introduced to dynamically adjust the observer bandwidth. Finally, both simulation and experimental results are provided to validate the superiority of the proposed approach.