Adaptive fuzzy robust H∞ control for motion and vibration suppression of fully flexible-link space robots

This study addresses a fully flexible-link space robot with uncertain parameters, focusing on dynamic modeling, trajectory tracking and vibration suppression. The system’s dynamic model was derived by employing the linear momentum, Lagrange’s equations, and the assumed mode method. An adaptive fuzzy H∞ robust control scheme was then designed to achieve precise tracking of the desired position. Subsequently, a hybrid trajectory was introduced, combining joint stiffness motion and flexible link vibration through the concept of virtual control and expected trajectory. The trajectory was specifically formulated to address both the motion and vibration characteristics of the space robot. An adaptive fuzzy H∞ robust control scheme was applied to track this hybrid trajectory, ensuring both accurate position tracking and effective vibration suppression. Numerical simulations confirmed the efficacy of the proposed control strategy, demonstrating its ability to simultaneously track the position of a two-flexible-link space robot while suppressing vibrations in the flexible links, thereby achieving integrated control of motion and vibration.