Robust Motion Control of an Oscillatory-Base Manipulator in a Global Coordinate System

This paper presents a control design method for motion control in a global coordinate system of an oscillatory-base manipulator, which can be regarded as a model system of mechanical systems installed on vessels or oceanic structures. This paper proposes a control design method for such systems exploiting H_∞ control and proportional and derivative (PD) control. In order to evaluate the proposed method, tracking control simulations and experiments were conducted for both attitude control and position control with practical constraints such as sensor error and actuator saturation. Furthermore, the proposed controller was compared with a conventional proportional, integral, and derivative (PID) controller. The results demonstrate that the proposed controller is successfully effective and is superior to the PID controller. Moreover, robust control experiments and robust stability analyses using our proposed machinery show that the proposed controller has strong robustness against physical parametric perturbations. Our developed robust stability analysis machinery is based on the state-dependent coefficient form and applicable to a wider class of systems than the previous one.