Vibration control of 3P(S)4 class parallel mechanisms for high speed applications using Quantitative Feedback Design

Parallel manipulators are in demand for high-speed industrial applications due to low inertia and high stiffness. However, vibration may still occur that limits the utilization of these manipulators for the operations at high speed. In this study, we cope with the residual vibration of the 3P(S)₄ parallel mechanism that occurs at the end of high-speed motion. First, by using Lagrangian formulation, inverse dynamics of the mechanism is analyzed to linearize the system. To achieve robust control against residual vibration at high speed, Quantitative Feedback Theory is applied that utilizes templates and offers design transparency. As the challenge in this study is vibration, this frequency-domain robust control design approach has a potential to solve it. Verification of the applied method is conducted through high-speed motion experiments with PID and QFT methods. Settling time with QFT is 72% smaller compare to PID control.