Robust position control of Delta Parallel mechanisms using dynamic model and QFT

This paper presents a solution to the residual vibration of 3-DOF Delta parallel robots. As the parallel mechanism is highly nonlinear, inverse dynamics analysis in explicit form by using Lagrangian formulation is proposed to linearize the system. To apply the Lagrangian method to the parallel mechanism, the structure is divided to sub-chains by imaginary open tree method. After deriving inverse dynamics in analytical form, system is linearized. To control the linearized system, Quantitative Feedback Theory is applied and vibration suppression during the high-speed motion is achieved. Usefulness of the linearization and QFT method to control the high-speed parallel mechanism is shown through experiments.