Parallel dynamics computation and H∞ acceleration control of parallel manipulators for acceleration display

We propose a control scheme of parallel manipulators focusing on the accuracy of acceleration on the endplate, which is an important factor when parallel manipulators are used as acceleration displays. We use two controllers-a dynamic controller to achieve accuracy of position and to stabilize the system, and an H_∞ controller to feedback the acceleration measured on the endplate. The main problem of dynamic control is computational complexity. In order to reduce computation time for inverse dynamics, a parallel processing method called multi-thread programming is applied. The H_∞ controller is added outside the closed loop of the dynamic control to remove the vibration of the structure and the influence of modeling errors in the dynamic controller