Abstract
We present a motion control method for a hydraulic parallel-link servomechanism with three degrees of freedom on a plane. The system controls both the profile-tracing path in (x-y-θ) space and the acceleration waveform of the end effector. The method developed in this research is named the multipreview control method which is an extension of the conventional displacement preview control method. The multipreview controller uses a future value of the reference displacement signal and its first and second derivatives. To extend the conventional displacement preview control method to the multipreview method, a new error system was introduced in the derivation of the optimal control design. The experimental results show that the multipreview controller is effective for satisfying the requirements in the control of both the profile-tracing path and the acceleration waveform of the hydraulic parallel-link servomechanism.
