An Improvement by Unstable Controller in Disturbance Suppression Performance of Two-inertia System with Low Stiffness and High Inertia Ratio

Abstract

In order to improve control performance given by stable controller for disturbance suppression problem of two-inertia system with low stiffness and high inertia ratio, this paper proposes a simple structure of controller which has a similar characteristic of unstable controller given by H_∞ control design. The proposed controller has two tunable parameters, and a tuning procedure to minimize the closed-loop gain with desired stable margins is given, by which the proposed controller can be easily adjusted when physical parameters are changed. The optimal closed-loop gain by conventional control method (proportional control) and an rate of improvement by proposed method are theoretically given in terms of physical parameters of plant. The validity of the proposed method is shown by experimental results.