Robust dynamic stiffness design of linear servomotor drives

The pseudo derivative feedback with feedforward (PDFF) control scheme has three constant gains for tuning to achieve good trade-off design between command response and stiffness. For dynamic stiffness enhancement, this paper employs the H∞ loop shaping design concept to obtain a so called advanced PDFF controller which allows dynamic gains in the feedback loop and the pole/zero relationships between the proposed H∞ controller and the closed-loop system are investigated. A linear servomotor design example is given to show how to achieve the desired specifications based on the derived pole placement properties. Experimental and simulated results are given to demonstrate the effectiveness and feasibility of the proposed method.