A robust vibration suppression method enabling high-bandwidth for a three-inertia system

In transmission systems, torsional vibration induced by structural flexibilities in mechanical components poses a great challenge to achieving enhanced system performance. However, most results are developed for a simplified two-inertia system leading to the closed-loop bandwidth not being wide enough and limiting the control performance. This paper presents a novel vibration suppression method for a three-inertia (3-I) system, which enables the closed-loop bandwidth up to or exceeding the primary resonant frequency. Exploiting a dual-loop control structure, damping improvement and enhanced tracking performance can be realized by designing damping controller and H∞ tracking controller separately. Different with the existing results, the damping loop is synthesized via phase shaping using the vector locus of the open loop system. Sensitivity gain is reduced around the resonant modes enhancing the robustness against resonant frequency variations. The H∞ tracking controller of outer loop is then designed only by focusing on the system stability, closed-loop bandwidth and settling performance. The effectiveness of the proposed method has been verified by simulation results.