Robust Control Based on Disturbance Observer and Polynomial Coefficient Approach for Mechanical System

Abstract

This paper proposes a new robust speed control system based on disturbance observer and coprime factorization for mechanical systems. The proposed system takes account of large variation of inertia ratio. It has the two loop systems. The inner loop system is the state feedback and the state observer system, which is designed by coprime factorization. In this paper, the poles and parameter variation effect of inner loop system are newly determined by using the polynomial coefficient approach. The outer loop system based on disturbance observer satisfies the robust stability condition on parameter variation. The reference response easily defines the desired transfer function from the speed reference to the load speed. The numerical simulation results show that the proposed system well regulates the load speed and suppresses the torsional vibration phenomena.