A robust servosystem for a plant with variable operating conditions

This paper considers design of a robust servosystem for a plant whose dynamics changes according to its operating conditions. The plant is described by a linear interpolation of proper stable coprime factorizations of transfer functions of two representative models. Stabilization problems for such interpolated models have been extensively considered using fixed controllers, or applying interpolated controllers which are linear interpolations of coprime factorizations of two stabilizing controllers for the representative models. In this paper, we extend the results obtained by interpolated controllers to the design of a robust servosystem. We propose a two-degree-of-freedom controller which consists of interpolated feedback and feedforward compensators