Fixed-Order H∞ Decentralized Control with Model Based Feedforward for Elastic Web Winding Systems

This paper presents centralized and decentralized fixed order H _infin controller designs with model based feedforward for web winding systems which provide improved web tension and velocity regulation. First, mathematical models of the fundamental elements in a web process line are presented. An improved state space model is then derived for the entire system; the model enables calculation of the phenomenological model feedforward signals and helps in the synthesis of H_infin controllers around the set points given by the reference signals. Different H_infin control strategies with additive feedforward have been synthesized, especially H_infin based PI controllers which are relevant for industrial applications. The strategies have been validated on a nonlinear simulator identified on a 3-motor winding test bench