Robust H∞ fixed order control strategies for large scale web winding systems

Demand for improved performance under a wide variety of dynamic conditions and web materials is placing additional emphasis on developing new advanced control strategies. This paper presents centralized and decentralized fixed order H∞ controller results with model based feedforward for web winding systems which provide improved web tension and velocity regulation. First, mathematical models of fundamental elements in a web process line are presented. A state space model is developed which enables calculation of the phenomenological model feedforward signals and helps in the synthesis of H∞ controllers around the set points given by the reference signals. Different H∞ control strategies with additive feedforward have been validated on a nonlinear simulator identified on a 3-motor winding test bench.