State feedback control with full or partial integral action for large scale winding systems

In web transport systems, the main concern is to control independently speed and tension in spite of perturbations such as radius variations and set point changes. In this paper we present multivariable H/sub 2/ controllers applied to winding systems. Two controller structures are considered: a centralized for a three-motor winding system and a semi-decentralized controller without overlapping for a large scale system, materialized here by a nine-motor winding benchmark. These controllers, based on state feedback, are designed with bilinear matrix inequality (BMI) optimization. In order to cancel steady state errors in response to constant reference signals or constant disturbances two solutions are considered: the use of a static gain compensation matrix and of full or partial integral action. Simulation results are given for both of these systems, based on models identified on an experimental bench.