Robust decentralized overlapping control of 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 changes of setting point. Industrial systems typically use decentralized PID controllers but these techniques do not achieve good decoupling. Multivariable centralized controllers have been shown to provide better results but they are not suitable for large systems due to their high orders. We present a multivariable decentralized control strategy applied to a large scale winding system. After introducing the overlapping decomposition method, the decomposition step is discussed for our special case. Simulation results using H_∞ controllers show that disturbance rejection and coupling between web tension and velocity are significantly improved.