Observer-based tension feedback control with friction and inertia compensation

Low cost and high productivity are two primary goals in design of a web transport system. One approach to achieve low cost is through the implementation of observer techniques in place of tension transducers. To achieve high productivity, it is normally required to increase the process speed. However, as the process speed or variation of the speed is high, system friction and inertia of rotation of rolls could cause problems in implementation of observer techniques for tension estimation and control. Few of the previous studies have considered the problems of friction and inertia in a single article. This paper proposes an observer with friction and inertia compensation. The proposed observer has a feedback configuration and it is able to estimate web tension precisely regardless of the effects of friction and inertia. Linearization and decentralization techniques are implemented. Design of the proposed observer-based tension feedback controller is performed in the frequency domain. Eccentricity of unwind roll is considered as sinusoidal disturbances to the system. A procedure for design of the proposed controller and eccentricity of rolls are discussed. Simulation and experimental works have been performed and they show that the proposed observer-based tension feedback controller performs as well as a classical tension feedback controller using a tension transducer.