New decentralized control in processing machines with continuous moving webs

Abstract

Web-products are manufactured in sections of rollers which transport the web according to specific technological demands. To achieve the required final product, the transport of the web has to be successful without material defects and losses. To fulfil these demands, the tension in the web during transport must be kept on a desired value within close limits. Therefore, electrical and mechanical quantities of the drives have to be controlled by closed loop control systems.

The rollers in such processing machines are coupled by the web and are driven usually by electrical motors. So the processing machines are multi-motor drives and from the view of control a multi input - multi output system.

To improve the dynamic behaviour of the controlled system, new concepts with decoupling state space control are considered in this paper. The goal of the control are non-interacting, decentralized control-loops. Two decentralized control methods were developed and are described.

The first method is called DECENTRALIZED DECOUPLING. The state space controller of low order for each subsystem makes the controlled subsystems approximately unobservable and uncontrollable from the neighbouring subsystems. The second method is FUZZY-CONTROL which is in examination just now.

The new control methods are applicable for both, DC- and AC-drives. The identification of the process variables and the calculation of the control algorithm is performed by a microcomputer system.