Closed-loop identification and instability of web transport system

This paper deals with the experimental identifications of a decentralized control system for a web processing and transfer, where the velocity and tension are controlled at each corresponding subsystem. To satisfy the identifiability of closed-loop identification, we employed the output over-sampling method. The overlapping decentralized decomposition is effective because the identification can be carried out for each subsystem, leading to the possibility of understanding the system physically. The identified model shows valid behavior with minor differences regarding the initial period of operation. We discuss the instability problem based on the identified transfer functions.