Speed estimation and control in a belt-driven system for a web production process. Part 2: Control strategy

This paper addresses the problem of estimating and controlling the speed of a belt-driven casting drum in a web production process, where direct measurement of drum speed is infeasible. Techniques for estimating web tension and casting drum speed, using measured values of brake and drive torque demand and speed, are described and verified by application to a laboratory casting drum facility. The estimates of web tension and casting drum speed are incorporated in a new speed control strategy, which counteracts the effects of creep and slip between the drive belt and pulleys. Experimental results demonstrate much improved steady-state speed holding and transient speed response of the casting drum, in comparison with the performance of the original controller: the steady-state speed error with nominal (50 per cent) web tension is reduced from 0.8 to 0.1 per cent, while the peak transient speed error for a 25 per cent change in web tension reduces from 4 to 0.5 per cent.