Lateral control of a web using estimated velocity feedback

Abstract

The focus of this paper is on lateral control of a web using estimated motor velocity feedback. A reduced state velocity observer is designed to estimate the motor velocity based on the measured lateral position of the web and the motor input. Estimated velocity is used for inner-loop motor velocity feedback instead of measured velocity from a tachometer. Two approaches are investigated in the design of the reduced state velocity observer; the first is based on the motor dynamics and the web lateral dynamics and the second is based on the motor dynamics and the static gain of the web lateral dynamics. The second approach results in a simple low-order velocity observer when compared to the first approach.

The proposed designs are experimentally investigated on a Fife remotely pivoted steering guide. The performance of the lateral control system with estimated motor velocity feedback is compared with the tachometer feedback and results are discussed. Representative experimental data from the two approaches indicated above is presented. Experimental results on the example considered shows that the observer can successfully replace the tachometer to close the inner velocity loop in lateral control systems.