The University of British Columbia

Control performance close to the sheet edges is often unsatisfactory because of the inadequate knowledge of edge response model. The design of paper machine cross directional control systems is normally based on actuator response models obtained in the centre rather than the machine edges. Various assumptions are made regarding edge responses but those are often made for mathematical convenience and do not reflect the true nature of the actuator behaviour. Therefore, the edge actuators of the CD control system are often left uncontrolled. This paper attempts to establish the nature of the slice lip edge response in comparison with that at the centre of the machine. A physical edge model that has been proposed on the basis of dispersive wave theory is investigated. Superposition and linearity issues in actuator response are also examined.