Control Algorithms for Cross Directional Control: The State of the Art

Abstract Successful control of cross directional variations in sheet properties, as with any control problem, requires consideration of suitable measurements and measurement processing, suitable actuators, and a suitable control algorithm. Also, as with any control problem, the choice of a suitable control algorithm depends upon the behavior of the process, in terms of its response to the selected actuators and the nature of the variations to be controlled. This paper discusses the requirements for suitable control algorithms. Although the discussion centers on applications to paper making, the general principles are applicable to other sheetmaking processes.