The paper describes recent progress in two-dimensional estimation and contr
ol methods for web forming processes such as paper making. In particular, i
t outlines some of the developments in two-dimensional methods that have ta
ken place in the Control Systems Centre since the Control '92 Conference [1
] and relates them to recent sensor research. The basic premise for this pa
per is that continuous web forming (such as takes place at the wet-end of a
paper machine) or related coating processes are two-dimensional dynamical
processes in which the machine direction (MD) and cross direction (CD) form
the two dimensions. The two-dimensional paradigm leads to a set of techniq
ues with which to estimate, predict and potentially regulate the MD/CD proc
ess in a way which acknowledges and accounts for the mutual dependence of t
he machine and cross machine directions.