An improved algorithm for estimating paper machine moisture profiles using scanned data

An improved estimation algorithm for use in processing data generated online by a scanning sensor is described. The algorithm is to be used as part of a paper machine control system to maintain the moisture content of the sheet at a target value. The algorithm rapidly estimates, in the presence of noise, cross and machine direction moisture profiles. The basic algorithm consists of a modified least-squares parameter identifier for estimating cross direction profile deviations and a Kalman filter for estimating machine direction disturbances. Simulation results showing the effectiveness of the algorithm in estimating known profiles are given. Results of the offline application of the algorithm to industrial data are also given. Online tests have been performed to demonstrate the improvements in accuracy and speed of detection of process upsets