Abstract: The present invention is directed to a method and apparatus for controlling a process which may include long process delays, using an internal model-based control strategy wherein any external disturbances are effectively taken into account in a manner which results in a stable, predictable output. In accordance with exemplary embodiments, rather than using a mismatch signal .epsilon. as a feedback signal to address mismatches due to both modelling errors and to any external disturbance component, exemplary embodiments feedback an adaptive prediction of the mismatch signal. In accordance with exemplary embodiments, the adaptive, predicted mismatch signal possesses a value which takes into account the process time delay, or the process time delay plus some additional delay, to allow time for the control system to respond.

Abstract: The present invention is directed to a method and apparatus for filtering a signal of a control and/or signal processing system in a manner which achieves both rapid tracking of signal transients (e.g., step changes in the signal) and heavy filtering of noise during steady-state operation. In accordance with exemplary embodiments, nonlinear features are combined with a conventional exponential filter to achieve both of these objectives. Exemplary embodiments are easy to use in a control and/or signal process system, and perform in a highly accurate manner. For example, in accordance with exemplary embodiments, a filter is configured with a deadband component which constitutes the sole adjustable component of the filter.

Abstract: The present invention relates generally to the control of processes which include relatively long time delays, yet which are susceptible to transient external disturbances, such as high-speed sheetmaking processes. Exemplary embodiments include a control system architecture that combines internal model-based control with state feedback in a manner which provides robust control, yet provides rapid rejection of external transient disturbances even in processes including relatively long time delays.