Non-linear filtering for distributed parameter systems having a small parameter
M.A. Soliman, W. Harmon Ray · International Journal of Control · 1979
A general non-linear filter is derived for dynamic systems described by partial differential equations containing a small parameter multiplying the time derivatives of some state variables. By allowing this small parameter to approach zero, it is possible to approximate the system filter equations by low-order slow and fast filters. As an example, a fixed-bed chemical reactor is used to demonstrate the application of the present theory.