Minimum Variance Control and Performance Assessment of Time-Variant Processes

Abstract This paper is concerned with 1) an explicit solution of the minimum variance control law for linear time variant (LTV) processes in the transfer function form, and 2) performance assessment of LTV processes using minimum variance control as the benchmark. It is shown that there exists a time-variant, absolute lower bound of process variance that is achievable under LTV minimum variance control and can be estimated from routine operating data. This lower bound can subsequently be used as incentive analysis of implementing LTV or adaptive control. The proposed methods are illustrated through simulated examples and a case study on industrial process data.