Closed Loop Relay Estimation of Uncertainty Bounds for Robust Control Models

Abstract

This paper describes an ad-hoc technique for the closed loop experimental estimation of perturbation bounds for robust control models. The approach is based on the closed loop relay identification method proposed by Åström and Hägglund. A series of lead compensators is designed such that the closed loop system limit cycles at progressively higher frequencies. Beyond a certain frequency, consistentlimitcycling no longer occurs. The heuristic is that at this frequency uncertainty (or perturbations) should dominate the model. The idea is illustrated by application to a process control experiment.