An estimation approach for process control based on asymmetric oscillations

Abstract

[Abstract] An estimation procedure for process control has been developed based on the information obtained from the oscillations that a non-linear element as a simple relay introduces in the feedback loop. Features of the method are: (1) the procedure does not demand a priori process information, (b) non-iterative algorithms are needed to derive the process parameters, (c) only one test is needed, and (d) it allows identifying the process at a user-specified phase lag in the third quadrant. The method is presented for estimation of most common transfer functions found in chemical and process industry: integrators, first-, second- as well as processes with non-minimum-phase dynamics.