Identification of non-minimum phase processes with time delay in the presence of measurement noise

Bajarangbali; Somanath Majhi

doi:10.1016/j.isatra.2015.03.015

Identification of non-minimum phase processes with time delay in the presence of measurement noise

ISA Trans. 2015 Jul:57:245-53. doi: 10.1016/j.isatra.2015.03.015. Epub 2015 Apr 15.

Authors

Bajarangbali¹, Somanath Majhi²

Affiliations

¹ Department of Electronics and Electrical Engineering, Indian Institute of Technology Guwahati, 781039, India. Electronic address: bajarangbali@iitg.ac.in.
² Department of Electronics and Electrical Engineering, Indian Institute of Technology Guwahati, 781039, India. Electronic address: smajhi@iitg.ac.in.

PMID: 25890691
DOI: 10.1016/j.isatra.2015.03.015

Abstract

Time domain based generalized analytical expressions are derived to estimate the exact model parameters of a class of stable non-minimum phase (NMP) processes with time delay. The novelty of the proposed method lies in generalizing a second order plus time delay (SOPDT) NMP process model in terms of a class of models like first order plus time delay (FOPDT), SOPDT underdamped, critically damped and integrating processes. The mathematical expressions are employed to estimate four accurate parameters at a time. Relay with hysteresis reduces the effect of noise and further mitigation of noise is achieved through a denoising block yielding a clean process output. Processes modeled in the form of transfer functions are considered to validate the technique.

Keywords: Limit cycle; Measurement noise; Non-minimum phase; Relay with hysteresis; Time domain.