Identification of nonlinear state-space time-delay system. Issue 1 (19th June 2019)

• Record Type: Journal Article
• Authors: Liu, Xin; Zhang, Hang; Zhu, Pengbo; Yang, Xianqiang; Du, Zhiwei
• Is Part Of: Assembly automation. Volume 40:Issue 1(2020)
• Page Start: 22
• Page End: 30
• Publication Date: 2019-06-19
• Subjects: Particle filter -- Expectation maximization algorithm -- Latent variables -- Nonlinear system identification -- State-space time-delay model; Automation -- Periodicals; Automatic machinery -- Periodicals; Assembly-line methods -- Periodicals; Industrial engineering -- Periodicals; 670.42705
• DOI: 10.1108/AA-08-2018-115
• Languages: English
• ISSNs: 0144-5154

Abstract

Abstract : Purpose: This paper aims to investigate an identification strategy for the nonlinear state-space model (SSM) in the presence of an unknown output time-delay. The equations to estimate the unknown model parameters and output time-delay are derived simultaneously in the proposed strategy. Design/methodology/approach: The unknown integer-valued time-delay is processed as a latent variable which is uniformly distributed in a priori known range. The estimations of the unknown time-delay and model parameters are both realized using the Expectation-Maximization (EM) algorithm, which has a good performance in dealing with latent variable issues. Moreover, the particle filter (PF) with an unknown time-delay is introduced to calculated the Q-function of the EM algorithm. Findings: Although amounts of effective approaches for nonlinear SSM identification have been developed in the literature, the problem of time-delay is not considered in most of them. The time-delay is commonly existed in industrial scenario and it could cause extra difficulties for industrial process modeling. The problem of unknown output time-delay is considered in this paper, and the validity of the proposed approach is demonstrated through the numerical example and a two-link manipulator system. Originality/value: The novel approach to identify the nonlinear SSM in the presence of an unknown output time-delay with EM algorithm is put forward in this work.