Delay identification in time-delay systems using variable structure observers

Abstract

In this paper we discuss delay estimation in time-delay systems. In the Introduction a short overview is given of some existing estimation techniques as well as identifiability studies. In the following sections we propose several algorithms for the delay identification based on variable structure observers.

Decentralised delay-dependent static output feedback variable structure control

“…However, in some industrial systems such as flow through pipes and web forming processes, the delay existing in the process is known, and can thus be employed in the control design and/or the observer design [19]. Moreover, if the time delay is unavailable, the approach proposed in [2] can be employed to identify the time delay.…”

A gradient-based parameter identification method for time-delay chaotic systems

“…subject to constraints (14). We solved this problem using a Matlab program that integrates the SQP optimization method with the algorithm described in Section 3.2, where the initial guesses for ζ 1 , ζ 2 , and τ are obtained using the randomization method with N = 10.…”

“…On the other hand, although gradientbased optimization techniques have excellent local searching capabilities, they have yet to be fully exploited to solve the parameter identification problem for time-delay chaotic systems. In addition, the existing identification methods for nonlinear time-delay systems (see [12][13][14][15][16][17]) are not suitable for chaotic systems, as such systems typically contain nonlinear terms with more than one unknown delay/parameter.…”

Online time delay identification and control for general classes of nonlinear systems

“…Niculescu and Gu also presented a broad overview, that particularly focused on engineering applications and recent progresses of stability and control of time delay systems [2]. A significant amount of research was devoted to designing time delay identification algorithms [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14]. Most of the past research on time delay identification were usually presented for linear or linearized systems and review of the relevant past research highlights the fact that there are no time delay identification algorithms for general classes of nonlinear systems.…”