Skip to main content

Event-triggered control of nonlinear singularly perturbed systems based only on the slow dynamics

Research Authors
M. Abdelrahim, R. Postoyan and J. Daafouz
Research Year
2015
Research Journal
Automatica
Research Publisher
NULL
Research Vol
Vol 52
Research Rank
1
Research_Pages
PP. 15-22
Research Website
NULL
Research Abstract

Controllers are often designed based on a reduced or simplified model of the plant dynamics. In this
context, we investigate whether it is possible to synthesize a stabilizing event-triggered feedback law
for networked control systems (NCS) which have two time-scales, based only on an approximate model
of the slow dynamics. We follow an emulation-like approach as we assume that we know how to solve
the problem in the absence of sampling and then we study how to design the event-triggering rule under
communication constraints. The NCS is modeled as a hybrid singularly perturbed system which exhibits
the feature to generate jumps for both the fast variable and the error variable induced by the sampling. The first conclusion is that a triggering law which guarantees the stability and the existence of a uniform
minimum amount of time between two transmissions for the slow model may not ensure the existence of such a time for the overall system, which makes the controller not implementable in practice. The objective of this contribution is twofold. We first show that existing event-triggering conditions can be adapted to singularly perturbed systems and semiglobal practical stability can be ensured in this case. Second, we propose another technique that combines event-triggered and time-triggered results in the sense that transmissions are only allowed after a predefined amount of time has elapsed since the last transmission. This technique has the advantage, under an additional assumption, to ensure a global asymptotic stability property and to allow the user to directly tune the minimum inter-transmission
interval. We believe that this technique is of its own interest independently of the two-time scale nature
of the addressed problem. The results are shown to be applicable to a class of globally Lipschitz systems.