International Federation of Automatic Control
3rd IFAC SYMPOSIUM on SYSTEM, STRUCTURE and CONTROL

Foz do Iguassu, Brazil October 17th - 19th, 2007

Friday Afternoon

Session FA1: Constrained Control


Chair: João Manoel Gomes da Silva Jr. - Brazil
Co-chair: Tsuyoshi Kiyama - Japan
Room: Assunção
2007-10-19
From 13:30 to 15:30
Positive Observation Problem for Linear Time-lag Positive Systems
M. Ait Rami; U. Helmke; F. Tadeo
Contact: Mustapha Ait Rami - Spain
15:10-15:30
Abstract:
This paper deals with the problem of positive observation for linear positive time-lag systems for which the states take nonnegative values whenever the initial conditions are nonnegative. That is, the design of positive observers (possibly with time-lag) which guarantee nonnegative estimates of the current states of linear time-lag positive systems. The provided conditions for the existence of a positive observer (extended Luemberger-type) are necessary and sufficient and solvable in terms of Linear Programming (LP). Also, it is shown that it is no longer possible to stabilize any unstable time-lag positive system by using extended Luenberger-type positive observers. Copyright © 2007 IFAC.