For linear, square, multi-input-multi-output, minimum-phase, relative-degree one or two systems, proportional output feedback controllers are studied. In particular, we show that derivative feedback can be replaced by delay feedback, essentially an Euler approximation of the derivative, if the delay is sufficiently small. Stability regions are determined and related. (C) 2004 Elsevier B.V. All rights reserved.
- relative degree two
- output feedback stabilisation
- minimum phase systems