STABILITY MARGIN
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(2) |
| ID | ◀ 3166 ▶ |
| Object type | General information, Methodology or model |
The values comprised between the uppermost and lowest fluctuations thresholds of some parameter critical for the survival of a system.
ROSENBROCK and Mc MORRAN, quoted by B. PORTER state, for instance: “… an essential requirement for most industrial control systems will be that changes of loop gains, between zero and the design values and in all combinations, should leave the system with an adequate stability margin” (1976, p.227).
As observed by these authors “… optimality does not insure this” (Ibid). (Optimality being understood, as it too frequently is the case, as maximality: productive optimality is not the same as systemic optimality).
Furthermore, a well managed system should ideally remain well within the limits of its stability margin, and avoid nearing to closely its thresholds of stability, in order to avoid too high regulation costs and sometimes very high risks.