REGULATOR
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(2) |
| ID | ◀ 2809 ▶ |
| Object type | General information, Methodology or model |
Any device whose use is “to keep the output variables of the system constant in spite of disturbances, which are represented by the input variables” (G. KLIR, 1991, p.155).
Any input can indeed be viewed as a disturbance, even if necessary for the system: ingested food, for example, must be appropriately metabolized under control of physiological regulators.
Regulators are generally error-controlled. In the words of ASHBY: “In this case the regulator's channel for information about the disturbance has to pass through a variable (the ”error“) which is kept as constant as possible (at zero) by the regulator R itself. Because of this route for the information, the more successful the regulator, the less will be the range of the error… To go to the extreme: if the regulator is totally sucessful, the error will be zero unvaryingly, and the regulator will be cut off totally from the information (about D's value) that alone can make it successful — which is absurd. The error-controlled regulator is thus functionally incapable of being 100 percent efficient” (1958, p.93)
(D is for disturbance) (See hereafter: “Regulator Paradox”)
However, as stated by R.C. CONANT and W.R. ASHBY: “Error-controlled regulation is in fact a primitive and demonstrably inferior method of regulation… The regulations used by the higher organisms evolve progressively to types more effective in using information about the causes (at D) as the source and determiner of their regulatory actions” (1981, p. 190)
This is related to anticipatory behavior, early warnings (as disturbances are announced if and when their forerunning causes are perceived or registered), and feedforward.