SERVO-MECHANISM
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(2) |
| ID | ◀ 3027 ▶ |
| Object type | Discipline oriented |
A device that consists of a sensor, an amplifier and a motor and is used to maintain the steadiness of the mechanical device of which it is a part.
A servo-mechanism is in fact a 2$^{nd $ level feedback applied in specific ways in accordance with the permanent nature and function of the regulated system
The servo-mechanisms are needed to regulate the regulating (or control) subsystem's variables in order to adapt them to the changing environmental conditions.
J. MILSUM writes: “… the output is required to follow or ”track“ slavishly an often-varying desired, reference or command input” (1968, p.43).
Examples are “ … power steering of cars,… or neuro-muscular systems used for positioning of limbs, eyes, etc.” (Ibid, p.42).
The study of servo-machanisms is interesting in relation to the behavior of living systems. According to G. SOMMERHOFF: “…since many servo-mechanisms produce some type of goal-directed behavior it is not surprising that some of the general concepts of servo theory can illuminate parallel forms of goal-directed behavior in living systems — concepts like error control and feedback loops, for instance. But there are many limits to this. The goal of the activity of a servo-mechanism is set by an external command. This command provides the reference signal from which the error signals are derived to which the feedback mechanism responds with the necessary corrections” (1969, p.153). Moreover, as noticed also by SOMMERHOFF, in biological (and social?) systems, the commands are integrated in a hierarchy of oriented behaviors. And still: “…the concept of error signal is also beset with difficulties… in such goal-directed processes as embryonic growth, maturation, learning, evolution, etc… — or even in such simple cases as a rat taking the correct turning at a choice point of a maze” (Ibid.).