Difference between revisions 986087 and 1501889 on enwiki

'''First Order Control''' is when a desired result is attempted by adjusting a scalar (first order) control.  Such mechanisms, where first order change sucessfully produces desired results, are called first order mechanisms.  First order control is contrasted to [[Higher Order Control]].

While many simple mechanisms are completely first order, most complex mechanisms are only first order within a range of operation.

And example of such a control mechanism is a trackball used to control a mouse cursor: a particular motion of the trackball causes a corresponding motion of the mouse cursor, until the cursor reaches the edge of the display. (The rigorous will note that a trackball is truly two scalar controls.)

'''Failure of First Order Control: Range''' [obviously] if a control mechanism is manipulated in a first order fashion outside the range where it exhibits first order behavior, the results may be unpredictable. The failure to recognize that a mechanism is not first order or is operating outside its first order range is one of the primary causes of those mishaps described as being due to operator error. An example of this is the behavior of a car on rain-slickened asphalt: it is not true that the(contracted; show full) is often intentionally provoked. Certain to benefit from fallacious control that involves violence are hawkish and fascist political parties, armament manufacturers, and security forces. Other forms of fallacious control exist and should not be discounted, as when increased taxes inspire increased tax evasion: this can lead to the impoverishment of honest tax-payers and success for the dishonest.

'''References'''

<i>Change</i> [[Paul Watzlawick]] [find urls]