en>Goudron: /* Storage principles */ Wikified, typo checked, edited out redundant redundancies out.

2014-02-01T22:20:09Z

Storage principles: Wikified, typo checked, edited out redundant redundancies out.

New page

{{Merge to|Servo control|date=October 2011}}
'''Servo bandwidth''' can be defined as the maximum trackable [[sinusoidal]] [[frequency]] of [[amplitude]] A, with tracking achieved at or before 10% of A amplitude is reached. The servo [[bandwidth (signal processing)|bandwidth]] indicates the capability of the [[Servomechanism|servo]] to follow rapid changes in the commanded input.<ref>{{cite book | title = Industrial Servo Control Systems: Fundamentals and Applications | author = YOUNKIN | page = 42 | year = 2002 | publisher = CRC Press | isbn = 978-0-8247-4352-9 }}</ref> It is usually specified as a frequency in [[Hertz]] or radian/sec.<ref>{{cite book | title = Power electronics handbook: devices, circuits, and applications | author = M. H. Rashid | page = 902 | publisher = [[Academic Press]] | year = 2006 | isbn = 978-0-12-088479-7 }}</ref>

== Explanation ==
{{Section OR|date=October 2011}}
Bandwidth of systems is generally defined to be the frequency at which the system's amplitude is <math>\tfrac{1}{\sqrt{2}}</math> times the signal amplitude. But if we apply same logic to servo systems it is difficult to analyze and develop a system to a sufficiently accurate specification. This is because of [[ambiguity]] with regard to frequency at which the amplitude should go to <math>\tfrac{1}{\sqrt{2}}</math>.

A simple and sound definition can be sought regarding this.
Let us say we want to design a position servo control system with following specifications:
* Bandwidth: 10 Hz
* Allowed amplitude range : ± 50°

The above definition is not enough to design a practical control system. The definitions above have inherent problems with regard to what amplitude the [[manufacturer]] should take to design the servo with 10 Hz bandwidth.
If the manufacturer takes the amplitude to be ±20° and rise time for this amplitude to be 0.025 sec (10 Hz sinusoid)
and some other manufacturer takes amplitude to be ±50°, the acceleration requirements calculated by two will be very different.

This leads us to understand that giving servo bandwidth alone with no amplitude specification is almost useless. Also defining the bandwidth as per normal bandwidth definition does not help (ambiguity with regard to frequency at which the amplitude should go to <math>\tfrac{1}{\sqrt{2}}</math>).

== References ==
{{reflist}}

[[Category:Wave mechanics]]
[[Category:Control theory]]

Supercapacitor - Revision history

en>Goudron: /* Storage principles */ Wikified, typo checked, edited out redundant redundancies out.