Find the range of K for stability

  • Thread starter Thread starter jdoe10
  • Start date Start date
  • Tags Tags
    Range Stability
Click For Summary

Discussion Overview

The discussion revolves around determining the range of K for stability in a closed-loop control system. Participants are examining the mathematical formulation of the system and the implications of feedback on stability.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents a closed-loop transfer function and suggests that K must be greater than 1/2 for stability.
  • Another participant challenges the formulation of the closed-loop transfer function, asserting that the correct expression involves the loop gain and negative feedback factor.
  • A third participant speculates on the roles of K and GOL, suggesting K is an adjustable amplifier block and GOL represents the open-loop gain of the plant.
  • Subsequent posts request additional information, such as a block diagram, to clarify the context of the problem.

Areas of Agreement / Disagreement

Participants do not appear to agree on the correct formulation of the closed-loop transfer function, indicating a lack of consensus on the approach to determine the stability range for K.

Contextual Notes

There are unresolved assumptions regarding the definitions of GOL and K, as well as the mathematical steps involved in deriving the closed-loop transfer function.

jdoe10
Messages
3
Reaction score
0

Homework Statement


Find the range of K for the closed loop system to be stable.
##G_{OL}(s) = \frac{10}{s-5}##

Homework Equations

The Attempt at a Solution


##G_{CL}(s) = \frac{KGol}{1+Gol}##
##G_{CL}(s) = \frac{10K}{s-5+10K}##
##-5+10K>0##
##K>\frac{1}{2}##
is this correct?
 
Physics news on Phys.org
No - the quation for Gcl is not correct (assuming Gol is the open-loop gain and K is the negative feedback factor).
We have Gcl=Gol/(1-LG)
with Loop Gain LG= - Gol*K.
 
In this context I am guessing that K is the amplifier block before the open loop gain that can be adjusted, also known as the DC gain of the controller. I am guessing Gol is really the open loop gain of the plant.
 
Jdoe10, can you provide us with a block diagram or more information?
 
jdoe10 - please, please, be so kind and give us the chance (necessary information) to answer your question.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
26
Views
4K
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 7 ·
Replies
7
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K