Block Diagram Reduction: Steps to Find Closed Loop Transfer Function

AI Thread Summary
The discussion focuses on reducing a block diagram to find the closed loop transfer function. The initial steps include adding feed forward paths, cascading transfer functions, and reducing a minor feedback loop. Participants suggest that simplifying the summation junctions into two 2-input summations can make the problem easier to solve. There is a consensus that this approach simplifies the overall reduction process. The thread emphasizes the importance of correctly structuring the block diagram for accurate results.
cd19
Messages
50
Reaction score
0
1. Homework Statement
Block2.jpg

2. Homework Equations

I need to reduce the above block diagram to find the closed loop transfer function

This is my solution to the reduction part of the problem:

i) Add the feed forward paths; (10 + 10)

ii) cascade G(s)2 x G(s)3 , {G(s)2 = 1/1+12, G(s)3= 20/s}

iii) Reduce the minor feedback loop (0.2s) : using, G(s)/1+G(s)H(s) [G(s) being part ii]

iv) then finally cascade blocks in forward path


3. The Attempt at a Solution

This should be my open loop transfer function and from there I can get closed loop BUT I'm getting something wrong in my above reduction which I can't figure out. Anyone see where I'm going wrong?
 
Physics news on Phys.org
Can anyone help me out

this is the answer for the closed loop function
closed1.jpg
 
first convert the 3-input summation into two 2-input summation.
and after that i will become very easy to solve
 
This question was asked in May 2011.

Hopefully it was solved by now.

But yes I agree with trapti once you separate the middle summing junction into two it is very simple.
 
Back
Top