- 25th December 2007, 18:24 #1

- Join Date
- Jul 2007
- Location
- India
- Posts
- 34
- Helped
- 0 / 0
- Points
- 1,151
- Level
- 7

## transfer function of dc motor

hi

i am in need of finding the transfer function of a 12v dc motor with maximum of 500 rpm.

can any one suggest how can i do it.?

i am intending to set up a closed loop control to control the speed of the motor using PWM via PID controller.

i am in need of it to find the transfer function to find the PID values

some one help me ...!

- 25th December 2007, 18:24

- 25th December 2007, 19:48 #2

- Join Date
- Aug 2007
- Posts
- 73
- Helped
- 5 / 5
- Points
- 1,692
- Level
- 9

## transfer function dc motor

hi,

Go to this link: http://www.engin.umich.edu/group/ctm...tor/motor.html

It has what you need. Also u can find to this link some examples in matlab in order

to calculate your PID controller.

Good Luck!

B.

2 members found this post helpful.

- 25th December 2007, 19:48

- 27th December 2007, 03:40 #3

- Join Date
- Jul 2007
- Location
- India
- Posts
- 34
- Helped
- 0 / 0
- Points
- 1,151
- Level
- 7

## small dc motor transfer function

happy that i got this link.

from the link i guess the whole thing is for a bigger size motor.I want to know the procedure to do the same for a small size 12V dc motor.The experimental procedure involved is wat i am looking for.

- 27th December 2007, 03:40

- 29th February 2008, 19:21 #4

- Join Date
- Jan 2008
- Posts
- 7
- Helped
- 1 / 1
- Points
- 903
- Level
- 6

## transferfunction of dc generator

it is dead simple,,All what you want to do is to supply frequency ( square wave pulse which represent step input) to the motor using frequency generator, then you can use osciloscope to plot the out put of the motor.

by uisn simple freauency response methods you can find out the transfer function of the motor.

let me know if u need more information about that

regards

- 23rd March 2008, 18:33 #5

- Join Date
- Jan 2008
- Posts
- 7
- Helped
- 1 / 1
- Points
- 903
- Level
- 6

## dc motor transfer function experimental

hi,

use frequeny genrator to supply squrare waves to the motor , after that use oscilliscope to plot the response of the output.

it can be clearly seen if the the motor is first,second or higher order.

if it is a first order system. used the 0.36V point to find out time constant T, and divde the output of the system by the input to work out the DC GAIN. K.

dont forget thtat the standard form of the first order system transfer function is

DC GAING(K)/1+Time contstant(T)

if the system is not first order system , then let you need to used another method to work out the damping ration,angular frequency.and the gain.

u need to do some reasearch about that. let me knwo if u r stuck with it though.

hope that helps

Kind regards

Mohamed

1 members found this post helpful.