DC motor Speed Synchronization issue

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DC motor Speed Synchronization issue

Postby sysysy » Thu Dec 09, 2010 7:43 pm

I used 2 dc motor in control my robot car.

both motor are same type and supply voltage also same.
But there still not able to run in same speed, hence make the robot not able move in straight line.

Since, before that i not realize is it a better way to use the dc motor with encoder, so it cause me trouble now. :cry: :cry: :cry:

May i know any other method to solve this problem? or i can make the encoder and interface with my motor? (my motor do not have back shaft!!!)...dunno how to connect the optical disc encoder also...

hope anyone can give me advice. thanks...


Regards,

sysysy
sysysy
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Re: DC motor Speed Synchronization issue

Postby yonghui » Thu Dec 09, 2010 8:29 pm

hi,

if ur wheels have pattern that can be recognize by the IR ray, then u may use IR sensor to give required pulses.



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yh
thanks&regards,
yh
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Re: DC motor Speed Synchronization issue

Postby sysysy » Thu Dec 09, 2010 11:18 pm

Thanks for the reply...

i think for now, this is the only way...

In between, i read some article in internet,
the encoder should put at the back shaft there, because wanna sense the rpm before it go through the gear?

is it? if so, why?

haha, juz for curious purpose... :-)

Thanks a lot.

Regards,

sysysy
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Re: DC motor Speed Synchronization issue

Postby yonghui » Fri Dec 10, 2010 1:25 pm

hi,

if u put encoder before gear, u will get higher accuracy because u are goin to get more pulses per turning of the wheel.


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yh
thanks&regards,
yh
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Re: DC motor Speed Synchronization issue

Postby sysysy » Fri Dec 10, 2010 8:26 pm

Hi,

Once again thanks for the reply.

Following question, juz for learning purpose.

if u put encoder before gear, u will get higher accuracy because u are goin to get more pulses per turning of the wheel.


That mean the encoder only can connected to the back shaft if before gear.
So, my question, there is no other method to modify the motor?

Is there any extend back shaft dc motor sell in market?\

Thanks.

regards,

sysysy
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Re: DC motor Speed Synchronization issue

Postby yonghui » Fri Dec 10, 2010 8:34 pm

hi,

i think no one will go extend the shaft of motor just for encoder.
there are motors come together with encoder:

http://cytron.com.my/listProductGroup.php?pid=GzMRPB42LyoFDSAuCwosEzqEaOaQs62nMVrg8FPyNo8=

and i think there are method of estimating the speed using the back EMF of the motor.
viewtopic.php?f=24&t=10587&p=12953&hilit=EMF#p12953

or adjusting manually the PWM pulses to get roughly straight line, repeatly modify-test.

u have any picture of ur wheels and motor?

regards,
yh
thanks&regards,
yh
yonghui
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Re: DC motor Speed Synchronization issue

Postby sysysy » Fri Dec 10, 2010 9:37 pm

Thanks a lot for your information.

Really appreciate this...it help me alot.

U r kind man.

Regards,

sysysy
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