360 degree continuous Servo motor Driver

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360 degree continuous Servo motor Driver

Postby weihong » Mon Aug 10, 2009 10:41 pm

I'm recently doing my final year project! Need to control 2 servo to move according to certain degree! And now facing a huge problem!

1. Cant find a servo motor that can turn 360 degree or 360 degree continuously in cytron! ( but can get 1 in parallex)-Continuous Rotation Servo (#900-00008)

2. Cant find a servo motor driver that control 360 degree servo motor!

3. Stepper motor is my 2nd choise but......i cant find a stepper motor driver that can control 2 stepper motor...only can control 1! Meaning to say if i got 2 stepper motor...i need 2 driver...it's kinda waste for me.....

So....any1 can tell me what is my solution or any guide to the right direction??
Thanks a lot! And you help is very much appreciated!
weihong
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Re: 360 degree continuous Servo motor Driver

Postby sich » Wed Aug 12, 2009 9:52 pm

weihong WROTE:I'm recently doing my final year project! Need to control 2 servo to move according to certain degree! And now facing a huge problem!

If you need to move according to certain degree, you cant use a modified RC servo which can rotate 360 degree. You'll need a standard RC servo. Please explain further about your project so that forumers here are clear on what you want to do and give more constructive advice.

weihong WROTE:1. Cant find a servo motor that can turn 360 degree or 360 degree continuously in cytron! ( but can get 1 in parallex)-Continuous Rotation Servo (#900-00008)

Cytron's 360 degree RC servo: http://www.cytron.com.my/viewProduct.php?pid=AxcTKS8LHDU9KjsyNCQmDAsHj6a2W18oVENVYqrweW8=&store=
This product is different from Parallax's continuous rotation servo. For parallax, you still need to generate precise pulses to control the rotation speed and direction. With Cytron's C36S (360 Degree), you can control it using normal H-bridge circuit or MD10B DC motor driver because there's no more servo circuit inside this C36S (360 Degree). So it depends on which method you want to use to control your "modified RC servo".

weihong WROTE:2. Cant find a servo motor driver that control 360 degree servo motor!

C36S (360 Degree): Construct simple H-bridge circuit (or use MD10B) and generate PWM to control the speed.
Parallax continuous rotation servo: Generate precise pulses to drive the servo or you may use any servo motor driver like Cytron's SC16A (16 Channels Servo Controller). But this type of driver usually support up to 8 or 16 channels. It's more than you need if you only need to control 2 motors.

weihong WROTE:3. Stepper motor is my 2nd choise but......i cant find a stepper motor driver that can control 2 stepper motor...only can control 1! Meaning to say if i got 2 stepper motor...i need 2 driver...it's kinda waste for me.....

Stepper motor is too difficult to control by using one controller. The algorithm is very complex and the stepping timing is very important. That's why usually one driver only support one stepper motor. The norm is we need to use 2 drivers to control 2 stepper motors. Cytron's stepper motor driver is SD02B. It can be control using both I/O pins or UART communication. Anyway, each SD02B also drives one stepper motor only.
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Re: 360 degree continuous Servo motor Driver

Postby weihong » Wed Aug 12, 2009 10:27 pm

A standard RC servo cant move 360 degree! My project is about a storage system!
1servro is to control the level of storage and 1servo is to rotate the storage!
For the rotational part, i need the servo to rotate 60degree each time.and the most important is need to rotate up to 360 degree. I'm still wondering want to use a PIC16f877a to control both servos or use driver and control through computer!

For parallax servo...generate precise pulses can control the degree?
"With Cytron's C36S (360 Degree), you can control it using normal H-bridge circuit or MD10B DC motor driver" this h-bridge can control the degree of motor? Or juz speed and direction?Can you share me some sample h-bridge circuit?

"Parallax continuous rotation servo: Generate precise pulses to drive the servo or you may use any servo motor driver like Cytron's SC16A (16 Channels Servo Controller). But this type of driver usually support up to 8 or 16 channels. It's more than you need if you only need to control 2 motors."
SC16A only can generate pulse up to 180 degree right? Can it control the servo up to 360 degree? I mean 1 time turn 60 degree and turn 6 times to 360 degree? (6 pulses)
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Re: 360 degree continuous Servo motor Driver

Postby sich » Thu Aug 13, 2009 11:24 am

There are no modified RC servo that allows u to control the rotation degree. Not for Cytron's 360 degree RC servo or Parallax's continuous rotation servo. Both serve as normal DC motors, but with different controlling methods. You can control the speed and direction only.
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Re: 360 degree continuous Servo motor Driver

Postby ZaM » Tue Nov 23, 2010 6:26 pm

bleh kawal servo motor untuk 60 darjah..tp servo tu kene modified dulu..buang stopper n turunkan potentiometer..bagi pulse 1.5ms dulu untuk dapatkan center,then baru tutup smula casing..nk dapatkan 60 darjah just bagi pulse 1ms untuk beberapa loop then bg pulse 1.5ms untuk stop...try n error untuk dapatkan jumlah counter tu...
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Re: 360 degree continuous Servo motor Driver

Postby yonghui » Wed Nov 24, 2010 9:26 am

hi,

i saw someone modified servo for 360 degree, they use IR sensor as encoder to detect the position.

http://www.embeddedtronics.com/servo.html

i cant find back the link that people modify and add rotary encoder build by IR sensor d :(

they marking black and white on the gear, when the gear rotate, it will cause the small Ir sensor to generate pulses, the gear the not the last gear(slowest), but rather the faster one to generate more pulses to more accurate control.




regards,
yh
thanks&regards,
yh
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Re: 360 degree continuous Servo motor Driver

Postby yonghui » Wed Nov 24, 2010 9:37 am

++

why dont use this


http://cytron.com.my/listProductGroup.php?pid=Mg44FgQkARcPMx46DgEID5qYQZdX0KnFVlfbhDlugVk=

cytron's DC geared motor with encoder, u can perform the positioning with encoder.
and yet its simple to control too compare to stepper motor. just get a motor driver card and control it, and position it with the encoder pulses calculation.
i think ur project wont need too precise position control right? adding sensor for resetting the encoder counter if everytime the motor return to origin position will work fine.



regards,

yh
thanks&regards,
yh
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