Which type of servo motor are you talking about ? A "hobby" servo or a quadrature feedback DC motor ?
A Hobby servo without modification rototes only through 180 or 270 degrees. However it does have feedback (in other words if you try to force the motor away from it's position it will resist and when you leave go, the motor will go to the position is belongs).
A stepper motor has a certain number of position per revolution, however it doesn't have feedback, so if the motor is held it will lose it's position.
A quadrature DC servo motor, is basically a DC motor with an quadrature pulse wheel attached to the rotor. These usually require a dedicated controller. They can move very fast and have incredible accuracy.
What parameters are you interested in ?
Bean.
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Stepper motors will usually out last servo motors over the long run of·use.· Stepper motors are quiet compared to most servos.· Servos on the other hand are lighter and they take less wiring to connect to compared to stepper motors.
Thanks Bean for the explanation. I'm somewhat interested in using a motor for robotics purposes. It doesn't have to be extremely powerful. Since I'm using it for experimentation I would prefer something that is cheap aswell. And of course it needs to be controllable by the BS2.
A servo modified for continuous rotation is a very good inexpensive choice for a drive train. Since the servo has built-in gear reduction, the wheels can be mounted directly to the servo shaft. Like the Boe-Bot.
Bean.
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Check out· the "SX-Video Display Module"
If it's just for experimentation, take a look at an old 3.5" or 5.25" drive...
There are two stepper motors there, one small one with a worm-drive and a flat one. both comes with drive IC's, too... (you will need to search out the datasheets on the web yourself)
Other good places to look are old scanners and inkjet printers. These also contains a lot of nice mechanical parts.
(Cogs, drive belts, switches and other goodies
Drud0616
Posts: 26
Comments
A Hobby servo without modification rototes only through 180 or 270 degrees. However it does have feedback (in other words if you try to force the motor away from it's position it will resist and when you leave go, the motor will go to the position is belongs).
A stepper motor has a certain number of position per revolution, however it doesn't have feedback, so if the motor is held it will lose it's position.
A quadrature DC servo motor, is basically a DC motor with an quadrature pulse wheel attached to the rotor. These usually require a dedicated controller. They can move very fast and have incredible accuracy.
What parameters are you interested in ?
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Check out· the "SX-Video Display Module"
www.sxvm.com
"A problem well defined, is a problem·half solved."
·
Dave
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Dave Andreae
Tech Support
dandreae@parallax.com
www.parallax.com
·
Dave
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Dave Andreae
Tech Support
dandreae@parallax.com
www.parallax.com
Post Edited (Dave Andreae (Parallax)) : 3/20/2005 9:39:41 PM GMT
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Check out· the "SX-Video Display Module"
www.sxvm.com
"A problem well defined, is a problem·half solved."
·
Dave
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Dave Andreae
Tech Support
dandreae@parallax.com
www.parallax.com
·
There are two stepper motors there, one small one with a worm-drive and a flat one. both comes with drive IC's, too... (you will need to search out the datasheets on the web yourself)
Other good places to look are old scanners and inkjet printers. These also contains a lot of nice mechanical parts.
(Cogs, drive belts, switches and other goodies