Oscillating Motor 1

[jaredy]

I am looking for a high speed oscillating motor (if such a thing exists) that is small and light for a 12v application. If it doesn't exist, does anyone know of an easy gear assembly to accomplish the task?<br>
Thanks!

 

[umn]

I don't have a solution as of now, but curious to<br>
understand more...<br>
By oscillating motor, do you mean something that creates rotary oscillation that goes clockwise and anti-clockwise repeatedly, at high speed?

 

[jaredy]

Yes. About a 45 to 60 degree arc rapidly repeating. I need to get about 30 arcs per second.

 

[merbas]

we said this type of motors "step motor". when you give a pulse, it is turning the certain arc par example 30 degrees.<br>
If you apply these pulses continuesly, the motor will turn as well. 30 degrees is not specific, you can find it easyly<br>
Isearch for you also, but very important thing is this motor turn what? what is the I value of the system.<br>
<br>
I value is stablety or resistance to movement.It is a sort of moment.

 

[jaredy]

The motor would be "rocking" a small laser diode module back and forth about 30 times per second. I can't go in a complete circle due to difficulties with supplying power to the laser and weight. The rocking at that speed can't hit on either side. It would be too violent and destroy the laser.

 

[umn]

I agree to merbas' suggestion on stepper motors which can be precisely driven by pulses, but can they provide the speed of 30 arcs per second, as per jaredy's requirement? I guess the load will be light. Then, what about fabricating a simple mechanism (that converts continuous rotary motion to rotary oscillations) driven by a low cost dc motor? <br>
<br>
Merbas, any thoughts on this?<br>

 

[jaredy]

On the right track!

 

[mattc]

I've built lots of little gadgets using Radio Shack kits. Their motor kits are actually quite good. There are many ways to translate rotary into linear motion and there is no difficulty in translating the linear into curvilinear motion. All for less than 20 bucks! The RC (remote control) stuff is a little pricey, but you'll find the brass knuckle joints, shafts, and collars worth it. Most hobby shops carry the same stuff and charge a little more, too.

 

[DD]

Any DC motor with an optical or magnetic encoder will do. Count the pulses from the encoder an reverse polarity to make the motor go the other way. If inertia is a problem decelerate the motor gradually.

 

[umn]

DD, do you feel it will be possible to obtain the reversal at 30 times a second by this method? Even with very little load inertia, detecting the position and applying reverse polarity to an ordinary dc motor at this rate, I think may not be very dependable-

 

[TerryT3]

jaredy, have u considered Piezoelectric Actuactors? From the sound of things, u'll be introducing more problems by going the route with motors of any kind i.e. soft start/stop, overcoming inertia, reliability, etc.. not to mention the stresses (mechanical and electrical) at 30 cycles/s.

 

TerryT3,Piezos in my experience are fragile and hard to keep calibrated for a precise displacement. I believe that mattc has the idea.

 

[motormouth]

Try <A HREF="

http://www.hsi-inc-com"

TARGET="_new">

http://www.hsi-inc-com</A>.

They supply many bar code reader manufacturers with oscillating stepper motors (series 11000 to 36000) from 11mm to 36mm diameters with frequencies up to 50Hz, depending on load inertia.<br>

 

[forrestw]

The easiest way to do this is to attach an arm from the rim of a wheel on the motor to a pivot arm of greater radius than that of the wheel. As the wheel turns the pivot arm will oscillate with smooth acceleration and deceleration. This has the added advantage that the mass of the motor does not oscillate so adding mass on that axis, either as a flywheel or larger motor will smooth the operation of the laser.