Most suitable motor for precise movements

[kbm10]

Can anyone help me in deciding the most suitable motor type for precise movements in position ? Is it stepper/dc with encoder (say optical encoder to give feedback regarding the correct position) ? Can anyone suggest good resources or a good book for embedded implementations of control systems ?

Thanks in advance,

 

[enjunear]

You might look into a servo motor, if you can handle being limited to a less then 360 degrees of rotation. They are used a lot in remote control vehicles (most notably, RC airplanes) because they have a built-in control loop to maintain the target position.

All you need to do it feed them a PWM signal to set the desired position.

**broken link removed**
https://www.rcmodelreviews.com/howservoswork.shtml

 

[doraemon]

Hello!

Your question lacks accuracy.
Precise movements in position is fine, but how precise and what's the amplitude?
Is it 1mm accuracy on 10 meters? Is it 0.01mm on 10 cm? In the first case, for
instance, you cannot find a 10 meters ball screw, but in the second case, you can
easily find 10 cm balls crews.
Another issue is the power. Do you need close to 1 kW or closer to 1W? In the
first case, I guess you will never find a 1 kW stepper.

As for books, I would first try to have a look at what you can find on the net.

Dora

 

[kbm10]

Hello!

Your question lacks accuracy.
Precise movements in position is fine, but how precise and what's the amplitude?
Is it 1mm accuracy on 10 meters? Is it 0.01mm on 10 cm? In the first case, for
instance, you cannot find a 10 meters ball screw, but in the second case, you can
easily find 10 cm balls crews.
Another issue is the power. Do you need close to 1 kW or closer to 1W? In the
first case, I guess you will never find a 1 kW stepper.

As for books, I would first try to have a look at what you can find on the net.

Dora

What's more, it should do this as quickly as possible and provide a high level of accuracy regardless of the effects of aerodynamic loads or other factors.
Yes I admit, my question was not not accurate. My tolerance is +/-70u from the desired position..Is it possible now with RC servo or stepper ? Also, in one movement I move atleast 0.1 mm and maximum 30 mm.

Thanks

 

[doraemon]

Hello!

Is it possible now with RC servo or stepper ? Also, in one movement I move atleast 0.1 mm and maximum 30 mm.

It's possible with both. You still don't say anything about the power (or force / torque, etc) you need.
If you want to move 1 ton on 30 mm, it's not the same as 10 grams.
Let's suppose you need a force of a few kgs, I think the easiest way is to use a stepper and a ball screw.
But you will also need some feedback because a stepper does not guarantee that you will not loose steps.
If the force is too high for its torque, then it simply doesn't spin and you will loose steps (and therefore loose
your reference).

Dora.

 

[enjunear]

What's more, it should do this as quickly as possible and provide a high level of accuracy regardless of the effects of aerodynamic loads or other factors.
Yes I admit, my question was not not accurate. My tolerance is +/-70u from the desired position..Is it possible now with RC servo or stepper ? Also, in one movement I move atleast 0.1 mm and maximum 30 mm.

Thanks

Motor motion is measured in angular terms, so what you need to do is convert you linear distances back to rotational amounts, then you can see what kind of rotary actuator will suit your needs the best. Since I don't know what your hardware configuration looks like, I can't help you do the math. Maybe giving us a picture of your setup would help?

As for "aerodynamic loads", you need to convert this back into a torque that the motor will need to be able to move against. Also, the aerodynamic load at 15 mph is MUCH less than the aerodynamic load at 65 mph, so accurate measures and/or goals and limits are useful in helping us to review your problem and find some solutions.