step motors?

[mr.engineering]

when do i need to use step motors?
building a robot,can i use dc motor only,or step will be better?
use step in rotation only?
try to give me any info on step motors..thanks

 

[mr.engineering]

does a servo motor replace the use of stepper and dc motors?

 

[dknguyen]

Like everything in engineering, having stepper motors and other DC motors have their place. It depends on what you want to do. IN building a robot, yes you can use steppers only. But there are some cases where it might be easier or better to use steppers (either functionally or the availability of motors that can do the job with the support equipment you have available).

A servo motor is just a motor with feedback. You can add feedback to a servo, stepper, or AC motor. They are two separate things.

Stepper motors are good
- when you don't feel like gearing down something (assuming you can find a strong enough stepper)
-you don't want to deal with the back/forwards motioninvolved in holding a DC motor in a fixed position. With a stepper you just move it to wherever you want and continuously apply power to the winding and it just sits there. No need to measure the position and correct it unless something is able to overcome the holding torque of the stepper.
-the motor has to travel slowly in the manners described above (steppers get the most torque when moving slowly)

 

[mr.engineering]

but i need to move fast,using line follower tracking,and also i need to make rotation easily
also i think it's hard to find high power steppers to move a robot by itself?

 

[dknguyen]

If it's for wheels that move something, a geared DC motor is probably better than stepper since all you have to do is apply PWM or power to the motor and it spins- no need for sequential winding switching.

Is there a reason you wanted to use steppers? Or you just wanted to use them because you wanted to use them?

 

[mr.engineering]

not because i wanted to use them only,because their torque is better,so can i use both of them,one (dc)for higher speed,and stepper for better rotation?
sorry cause i have no enough experience with motors :$

 

[dknguyen]

A DC motor can put out 3 or 4 times more power than a stepper motor (but you have to gear it down to get the torque).

 

[mr.engineering]

do i have to use a motor for each wheel?

 

[dknguyen]

No, but you probably need two motors. Either one for each wheel or one for the drive wheels and one for a steering wheel (and the steering motor will have to be a servo motor, or a stepper motor at the very least).