Do I need a 360 servo or stepper motor?

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Discussion Overview

The discussion revolves around the selection of a motor type for a system requiring at least 360 degrees of rotation, focusing on the comparison between 360-degree servos and stepper motors. Participants explore the suitability of different motor types based on specific requirements such as speed, response time, size, and the ability to hold a position.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Jarfi outlines the requirements for the motor, emphasizing the need for fast rotations, fast response time, and the ability to hold a position, while being compact.
  • Some participants propose that a stepper motor may be appropriate for the task, although one admits to limited knowledge about them.
  • Another participant suggests that a DC motor might suffice, questioning the necessity of digital step control versus a DC servo.
  • A suggestion is made to use a 90 or 180-degree servo with a speed increaser to meet the requirements, noting potential torque loss due to the gearing system.
  • Jarfi later mentions modifying the gears to reduce the required rotation from 250° to under 180°, indicating a practical adjustment to the initial requirements.

Areas of Agreement / Disagreement

Participants express differing opinions on the best motor type for the application, with no consensus reached on whether a stepper motor or a servo motor is more suitable. The discussion remains unresolved regarding the optimal choice.

Contextual Notes

Participants acknowledge varying levels of familiarity with stepper motors and servos, which may influence the suggestions made. There is also an implicit understanding that the requirements may be flexible, as indicated by Jarfi's adjustment of the rotation needed.

Jarfi
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Hey guys. Jarfi here,

I'm working on some gear, a system powered by a rotation that needs to move at least 360 degrees.

Requirements:

Fast rotations(used for stabilization)
Fast response time
needs to be able to hold a position like servos do
needs to be not too big, under 5x5cm area and under <3,5cm height
-okay with not too much precicion, it's not a 3d printer
-okay with not too much torque, it's not a robotic arm


Servo; larger area and small height, Ideal for the situation. Holds position, fast rotation/response time
but the only con was that a 360 degree servo is expensive and there aren't many out there, it's 90% 180°.

Stepper motor; ?

I just know that a stepper motor has continuous rotation, so that it's not limited to 180° like standard servos are. But is it good for the task? is it more or less expensive than a 360° servo? I've never worked with one so I'm a bit hazy on all this.

My thanks in advance
 
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I really know very little about stepper motors, but from what I've read I believe that such is the appropriate device for your purposes. Don't take my word for it, though.
 
I would have thought that a DC motor would have met the requirement.
Do you really need digital step control or just a DC servo?
 
Jarfi said:
Hey guys. Jarfi here,

I'm working on some gear, a system powered by a rotation that needs to move at least 360 degrees.

Requirements:

Fast rotations(used for stabilization)
Fast response time
needs to be able to hold a position like servos do
needs to be not too big, under 5x5cm area and under <3,5cm height
-okay with not too much precicion, it's not a 3d printer
-okay with not too much torque, it's not a robotic arm


Servo; larger area and small height, Ideal for the situation. Holds position, fast rotation/response time
but the only con was that a 360 degree servo is expensive and there aren't many out there, it's 90% 180°.

Stepper motor; ?

I just know that a stepper motor has continuous rotation, so that it's not limited to 180° like standard servos are. But is it good for the task? is it more or less expensive than a 360° servo? I've never worked with one so I'm a bit hazy on all this.

My thanks in advance

Off the top of my head from the info on your post that precision or torque aren't critical but holding is just use a 90 or 180 servo with a 4 or 2:1 speed increaser. (the opposite of a reducer) . Bear in mind you will lose torque proportionally to the change in speed plus some inefficiencies in the power transmission through the gears.
 
Norm Morin said:
Off the top of my head from the info on your post that precision or torque aren't critical but holding is just use a 90 or 180 servo with a 4 or 2:1 speed increaser. (the opposite of a reducer) . Bear in mind you will lose torque proportionally to the change in speed plus some inefficiencies in the power transmission through the gears.

Ah yes, that is wise... I ended up doing something similar, just narrowed down the rotation required from around 250° to under 180° by modifying the gears
 

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