Servo brands for small robotics application

Hello Everyone,

I'm trying to do a small-scale robotics application where I'll be needing affordable servomotors and I'll be 3D printing as much as the structure as possible. I don't need continuous rotation.

I'm not very familiar with the hobby servomotor market and I need pointers for good brands out there. I've seen a lot of Hi-Tec servos out there but I've never used them personally. I've used the Dynamixel series before and I was pretty satisfied, but anything larger/more powerful than AX-12A is overkill for my project, both in terms of torque and price.

I went and did a quick lookup for Hi-Tec servos, as they are my current baseline for the hobby servo market. Here are my observations:

  1. When I looked up the price ranges, I saw that many Hi-Tec servos are not great in terms of torque compared to AX-12A. It's true that they list the stall torque and not the operational torque in AX-12A datasheets; but even in that case, taking 1/3 of the stall torque (pretty adequate I think) still beats most Hi-Tec servos out there assuming that the torque they list is operational torque.

  2. Hi-Tec servos are not that much cheaper either when compared to the AX-12A.

  3. AX-12A has a mounting assembly for a free running axle opposite of the driven axle: This would eliminate my need to mount a free running axle on the hull. This is not the case with any of the hobby servos I saw out there.

  4. The drop packet daisy-chained bus of AX-12A would help me reduce the cost of the driving circuit. All hobby servos I saw, including "digital" ones, are PWM driven, meaning there should be separate PWM channels on the driver circuit per motor. Also, the punch controller of AX-12A is programmable, which is a plus. Is there a "true" digital hobby servo out there?

  5. Another thing that put me off is that there is no real datasheet to Hi-Tec servos on the manufacturer's page.

What do you think?

Thank you very much.

Good, fast, cheap, chose any two!

Why don't you use the AX-12A servos as they seem to meet your needs?

zoomkat:

Good, fast, cheap, chose any two!

Why don't you use the AX-12A servos as they seem to meet your needs?

Right, I think I forgot to mention this. AX-12A are a bit too large and heavy for my application. Also, I would like to have an idea of the performance of a hobby servo by using it in such an application.

You need to make some clarification as to what "my application" is.

It will be a small multi-DOF legged robot. If possible, I want to make it very small.

Can you recommend me general servo brands; something like “this brand is widely used and accepted” or “stay away from this brand” ?

I don't know anything about servos that can be daisy-chained.

Regular servos only need a single signal connection to an Arduino so they are not much of a burden

If regular hobby servos are suitable my suggestion would be to use the cheapest available at a suitable size/torque and replace them with better ones if they break.

There will be lots of other challenges in your project. I would not waste time worrying about specific servo choices at this stage.

...R

The question was which brands are good, not about any specific servo application. There are
a lot of cheap and shoddy servos out there the OP wants to avoid.

It will be a small multi-DOF legged robot. If possible, I want to make it very small.

Below are some small multi-DOF legged robots. You might look to see what types of servos they use.

https://www.youtube.com/results?search_query=mini+hexapod