Motor for Neuro project - slow/smooth/accurate

Robotics and electronics discussion Mechanical design and actuators
1

Gday

I would like a motor system to control the position of a small laser diode and not being a technical experts in these areas would like some input and advice.

The requirements are:

  • move smoothly at various speeds from 5deg/s to 60deg/s (no jitter)
  • move accurately at all angles - it’s accuracy has to be finer than 1deg
  • be able to change speeds (and preferably acceleration) during a movement.
  • quiet to use, as our experiments are conducted in an anechoic chamber.

Currently i got my student to prototype and test an arudino + small servo.
At speeds > 100deg/s it has no problem. However, that’s too fast for our needs.
At the lower speeds there is too much jitter.

We prefer to use the arduino because our experimental software platform is Matlab, which can talk to the arduino already.

I have also looked at stepper motors with 0.9 degree/step accuracy but have not tried them.

What options are out there? Are stepper motors accurate/quite/smooth enough? or are Servos the way to go?

any advice/info appreciated.
thanks.

johahn

2

Hello.

If you are happy with the volume of a servo, a properly-driven stepper motor should not be a problem, and, with microstepping, you can get better than single-step resolution.

- Ryan

3

Hello.

If servos are close to what you want, I think you should stick with them. The jitter you are seeing is probably because you are not controlling them well; you might want to use a dedicated servo controller, such as our Micro Maestro, which will give you much better control over speed and acceleration than you are likely to get out of an Arduino yourself (without doing a lot of work). Your servo could also be a limiting factor; unless you are already using a really fancy one, if you continue having problems, you can expect to easily improve things by getting a better one.

- Jan