Jitter noise on 150:1 Metal Gearmotor 37Dx57L mm 24V (Helical Pinion)

Robotics and electronics discussion Mechanical design and actuators
1

Hello, we are evaluating the Pololu - 150:1 Metal Gearmotor 37Dx57L mm 24V (Helical Pinion)

150:1 Metal Gearmotor 37Dx57L mm 24V (Helical Pinion)

  • without encoder.
    The motor position reaches it setpoint voltage readily but there remains jitter or noise of about 2% on this setpoint.
    Although this is not a dealbreaker for our application, any input on
  1. if the jitter will damage the motor over extended use
  2. cause of the jitter (noise on 24V supply ?)
    thanks
2

Hello.

Unfortunately, it is not completely clear what you are describing. Can you try to clarify and post more details about how you are using the motor and what it is doing? Pictures or a video showing the behavior you are asking about would be helpful. (The forum does not allow users to post very large videos, but it does work well with videos linked from other sites (like YouTube or Vimeo.)

- Patrick

3

Hi Patrick – we are using the Pololu 4687 w/o encorder motor to drive to and hold at an angular position prescribed by an open loop voltage. The torque is expected to be much less than stall torque.

Although the pololu motor easily servos to the setpoint, it appears to have a jitter or noise which another motor does not have even if supplied by the same power source.

4

Can you post a video that demonstrates behavior you are talking about?

By the way, your last post included what looked like an automatically generated signature which included contact information. Since this is a public forum, we do not recommend posting contact information like that; I edited your post to remove that.

- Patrick

5

Patrick – thanks for your note.

I do not have a video. To clarify the issue, the motor is supplied with a varying voltage in response to feedback from a separate Voltage/Current/Phase sensor on an RF power line.

The issue is that the resulting angular position of the Pololu motor is noisier, with more jitter than motors from other suppliers.

Is this simply a question of faster, more sensitive response of the Pololu 4687 motor, or something else?

Ramesh Gopalan

6

Hello, Ramesh.

In general, control systems require tuning of the control parameters in order to work well. It sounds like your system is probably tuned specifically for these other motors, which would explain why it works well for them and less well for ours. Have you tried retuning it with our motor?

- Ben