Testing DC Motors on a Robot with DIY Rotary Encoders

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

tonygo — Mon, 24 May 2021 14:44:04 GMT

If you used a Pico to do the slot counting on the second core and just pass back the ratios to the main core for speed correction.

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

fmilburn — Tue, 02 Mar 2021 17:52:03 GMT

Just saw this interesting and informative article on controlling DC motors at low speed: Overview | Improve the Low Speed of Brushed DC Motors | Adafruit Learning System

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

dubbie — Tue, 02 Mar 2021 12:55:03 GMT

Frank,

I was looking at some similar detectors for mobile robots only this morning so your Blog was of great interest. I am interested to know how you arranged the sensor to be at the correct height so that there isn't any variation in the alignment of the slots in the disk to the detection area of the sensor - or is there sufficient tolerance to take care of any variations? Also, do you think it would be possible to create a disk with more slots? Also, also, doesn't the infrared just shine through the plastic of the disc whether there is a slot or not? I've tried using 3D printed parts for optical interruption and it didn't work that well - just diffused everything into a blur.

Dubbie

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

three-phase — Mon, 01 Mar 2021 21:27:35 GMT

Nice blog, I wonder if it would be possible to measure the friction of the motors in a mechanical manner for a comparison.

Kind regards.

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

DAB — Mon, 01 Mar 2021 20:18:24 GMT

Nice post.

I like the tread base.

DAB

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

genebren — Mon, 01 Mar 2021 15:11:44 GMT

Great work on your robot project. It appears that there is a definite right/left difference going on in your sample runs. It could be electrical (resistance/driver) or mechanical (friction/motor). You might want to try swapping the wiring on the motors to see if the difference follows the swap (likely electrical). Otherwise the motors seem to bunch up pretty closely. Ideally the control loop will correct the issues, but it might help to get the left/right motors to perform a little more constantly.

Very cool!

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

shabaz — Mon, 01 Mar 2021 12:37:24 GMT

Hi Frank,

This is really nice to see the custom work for the encoders. I worked on a transceiver project where the engineers created a similar solution for a custom frequency control dial. It was super-reliable.

Photo from ebay (reflective, but principle the same of course).

[View:/resized-image/__size/621x411/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-7bb68ce2-1d75-4816-8e66-f0d0549d5ff4/contentimage_5F00_207449.png:621:411]

RE: Testing DC Motors on a Robot with DIY Rotary Encoders

neilk — Mon, 01 Mar 2021 10:32:11 GMT

Nice post, Frank.

Very interesting to see the different behaviour of the 2 motors; without some sort of balancing - PID - would be difficult to get this beast to travel in a straight line.

Neil