Swerve using all REV

FIRST General Forum
1

if there are teams using all REV components for their swerve modules/drive what settings do you use in your spark max motor controllers? I have provided a screenshot of what we are currently using.

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We do, we use all NEOs on SDS MK2 with Translation motors at 30A current limit and Rotation at 25A current limit.

Last year we were a little higher on current limits so YMMV

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Are you all using 550s for steering? Or, are you using two full neos per wheel?

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2 full NEOs, MK2 from Swerve Drive Specialists, I forget the gear ratio for rotation, we have standard steel gear ratio for translation

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5

Ever run into sputtering? Starred happening to us today. Similar the looking like a brown out. Robot would stutter.

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Only if we run the battery very low on accident. With the current limiting it keeps you from pulling too many amps and dropping the battery voltage too low. We have found using current limiting in some form on all of our NEOs works nicely. On a good battery we can get about 7 minutes of complete matchplay (only do this for practice in our facility, robot gets a fresh charged battery for ever match)

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This is what we saw on Saturday

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It’s definitely browning out (you can see the RSL flickering to the beat).

A few things I would check:

  1. Battery voltage. Does this only happen after driving it for a bit, or always? Look at the driver station and the log to see the battery voltage.
  2. Control loop response. Open up a dashboard and plot the steering controller output and the setpoint. If the steering controller on the modules is poorly tuned it could oscillate and/or demand way more current than needed (multiplied by 4). The SDS example code has some PID values you can start with, but without graphing the actual response the best you can do is hope its good.
  3. Mechanical assembly. If the module is not assembled well, the steering controller may struggle and show all of the symptoms as above. This can also cause high current draw + brownouts.
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Started happening during drivers practice on Saturday. We have been using the same modules for one comp this season already and did not have issues at that time.

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Do you brown out when anything else runs on the robot? Maybe you have a loose battery cable? In the driving video it seems to brown out when accelerating hard and the video on it’s side seems to brown out when the motors rotate directions.

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Can you post some DS logs? This will give us a better idea of how the load is spread and perhaps identify other issues.

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https://drive.google.com/file/d/1vwvNoi11e3lLhjNO-VKPCD8gTmp07m-L/view?usp=sharing

In that zip file there are two sets of logs one folder contains logs from two runs where the stuttering happened and then another folder where the stuttering stopped. We still dont know what caused the stuttering BUT we did redeploy the code from our first event that we had NO issues with the drive at all and the stuttering happened. So the code is not the issue from our assessment. Any help is greatly appreciated.

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Additional video from last night: https://youtu.be/PyEAe-I5D5Q

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