Robot periodically spasms out


So basically we’ve been having an issue all season where shortly after we enable teleop or auton sometimes, our robot will “spasm out” pistons will rapidly extend and retract, our compressor will turn on and off rapidly, if we’re driving at the time our drive motors will stop and go. This has never happened in a match but I am very concerned that it will.

Robot specs:

Rio 2.0

Freshly charged healthy battery each time?

Solid laptop being used for driverstation?

Sounds like classic packet loss. The question is, what’s causing packet loss? Sometimes can be straight forward, other times not to much.

We’ve checked our driver station logs and there isn’t any packet loss like that, yes we’re using a good laptop and a fresh battery and it still occurs.

I’m going to go through all of yesterdays driver logs and see if there are any times with large packet loss

Interesting. Concerning.

Are you up to date on the driverstation version?

Any chance you might have some CAN errors pop during these spasm events?

Yeah if you can post logs or screenshots that would help as well.

No can errors appear and we are on the most recent driver station version. I don’t have the laptop we use with me right now, I’ll have access to it in about 20 minutes to go through all the logs

Cool! In the meantime/in addition:

Can you walk us through anything else you can checked so far as well? Including what you’ve checked with the radio, radio power, PDH, pneumatics hub power, etc? Network switch?

Pretty much list anything you’ve already checked so we can give you better advice.

I think it’s a packet loss issue, looking at yesterdays logs this is what every few (1 every 5-10) show:

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Yup, figured. Unfortunately diagnosing these issues isn’t always straight forward. So yeah if you could drop in a post about what you’ve already looked into, lets go from there. Both on the robot and on the laptop please.

We’ve reimaged our rio and tried different radios. Other than that we really haven’t been focusing too much on the issue because of how intermittent it is and how it never happens at competition.

We have experienced this on our practice field due to all the other wireless networks in place. Possible issue?

We experienced this issue this season on our practice field twice and during a real match once, symptoms were high packet loss and the robot driving uncontrollably. We switched out our driver station laptop and have not had the issue since

Same problem here. Also doesnt happen on the comp field. Wish we could figure this out. Replaced every wire, tried different computers, 5 Ghz, 2.4 Ghz, password, bandwidth limit, no limit, default code, no code. It just always spikes a little. The pistons turning could be due to teleopInit() being repeated and if pistons are activated there then it will basically toggle them.

Potential duplicate of Severe (>100%?) packet loss?

With something fairly cyclic like this, my first guess goes to a background process running on the computer. Make sure all of your firewalls are disabled, any auto-updaters are turned off, nothing is running in the background, etc. Sometimes an app can decide “I need to check RIGHT NOW if I have an update” and freezes the internet traffic until it finishes checking, not ideal when you want near-realtime communication with your robot.

Are you using a rio 2.0?

Yes, we are. However, the latest wpilib update regarding shuffleboard seems to have helped alot. Shuffleboard would max out GPU usage, in turn slowing the drivestation.

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