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Unread 05-02-2007, 23:47
Dave Flowerday Dave Flowerday is offline
Software Engineer
VRC #0111 (Wildstang)
Team Role: Engineer
 
Join Date: Feb 2002
Rookie Year: 1995
Location: North Barrington, IL
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Re: does anyone have OI and RC radio issues

As a follow-up from our testing tonight, here's what we found:
  • The connection was very unreliable for us, just as others have noted. A multi-second dropout occurs every 15-30 seconds while driving (even when not under heavy load). Does not appear to be a battery issue to me (fully charged battery and backup battery, and voltage on the OI looks good).
  • The "run on" problem didn't seem apparent, but now the problem is opposite: every time there's packet loss the robot shuts down (triggering single-action solenoids to de-activate, stopping the drive motors, etc). Basically, if the robot doesn't have data, it has two choices: keep doing what it was doing for a bit, or play it safe and shut down. Obvious safety concerns exist with the first (and what was seen in R13 firmware), but serious performance issues exist with the second (as seen in R14).
  • I confirmed that the new radio modems add significant latency. There's probably 300ms of latency with the new modems. Switching to the old modems eliminated this. I think this will be quite a hindrance to drivers (though I imagine they will mostly adapt and have to predict movements more).
I'll be contacting IFI tomorrow with this information.

Last edited by Dave Flowerday : 06-02-2007 at 15:25.