Radio/RC Problems for 2007 Season

[petek]

Originally Posted by nparikh

What do you mean by bigger/higher capacity battery? Aren't you required to use the ones to spec in the manual? (and which battery--12v or backup?)

Assuming Dave's referring to the backup battery, we can use one different from the KOP. <R73> states "any other commercially available 7.2V NiCad battery pack may be used". You still are stuck with charging from this year's KOP wall wart or the on-board circuit from IFI, however.

[Dave K.]

Originally Posted by Chris_Elston

I can't even imagine what that is going to do with teams that have PID installed...with the error accumulating could be asking for crash em up bash em up and it won't be your drivers fault...

See this thread for a couple different ways to see when packet loss is occuring and when the RC has disabled the outputs.

For any motor controls with an "I" term in them, you'd at least want to prohibit the integrator from accumulating additional error, otherwise when the outputs are re-enabled, the motor speed/position will jump/lunge.

For this type of system, the new RC master code actually makes the situation worse. Rather than continuing on into the wall/door/locker/ankle that the robot was aimed at prior to the radio link going down, now it will pause, accumulate error, and then accellerate into the object.

[Dave K.]

Originally Posted by petek

Assuming Dave's referring to the backup battery, we can use one different from the KOP. <R73> states "any other commercially available 7.2V NiCad battery pack may be used". You still are stuck with charging from this year's KOP wall wart or the on-board circuit from IFI, however.

Yes, I was referring to the NiCd backup battery.

Team update 13 includes a warning that the 'charger' included in the KOP is actually just a power supply and that it will overcharge the NiCd battery pack, and includes a warning not to leave the batteries unattended.

So the wording has been changed to say "a" 7.2V NiCd charger is to be used.

[Jack Jones]

The poll lacks the response that fits for us, which would be;

“Yes, we have radio problems. But the fix is beyond our control.”

Just because you’ve mounted it on top of the flagpole, turned off all cell phones and motion detectors, had everyone hold their breath, and etc, and it appears to be working adequately doesn’t mean it is. Not when the old radios have performed so well for years without any hack fixes.

We have done none of those things because we believe the only fix will be to revert to the old radios. We’re working under the assumption that an Update will come any day saying just that. If not, then what happens the first week with six robots and six radios running in the metallic environment under high-powered lights in front of a cell phone toting audience should prompt a recall before our first week at GLR.

[Eldarion]

Originally Posted by Jack Jones

The poll lacks the response that fits for us, which would be;

“Yes, we have radio problems. But the fix is beyond our control.”

Just because you’ve mounted it on top of the flagpole, turned off all cell phones and motion detectors, had everyone hold their breath, and etc, and it appears to be working adequately doesn’t mean it is. Not when the old radios have performed so well for years without any hack fixes.

We have done none of those things because we believe the only fix will be to revert to the old radios. We’re working under the assumption that an Update will come any day saying just that. If not, then what happens the first week with six robots and six radios running in the metallic environment under high-powered lights in front of a cell phone toting audience should prompt a recall before our first week at GLR.

Very true...we are in the same spot.

Something that may factor into the problem here is that IFI's supplier (Electrowave) can no longer build radios due to a lack of parts. (This is on another thread somewhere, but there are so many threads relating to these radio problems that I have lost track which one! )

Even if IFI allows the use of the old radios this year, it is still a temporary solution, unfortunately.

[Mark McLeod]

Massive response from IFI in Team Update #15.

Innovation First
FOR IMMEDIATE RELEASE
February 27, 2007
FIRST Robotics Competition Radio Modem Re-Programming Information
We would like to address the growing concern within the FIRST community about the integrity of the new IFI Radio Modems used in this year’s system. As with any new product or technology taken to production for the first time, we have identified several issues that may affect the performance of the overall system.
We have taken the feedback received VERY seriously, and have been tirelessly researching to figure out exactly what problems teams have experienced. There is not one single large problem, but instead there are several smaller ones which contribute to the sporadic issues some teams have seen. Now that we have a better handle on what our users have been experiencing, we are prepared to address the issues present in the system.
The intent of this communication is to inform the community of the issues we have found, the symptoms, how best to address these issues and the impact this will have on the teams. Many teams will not experience any glitches, however to prevent problems from occurring at competition we hope every team educates themselves and implements the solutions described below.
In short, each team will need to have their RC radio re-programmed at competition by the IFI staff. Each team will also need to update their RC with RC Master Code v.15 before competing. For technical reference, the following is a list of the issues reported and confirmed by our engineering staff along with some background, the issue identified, and the solution.
...(more)