Recently, we have noticed many teams suffering from the issue where the brain suddenly crashes and becomes completely unresponsive, only displaying a white screen. We have had this occur to us several times as well during practice and once during a tournament. Due to its nature of completely disabling the robot and the potential to drastically alter the outcome of the match, we were wondering if teams who experience this issue during the tournament would be able to call a replay of the match. Furthermore, with the best of one system, this issue is even more prominent, as teams who are affected by it will most likely get eliminated, even if they do not deserve to be eliminated. I think a replay should be allowed, as this issue occurs seemingly randomly and can completely alter the outcome of a match.
+1 I agree
As the rules are currently written, this is not cause for a replay. However, I agree with you and actually have a Q&A up to see if there is something that can be done:
The replay criteria focuses on field fault or referee misapplication of game rules, not robot fault.
VRC Replay Criteria
At the same time, replays can be called for other reasons, such as when one of the VEXU skills finals at this past worlds was replayed due to a vexnet disconnect. But I agree that as they are written currently, the rules do not allow for replays because of a WSOD.
Thanks for your support, I hope the RECF decides to implement this before regionals. It would be horrible to have a team lose a match during regionals because of the white screen, and not receive an invitation to worlds.
This should definitely be included for a cause of a replay. There have been many matches in which teams loose because of a white screen.
I just don’t think it’s fair to penalize a team over something they can’t control
Write to the GDC and see if they can improve things. I am just relaying the guidance given for replays right now.
So should cortex (known) connection issues also be an automatic replay?
In my opinion, yes. In most ref’s opinion, no.
When you disconnect on the cortex you are still able to reconnect, but when you white screen the robot is completely immobilized and you cant reconnect until you power cycle, making white screening a far more match affecting issue
Can we say definitively what causes white screen?
If it’s a loose battery cable it could be the fault of a team.
If it’s static then why don’t cortex bots get similar consideration for ESD problems.
Is it a problem inherent to some but not all V5? or all?
Some causes might deserve a replay rule for white screen, other reasons maybe not. But I guess if we knew exactly what the specific cause was we could probably prevent it all together. In any case, white screen during a match is really sad.
Question for the utes: matches being disrupted for robot technical issues is a thing that has been around since the beginning of youth competition robots. Can you think of some reasons why “replay when any robot fails in a mysterious way” has never become a rule in any VEX or FIRST competition? The people who make the rules aren’t dumb, what could be their reasons?
That’s a good point @Rick TYler. I’d be interested in seeing exactly how often this happens, whether it’s one of those supposed 99.5% reliability (from the legacy VexNet system) things, or if it’s more often.
Either way, I would think that if only one robot experiences the “white screen of death” in the match, then it wouldn’t really be grounds for a replay. This follows the pattern from previous hardware failure rulings, at least. However, if two or more robots white-screen during the match, or if white-screens are a common occurrence during the whole tournament, then that’s a whole different problem and probably would warrant a replay.
Otherwise I do agree with other responses; it’s more important to know what causes the problem in the first place.
My guess is that it is unlikely to be caused by loose battery cable, because the hardware was just released with little time for wear and tear and V5 cables from Molex appear to be of much better quality than the Cortex power connectors.
I think, it is caused by ESD and is not specific to particular V5 brain or production batch, but instead depends on the local field condition (was it sprayed with anti-static?) and also on specific robot design.
Some robot’s chassis must be better at shielding V5 brain from ESD, while others must have unintended configuration that actually makes it easy for ESD to whitescreen the brain.
I agree that whitescreen is a very annoying “feature” of V5 brains and BO1 make it even more so, but at least, it is not as bad as losing motor ports at a rate of a couple per week.
Unfortunately, it seems to happen frequent enough to cause teams some unpleasant losses, but not frequent enough to easily conduct systematic tests to determine exact cause and the best solution or a workaround.
The best we could do at this point is, probably, to assume that it is caused by an ESD and try to protect robots accordingly.
If any team has experienced white screen, the first thing I would do, would be to write down where it had happened, condition of the air (dry?) and the field (anti-static sprayed?) and how many robots were on the field and what type of wheels they had.
The second thing would be to see if your robot has any end-manipulators that are electrically disconnected from the rest of the robot chassis (use multimiter) and frequently come in contact with field tiles , perimeter, or other robots. If you have any motors or sensors mounted on such manipulators their data and power wires might be the easiest path for the static to discharge into V5 brain.
I would try to electrically connect all major metal parts of your robot together, especially those that come in contact with the field and only then connect the chassis to the electric ground rail of V5 brain (use 3-wire cables with orange jumper switches for that).
Also, if the field is not sprayed with any anti-static, use some anti-static wipes (or laundry dryer sheets that have some anti-static) to apply it on all surfaces of your wheels.
This way you could both minimize generation of the static charge and, if it still accumulates, let it dissipate over larger surface area capacitance of your robot’s chassis instead of letting it strike with all the energy concentrated on the V5 brain electronics.
a white screen during the finals match would maybe cause a replay from the right ref, but you aren’t guaranteed a replay for white screening at all.
Unfortunately, I was in this exact situation and it didn’t come out as a replay. I do not think you will find many if any refs that would replay. The white screen occurred 5-10 seconds into driver control, so it definitely had an impact on the match and is about as match affecting as you can get. That was the only time I have ever white screened this season and I have competed in nearly 100 matches so far. Does not seem like a very common issue, but a very painful one. I think what is needed more than a clause for replay is a fix for the problem. As much as it sucks it has not seriously affected my season. However, I am worried about the possibility at both worlds qualifiers and worlds. Bo1 is enough worry, I don’t need white screens added to the mix.
Thanks for your advice, we’ll try to implement this
A team could also program a button to white screen the robot. I just don’t think this is ever going to fly.
While I agree it’s incredibly frustrating, working with new equipment does have that tradeoff that the bugs have not gotten worked out yet. V5 has many advantages over Cortex, but this is an advantage that Cortex has over V5… The Crotex has been around long enough that we know how it works and for what it does it is dependable.