Re: Team Update #18
 

The spec is that your MINIBOT has to TRIGGER the TOWER. They didn't specify exactly what it takes to do that. But you still have to do it. If your MINIBOT does not do that, then modify your MINIBOT so it does. If that means slowing it down....oh well.....

Re: Team Update #18
 

Nominal measurements, nominal specs, last-minute changes to fix last-minute problems... These are common in FIRST, have been common in FIRST at least as far back as when I started 827 and got crushed by 254 at the Silicon Valley Regional.

Some level of overengineering, and not engineering things too close to your target, is required all the time, methinks.

Re: Team Update #18
 

The discussion seems to be divided into two groups: those who have a fast, high-impact minibot and have experienced first-hand a target not triggering when it clearly should have, and those who do not have this first-hand experience, but speculate on whether the system is or isn't reliable. I put more credence with those with first-hand experience.

Regarding "the bolts"....it seems that they should have been fixed to the lower plate, and moving through the upper plate, so that they move with the lower plate no matter where it is contacted, rather than being fixed to the top plate and protruding through the bottom plate, so that they create 4 areas which block the minibot from triggering. From my understanding of the drawings, this would be an easy change to make.

Re: Team Update #18
 

I put more credence with those who read the rules and understand what the rules require the TEAMS to do.

There is no "should have TRIGGERED the TARGET" in the rules. You do it, you get credit. You don't do it, you don't get credit for it.

Part of the design challenge is to make sure your MINIBOT TRIGGERS the TOWER. Some TEAMS seem to have missed that. Apparently they thought the challenge was to get a minibot up the TOWER as quickly as possible.

Re: Team Update #18
 

IF the triggering programs and times of triggering on the towers hadn't been changed by FIRST between week 1 and 2 then this wouldn't be a problem for me. What is a problem is that it is changed to a level of "it seems to be working" instead of "every minibot who goes up the pole and exerts the 2-4N of force will trigger the top".

And to top it off humans wont' be used as the backup when electronics fail... seems backwards to me.

Re: Team Update #18
 

That would be an example of speculating about what should happen, as opposed to experienceing what did happen. Surely you are not suggesting that there is no possibility of a malfunction.

Re: Team Update #18
 

I think this is an unfair categorization. I was standing on the side of the field at the end of almost every match at a week 2 regional and saw every minibot that did not trigger the post. There were not that many of them and of them and it could not be shown that they did not hit a bolt or did not turn and reverse before pushing up the pad.

If someone has a really good first hand account of a minibot that definitely did not hit the bolt and definitely did not bounce off too fast and still did not get triggered, please speak up so that the cause can be investigated.

Re: Team Update #18
 

If thats the case, then why did the first two weeks of the season use manual scoring to determine minibot race winners? There's no way for a human to know if a trigger was sensored from the ground. The GDC referred to the endgame as a race, we all refer to the endgame as a race, because it is a contest for teams to get their minibot up the tower as quickly as possible. Yes there are constraints, size, weight, motor usage, battery usage etc. One of those is the 2-4 N measurement the GDC added in to the game documentation.

The sticking point to me is that some teams clearly are exerting that force on the top plate. Maybe some of us feel more comfortable calculating the exact force required, but I'm comfortable enough with our minibot to say it hits the target hard enough to trip the switch. Now, if our minibot hits the target LONG enough to trip the switch is the big question because there is no requirement in the rules about length of time required to trip the switch.

If the GDCs intention was to make the entire challenge not just complying with the deployment rules, minibot part usage and the actual challenge of ascending the pole, but to also include the tripping of the sensor as a key factor, there should have been much more information provided besides "2-4 N". Whether this includes an approximate timeframe this force needs to be applied in or something else. To have every team interpret the field drawings of the tower sensor to determine if their minibot trips the sensor or not is insane to me.

Thats my only gripe. Now I don't know how big of a deal this all is. Al has told me to rest easy, and I trust Al, so I will do just that. I'll also be making sure our minibot runs are recorded on video just incase a sensor doesn't happen to trip. At least we'll be able to try to break down why it didn't that particular run.

-Brando

Re: Team Update #18
 

This observation received very little attention in this thread. Could it be a significant factor in the reliability of the triggering?

It seems it would be possible for it to bind on the pole, especially if the contact point between minibot and plate is far off-center causing the plate to tilt. Does anyone know what is the coefficient of friction between polycarbonate and galvanized(?) steel?

Re: Team Update #18
 

I believe speaking up about such an account is exactly what several posters have done.

Re: Team Update #18
 

I don't doubt that there were several instances where MINIBOTs did reach the top, but did not TRIGGER the TOWER. Unfortunately, the rules do not let that count for anything.

How can you claim there was a field malfunction if the exact requirements to TRIGGER the TOWER are not specified? It could just as easily be that the MINIBOT in question does not close the switch for a long enough time to trigger the field system.

I do understand that the system was changed to make it less sensitive to false triggering. But since the whole thing was not specified, I won't say that the field system no longer meets the specs. The ultimate spec is still that you gotta trigger it. Rather than complain about FIRST following their own rules, work on your MINIBOT to make it trigger every time. Ask on the Q&A what exactly is supposed to be required to make it trigger.

Re: Team Update #18
 

How can you claim it was a MINIBOT malfunction, if you don't know what to design your minibot for. If FIRST made us guess on what the maximum peg height would be, I don't think anyone would be happy.

Re: Team Update #18
 

Is there one that says: "Our minibots dimensions make it physically impossible to hit the bolts and we have a really tough to flip switch so that the plate must be pushed up and hit the contacts before it turns off"

If these cases can be organized and then demonstrated week 3 practice day then I will believe there are larger problems at work here.

Re: Team Update #18
 

Ken, what would be considered bouncing off too fast? What is the duration that teams need to contact the disc to ensure that the target is triggered?

Ken's point is a very valid one. Does anyone have any video of Minibots hitting the top target but not triggering the target during week 2? Right now we're just dealing in speculation which isn't leading to anything productive. From what I saw in Pittsburgh, the large majority of minibots were in fact triggering the top target. If this wasn't the case at a regional you were attending, let's try and figure out what the issue was that was causing these false negatives.

If the issue was minibots hitting the bolt heads, that's unfortunate but it can be argued that teams should have been prepared for that based on the published drawings. (I may consider that a flimsy argument, but that's neither here nor there) If the issue is that teams aren't contacting the top target for long enough, I'm more concerned as nowhere in any official specification or guideline have I seen a duration of impact clause.

Re: Team Update #18
 

The reason I'm reading this thread is to gather as much information as possible to ensure our minibot hits the trigger every time.

The only course of action is to work on your minibot to ensure it hits the trigger every time. What I don't agree with is that this course of action was a necessary evil of this game. Had the specifications been laid out ahead of time I would certainly not be complaining one bit if my minibot didn't hit the switch. What bothers me is that there seemed to be some kind of a specification regarding force and now that specification seems less important than the time it takes to trigger the target.

This is a healthy discussion, but I think theres too many unknowns to really take it farther. I think we can agree that the teams responsibility is to trigger the target, what we need is some direction from FIRST on what exactly that entails (your Q&A suggestion is a good one).

-Brando