FRC 2010 Team Update #5

[Alex Cormier]

http://www.usfirst.org/roboticsprogr...nt.aspx?id=450

Some interesting updates and fixes.

[Racer26]

Daww, i cant pick up an E-stopped robot to earn ELEVATED or SUSPENDED points for it? GDC, you're no fun.

[Chris is me]

Red card for "inappropriate use of the E-stop"? Wow, that will be fun to argue with refs about. There's a software problem and it can't drive, so we e-stop, but it's not obvious, so we get a red card?

[Vikesrock]

Originally Posted by Chris is me

Red card for "inappropriate use of the E-stop"? Wow, that will be fun to argue with refs about. There's a software problem and it can't drive, so we e-stop, but it's not obvious, so we get a red card?

Under the changes in the rules, the robot not being able to drive is not an appropriate use of the E-Stop as it is not a safety issue.

[Chuck Glick]

Originally Posted by Chris is me

Red card for "inappropriate use of the E-stop"? Wow, that will be fun to argue with refs about. There's a software problem and it can't drive, so we e-stop, but it's not obvious, so we get a red card?

I'm going to have to echo this thought. It was my understanding that if you had no control of your robot it was the responsible thing to do by pressing the e-stop in the event that the robot decides to move on its own. After attending many a FIRST event I know for a fact that sometimes a bot will run its auto mode at an unknown time due to a field error. Therefore wouldn't it make sense that if your bot is unresponsive to driver control that you hit the e-stop as a safety precaution?

[Karthik]

The changes to <S03> and <G27> have eliminated some fun strategies. However, these changes do make sense considering it's called an "Emergency Stop".

[Chris is me]

Originally Posted by Vikesrock

Under the changes in the rules, the robot not being able to drive is not an appropriate use of the E-Stop as it is not a safety issue.

Ah. Well, I've always wished to hit the E-Stop when a robot couldn't drive so it couldn't get penalized (e.g. can't drive while touching the opponent's Tower before protection time). Now my mechanical or programming failure will get me penalties. If it were a safety issue, I'd get this protection. I guess I should make a "force safety issue to happen" button on my remote so I still get this?

I dunno, I can just see this being an issue at least once.

[GaryVoshol]

Originally Posted by Chris is me

I guess I should make a "force safety issue to happen" button on my remote so I still get this?

Hmm, last year Paul was going to make a battery ejector button. This year will he have to install a smoke release button?

[Chris is me]

Originally Posted by GaryVoshol

Hmm, last year Paul was going to make a battery ejector button. This year will he have to install a smoke release button?

I was actually just thinking of the post referencing that when I made mine. I would never do such a thing, but this rule makes a battery ejector a good idea. :/ Oh well. Not the end of the world, just something else to consider.

[Peter Matteson]

Originally Posted by GaryVoshol

Hmm, last year Paul was going to make a battery ejector button. This year will he have to install a smoke release button?

Isn't that just a stalled Fischer?

[jgannon]

Originally Posted by Karthik

The changes to <S03> and <G27> have eliminated some fun strategies. However, these changes do make sense considering it's called an "Emergency Stop".

Can you elaborate? I'm having trouble envisioning any strategic benefit to e-stopping your robot that couldn't be achieved through the control system.

That aside, I'm pretty strongly opposed to the changes to <S03> and <G27>. I have e-stopped our robot in the past when there wasn't an impending safety issue. Once, the battery in our Chicklet ran low, causing it to send out random commands, and causing the robot to start chewing itself up. In retrospect, unplugging all the controls would have had the same effect, but we couldn't make that diagnosis during the match, and it was a lot quicker to just disable the robot. In another case, the robot took a major impact, a 6-gauge wire came loose, and we lost power. Hitting the e-stop deactivated the hurricane light over our driver station, giving the other alliance a signal that they didn't need to run into us any more. These are not safety issues, but I feel that we're well within our rights to protect our robot as best we can when things go awry.

I fully agree with Chuck that a non-responsive robot is a potential safety issue, even if it isn't apparent to an outsider. Remember the 8.3V glitch from 2006? If you were watching the Operator Interface, you could tell that the robot was about to flip out. I believe that my drivers and I are the people most qualified to determine if our robot is potentially unsafe, and I really resent that now I'm going to hesitate before I e-stop, even if there's an absolute safety hazard, so I can think about whether the head ref will see it the same way I do. That's not safe.

If this rule stays on the books until the competition, I'll likely instruct my drivers to yank the Ethernet cable out of the Classmate in emergency situations, safety-related or not; no rule prohibits it, and I'm expecting that FMS would react as if you e-stopped. GDC, please reconsider.

[dodar]

I like the addition of being able to control a ball with a mechanism that goes above the bumper zone

[JesseK]

Originally Posted by Karthik

The changes to <S03> and <G27> have eliminated some fun strategies. However, these changes do make sense considering it's called an "Emergency Stop".

It's posts like these that are the reasons that the GDC must be so strict with their intent

[Don Wright]

Originally Posted by jgannon

Can you elaborate? I'm having trouble envisioning any strategic benefit to e-stopping your robot that couldn't be achieved through the control system.

Your opposing alliance can reliably get an 8 point hang from the center field position of the tower.

Before the 20 second final period starts, you drive your robot to the position they need to be in and you block the tower (even touching their tower) and press e-stop.

If they can't move you, you now stopped them from getting 8 points and because you are e-stopped, you can't get any penalties...

Well...not anymore...

[jgannon]

Originally Posted by Don Wright

Your opposing alliance can reliably get an 8 point hang from the center field position of the tower.

Before the 20 second final period starts, you drive your robot to the position they need to be in and you block the tower (even touching their tower) and press e-stop.

If they can't move you, you now stopped them from getting 8 points and because you are e-stopped, you can't get any penalties...

Well...not anymore...

Aha, that's kind of cute. Thanks for explaining. Nonetheless, I still see a lot of problems here:

I'm not convinced that this needed to be fixed. It's not the cleanest tactic, but it's clever and not a game-breaker.

I'm not convinced that it couldn't have been fixed without touching <S03>. Instead, further change <G27> to void the clause when it is being used as part of an intentional defensive strategy.

I'm not convinced that it's been fixed as-is. The same effect is still very achievable without violating <G34> and <G35>, particularly since the defender is protected by <G13>.