Low Goal Defense
 

Is it valid to extend an appendage less than 20 inches into the low goal from the side, as a form of defense? There is a space from the side when the robot is in the goalie area, and an appendage could be extended into the low goal from this.

Re: Low Goal Defense
 

An appendage that is less than 5 feet (60 in) from the ground is legal, as long as it stays within 20 in of the frame perimeter. As far as the legality of putting that appendage into the low goal, that's not specified, so that's a Q&A question. I wouldn't put it past FIRST to outlaw that.

Re: Low Goal Defense
 

There is a rule (forgot the number) disallowing actions by a robot that interrupt the flow of the game. So, covering all three open faces of the goal could only be done intermittently, like while the ball is arriving.

If your blocking device leaves too little room for the ball to enter goal, and it is maintained in that blocking position while a robot is trying to insert the ball into the goal, then you would likely get penalized.

-Dick Ledford

Re: Low Goal Defense
 

This strategy is not a violation of the blockade rule. The blockade rule's key requirements are 1) multiple robots 2) attempting to interrupt game flow by preventing movement past the multiple robots.

Re: Low Goal Defense
 

Blocking INSIDE the low goal is a pretty bold concept. Although it seems to comply with all the rules (20 inch extension rule, etc.) I see no mention of blocking the goal itself. In other words, it appears it is perfectly legal. It would be a good question for FIRST Q&A. Very bold idea. Good luck.

Re: Low Goal Defense
 

Placing your robot appendage(s) into (or over faces of) the cube of the low goal at a spot(s) intended to redirect the balls from entering the goal could also be considered possessing their ball, since you are obviously intending their direction to go away from the scoring direction.

-Dick Ledford

Re: Low Goal Defense
 

Touché. I overlooked that rule. I take back what I said. It is most likely not legal. I would still ask FIRST though.

Re: Low Goal Defense
 

Then wouldn't having any method of blocking the balls in the 6 inch cylinder also be "possesion"? What is the difference between that and the appendage to the low goal?

Re: Low Goal Defense
 

If it is legal, they will most likely make an amendment to clarify that making it illegal, considering its not exactly in the spirit of FIRST :/

Re: Low Goal Defense
 

3.2.3.4 G12, the rule which disallows the "launching" of an opponent's ball, also defines "deflecting" as "being hit by a propelled BALL that bounces or rolls off of the ROBOT." Deflecting is legal with regard to contacting the opponents' ball. An arm extending into the low goal would be considered to deflect the ball, not launch it, for it is merely being hit by a ball projected by the opposition.

Re: Low Goal Defense
 

Just because something is not in the spirit of FIRST (whatever THAT means--trust me, everybody has a different take on that, including the GDC) does not mean that it is illegal, or that it will be made illegal in the future.

For example, in 2010, I'm sure a lot of people thought that catching a ball right off the return was "not in the spirit of FIRST", particularly when it was returned to pretty close to the goal. Never ruled illegal, though, and multiple robots did it.

I'm thinking that there won't be a change to say it's illegal, partly because there's that other low goal and it's very difficult to block them both.

Re: Low Goal Defense
 

Well then blockading the low goal with stationary robot body and any appendages protruding into the goal may be technically legal, but if the bot attempting to score merely presses the ball against your bot's appendage(s) or body, that would likely trigger the "possessing an opponent's ball" penalty, so it's too risky IMO.

I suspect a new rule will be added to make inserting appendages into an opponents low goal illegal.

-Dick Ledford

Re: Low Goal Defense
 

In this case it would actually be the other alliance being penalized. You can't force another robot into taking a penalty.

Re: Low Goal Defense
 

The question would be who is forcing the result to happen. That could go either way. If your bot is defending mine, and I try to shoot past you, but ball sticks in your robot, are you saying you won't be penalized, because my bot forced the penalty on yours by merely shooting?

Unless my shot was not headed toward any valid target, that would be an unlikely ruling, and I suspect my bot pushing ball into low goal with your bot's appendage preventing scoring would also yield penalty to your bot.

I guess the critical factor is whether your bot remaining stationary during any contact with ball absolves your bot of receiving any penalty. If so, then it seems like a seriously good defensive strategy.

-Dick Ledford

Re: Low Goal Defense
 

Possessing the other Alliance's ball is directly stated as a penalty (G12), so if the ball gets stuck in your robot, you will get a penalty. However, if the other alliance came and purposely put their ball on/in an opposing robot, they would most likely receive a technical foul under G16. Errant shots should not receive G16 penalties, though.

I don't think low goal defense will ever be a penalty, though. In the blue box for G12, deflection is explicitly stated as legal and not possession (“deflecting” - being hit by a propelled BALL that bounces or rolls off the ROBOT).

Re: Low Goal Defense
 

You are over thinking this. Since:

A BALL is considered SCORED in an ALLIANCE’S GOAL if
A. a ROBOT causes one (1) of their ALLIANCE’S BALLS to cross completely through the opening(s) of one (1) of
their ALLIANCE’S GOALS without intervening human contact,
B. the ALLIANCE ROBOT last in contact with the BALL was entirely between the TRUSS and their ALLIANCE’S
HIGH GOALS, and
C. the BALL is not in contact with any ROBOT from that ALLIANCE.

This means you can simply push into a low goal, you have to launch/throw into the front, side top of the low goal. I think this is harder than people think. Defense on low goals is easy, put stationary robot with a 20 inch extension by the corner and that low goal is un-scorable. - However that leaves the other low and both high goals open, plus your defensive robot isn't helping your alliance score points.

Re: Low Goal Defense
 

Considering that deflections are specifically called out as not being possessions, and thus legal, yes, I would say that remaining stationary prevents any penalty.

Re: Low Goal Defense
 

This is a very interesting take on the definition of SCORED. I am assuming that you meant to say "can't" as the 4th word in your description. If not, I apologize for analyzing something that you did not intend to say.

I am pretty sure that a ball which a robot pushes into the low goal will still be considered SCORED. In this situation, after the pushing robot has moved away:
A. The BALL is completely through the opening of one GOAL
B. the ALLIANCE ROBOT last in contact with the BALL is entirely between the TRUSS and their ALLIANCE’S
HIGH GOALS
C. the BALL is not in contact with any ROBOT from that ALLIANCE.

Hence, all of the criteria for SCORED are met, and the BALL will be considered SCORED.

In a different scenario: a robot pushes the BALL into the GOAL with a fist-like mechanism that extends into the GOAL. As long as the fist is touching the BALL, the BALL is not considered SCORED since it is in contact with the ROBOT. As soon as the contact is broken however, the BALL will be considered SCORED.

Re: Low Goal Defense
 

in rule 3.1.4 c in game manual, it states"a ball is considered scored in an alliances goal, if the ball is not in contact with any robot from that alliance", does anyone understand thios rule. is it simply that the ball must be fully disengaged from the robot at games end?

Re: Low Goal Defense
 

Due to team update #1, this is no longer legal. Good thoughts though.

see:

http://frc-manual.usfirst.org/Updates/0#term127

or this thread

http://www.chiefdelphi.com/forums/sh...hreadid=124255

Re: Low Goal Defense
 

Erm ... not quite true.

The low goal can still be blocked by an extension IN FRONT of the low goal, just not into the low goal.

Re: Low Goal Defense
 

With team update 1, you can extend to go around, but not within. I believe that was an earlier strategy? To help burgeon this strategy, If you put a slide drive, and build a robot that could block a goal on either side, you could just strafe side to side, going in the direction of the opposing robot. Put a vertical extension on this bad boy and you'll also be blocking the high goals as well. I think this is brilliant.

Re: Low Goal Defense
 

What does game's end have to do with a ball being considered scored?

If a ball enters an alliance's goal, it needs to not be in contact with any robot on that alliance to score. That simple.

The rule you may have been thinking of is R7, in 4.1.7, which simply says that you have to be able to remove the ball while the robot is unpowered.

Re: Low Goal Defense
 

So no there is an explicit rule saying you can't do that