Section 4.3.1<S03> and turrets

[JoelP]

<S03> Shooter Mechanism must remain inside the ROBOT - Any mechanism used to throw balls must be
contained within the original 28” x 38” x 60”starting envelope of the ROBOT and must be shielded such
that the mechanism cannot make contact with other ROBOTs. A ROBOT that violates this rule will be
considered unsafe per <S01>.

I believe this rule was implemented to prevent teams from building huge expanding shooting mechanisms that go to the 5'x5'x5' limit. However, I'm wondering if this rule also applies to rotating turrets. According to this rule, shooting mechanism on a rotating turret would have to be limited to 28" in diameter or it would break out of the 28"x38"x60" starting envelope when the turret is turned to the side. Did FIRST really intend to limit shooting mechanisms on turrets to 28"?

Diagram to help explain:
http://i37.photobucket.com/albums/e65/joel52490/ex.jpg
grey=robot with maximum dimensions
blue=turret
red=shooting mechanism
On the right you can see that if the shooter is larger than 28" then it will go beyond the starting dimensions.

Edit: Yikes you guys are fast :yikes:, I'm not sure if it is necessary but I will clarify a bit, the left image is the starting dimensions, completely within the envelope. On the right the turret is rotated 90 degrees and now the shooting mechanism is outside the starting envelope but it hasn't expanded or changed dimensions whatsoever, only orientation.

[Matt Adams]

Did FIRST really intend to limit shooting mechanisms on turrets to 28"?
Yes.

Matt

[Greg Needel]

I would interpret the rule to mean that your entire system barrel and all must fit within the envelope of the bot. So your situation would not be illegal.

[Kelvin Ng]

[QUOTE=JoelP]<S03> Shooter Mechanism must remain inside the ROBOT - Any mechanism used to throw balls must be
contained within the original 28” x 38” x 60”starting envelope of the ROBOT and must be shielded such
that the mechanism cannot make contact with other ROBOTs. A ROBOT that violates this rule will be
considered unsafe per <S01>.

I believe this rule was implemented to prevent teams from building huge expanding shooting mechanisms that go to the 5'x5'x5' limit. However, I'm wondering if this rule also applies to rotating turrets. According to this rule, shooting mechanism on a rotating turret would have to be limited to 28" in diameter or it would break out of the 28"x38"x60" starting envelope when the turret is turned to the side. Did FIRST really intend to limit shooting mechanisms on turrets to 28"?
QUOTE]

For turrets, sounds like the cannon has to be contained within the 28" width limit.

EDIT: seems like everybody is jumping onto this question. =P. I think the rule should be reworded so:

<S03> Shooter Mechanism must remain inside the ROBOT - Any mechanism used to throw balls must be contained within that particular ROBOT's starting dimensions and must be shielded such that the mechanism cannot make contact with other ROBOTs. A ROBOT that violates this rule will be considered unsafe per <S01>

The entire intention of the rule is stated in the third line, so the mechanism does not make contact with other robots. Therefore, for turrets, the cannon must be at longest, 28".

[Matt Adams]

I would interpret the rule to mean that your entire system barrel and all must fit within the envelope of the bot. So your situation would not be illegal.

I guess I disagree. This seemed really obvious to me, but it's possible I'm wrong.

The rules say you must start in a 28 x 38 x 60 box.

The rules say that can expand to a 60 x 60 x 60 box.

Why would they have this rule if they didn't intend to constrain this mechanism to the original robot footprint? If it doesn't mean to contrain the mechanism as the pictures show, isn't this a redundant rule on a specfic component?

Matt

[MikeDubreuil]

<S03> Shooter Mechanism must remain inside the ROBOT - Any mechanism used to throw balls must be
contained within the original 28” x 38” x 60”starting envelope of the ROBOT and must be shielded such
that the mechanism cannot make contact with other ROBOTs. A ROBOT that violates this rule will be
considered unsafe per <S01>.

Let me just say this question should be answered by FIRST Q/A or maybe someone from the GDC can chime in....

I think this is a rule where a judgment call on safety must be made. Whether your robot is unsafe depends on where the "throwing mechanism" is on your robot. This rule depends on the interpretation of throwing mechanism. I would say that the throwing mechanism is the device that actually transfers power to the ball. For instance, a spinning wheel, catapult or whatever. That must be in the 28" x 38" x 60" package. However, if your cannon is just guiding the ball to a certain angle I think it can come out of the original package, as long as it doesn't extend past 5' x 5' x 5'.

[Goldeye]

As the rule is worded. it should stick to the 28 inches. However, it should be worded as Kelvin suggested...which would only make the space smaller, not larger
Nonetheless, I don't think the rule's intent would ever allow the shooting mechanism to be out of the small box.

[JoelP]

Let me just say this question should be answered by FIRST Q/A or maybe someone from the GDC can chime in....

I think this is a rule where a judgment call on safety must be made. Whether your robot is unsafe depends on where the "throwing mechanism" is on your robot. This rule depends on the interpretation of throwing mechanism. I would say that the throwing mechanism is the device that actually transfers power to the ball. For instance, a spinning wheel, catapult or whatever. That must be in the 28" x 38" x 60" package. However, if your cannon is just guiding the ball to a certain angle I think it can come out of the original package, as long as it doesn't extend past 5' x 5' x 5'.

I think Mike is on to something here. If the throwing mechanism is a spinning wheel and it remains contained within the starting envelope in the turret, then it wouldn't matter if part of the guiding cannon/tube/etc. extended past the starting dimensions. Since it refers to <S01>, the rule is probably intended to keep fast spinning mechanisms and other dangerous mechanisms contained well inside the robot, instead of hanging off the side. However, I believe if the throwing mechanism used was a conveyor belt design that ran the length of the cannon/tube, then it would be in violation of this rule.

[Kris Verdeyen]

<S03> Shooter Mechanism must remain inside the ROBOT - Any mechanism used to throw balls must be
contained within the original 28” x 38” x 60”starting envelope of the ROBOT and must be shielded such
that the mechanism cannot make contact with other ROBOTs. A ROBOT that violates this rule will be
considered unsafe per <S01>.

You drew it wrong - the shooting mechanism didn't escape the 28"x38"x60" box, the base did, which is, of course, perfectly legal. Of course, it still has to be shielded from hitting other robots, but with ten extra inches you can use now, I'm sure you can figure something out.

[Salik Syed]

clever... Kris!
yeah ... your turret is still in side the 28X38 box... its just your chassis thats sticking out! lol

[geeknerd99]

I posted a thread on this earlier. (http://www.chiefdelphi.com/forums/showthread.php?t=41537)

It's a bit dicey, but when you factor in 360 degrees of spin, you're given a 28 inch square footprint in order to build your turret. That's pretty big, unless you're utilizing some sort of launch mechanism we haven't thought of.

Somebody should probably get this to the Q&A sometime, if it hasn't been done already.

[Cyberguy34000]

Wow Kris! That's clever! I only hope the refs have a similar perspective...

[Pat Fairbank]

From the FIRST Q&A System (http://forums.usfirst.org/showthread.php?t=185):

Q: Rule S03 states that the shooter mechanism must remain within the original starting envelope of the robot. If a robot uses a pitching machine style shooter, followed by a barrel to direct the ball, does the barrel count as part of the shooter mechanism? I assume the intent is to keep moving/dangerous parts out of the reach of other robots?

A:The barrel does count as part of the shooter mechanism and must remain within the original starting envelope.
It sounds like anything that is part of the shooting mechanism (turrets, barrels, etc..) must conform to this rule.

[Kelvin Ng]

Although this is a bit off topic, remember: when a component of the turret's aim angle is perpendicular to its velocity, the ball trajectory is going to be off a bit. A barrel will exert a force (depending on barrel length) upon the ball sideways, veering the ball off course. In addition, the component of the robot chassis's velocity perpendicular to the ball launcher's aim will also exert a force on the ball in the sideways direction. This might have to be accounted for by programming? Perhaps a shorter barrel would be a better idea, keeping you within your size restrictions. A turret is meant to be able to shoot while the robot is moving from any direction, so a long barrel may make it less accurate.