Quote:
Originally Posted by JesseK
Imagine what happens to the trailer, practically speaking, when it starts whipping around the back of the robot. The trailer will want to tip left/right (aka roll) when it changes lateral directions. This puts extreme forces on the contact point of the trailer tongue and the robot hitch. Enlarging the hole at the contact point allows for the trailer to roll and tip slightly without damaging the trailer tongue or the hitch. I for one am very glad of this change as it reduces the torsional reinforcement our hitch mount needs since our drive train is designed to strafe and drift. Part of engineering is to at least have considered the realm of implications and possibilities of a particular design before going forward. It's impossible to figure them all out, which is why engineers usually create room for error in their designs.
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1. The original hitch design (Prior to REV A) allowed the trailer to roll freely. REV A (before the kickoff) added a close fit pin which eliminated this roll.
2. If the GDC wanted to allow limited roll, it could have modified the hole added by REV A. This would not have affected pitch.
3. REV B now allows about plus or minus 10 degrees of roll and
pitch. Under some pitch loads, it also allows the 1018 steel cylinder to be levered against the aluminum C channel.
4. I'm glad that you think this change benefits your design. When the design of a component changes there are usually some that benefit, some that are harmed, some for which the change is irrelevant, and some who remain in ignorant bliss.
Quote:
Originally Posted by JesseK
Why do people consistently post that they think the GDC is out to get them when they clarify the rules? 
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I don't know. But what does that have to do with this discussion? We certainly don't think the GDC is out to get us. And this certainly isn't a clarification! But the fact is that the design of a major component has been changed in a significant way and we still think that such spec changes should at least be accompanied by an explanation.
It may be that this is new territory for the GDC with a major component of the robot supplied as part of the field. This introduces a new element to the engineering - mating with an externally specified and supplied component. I think that this is a good thing that opens up new opportunities. But I think that specs for a component of the robot system and a the specs for game piece are of a different character. If the intent is for the piece to be an integral part of the robot on the floor, then the specs should be frozen at kickoff and not changed without both good reason and cogent explanation.
Just my $0.02