pic: Custom Chassis 2576

[EricH]

Originally Posted by TheMadCADer

You've misunderstood what I'm talking about regarding the string. This string is a fixed part of the robot, not the visual aid. The string used to identify and measure the Frame Perimeter is different and irrelevant.

I was directly responding to your saying that R2 and the definition are at odds--no other part of your post, or any previous post. They aren't--and they still aren't. If you wrap a string, and it remains part of your robot, it isn't structural (unless you know of uberstrong string that I don't), and therefore is not the frame perimeter.

Let's break R2 down into what it's ACTUALLY saying.

The ROBOT must have a FRAME PERIMETER polygon defined by the outer-most set of exterior vertices on the ROBOT (without
the BUMPERS attached) that are within the BUMPER ZONE, contained within the BUMPER ZONE, that is comprised of fixed, non-articulated structural elements of the ROBOT. Minor protrusions no greater than 1⁄4 in. such as bolt heads, fastener ends, and rivets are not considered part of the FRAME PERIMETER. [Replaced "Frame Perimeter" with its definition and removed a repetitive section.]

Now, what part of that would allow a string, which is not made of unobtanium, to define even part of the frame perimeter? Nope, I'd call it a minor protrusion. It's not structural--strings don't exactly push well, and it's difficult at best to build a frame completely in tension--and the argument could be made that it can articulate. You tryin' to use the tailor's measure as a belt?

They aren't saying different things. They're saying the same thing in two slightly different ways. If someone were to show up at inspection and try to claim a string as a structural element, they'd be rebuilding that part of their robot if any other bumper rules--particularly support--were violated.


Now, with respect to the rest of your last post: Woefully inadequate. After all, what's to prevent someone from showing up with bumpers on a post on a corner mounted in such a way that the first hit leaves them disabled for a bumper rules violation? I don't know if you've ever inspected, but I have--if you open up the support rules like that, an awful lot of teams will be missing their 2nd matches due to inadequate supports, just trust me on that. If simply re-inspecting is going to be the solution, sorry, but I really hope that you're volunteering, 'cause by the time teams come looking after their first match with inadequate support, the few inspectors still "on duty" will be focusing in on teams with more pressing issues--like an illegal motor, or a faulty pneumatics system, or their first match is in ten minutes and they need a full inspection.

Support needs to be defined in such a way that it's relatively simple for an inspection team to determine that a team is good or not. "Looks good" from an inspector may or may not be adequate validation for a design--I can think of several inspectors that I'd trust that from, because they've been around a while; others that I've heard of, not so much. Try writing the rule such that the support test is included in the rule--say "RXXXX: Bumpers shall be adequately supported. Inspectors will check by dropping a 5-lb weight onto the bumper from 5' above it; if the bumper moves or breaks, it shall be rebuilt until it passes."

[TheMadCADer]

Originally Posted by EricH

I was directly responding to your saying that R2 and the definition are at odds--no other part of your post, or any previous post. They aren't--and they still aren't. If you wrap a string, and it remains part of your robot, it isn't structural (unless you know of uberstrong string that I don't), and therefore is not the frame perimeter.

Let's break R2 down into what it's ACTUALLY saying.

The ROBOT must have a FRAME PERIMETER polygon defined by the outer-most set of exterior vertices on the ROBOT (without
the BUMPERS attached) that are within the BUMPER ZONE, contained within the BUMPER ZONE, that is comprised of fixed, non-articulated structural elements of the ROBOT. Minor protrusions no greater than 1⁄4 in. such as bolt heads, fastener ends, and rivets are not considered part of the FRAME PERIMETER. [Replaced "Frame Perimeter" with its definition and removed a repetitive section.]

Now, what part of that would allow a string, which is not made of unobtanium, to define even part of the frame perimeter? Nope, I'd call it a minor protrusion. It's not structural--strings don't exactly push well, and it's difficult at best to build a frame completely in tension--and the argument could be made that it can articulate. You tryin' to use the tailor's measure as a belt?

They aren't saying different things. They're saying the same thing in two slightly different ways. If someone were to show up at inspection and try to claim a string as a structural element, they'd be rebuilding that part of their robot if any other bumper rules--particularly support--were violated.


Now, with respect to the rest of your last post: Woefully inadequate. After all, what's to prevent someone from showing up with bumpers on a post on a corner mounted in such a way that the first hit leaves them disabled for a bumper rules violation? I don't know if you've ever inspected, but I have--if you open up the support rules like that, an awful lot of teams will be missing their 2nd matches due to inadequate supports, just trust me on that. If simply re-inspecting is going to be the solution, sorry, but I really hope that you're volunteering, 'cause by the time teams come looking after their first match with inadequate support, the few inspectors still "on duty" will be focusing in on teams with more pressing issues--like an illegal motor, or a faulty pneumatics system, or their first match is in ten minutes and they need a full inspection.

Support needs to be defined in such a way that it's relatively simple for an inspection team to determine that a team is good or not. "Looks good" from an inspector may or may not be adequate validation for a design--I can think of several inspectors that I'd trust that from, because they've been around a while; others that I've heard of, not so much. Try writing the rule such that the support test is included in the rule--say "RXXXX: Bumpers shall be adequately supported. Inspectors will check by dropping a 5-lb weight onto the bumper from 5' above it; if the bumper moves or breaks, it shall be rebuilt until it passes."

PM'ed. This isn't the place.

[Duncan Macdonald]

Did you actually put it on a scale to verify the weight savings? I would be surprised if there was a significant savings by using a material ~45% as dense and twice as thick.

The frame as configured does not pass bumper rules and needs additional thickness in the corners. It does just squeeze into the size limit but how do you expect an inspector to measure 0.005 or 0.020 with a tape measure that probably measures in 16ths? Do you lose that much usable space by making the frame a quarter inch narrower? I promise it will get you through inspection faster.

Do you have your manipulator mounting planned? One of the nicest features of the kit frame is that there is a mounting point every inch.

It took a long time for one of my teams to learn that just because you have resources available doesn't mean it is smart to use them.

[jsasaki]

Make sure you grease your gearboxes!