legality of bolt and screw heads breaking plane of chassis meeting bumpers

[artdutra04]

Originally Posted by Daniel_LaFleur

Also, when asking for the reasoning, you might want to consider "because we said so" as a valid answer, lest your customer take his multi-billion dollar buisiness elsewhere. You see there may be many possible reasons why they cannot disclose information to you (IP issues?). Consider this just a design constraint.

Maybe I should have stressed more that issues in life like this are never white-and-black, but usually blurry grey areas that need context on a case-by-case analysis.

Doing any kind of classified work with need to know basis obviously means you don't ask questions and just do your job. But for non defense/classified work, I've seen first hand or heard of many other stories where the given specs were indeed misguided, and upon further back-and-forth questioning, a mutually beneficial agreement was found.

One such case a professor of mine told me recently, was of a large manufacturing corporation contracting out work for a french fry sorting machine. But when one did the math, their requested weight tolerance for the bag of french fries was 1/4 the weight of a single french fry. How would you bag something as multifarious as french fries and keep a weight tolerance of 1/4 of a french fry? Had my professor's company simply accepted these specs without asking questions, they would have had to create an unnecessarily complex sorting machine to sort individual french fries by weight and bag them one at a time, possibly with a french fry slicer to cut fries in half to get within the given weight specs. This would have been a much slower and more expensive machine than would have been necessary, and would have cost the client more money (both initially and in annual O&M costs) and possibly would have cast the contracted company in a bad light for coming up with an unnecessarily complex and expensive solution. But...

When they asked their client and showed them the math that the given specs were +/- 1/4 of a french fry, the client acknowledged the error and redid the specs to allow a wider error range.

For myself personally, I've worked for a company which produced an integrated system for clients that lacked X feature which all competitors had, but only because our integrated system was better designed to eliminate the need for X feature without any side effects other than a cheaper bottom line. Because most competitors had X feature, bids would often come in requesting this given feature, despite the fact that X feature was notorious for never actually working in the environment they were subject to. Nearly all of the time, when we talked to the clients and explained that our system was designed in a way to eliminate the need for X feature, saving initial and O&M costs, and that most competitors' X feature would almost always fail within three months of installation (and would then be bypassed anyway by the client's technicians), the clients would come to a mutual understanding and accept our bid.

Thus, it's all about context. Sometimes it's appropriate to question the given specs to better serve the customer (potentially saving them money), other times just do your job and don't ask questions.

Originally Posted by Daniel_LaFleur

All in all, you might consider just putting your efforts into making sure that those who didn't follow the letter of the rule still get on the field, rather than bash those who put the design constraint in place.

Both can be done without negatively affecting each other. And I understand your reasoning on this; plenty of times in the past I've posted that teams shouldn't whine when other teams have "better" robots or "better" facilities, but they should instead work harder to become one of those said teams. But for those cases, that's an example where the cause for the individuals' whining can be directly attributable to their own specific actions (e.g. if they work harder, they can fix the situation they are in). In this case, no matter how hard one works, the bumper rules are still the bumper rules, and thus it's acceptable to "whine" to make sure those who could rectify the situation have a true understanding of the impact of said rule on the community at large.

I've personally always been one who calls things like they see it. Maybe it's blunt, but it's better to get right to the point than dance around the tree sugarcoating problems and hiding how they truly impact the affected people or entities. Bolt heads behind bumpers are completely understandable, and so is the allocation for small pockets in the plywood backing to allow bumpers to sit flush for strength reasons.

But when the rules as written would not even allow for a 1/16" high button-style rivet head above or below the bumpers... that's just a needlessly restriction on FIRST teams. 50-75% of robots should not show up at their first event unknowingly illegal; if it does occur, then that's obviously a sign the rules were too bloated and/or full of ambiguities to be comprehended by the average Joe FIRSTer.

[Dick Linn]

Robots shall have a base-plate of prefabulated plywood, surmounted by a malleable logarithmic casing in such a way that no two spurving bearings can be in a direct line of contact with another robot's pentametric fan. ...

[Dmentor]

Originally Posted by artdutra04

Doing any kind of classified work with need to know basis obviously means you don't ask questions and just do your job.

At risk of going even farther off on a tangent, I thought I’d clarify this sentence. Working in this type of environment does not prohibit communication instead it limits how and with whom that communication occurs. If anything, communication within these projects can be even more crucial because we are frequently pushing the envelope of technological feasibility. My experience across a spectrum of projects with security restrictions is that engineers maintain an almost constant dialog with program management, peer engineers, customer engineers, R&D labs, subcontractors, etc. Within really complex systems, it is nearly impossible for any one person to be an expert in all detailed aspects. Thankfully, we work in integrated teams so that we don’t have to. There are definite down sides of working in restricted environments such as this but you can also do some really cool engineering.

[RRLedford]

The requirement for 100% full, CONTINUOUS, intimate contact of bumper plywood with the entire perimeter of the frame is rather excessive. Especially when there is no similarly draconian requirement for exactly where within the 5" height of the plywood that the frame makes contact. If frame only touches at the top or bottom 1" of the plywood, the bending torque force with a 4" cantilever of unsupported plywood at middle of side is also very serious with dynamic impacts!
It would make much more sense to have a simple spec for a maximum allowed spacing distance between points of support of frame in contact with bumper's plywood. If this spacing distance was between 3-6" the chance of breaking plywood would be minimal.

We currently have three aluminum plates on all four of our bumpers, one at each end and a 3rd in the middle. They are mounted with flat head screws going both ways, outward into T-nuts on plywood and inward into T-nuts inside frame slots. Screw heads are all countersunk into the thickness of the aluminum plate. The plates also stick up higher than the top of the bumper so that we can access the mounting holes for the plate-to-frame screws.

We were assuming that these plates were part of the bumper, since they fit within the 1" max. thickness of plywood plus mount H/W, but now we have the issue of plates only giving intermittent contact with frame-to-plywood. We also have the issue of plates sticking up past plywood. Is this still legal, as long as the aluminum plates still remain within the 10"-16" above floor bumper zone?
Perhaps we should consider treating the plates as part of the frame, and then filling in the gaps between the plates with similar thickness aluminum bar along the frame face, to give a 5mm expanded frame perimeter. Fortunately, we are not at the max 28"x38" size already and have some room to do this.
-Dick Ledford

[Dick Linn]

Somehow, I prefer the days of battle scars to the bumpers of today.

[Al Skierkiewicz]

Dick,
I am your Lead Robot Inspector in Chicago. I will lead you through the fine points in two weeks. We will get you playing, guaranteed.
BTW, I assisted the original Francis Parker team, Frank's Garage and came to the school then to check on progress.
See you in a few weeks or you can come up to Milwaukee next week and see how things go at a regional event. If nothing else, come up on Saturday and check out other teams and watch the game play. I will be inspecting there as well. Just ask for Big Al and someone will point me out.

[Pausert]

Originally Posted by Dick Linn

Somehow, I prefer the days of battle scars to the bumpers of today.

I like to imagine my robot with mensur schlager scars.

[Al Skierkiewicz]

Originally Posted by Pausert

I like to imagine my robot with mensur schlager scars.

Flashes to a darkened shop, late at night, candles burning and the sound of swishing blades in the air...