Hey guys, here is the design of our robot made up in Inventor. What do you think? This is our rookie year, so all criticism, suggestions and questions are welcome! Here are links to all of our views! (I can’t figure out how to post a photo!)
<R16> is the number…But the cylinder is not part of the rule; the measurement is point-to-point on any part of the robot.
Edit:
Jason and Ryan, note that the cylinder part is in parenthesis and is preceded by “e.g.”, which means “for example”. Q&A clarified that it was an example and not the rule last week.
And to post pictures on CD, go to CD-Media and there should be a little link that says “upload” under “Photos” (generally, all images). There are some restrictions, mainly file type and size.
<R16> Once the MATCH has started, the ROBOT may assume a PLAYING CONFIGURATION that
exceeds the size dimensions specified in Rule <R11>. While in the PLAYING
CONFIGURATION, the ROBOT may expand up to a maximum horizontal dimension of 80
inches (e.g. all parts of the ROBOT must fit within an imaginary 80-inch-diameter upright
cylinder). There are no height limits for a ROBOT in its PLAYING CONFIGURATION at any
time after the start of the MATCH.
Thanks for mentioning that, We just measured out our robot and such, and it should be able to fit that rule as long as we don’t deploy the full arm to pick the trackball up. Thanks!
I would think about reinforcing that arm. Arms that are only one piece of chassis metal thick can be prone to serious swaying, anyone know saw us in Silicon Valley knows what Im talking about.
From the looks of your grabbing mechanism, they would violate rule R05 which states that teams must prevent harm to game pieces from sharp points or pinch points, which seems to classify the end of your grabber.
Will you fit in you starting dimensions, the grabber looks far too wide
I really like the way you’re actuating your claw. It’s a really good design and it looks reliable. Like everyone said, just make sure you’re within 80" and reinforcing your arm. It looks great.
So, I’ve been reading rule <R16> and I was wondering, our arm has the capability to go past 80 inches because we need to be able to lift a trackball up to the overhead platform. We don’t plan to extend our arm past the 80 inch limit horizontally, but is our arm illegal anyway because it can go past 80 inches?
If you can go past 80" horizontally, but never do, you’re ok per this Q&A answer http://forums.usfirst.org/showthread.php?t=8181. If you can restrict it in software, that would be wise, so that you can easily demonstrate compliance and to prevent mistakes in the heat of competition.
I had a similar idea as this for herding the ball rather than picking it up - but one challenge to be aware of is that the overall width and length of the robot must not exceed robot limits at the starting position (28" x 38" I believe). Once the match starts then you can deploy your mechanism to be larger than that.
then, of course, you have the 80" rule that others have mentioned.
Make sure you understand how the pneumatic system works. As rookies last year, we designed an arm that bears a strong resemblance to yours, but didn’t realize that the pneumatic cylinders can be either all the way out or all the way in, not stopped in the middle with the provided parts. We came up with a hack that used two solenoids per cylinder to achieve midpositions, but we had major control problems and ended up having to remove our arm. The cylinders you have also look undersized to me; I have doubts they will be able to hold the arm and trackball up.
That’s a really cool design, just avoid making the mistakes we made with pneumatics.
Have you done any rough calculations of the forces required to raise such an arm with the weight and leverage involved? Especially with the limited air pressure and volume available… Can anyone help them out here?
We wanted to perform those calculations to see if our arm was feasible, but nobody quite knew how to do them, and we couldn’t find a website that explained the process, so if anyone could tell us how to caculate those things, that would be great!
I’d also like to thank everyone who’s helped us out, when we made this thread, we thought we would get some help, but the amount of help we got is surprising. Thanks so much!:yikes:
Hey Maple Grove, this is Anoka, I was wondering what the dimensions of the circular pieces of the claw, and how they fit within the robot dimensions. It look’s like a solid design. Good luck this year!
Ryan, do a search on “class three lever”. Just try to do the calculations on the middle elbow joint, ignoring the rest. It isn’t too hard to “ball-park” it.
Better yet, borrow a bowling ball. Hold it straight down by your side, and have someone try to lift your arm and the ball by pressing up on the bottom side of your arm an inch or two below your elbow joint. That will give you an idea of the force necessary to raise that arm. You only have so much air pressure available. You can “super size” the cylinder, but you only have so much energy available in the compressed air tank and what the compressor can deliver on demand.
I would be concerned with dropping the ball. I’m not sure that claw will be able to squeeze it tight enough. Some drawer-liner will definitely go a long way in providing “grip” to your manipulator.
I’d also be concerned with such skinny pieces of wood being broken. Our manipulator last year stuck out less than yours, and it got smashed several times :(. What we eventually did was wrap the wood with fiberglass; this made it very strong and it never broke again.
Just some tips to improve your design. Otherwise I think it is pretty slick! Good job CAD-ing your robot your rookie year! It took us 11 years before we did that!
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