Official Team 2526 Robot Model!!
 

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!:confused:)

http://s127.photobucket.com/albums/p...onTopview1.jpg

http://s127.photobucket.com/albums/p...nsideview1.jpg

http://s127.photobucket.com/albums/p...omatoniso1.jpg

Re: Official Team 2526 Robot Model!!
 

does it stay within the 80in cylinder rule?

Re: Official Team 2526 Robot Model!!
 

80in. cylinder rule? I can't find that, what's the rule number?

Re: Official Team 2526 Robot Model!!
 

R16 says that your robot must fit within an 80 inch diameter cylinder at all times during the match.

Re: Official Team 2526 Robot Model!!
 

<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.[/edit]

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.

Re: Official Team 2526 Robot Model!!
 

Here's the exact rule

<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.

Re: Official Team 2526 Robot Model!!
 

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!

Re: Official Team 2526 Robot Model!!
 

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.

Re: Official Team 2526 Robot Model!!
 

1. 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.

2. Will you fit in you starting dimensions, the grabber looks far too wide

Re: Official Team 2526 Robot Model!!
 

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.

Re: Official Team 2526 Robot Model!!
 

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?

Re: Official Team 2526 Robot Model!!
 

Theres no height restiction, only a length/width restriction, the 80" rule applies only to horizontal dimensions

Re: Official Team 2526 Robot Model!!
 

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.

Re: Official Team 2526 Robot Model!!
 

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.

Other than that, I really like your design.

Re: Official Team 2526 Robot Model!!
 

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.

Re: Official Team 2526 Robot Model!!
 

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?

Re: Official Team 2526 Robot Model!!
 

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:

Re: Official Team 2526 Robot Model!!
 

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! ;)

Re: Official Team 2526 Robot Model!!
 

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.

Re: Official Team 2526 Robot Model!!
 

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!

Re: Official Team 2526 Robot Model!!
 

Figure out a way to brace the arm from swinging side to side too much. Turning with the ball lifted might well provide a heck of a lot of air drag causing significant problems.

A couple approaches...:
-Simple vertical rails on the side of the arms might help minimize swaying of the arm.
-Line the parts of each arm joint with aluminum plate (3/16 or 1/4, is my suggestion), and run a larger bolt size through that.

If you want help with the calculations, contact a local college with any sort of engineering at it... I'm sure you'd be able to get a professor to donate a couple hours of time doing/showing how to do the calculations to determine which cylinders you'll want.

Definitely make design changes so that you can get those arms in your starting box... You might need to be creative (but smart) with a method of having the claws start folded vertically, and then drop down and lock in place.

Re: Official Team 2526 Robot Model!!
 

Can you explain the hack further? We are looking at a way to get multipositions from a piston and this could be very helpfull.

thanks

Re: Official Team 2526 Robot Model!!
 

Are you sure those pistons will be able to pick up the ball?

Also, since you're using C-channel on the arm, be wary of any twisting that may occur during the match.

It's great that you guys realize the importance of modeling your robot with CAD software!

Re: Official Team 2526 Robot Model!!
 

Take a look at this thread. I tried to explain what we did, and there is in my opinion a much better idea there as well.

Re: Official Team 2526 Robot Model!!
 

hey, i like your design, like evryone is saying about size and sharpness, sharpness can be controled by just makeing that graber more "safe" lol and then the size i thought id through in that i belive that it just has to fit that rule when it is all folded up and in its starting spot but once it is on the go and time is running then you can have it going crazy large like a transformer lol and also i would personaly look at your electrical bord setup, i belive what your doing is right, it just seams "off" to me :D

good luck building!
-Vic, 1510

Re: Official Team 2526 Robot Model!!
 

a couple of things that I would reccomend.

1. Make sure you are with your starting Dimentions (width, and Length)
2. Make sure you have more mass on the bottom, our team had to switch to a low rider so that our center of gravity would be lower...this Trackball is MASSIVE! it will cause your robot to tip.
3. The tips of your end effector look a little dangerous to the field elements.

over all, it is a fabulous design and congratulations for coming up with it so early in the season. good luck and don't hesitate to ask more questions.

Re: Official Team 2526 Robot Model!!
 

hey !!! whats the height and how wide is your robot because before the match starts ... it has to fit within a 38 by 28 inch rectangle ..... doesnt it ???

but nice work !!!!!

Re: Official Team 2526 Robot Model!!
 

You'll be very disappointed with multiple positions using pneumatics. Also remember that gases compress, so if the load on the piston changes, it will move.

It can be done, however, with a double-solenoid valve (3-way), which is an off-the-shelf item. We used the gray solenoid valves, not the blue Bosch ones, and special-ordered them. No need to fool with two solenoid valves and fancy plumbing to modulate the exhaust port....

Don

Re: Official Team 2526 Robot Model!!
 

the design looks great, similar to what we are building.....i dont quite see how yours folds up to fit within the 28x38x60...also as far as cylinders go, you'll need massive amounts of power, get the biggest bore possible for the bottom part of your arm...you might consider a design like this (excuse the poor designing and off scaling but i did it quickly in paint)

Re: Official Team 2526 Robot Model!!
 

Stick with the halos. Halos are your friend! Hence my new sig.

I'm curious as to how you plan to reinforce the halo claws so that a falling/bouncing ball doesn't destroy them. You could make them out of honeycomb aircraft aluminum and build in a break-point at the mount, with black rubber hoses to pad the sharp corners, but even that is fairly heavy. We're still prototyping different things for ours; we love the idea but we're becoming stumped on how to make one that's quality enough to last several competitions.

Still, glad to see a great idea wasn't only ours!

edit -- just noticed something else with your actuation --
It looks great in CAD, but I wonder how you mated up the pneumatic cylinders that are mounted to your 2 halo claws. They're sitting out there, freely able to move. In practice, this has created a problem with our prototypes: when the cyllinder goes out and opens your "claw", the claw is symmetric, and your top and bottom claws are lined up with each other perfectly. However, when the cyllinders go in and your claw closes, I seriously doubt your claws will still line up. The reason is that there is minutely more friction on one side of your claw than the other, and if there are no restrictions on how far inward one side of the claw can go the side with less friction will go past its symmetric position. I hope I'm making sense of this, I'll get a picture of our prototype later if I'm not.

Re: Official Team 2526 Robot Model!!
 

Quote:

Originally Posted by RyanJK (Post 681491) Here are links to all of our views! (I can't figure out how to post a photo! )

Use the last code on the page for the picture.
The code labeled: IMG Code - Forums & Bulletin Boards
Example:

Code:

---

[ IMG ] http://i127.photobucket.com/albums/p129/zrop/Automatonsideview1.jpg [ / IMG ]

---

Without the spaces of course.

Pretty wild design btw.. I would consider strengthening the arm quite a bit. These balls weigh a lot, and especially at 6.5 ft' will make your robot extremely top heavy and put a lot of stress on your arm.
The cylinders look to be less than would need to raise that weight of the ball and the arm. You may want to experiment with that.. or. add in a window strut from a (rear window of minivan for example) in some places to act as a helper.

Consider moving the battery to the rear of the robot for counter balance of your arm. I'm guessing your center of gravity is now more towards the front, which will result in you tipping over when you go to lift the ball.

Your heaviest items on your chassis should all be towards the back (compressor, battery, extra pieces of steel rod mounted in the back.. lol (I'm not kidding.. we've had to do that before) to counteract the action of raising the ball in the front of the robot.

Good luck with the design! Look like a great start.