FIRST Team 2980's 2012 Open Source Robot

FIRST Robot Showcase
1

Hey all,

Team 2980 is once again going to post everything we come up with. We receive a ton of help from the FIRST and Chief Delphi community and want to give back as much as possible.

Our team goes uses the first week for prototyping and design. At the end of the first week we share our designs with the greater community and have them select the design that we will finalize and build. This years plan is to build a robot capable of dumping into the second row, and shooting from the safe zone at the top of the key. From there we hope to shoot for the top and middle row.

We’ll try to post some more detailed shots as we finalize the design today and Monday.

Key things and ideas:

We want to use a belt driven ball harvester to convey balls from the floor to the hopper/dump bucket.

We designed the drive train with a dropped mecanum set up using 4 powered traction wheels 2 inches off the ground that lift the robot up so that the mecanum wheels are slightly protected for driving over the bump.

We want to have a pole slapping mechanism for pushing down the Bridge for the end game.

Issues:

The magical dumping ball hopper…

So making a box that can dump seams easy…trap door in the bottom to let balls in but not out, open top for pouring balls out… use a piston to lift the and tilt the box to just over 90 degrees pouring the balls out into the hoop…Uses gravety…easy peasy.

cannon hopper…Balls come up through the bottom trap door, then a piston pushes them forward in loading them into the cannon…Piston retracts letting another ball light up to be fired…also seams relatively simple…

Now we need to combine those two things into one thing…

Aiming…

The community really wants us to use either a camera/ultra sonic detector combo, or mount the kinect on our robot.

Using the ultra sonic sensor mounted on the cannon… The sensor measures the distance to the wall and regulates the speed of the spinning wheels in order to get the ball to go the right distance based on the desired target height…

The camera would be used to detect the reflective square above the hoop, or for our driver to use to line up shots.

Thinking of using a piece of plastic mounted in front of the camera to calculate the range to the target.

Ok…so those are at least some of our ideas…

Team 2980

2

We’re having a sad day and could use some advice…

We were planning on using the fisher price motors with the planetary gear box mounted to them in order to power our ball cannon…

Given that they are out of stock, and We’re not holding our breath on them being back in stock any time soon…We are going to need another plan.

This is something we have very little experience with. Any ideas?

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Which Fisher Price Motor were you hoping to use? And how many?

4

its not the motor…9013…its the planetary gear box that seams to be the problem. We have two of the 9013s…just no planetary gear boxes.

Sort of hoping they will either come back in stock or someone will have two that they are not using.

I guess…lesson learned…we’ll buy a ton of stuff in the off season just in case for next year.

We may go with the AM gearhead motors…

So we are doing some math to try and figure this one out…

We want the ball moving at up to 27 fps when it leaves our shooter…

So…we figure if 50 percent of the wheel speed goes into the ball as it passes through the shooter…

so rotating 8 inch diameter wheels 3 times a second? so basically we would have to have the wheel spin 4 times as fast as the motors?

my brain hurts at this point…

5

Here is another option, take the first stage (or two, depending on what ratio you want) of plastic gears out of the big plastic FP Gearbox, and you can build a very simply gearbox from those gears. A couple shafts, some bearings, 1/8" Aluminum plates, a little milling and BOOM! FP Gearbox.

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BOOM! FP Gearbox.

Yeah…that is another option we are looking at. We’ll post the solution once we come up with it…

7

Don’t worry the planetaries will be back in stock. You could also use a Cim-sim.

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Relying on gravity with balls like these can be a dicey thing. If they are anything like poofballs they will get stuck at the worst times.

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Ok, so we sort of moved backwards today…The magic bucket hopper is starting to take shape, but it keeps presenting us with new challenges…We somehow didn’t notice that the piston stuck through the middle of the ball harvester…oh reality…why do you mock us?

We are hoping to mock up at least one drive train on Monday along with our field elements (we like to build 2 copies of our robot.)

One hope is that if we can get this thing modeled in CAD, then hopefully the actually building of it will be faster…

Here is to the end of week one…

10

So we seam to have solved a few of the “magic box” problems… We will probably try to make it out of cardboard during Monday’s long meeting.

Thanks for all of the help today. We’ll post the inventor files in the next few days.

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Cool thread, I’ll be following your build progress!

I’m curious, what kind of shop and manufacturing capabilities do you have available? Using the first stage out of the plastic FP gearbox in the kit of parts is an easy workaround for not being able to buy AM planetaries if you have the ability to manufacture transmissions. Here’s an example.

I would echo this statement… you can run into a lot of problems if you rely on gravity/momentum to move a game piece. We have a rule for our design team this year: the ball must be compressed against a roller/belt at all times when it is in the robot. That’s not to say your design won’t work, but you want to make sure you test it enough to ensure it is reliable and won’t get jammed.

Highly recommended! Try to get a quick prototype set up for some of the ideas you’re not certain about to see if they’ll work.

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our shop is a work in progress…We have some tools…band saw and drill press…a mill/lathe combo and some hand tools.

A guy donated a Scratch buillt CNC but it is pretty small and we haven’t cut any shapes with it yet. He’s currently deployed and never got it cutting before donating it.

we have another teacher who was a professional welder in a previous life. he helps with any welding needs which is amazingly awesome.

As for the gear boxes, we just ordered 2 CIM-u-lator gear boxes…We probably should have ordered four, but this one was of pocket for our lead mentor. we would have had to wait for a PO to process and that can take weeks and he is already getting us all the lumber to make our field elements…

now that we found those and have our magic box set up, we should be back on track on monday.

Again, thanks for all of the help today.

Oh, and “CIRE” a guy from wisconsin I believe told us our wheels should be able to spin at about 2000 rpm, so 33 times a second or so to get the distance we need.

Hopefully the fisher price motors we have will hold up.

13

Couple of things. Today was pretty productive. We got the backboard framed up and the backboards cut out…We even got 1 hoop in the mail. Probably should have gotten more.

We got the bridge/bump made. Our bridge isn’t calibrated. It tips way too easily. we’ll have to figure it all out before too long.

One of the Team dads has access to some pretty cool metal working tools. He is going to stamp out our drop brackets with some scrap material at his work. This means we should be able to have a running drivetrain by Saturday.

The frame material gets here this week also. Looking at a busy week.

Finally, we are finalizing our hopper/dumper box. We will need some sort of agitator. Not sure how we’ll work that out. Some were thinking we could add an offset weight to a banebots motor. Hopefully that won’t shake the box to pieces.looks like if things work out wiht the lid we can poor balls into the middle hoop for a pretty reliable 2 points per ball. Perhaps we can even score during they hybrid period.

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So were really starting to finalize our drawings. We are hoping to put in our last order to Andy Mark tomorrow. :slight_smile: ( as if)

In anycase, we are still hoping to go with a combo dumper/shooter…

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So I had an idea that we’ll need to test in terms of agitators…the KOP fans with 2 or 3 of the blades cut off…

This week has been both good and bad. We haven’t been able to work because of snow days, but really we would have been waiting anyway. We need to get a purchase order in to Andy Mark, and due to snow haven’t been able to do any ordering. Now our shipping costs will go way up, but that is the price you pay.

The designs are almost completely finalized. We really have some tips and tails stuff with the drawing, but all of the kinematics have been worked out for everything except for the flopper for pushing down the bridge.

now of course we worry…is it wide enough? Is it strong enough? Is it accurate enough? Will it really be able to drive over the bridge?

Oh…the stress!

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Wat motor are you using to drive your shooter?
Does this somehow dump too?

Just curious.
Thanks
R3P0

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the current plan is to have the bucket at the top pivot backwards and poor balls out the back of the robot. the bucket lid will be 15 inches long and sit 1 inch inside the frame. Making it a 14 inch extension.

For the shooter we are using 2 fisher price motors? Have to check the rules but I think we can use two, driving a cim-ulator gear box coupled to the shooter wheels.

we are hoping to post cad files, but the current drawing is still incomplete and has some issues that need to be finalized before we can do that. Also it is currently 30 some odd megs as a compressed file.

thanks for the interest.

18

This is legal, see R48. CIMulator is a nice gearbox, too.

[R48]
The only motors and actuators permitted on 2012 FRC Robots include:

    up to 4 CIM motors (part #FR801-001, M4-R0062-12, AM802-001A, 217-200, PM25R-44F-1005 or PMR25R-45F-1003),
    up to 4, in any combination, of the BaneBots motors provided in the KOP (acceptable part numbers are M7-RS775-12, M7-RS775-18, M5-RS550-12, M5-RS550-12-B, and M3-RS395-12),
    up to 2 window motors (acceptable part #s are 262100-3030 and 262100-3040),
--->up to 2 FisherPrice motors (acceptable part #s are 000968-9012, 00968-9013, 00801-0673, and 00968-9015),
    up to 2 AndyMark motors (acceptable part # is am-0912),
    up to 2 AndyMark gearmotors (acceptable part # is am-0914),
    up to 2 Denso throttle control motors (acceptable part # AE2351000)
    up to 2 VEX motors (acceptable part # 276-2177)
    up to 2 window lift, seat, windshield wiper or door motors obtained through either the FIRST-Automotive Recyclers Association partnership or from a prior years’ KOP.
    electrical solenoid actuators, no greater than 1 in. stroke and rated at no greater than 10 watts continuous duty at 12V,
    drive motors or fans that are part of a speed controller or COTS computing device
    an unlimited number of COTS servos with a maximum power rating of 4W each at 6V.

I’m curious, what triggered your change from two horizontal shooting wheels to a single vertically mounted wheel?

Have you considered how you are going to align the shooter with the baskets?

If you could host it somewhere, I’d love to take a look at it. You are taking a neat approach with your robot.

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The current plan:

For aiming we are hoping to have a “slow poke” mode. Basically the driver presses a button on the driver station and that slows the drive motors way down so that she can agle the bot correctly. We want to couple this with the camera…piece of polycarbonate with some markings on it…line the markings up with the backboard and bobs your unckle. Finally would be speed…Two ideas on this.

Simple is we use the markings on the polycarb to guage distance, and then use a shaft encoder to set the speed of our spining wheels based on the distance

Harder…We use an ultrasonic sensor to "measure the distance to the wall, have an adjustable hood, and use computer vision to align the shot using the “slowpoke” mode.

Probably some combination of the two. We have the basics down in turs of programming…

For dumping, we want have the camera swivel 180 degrees, and drive backwards. We would possibly follow the red or blue line down the sides of the key and then squidge over at the burm.

We’ll try to get the cad files up by sunday night.

20

For dumping into the 2-point hoops, are you considering the fender below the baskets? You won’t be able to get right up to the front of the rim without a chute that extends beyond your frame perimeter and bumpers. With the 14" appendage limit a chute will still leave a small gap to the front of the rim.

Or, maybe I missed something and you’re going to tip your hopper over so that the hopper acts as a chute crossing over the fender.