Aerial Assist Robot Prototypes

I have uploaded a video of the progress of today's second shift onto the dropbox folder under the file by the name of this thread.

It worked pretty well, using elastics, and typically it would be taken back by a winch, but we replaced that with Connor for today.

The stick is about 6'2'' from the ground, the top of the truss, and also the bottom of the high goal. The prototype is 67'' (5'7'') from the truss, and the satellite we used was at 67 degree angle. Let us all know what you think about this.

Overall I think it is good, but could definitely use some tweaking, in order to get it to shoot farther.

I think part of the needed tweaking, if this design is going to be used, is that the puncher rod is going to have to be smaller. We really have to watch our robot's size this year- the design that seb, chef, ben and I had been working on was going alright when I had to leave, it just needed more power. How did the catapult-style design go after I left?

This looks promising enough, but it rules out a very solid design idea that I had been thinking of. Although I've been thinking of how to adapt a puncher to the "bed" style robot design ever since I saw this video.

Very impressed that team B made this progess, excellent

Very cool, just remember that the prototype is also a few feet off the ground, something we noted during shift A.

I would really like to see what a ram could do to launch the ball (probably less wear and tear on parts during constant use, compared to elastics).

of course the size will be smaller. and the catapult, of what I know it broke, but that could be fixed, i think it was just the wood, Ill let someone else explain that.

I think I may have an easier design for the catapult though. Instead of putting the elastic completely around the arm, attach it at the sides and then to the walls, so that it's not just sliding on the back part, makes the assembly awkward with it all the way around.

Yes maya that's correct, in that case it will still need a lot more power.

maya andymark 3 day robot tried with pneumatics, it took 6 air rams, still didnt give enough power using a catapult method and it drained a ton of air from system, i dont think its feasiblefor this

im not sure if though they found another way with air rams ill look it up though

i think andymark is behind on uploading some of their videos because they only have day 2 up but look at what i found about this ratchet gearbox ri3d uses it might be interesting cause i think we fried a motor last year

https://www.youtube.com/watch?v=SWO9OE8JZZk&feature=c4-overview&list=UUgtwgUTTxuldvAGW1u8SDSA

Looks good guys!

It looked like only one "wind" of surgical tubing on the plunger with some friction but in all it looks good for a proof of concept. Multiple winds of surgical tubing are easier than trying to tension up a single strand, on the "big ball" robot there were 4ish loops of elastics being stretched a lot.

Also i can't see if you're using thinner wall surgical tubing from home depot/lowes, princess auto sells thicker wall stuff in prepackaged 5ft lengths in their surplus section which is much more robust.

came in kip and it seems thinner than the ones that you used in the past yeah

About the ratcheting gearbox, both the big ball and soccer robots used worm gear motors to prevent back driving. Being able to drive the motors backwards was important in those setups in order to reduce the amount of force it took to shift into neutral (dog clutch setup from andymark shifters).

Brake setups arn't too common on frc robots but in 2010 there were teams who used the rotors and calipers from a bicycle disk brake when climbing the tower. I think a brake setup would be more reliable than the andymark dog clutches, especially with the amount of load seen in a winch setup. ie:wind to desired position and engage brake, and release the brake and reverse the motor when firing.

I have Added pictures to dropbox of the prototype as of 6PM yesterday (Jan 7).

We added the bottom piece to pick up and help catch the ball, added the Wood base instead of the rods, put on a roller the swings out to roll on the ball, made the overall catapulting piece a bit stronger, even though it broke... but they fixed it later on.

Since then they've changed a few things, like we are trying to use motor catapult instead of using an air ram, because of lack of power with the air ram.

Hopefully the guys going tonight will put pics up later.

On my lunch today I did some quick back of the napkin calculations for the motor driven shooter and I came up with,

A 10:1 gear ratio single speed gear box
2 CIM Motors
and an arm where the center of the ball sits at approximately 18" from the pivot.

I think that's a good starting point for experimenting.

- Ben

Will have Seb working on this tonight