23-01-2011 21:20

548swimmer

Re: pic: Our best 2011 robot design

I would recommend you make sure the joint where the arm slides is as close to flush as possible and extremely well braced. We had a similar design in 2007 and occasionally had issues with the gripper binding at the joint.

23-01-2011 21:42

Garten Haeska

Re: pic: Our best 2011 robot design

yea there will be alot of trial and error when making it, but thats just the fun of it! thanks for the info!

23-01-2011 21:48

Jacob Paikoff

Re: pic: Our best 2011 robot design

Very interesting, very cool idea. I hope it works well for you guys.

23-01-2011 21:52

Tytus Gerrish

Re: pic: Our best 2011 robot design

Wowh! i hope that works. i suggest making a structure around that hinge to prevent torsion, and bending in the x and y.
how does the elevator work, pulleys?

23-01-2011 22:05

nikeairmancurry

Re: pic: Our best 2011 robot design

Our lead mentor came up with something very similar...

23-01-2011 22:06

Garten Haeska

Re: pic: Our best 2011 robot design

torsion? and yes i was just too lazy to put the pulley in and i didnt put in a couple of cylinders just cuz i dont want to give away our entire robot.

23-01-2011 22:07

Jeffy

Re: pic: Our best 2011 robot design

Sweet, not something that came up in any of our design meetings. Thats Nice!

23-01-2011 22:10

sanddrag

Re: pic: Our best 2011 robot design

I must say, in a decade of doing FRC, I've never thought of or seen that before.

23-01-2011 22:13

Hawiian Cadder

Re: pic: Our best 2011 robot design

our team tossed around a similar idea, but we realized that a hinged arm does exactly the same motion, and doesn't require a slide.

23-01-2011 22:13

Garten Haeska

Re: pic: Our best 2011 robot design

Is that a good or bad thing?

23-01-2011 22:31

LLogan

Re: pic: Our best 2011 robot design

Our team did a very very similar design in 2007.


Here our lift is folded down. That piston actuates so that it becomes vertical.


Here is the lift unfolded to its full height.

IIRC, we were either seeded #1 or first pick that year, but we lost in the semifinals due to heavy defense.

We never tipped over, but we got pretty darn close a few times according to older members (I wasn't around in 2007). The inability to retract our arm to a lesser height was something our team regretted, I think.

I also believe we had some difficulty lining up the slides when it extended... can't really remember.

23-01-2011 22:35

DiscoKittyPrime

Re: pic: Our best 2011 robot design

One of the team members on my team came up with a similar idea but we decided that our luck with aligning slide rails like this wouldn't help (bad experience from '07 i believe). Best of luck to you and hope it works for you.

23-01-2011 22:39

Zholl

Re: pic: Our best 2011 robot design

That really depends. Just because someone hasn't done or seen or thought of something before doesn't mean it's good or bad. Whether it's good or bad will depend largely on how much you've taken any potential risks or problems into consideration and how well you deal with them when you implement it. You could have the greatest design ever, but if it's poorly implemented it won't work as well is a mediocre design with great implementation. There are certainly going to be some risks and potential issues with a design such as this, especially since it is a somewhat unorthodox approach, but it has potential, and if you pull it off well people will take notice of the fact that you did something different and succeeded

23-01-2011 23:04

548swimmer

Re: pic: Our best 2011 robot design

Just make sure the joints are really stiff, and you'll be fine!

23-01-2011 23:20

s_forbes

Re: pic: Our best 2011 robot design

Reminds me of 114 from 2007. Very neat looking mechanism, hope you can pull it off!

24-01-2011 11:39

Chris is me

Re: pic: Our best 2011 robot design

VERY similar to an idea 2791 was kicking around before the 60" rule change. I would recommend you use a very, very heavy duty hinge for that joint.

24-01-2011 15:34

Ian Curtis

Re: pic: Our best 2011 robot design

1276 built a similar hinged mast in our 2007 robot.

That joint needs to be beefy. As you can see we had a circular mast, and welded on square tubing which is where the joint actuated. There were also a set of guides inside the mast that helped guide it down.

It worked, but not nearly well enough. Our piano hinge was purchased at a hardware store, and was not up the rigors of competition. I don't remember the diameter of the pin in the hinge, but it was somewhere around 1/8" and the hinge ran the entire length of box tubing. We actuated it on Thursday (it was pushed up by the elevator), but ultimately we were not comfortable with leaving it that way during matches, so we bolted it upright and were a 6' tall robot (which was legal in 2007). As others have mentioned, you get quite a lot of torsion (twisting) and some pretty sever shockloads when it slams down if you are not careful. Also give some consideration on how it will be held in place once it actuates up... don't want it coming down mid match!

McMaster sells much beefier piano hinges than what we used, I would recommend using them. Go as thick as you can without paying out the nose.

24-01-2011 15:35

Bob Steele

Re: pic: Our best 2011 robot design

Just one question... are you tilting the tower back to keep your end effector inside the robot at the beginning of the match?

I am sure you know it can't start outside the frame perimeter...

Interesting design... Hope it works for you..

25-01-2011 00:49

Michael Corsetto

Re: pic: Our best 2011 robot design

I love this design, these nearly 10 foot rails are super fun! We had a lot of success with our design in 2007, seeding 1st at SVR with the second highest OPR. Also, these designs can be very light if made correctly.

Make that hinge STRONG! I would actually recommend making your own joint with some beefy 3/8 to 1/2 inch shaft and bronze bushings. Also, you will need a locking system of some sort since the pneumatic pressure alone (assuming this is how you will deploy the upper segment) will not be enough to keep it straight (and thus the rail joint smooth) if it the robot rocks back and forth.

Also, keep the tower in an inch or two from the edge of the robot frame, this gives you more flexibility in beefing up the tower.

Third, make the grabber rail taller so the torque from the grabber mass + gravity is distributed better.

This is all I got for now, feel free to ask more questions if you have any. I loved Rack'n'Roll, glad we get to play it again! Good luck!