95's Pre-season drive base done!

[Nathan Streeter]

Looks pretty nice!

I definitely agree with Brendan... I really love the slots over the Transmission shafts so you can just lift the gearbox right out (rather than pulling it through the center). I also like how narrow your pods/drive channels are... especially with the smaller frame perimeter rules, that can be a big gain!

I have to say, I'm sure you could get some big weight savings if you were to re-iterate this for the build season... going to 4" or 5" wheels (smaller wheels, smaller sprockets), making your drive channel plates shorter (perhaps 3-4" tall rather than 5-6" tall), and obviously doing some lightening on the belly pan... you could probably save 5-10 pounds fairly easily!

I'd definitely guess that you'd want more tying the two pods/drive channels to each other for stiffness... but I guess with giant bellypan may go a long way...

[JamesCH95]

Thanks again!

@brennonbrimhall

The control algorithim will look at speed and joystick input 'magnitude' and make a gear selection from there, like an automotive automatic transmission controller. If you're lightly on the accelerator pedal the transmission will up-shift very readily to reduce fuel consumption, but if you floor the accelerator pedal the transmission will downshift as many gears as it can to maximize acceleration.

Now, this is somewhat simplified with only 2 gears, but that's the idea!

@Nathan Streeter

Very good suggestions, thanks! We definitely plan on iterating this design, though since we're really hurting for funding this year (government lab as flagship sponsor + sequester = sad robotics team) we'll likely recycle the 6in components. The main weight-loss strategy will be 'trussing out' the side plates. Hopefully that will make them look a little sexier as well as reducing weight. That, and making the belly pan out of plastic instead of aluminum!

Upon further consideration I think that for a competition robot we would mount all of our game-related mechanisms to a plate that bolts on top of the drive base. This would potentially make game mechanisms modular and divorce the drive base design from the manipulator design, allowing them to be developed independantly. A top plate, coupled with the belly pan and bumper panels, would result in a VERY strong chassis structure.

And, frankly, bumpers have really reduced chassis strength requirements... hitting robots at full-speed just isn't what it used to be!

[Mr. Lim]

We have a CNC router in our shop that lends itself well to building "side-plates + stand-offs" drivetrains. They're straightforward enough for younger students to design. To machine, just throw a big sheet of plate on the CNC router, and cut 4 identical side-plates out of it in one setup. Dead-axle means you can use bolts as shafts, and the precision is moved to the wheels, bearings, sprockets, all which you can just buy. It's very forgiving, and is one of the most student-design friendly non-KoP drive setups around.

In fact, I think every single one of 610's "best" student designers have designed a 6wd "side-plates + stand-offs" drivetrain during their time on the team. It's pretty common to hear a mentor tell a student:

"You want to design WHAT? Design me a simple 6wd side-plates + stand-offs drivetrain first... then we'll talk."

Not only that, they've worked wonderfully for us on the field for the past two years. Aside from chain that stretches over time, carpet bits getting stuck in the sprockets, and wheel wear, they've been pretty solid for us.

I love seeing how other teams approach these same drivetrains. We've "gained inspiration" from a lot of other teams designs, and used them to improve our own on many occasions. I like your cut-outs for installing/removing your gearboxes.

A lot of the suggestions you're getting in this thread are identical to the ones we've fought with over the years. If you're curious to see our version of the "side-plates + stand-offs" drivetrain, we had one on our 2013 robot:

Picture w/ Electronics:
http://www.chiefdelphi.com/forums/sh...d.php?t=111975

Some of the little tricks that went into it:
http://www.chiefdelphi.com/forums/sh...49#post1298249

CADs:
http://frcdesigns.com/designs-2013/

Thanks for sharing, and hopefully we'll cross paths again sometime! Competing at BAE was an amazing experience last year!

[JamesCH95]

Mr. Lim, you see right though us!

This was our first non-KOP design in several years, and thus the first in several years with heavy student involvement. It was partly inspired by 610's 2013 chassis (hat tip) and a 2011 chassis from a NJ team with two a two-digit number that I can't, for the life of me, recall.

I really like the cable+tube handles, I definitely want to use them in the upcoming season.

GSR was a blast, I just wish our climber had been working as well as it did at CT...

Quick questions: are your side plates 1/4in? And what did that chassis wind up weighing?

[Steven Donow]

Originally Posted by JamesCH95

Mr. Lim, you see right though us!

This was our first non-KOP design in several years, and thus the first in several years with heavy student involvement. It was partly inspired by 610's 2013 chassis (hat tip) and a 2011 chassis from a NJ team with two a two-digit number that I can't, for the life of me, recall.

25. One of the most powerful drivetrains in FIRST

[AdamHeard]

Originally Posted by DevenStonow

25. One of the most powerful drivetrains in FIRST

Power is purely a function of motors, so anyone can be in that camp

[Akash Rastogi]

Originally Posted by JamesCH95

Mr. Lim, you see right though us!

This was our first non-KOP design in several years, and thus the first in several years with heavy student involvement. It was partly inspired by 610's 2013 chassis (hat tip) and a 2011 chassis from a NJ team with two a two-digit number that I can't, for the life of me, recall.

11 has a long history of plate + standoff drives, but I was never really a fan until the 2011-2013 designs. MORT's 2011 frame:

https://lh4.googleusercontent.com/-q...Q/DSC_0790.JPG

https://lh4.googleusercontent.com/-S...k/DSC_0789.JPG

https://lh3.googleusercontent.com/-Y...I/DSC_0810.JPG

https://lh5.googleusercontent.com/-i...M/DSC_0787.JPG

https://lh3.googleusercontent.com/-r...Q/DSC_0788.JPG

However, the 2013 iteration was the only one I really liked.

http://i.imgur.com/FlVBfQ6.jpg

http://i.imgur.com/799LDvG.jpg

[JamesCH95]

Originally Posted by Akash Rastogi

11 has a long history of plate + standoff drives, but I was never really a fan until the 2011-2013 designs.

That would be the one!

[Mr. Lim]

Originally Posted by JamesCH95

Mr. Lim, you see right though us!

Quick questions: are your side plates 1/4in? And what did that chassis wind up weighing?

Thanks for the hat-tip! But we certainly didn't invent the side-plates + stand-offs drivetrain, nor have we perfected it. One of the examples we show our students is one of 548's from a few years ago:



Our side plates were 3/16" I believe...

Our drivetrain was quite heavy by most people's standards. I want to say that everything in the Electronics Board picture was over 60 lbs (not including battery).

That's working off a weak memory, although if I made an egregious error, my hope is someone from the team can chime in and correct me.

[GraysonDaly]

Hello I'm Grayson! On this project I helped out a little bit with a lot of different parts, including machining, CADing, and assembly. My main contribution was putting together most of the left (I think) drive pod and doing the chains (which took me longer than I care to admit )