Drive train help.

[RogerR]

Originally Posted by Cothron Theiss

Team 3259 actually assembled their wooden chassis at the Smoky Mountains Regional this year. I don't know that they played in their first few matches, but by the time they got on the field, they had a powerful drivetrain that did well on defenses. If I remember correctly, they used 4 CIM's and two mini CIM's to power it, and it was impressively fast for something that was assembled the day of. If done correctly, wood is a perfectly acceptable material for an FRC chassis. Also, the BitBuckets have shown that wood works.

Unfortunately, we're not quite that fast. We discovered potential issues with the existing gearboxes, as well as the multifunction arm on the practice bot after bag day. We brought in new gearbox parts, as well as the electronics, as part of the withholding allowance, and made several modifications to the arm. We ended up stripping the bot down to the wood frame, and rebuilding it that morning.

As for wood, I think its a fantastic building material for robots; strong*, easy to cut, cheap, and nonconductive. Our method of building robots was inspired by the method developed by 173 in the early 2000s. Our frame parts are cut out of 3/4" birch by our friends on team 3844 on their CNC router, and then we assemble the frame using wood glue and wood screws (we pilot drill the holes to avoid splitting the wood). It's proved very robust over the past few years, including several years where we played some very aggressive defense.


*as with any material, "strong" is loaded term. Put enough holes in the wrong spot, and something will give. Also, we prefer plywood, where as it sounds like you guys will be using lumber. Both have advantages and disadvantages. If your worried about strength, overbuild it. As many have mentioned, wood is much cheaper than aluminum.

[Mechvet]

Wood is a fine material for off-season construction, just be wary of a few things:

• Axles, even dead axles, will need more support and care than that of an aluminum frame
• Pilot holes are you friend
• If you're unsure of the impact capability of a specific area, wrap it in fiberglass, cure with resin, and sand.
• Measure several times, drill/cut once.
• Wood isn't as "strong" in a tensile manner than aluminum, so care should be taken designing around shear forces and load bearing surfaces
• Wood compresses, (most) aluminum alloys do not. Plan accordingly.

[EmileH]

This kit which includes a transmitter and receiver plus a drive chassis might be of interest to you:

http://www.andymark.com/product-p/am-2552.htm

[roboruler]

Originally Posted by EmileH

This kit which includes a transmitter and receiver plus a drive chassis might be of interest to you:

http://www.andymark.com/product-p/am-2552.htm

It sounds like you guys are wanting to do this on a low budget.

I'd have a look at some of Hobbykings brushed ESC offerings, it'll end up way cheaper than the compartive Andymark ones( if you don't want the ability to use the parts legally in FRC)

http://www.hobbyking.com/hobbyking/s...d_Car_ESC.html

http://www.hobbyking.com/hobbyking/s...Mode_1_.htm l

The hobbyking transmitter is the exact same as the one Andymark sells and is half the price

[Billfred]

Originally Posted by roboruler

It sounds like you guys are wanting to do this on a low budget.

I'd have a look at some of Hobbykings brushed ESC offerings, it'll end up way cheaper than the compartive Andymark ones( if you don't want the ability to use the parts legally in FRC)

http://www.hobbyking.com/hobbyking/s...d_Car_ESC.html

Have you verified this will run on 12V? It looks like it's made for 2-cell LiPo packs or 5-6 cell NiMH packs, both of which are 7.X volts.

(full disclosure, I'm typing this from my desk at AndyMark.)

[FrisbeeFunTime]

Originally Posted by Billfred

Have you verified this will run on 12V? It looks like it's made for 2-cell LiPo packs or 5-6 cell NiMH packs, both of which are 7.X volts.

(full disclosure, I'm typing this from my desk at AndyMark.)

It is our intention to run this on 12v so the ESC's he presented would most likely not work. I've seen esc's rated for a 2s lipo run on 12v which resulted in it being permanently damaged and rendered unusable. This expiriene in now way makes it a definite that his suggestion won't work so we ill probs end up emailing hobby king about it.

[DaveL]

As a summer project, we built 3 wood robots using some scrape plywood. It measured 3/4" thick, which meant it was likely called 1".
I think the side were 3" high by 28" long.

Our bots had the same side rails at an aluminum bot, but in the corners we bolted a 1-1/2" square piece of wood. For the third bot we used some scrape aluminum "L" brackets instead of the wood to save space in the corners. The bottom plate was very thin (5mm) plywood with glued on bits of wood. During a high speed head on collision with another wood bot (using only 1 pool noodle for protection) the bottom plate broke its glue joint.

Actually the glue held, but the wood veneer was ripped off. Going forward, I would use more angle aluminum brackets. We made these from scraps of aluminum box sections by cutting them in half (on the diagonal looking from the open end)

Another thing we did was to use chain and mounted the transmission so it could slide up. That way we were able to tension the chains by raising the transmission. The slide was really just slots for the bolts to slide within.

Dave

[Ether]

Originally Posted by RogerR

its spelled *ya'll*, not *y'all*

Is that some kind of inside joke?

[D.Allred]

Originally Posted by Ether

Is that some kind of inside joke?

Warning - thread derailing comment.

It's y'all. Sometimes I incorrectly use "all y'all" to emphasize the plural form.

http://writingexplained.org/yall-or-ya-ll-difference

[JesseK]

We've done this before. It's pretty fun. Let's assume that you have some leftover parts from the season (CIMs, AM or VP gearboxes, a few sprockets (perhaps mis-matched) and some chain.

Make sure the wood for the frame is straight, and that it's a hard wood rather than pine. Ok, pine can take a little bit of punishment, but in my experience when you start adding weight on top of the chassis and then you do crazy things, the wood screws which hold the frame together start to strip out.

You can then cantilever your wheels via 3/8" or 1/2" dead-axle bolts through the 2x4 frame, and chain a gearbox to the wheels. Use one of the calculators in CD-media to figure out which motor, gearbox and chain ratio to use. You can get away with chain-driving only one set of wheels, depending on what surface this chassis will roll around on. Just be aware that the heavier the frisbee shooter, the more likely you'll want to drive all wheels since even hard woods will flex while cornering at speed.

Good luck

[messer5740]

I don't want to make a new thread for it pertains to drive trains, but can someone clarify what a west coast drive is? I know that West Clast Products are a common distributor of FRC parts, and I know that they have Vex Robotics versa frame, but is there something special that is different from the kit of parts chassis?

[Cothron Theiss]

Originally Posted by messer5740

I don't want to make a new thread for it pertains to drive trains, but can someone clarify what a west coast drive is? I know that West Clast Products are a common distributor of FRC parts, and I know that they have Vex Robotics versa frame, but is there something special that is different from the kit of parts chassis?

https://www.chiefdelphi.com/forums/s...st+coast+drive


This is one of the first results when you search for threads titled "West Coast Drive." It should answer most if not all of your questions.