A piece of plywood can be kind of heavy, or not…depending on what you use. 1/8" lauan plywood is fairly rigid, light, and not very expensive, usually available in part sheets from big building supply places.
Its a sawed off piece of our 06 ramp, I believe its 0.5" thick. We also used four different fuse boxes because that was all we had. I think the major weight came from the Big CIMs. As Cory said, those big CIMs weigh significantly more than the small CIMs. We used them because we didn’t have any of the small pinion gears that are needed for the small CIMs in the AM shifters.
Tensioning is really easy. You just loosen three bolts and slide the bearing block into place and tighten it down. And no, the blocks don’t slip. The chains will stay tight until they begin to strech.
Yes, there are many things we could have done to lighten it. But it all would have taken time and money and the purpose of this system is to create a simple prototype base.
For the competition version we may use 7075 or 7068 aluminum for the axels. Any advice on that?
Nothing too special you need to do. ours are just plain old 7075 1/2" main diameter, with 7/16" hexes on either end. No heat treatment or hardening necessaary
340’s proto frame weighs somewhere around there made of 3/4 bar stock. it’s so bulletproof. We love it.
What is being used to hold down the electronics and other stuff because in the 2007 season we screwed and bolted everything down.Bad idea it bit us in the butt big time.I heard zip ties are the best way to go.
I have seen some teams use zip ties as they are easy to cut and replace, I have also seen some teams use strong Velcro, as it is even easier to change a component then zip ties. As for me, we had a little room and just put a few extra spikes on the robot unwired that way we would only have to pull the wires off the bad one and we would be good to go.
This is a great drivebase. Kudos to you for not only getting a prototype put together in the off-season, but also having the guys and GP to post it on this site, for all teams to see.
The only advice I can think of at this time (for your competition version) is for a different material for the electronics board. The plywood is lightweight and easy to use, but a perforated sheet material (aluminum or gray PVC) works great. If you use this sheet, there is no need to drill holes when you mount your electronics and route your wires. I would suggest 3/32" thick aluminum or 1/8" thick PVC perforated sheet with 3/16" dia holes to start with. McMaster-Carr, MSC and other places sell this stuff.
This looks really solid guys! Doesn’t quite have the intimidation factor of those massive pneumatic wheels that your last drive base had, but I imagine it’ll serve you guys much better! In the last couple of years, we finally abandoned big pneumatic wheels as well, and we’ll probably never go back; it is so much simpler not to have to worry about whether wheels are equally pressurized, if anyone packed the tire pump, whether the tire is leaking air, and so on. (much lighter too)
I was planning on using the perforated aluminum on our robot next year, but I’m curious about how well it (and PVC too, which actually sounds like a more attractive material to me) handles the weight of the circuit breaker panels and the distro block. Have you experienced any issues with tearing or extreme bending with the heavier parts?
Allways good to see teams being productive in the off season.
55 Lbs isn’t bad at all, especially with the possible weight savings of a lighter board and the small CIMs.
Also, I’m liking the very minimal amount of fabrication that had to be done.
Overall, great job. I’ll be sure to look out for it at silicon valley.
We usually use 1/8" ABS plastic for the board. But its kinda expensive to waste on something that will never see competition.
Yes, all the components are held on with zip-ties. This is a great way to attach stuff IMO. We just drill one hole, stick a zip tie through, and stick another zip-tie on the bottom. This creates a little plastic bolt that can be cut and replaced as needed.
You may want to plug and chug this spreadsheet to play with various materials and diameters. It also includes the possibility of drilling them out.
Looks nice, I bet you with my experience in lightening, that, I could help you loose about 10-12 off of that 55. Other then that looks nice!