22-02-2005 04:29

elknise

Re: pic: Wooden Thunder, Team 1294

I saw your robot at the practice competition in Bellevue. You had a nice looking bot and it seemed to drive and handle nicely. Great Job.

Unfortunatly for us, Issaquah, we found out our robot was 14 pounds heavy, but we still had fun.

Hope to see you at the Pacific Northwest Regional in Portland.

22-02-2005 12:44

Chris Fultz

Re: pic: Wooden Thunder, Team 1294

Nice job, 1294.

You are making great use of the materials you have.

Good luck -!

22-02-2005 13:01

JamesCH95

Re: pic: Wooden Thunder, Team 1294

Props to you! Wood is a material very dear to my heart, but this is the first year our team hasn't used it. Looks like a solid bot, good work.

22-02-2005 13:20

Alaina

Re: pic: Wooden Thunder, Team 1294

It's...so...beautiful!!!!
I love wooden robots! The most successful robot my team ever built was made of wood. But we haven't used wood for the past 2 years. I miss working with wood. =(

22-02-2005 17:28

george56

Re: pic: Wooden Thunder, Team 1294

NICE ROBOT! its very old-school to use wood. (not that tahts a bad thing ) looks pretty solid though.

Good Luck at the competitions!!

22-02-2005 18:47

Rick TYler

Re: pic: Wooden Thunder, Team 1294

If we had a fully-equipped machine shop we might have gone that route, but we work in a woodshop and don't have a lot of money for paying someone else to do welding and machining, so we had to choose between wood and bolting together stock aluminum bits. My hobby is woodworking and I built a couple of sample components to show the students that wood can be light, stiff and strong if you design around its strengths. (For example, an 8-foot 2x4 weighs around 10 pounds. For comparison, a piece of solid aluminum stock a little over 1" square would weigh around the same -- but it would bend a lot easier. Of course, you wouldn't use solid aluminum bar stock, but we didn't use 2x4s either.)

Our towers are I-beams with 4-inch webs glued into .25-inch-deep grooves in the 2-inch wide flanges. We used zero-void 1/2-inch Meranti plywood. The two towers are joined by glued-and-screwed plywood panels for stiffness, and, frankly, to give us a big flat surface to decorate on the front. Blocks of pine are glued into the I-beams wherever we wanted to attach braces or the bearings for the arm mechanism. The bearings are captured by holes drilled into the insides of the pine blocks.

The electrical systems are mounted on 1/2-inch construction plywood and the tetra-gripping system is mounted on 1/2-inch construction plywood reinforced in key places with a second layer glued into place. If we hadn't been in such a hurry, we would have used 12mm Baltic Birch plywood.

The robot was built undersized to allow us to attach a bumper system within the 28x38 inch limit. To make sure we stayed within the box, we milled 1.25 inch side bumpers out of fir. The robot was a little too close to 38 inches to use this on the front and back, so we substituted 4/4 red oak. The corners are reinforced with heavy steel strapping usually used as a construction brace.

By the way, in the photo above, the tetra is being held over the back of the 'bot. We score on the other side.

Just thought you might be interested in some of the details of our Old School technology...

22-02-2005 20:04

elknise

Re: pic: Wooden Thunder, Team 1294

Why did you make your robot smaller to accomodate bumbers? Acording to R30 in 5.3.4 The Robot, Bumpers may extend outside the normal robot starting dimensions (in the horizontal plane) up to 4.” per side.

22-02-2005 20:36

Rick TYler

Re: pic: Wooden Thunder, Team 1294

My bad. "Bumpers" in FIRST land are allowed to extend past the maximum size, but they have to be soft and removable for weighing and measuring. We were somewhat concerned about 130+ pound robots moving at 15fps smashing into our nice aluminum side rails, so we gave up the "free" soft bumpers in exchange for solid support for the rails.

This paid off in the Bellevue trial event when one of our own teammates smashed into our side. There is a 1/4-inch chunk missing from the side beam, but no damage was done to anything else.

23-02-2005 15:14

elknise

Re: pic: Wooden Thunder, Team 1294

Yeah it was really rough there, robots got stuck in our arm twice and that little one without an arm was just all over the place.

23-02-2005 19:07

Gabe Salas Jr.

Re: pic: Wooden Thunder, Team 1294

Wow, nice craftsmanship. Did you guys experiment with different types of wood such as Mohagany or Red Wood before settling on a couple of specific types of wood for the overall robot design? Was there another reason for choosing wood for the robot design besides not having a machine shop readily available?

23-02-2005 21:40

Rick TYler

Re: pic: Wooden Thunder, Team 1294

First off, I might want to be your team when I grow up...

We didn't experiment because I already knew what we should use, and what we could afford. I've been a hobbyist furniture and cabinet maker for 15 years, and an amateur boat-builder for three. I already know the characteristics of different materials.

We used fir for the rail-protectors (don't want to call them bumpers) because it is strong, but resiliant. We want the wood to give a little in this spot or else we might have used oak, maple, or jarrah. All would have more impact resistance than fir, but they are much heavier and won't absorb as much of the impact energy. The front and rear are 13/16" red oak because I had some scraps laying around, and we were a little too long to use the 1-1/4 fir I had.

The tower is made from boat-building leftovers. I had a nice half-sheet of 1/2-inch marine-grade meranti. Again, in a perfect world I would have used 12mm okume for this (lighter), but that stuff costs $100 a sheet.

The tetra-grabber platform is fir construction plywood because that's what the arm team grabbed for the job. I would have used the okume -- or 12mm baltic birch -- but they wouldn't wait for me to get to the lumberyard to get some. Besides (recurring refrain) we already had the construction plywood on hand...

Our chassis is the KOP aluminum channel, and we used some steel tubing for arm components and the tower braces. The tetra grabbers are custom-fabricated steel and are our only welded pieces. The shaft for the arm is a steel tube captured in a pretty heavyweight piece of rectangular aluminum.

I think it's a nice blend of materials, and a great example of a decent robot built cheap. We think it will be a top-10 'bot at our regional.

Thanks everyone for the kind comments. I'll pass them along to the students. They built it.