2014 Field Build

Technical Technical Discussion
#1

This thread is to discuss the building of the field elements for the 2014 competition Aerial Assist.

We built the team version of the field to spec without to much trouble. It took us probably about 48 man hours to complete the pieces, including painting, cutting, assembling them.

Modifications we made

  1. We bolted the truss gussets to the truss so the truss could be disassembled for transportation. Some of the supporting angles cross truss sections, so we created a L bracket so they could be bolted rather than glue/stapled

  2. We use 1-1/4" staples and glue for the most part. Some areas were enhanced with 1-1/4" deck screws. Specifically around the high goal area. Also added small corner brackets to the high goal supports to help keep the square sturdy.

  3. Did not use the hinges on the low goal, except for the ramp. They way they were shown on the field drawings didn’t make sense.

  4. the horizontal supports, vertical squares and the top of the high goal are bolted together for ease of transportation.

  5. Undersize the truss supports by 1/16 - 1/8". The truss needs to slide onto the supports and if they are built to spec, the fit is too tight. We required some sanding to make ours fit.

  6. One set of high goals (1/2 the driver station) and one low goal is sufficient for practice.

  7. The color coded High Goal shows how we separated the components for easy transport.

We used 5 sheets of 1/2" plywood, 3 sheets of 3/4" plywood and 11 2x4s and a whole bunch of 1/4x20 bolts, washers and nylocks.

Things I would do differently now I know the game.

  1. Not build the truss. It is big, hard to transport, tough to build and costs a lot. Set up a 2x4 mock up of part of the truss to kick over.

  2. Build the low goal using Brandon Holley’s 2x4 model. (He should be posting it later).

Pictures of the assembly of the field elements.
http://s473.photobucket.com/user/robokong2493/library/2014%20field%20build

#2

We built an entirely different version for the Peachtree Regional Kick Off. Ray built a truss out of plywood, with solid plywood on all four edges, cutting out 8 in. holes along the top and bottom to reduce weight. These were built in 8 ft. sections. It looks good and appears strong enough for play.

I built the low goal our of 1 1/2 in. PVC pipe, being careful to keep the inside dimensions and ramp height the same as the regulation goal. I used PVC furniture fittings and it was quick and easy. I think it will be strong enough for real play in our off-season GRITS event. You can have all the furniture fittings you want in a couple of days ordered on;line. Just search for “PVC furniture fittings”. Note that prices are all over the map, so choose your supplier wisely. I ordered enough to do four goals for $140.

We also made the high goal our of 1 1/2 in. PVC pipe. To get the curve, we heated sand in the oven to 400 degrees F and poured it in the pipe, capping the pipe with cool sand. Once the plastic softened, we pulled the pipe around a plywood form. This worked well, too.

As a practical matter, for team use, you can just put together a PVC pipe goal with the correct inside dimensions. You don’t really need the curve on the end since a square end works just like the curved end as far as practice goes. Mount the PVC goal against a frame similar to what FIRST has in the plans and you are good to go. Be sure to mount it at the right height.

You can also make a truss out of PVC pipe. It won’t be as strong as the real thing, or even a plywood truss, but will be good enough for practice. Design is left to the students!

Dr. Bob
Chairman’s Award is not about building the robot, every team builds a robot.

#3

Nice! Thanks for sharing the photos and information; much appreciated.