Sunday, January 28, 2007

We Have Hit the Halfway Point

Yes, it's true. Something like 21 or 22 more days to go. Eek!

Firstly, thanks to all the freshmen who show up consistently (even for the supposedly nonexistant Sunday meetings) and are ready to help (or be patient when we don't have much for you guys to do). Today was one those days. But while not much progress was made on the building front, Chrissy, Kersten, and I were able to reassess our design and determine the mechanisms that still need figuring out for our final robot.

Here are the lists we came up with.

Little tasks to do:
- Drill new holes/fix existing holes in transmission mounting plate so they actually line up with the holes in the transmission!
- Make pillowblock bearings similar to the ones we have on Rosie (the black boxes--we should remove these tomorrow so we can show Jim). I (Julia) have the new dimensions for these.
- Hollow out the 3/4" diameter arm shaft that weighs a ton (it doesn't need to be completely indestructable)
- Weld the other end piece of the ramp release flipper to a shaft collar so that's it's removable
- Weld a battery mount
- Make Delrin wheels or slide for the end of the ramp so it doesn't snag on the carpet
- Drill holes in gears in transmission adapter for weight loss (we'll hold off on this until we're mounting them on the real chassis)
- Maybe mount electronics board (I said electronics could do this, but we should probably just ask them what they want and maybe drill holes based on where we want them on the chassis)
- Make a cover for the electroncis board or perhaps just cover the front face of the chassis with a sheet of polycarbonate
- Signage (1700, sponsers, too!)
- Bumpers (maybe later...)

To figure out:
- We'd like to make the secondary ramp longer so the angle robots have to drive up isn't so steep (30° is last year's angle and it wasn't ideal), but a big issue is weight! We weighed our prototype (which is missing a fair bit of parts) and it's about 100lb. YIKES!
- Ramp material: how does poly carb weight compare to expanded metal? (we're already planning to build a frame with bracing using aluminum extrusion)
-Where are we going to have spring hinges, regular hinges, dampers for our ramp? Are there dampers that prevent both extremely fast extension and compression? How are we going to position and deploy the TWO supports for each ramp (K, C, and I are thinking just cable to both the main ramp and the secondary ramp that'll force it into one position)? Ideally we'll make progress on this MONDAY AFTERNOON/EVENING AND BE ABLE TO PLACE AN ORDER!! :)
-ASK JIM/ED ABOUT TORSIONAL SPRING DAMPERS (for ramp) (and post pics of sketches for em)
- Make any necessary changes to prototype chassis dimensions and then have Jim weld it for us (as well as the tower of power and the ramp frames)

What we figured out:
-The transmissions mounted generally as they are on the prototype will work on the actual robot (so we only need one chain around the back two wheels--saving weigh, an extra support someone for mounting elsewhere, and messy chain tensioning stuff)
- We don't want to have two-level arm-motor gearing. Remember, KISS (keep it simple, stupid)! A 10 tooth sprocket on the motor and a sprocket with about 70 teeth up on the arm shaft should do the trick, though it'd be good to talk this through with Jim and/or Ed once more.

Tomorrow let's set some deadlines and then jump right in. Kersten is gonna start us out by picking up a whole bunch of aluminum extrusion from Alan Steel tomorrow. How cool would it be to finish our robot 2 weeks before ship date?!

Right, so as I see it, these are crucial things to focus on tomorrow (I may have missed something, so read the other lists, too!):
- The ramp: joints, materials, springs, dampers, cable, height (based on the height of the chassis) ,etc. Ed will be here, so we'll be able to get his input in this area. PLACE AN ORDER!
- Also ORDER a sprocket for the IFI arm
- Contact Jim about a session on Tuesday (and others this week, too)
- Along with the ramps, work on the arm. We don't even have this prototype yet, so let's make sure this is a priority!
--question I just had: can our current design hold a keeper?

See you all tomorrow!

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