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Saturday, January 22, 2011

Build Season Day 14 - Friday 1-21

Today we got some aluminum stock for our first round of frame pieces. Here they are cut to size:


As soon as we get more of the frame finalized, we will weld it all together and start attaching stuff, maybe as soon as Sunday. Some of you might think it silly, but we take a certain amount of pride in our new-found ability to mass produce to spec, and according to a plan (oh my!). Not the typical Fighting Calculator fashion....

A little more work was done on the minibot, particularly in the deployment method, since this has more immediate effects on the robot design. A few more grippers will be prototyped in the next few days to figure out what we want to put on the elevator. Conveniently, the elevator is pretty flexible as to what it will accept as an end manipulator, so we have some freedom there.

Tuesday, January 18, 2011

Build Season Day 11 - Tuesday 1-18

As of tonight, Jan 18th, all our brainstorming and prototyping has led us to this current state of robot affairs:

1. Drive train - Holonomic is good. We like it. We're going with it. The protobot we built is fun to drive! Here's a drive train summary:
a. Four 4" "dualie" Omniwheels (ordered last week).
b. One pair of wheels (Forward-Reverse) driven by dual-CIM motors through the new CIMple Box transmissions, using stock KOP sprockets
c. The other pair of wheels (Strafing) driven by single BaneBots 775 motors through yet-to-be-determined transmissions and sprockets (note: the BaneBots site still does not have ordering info available for their CIMulator gearboxes, which was one idea...)

2. Lift mechanism - general consensus resulting from our CADing & prototyping is that we now believe we can build a vertical elevator quickly & easily that will work very well. We have two competing designs being prototyped as we speak. At this point it would take an epic failure of both designs to bring back a fixed-shoulder, long-arm design into consideration.

Our current robot design:

3. Frame Design - Octagon shape, ~26.5" across. Dual-layered to provide real estate for mounting things. We have tentatively set up a Design Review meeting with sponsor Loftech on Friday afternoon. Still waiting for confirmation on the time. Loftech has offered to weld our frame again this year (yay!) and we're hoping they will even supply the raw materials (aluminum) as well (they will give us an answer on this after they see our design at the meeting).

4. Gripper Plans - we will begin prototyping (possibly starting tomorrow) at least two designs - one mechanical claw with thin flat-plate bottom, and one with an active roller mechanism that will suck in the tubes, and spit 'em out on the pegs.

5. Minibot - prototype 1A nearing completion - based on Kara's dad's initial concept of two-wheels contacting the pole, with off-axis minibot mass providing traction force. Also, Doug purchased a regulation-sized 10-foot, 1.75" steel pipe, and installed it in the shop for testing minibots.

So, the current immediate action items are:

1. Continue the prototyping of both elevators.
2. Finalize gearing on strafing wheels, and order needed parts.
3. Complete the remaining frame details in CAD.
4. Hold Design Review of frame model with Loftech, and release design to them for construction.
5. Start building prototype gripper assemblies.
6. Continue work on minibot prototype design, construction, and
testing.

Back to work!

Monday, January 17, 2011

Build Season Day 8

We started out by talking about different arm/elevator/lifter methods and have come up with 2 or 3 favorites that we are CADing. We made a spreadsheet of our ideas along with a rough ranking system.

Then we had a fundraising meeting. We still need money if we want to go to the Championship and lots of people now have volunteered to ask various companies for money. We are lucky to have the first $2000 we raise matched.

We decided to drive the prototype around again to show it off and get some more practice with it. In the process, the camera power cord (which had been disconnected from the '10 robot's camera, but not from the electronics board (i.e. it was floating around loosely)) ended up on the power source from the power distribution board. The cable got very warm and melted some of its plastic and is no longer usable. Everything else is fine. Then we decided that we should finalize our chassis frame so we could send it to Loftech to weld. This led to a discussion of how to support the arm which led to another discussion of arm designs. So we will try to have the different versions of the arms CADed ASAP. A small group of "design representatives" so to speak are planning a trip to Loftech to discuss our design with them.

Things to do:
Drive/chassis system:
Work out any remaining bugs in the code.
DRIVER PRACTICE!

Arm system:
More CADing!
Current primary design ideas include:
2 stage elevator (probably pneumatics) and a (shorter-ish) rotating
arm
a multi stage elevator similar to Team 25's from 2007 and a
fixed gripper

Gripper system:
More CADing! Or maybe some prototyping....
Current design ideas include:
powered wheels on the top and rollers on the bottom
powered wheels on the top and the bottom
a pneumatic grabber of some sort
the "Pez dispenser" design

Build Season Day 7

We took the prototype out for a spin and one of the CIMple boxes was being sketchy (as we had noticed on Thursday). Then we noticed that the key was no longer in the gear box..... After finding and inserting it, the prototype ran very nicely. You can find a video at http://qik.com/video/29163485. After seeing how maneuverable the prototype was, the general consensus was to go with the holonomic drive train.

We then built a to-scale scoring peg to model gripper methods so we could see how well they placed the rings and to get a general of the dynamics of scoring the rings. It can be clamped at different heights along the stair way to model any of the heights if we want. We concluded that its best to score vertically, but still possible in just about any other orientation.