Ãœberclocker Update 16, Nuclear Kitten update 3: A picture is worth 9000 words Edition

Sunday, August 10th, 2008 @ 6:14 | Bots, Nuclear Kitten 5, Pop Quiz 2, Project Build Reports, Überclocker

So I can’t find the sub-micron sized grain of dust or metal shaving that is caught in the lens actuator of my camera. Unfortunately, this means that I will have to start haunting Ebay and local consumer electronics outlets. Until then, I suppose everyone who reads this site (all -0.000001259 of you) will be in suspense, save the occasional grainy cell phone camera picture.

The basic rundown is that Ãœberclocker is ready to be wired and NK is also approaching mechanical completion.

Ãœberclocker

I drew up the “EBay” assemblies and prepared flat patterns to make them out of sheet metal. Unlike TB4.5SP1 which had all its electronics in a bunch, Ãœberclocker features “distributed electronics”. There’s not really an advantage to either method, just that I couldn’t find space in this bot to slam all the electronics in one place.

Each is a work of 1/16″ aluminum origami (read: smashing in a vise and banging on it while wielding a torch) that bolts to a close frame member. There is nothing secured to the baseplate, unlike TB (and all my previous bots). Furthermore, all of the Ebays are dismountable from the outside.

This is the left side Ebay, which houses the main switch and Convenient DB9 Connector of LiPo Balancingâ„¢. The big switch came off a 1980s era PC power supply which, despite being a 7 inch cube, could manage maybe 200 watts. It is mounted such that the top bezel is flush with the top cover plate of the bot. A little rectangle will be cut out of the top plate to pass it.

Since Ãœberclocker isn’t a severe duty bot, I decided to forego making a normally closed switch like I did for TB. The detent is strong enough for me to not worry about it randomly clicking off.

The rear Ebay clamps the batteries between itself and the rear of the bot. It also carries the Victor 883 controllers for the drive motors. The right side Ebay houses a third Victor and a small Banebots ESC to control the clamp motor.

fr0kp0t mounted. This was an afterthought, and I really didn’t want to take the entire thing apart again, so it was just clamped and hand drilled. The potentiometer is rather exposed for something which will be telling the fr0k everything about where it is in life, so it might get a larger metal cage. The pot is coupled to the fr0k through the shaft set screw.

There is currently no bottom hard mechanical stop for the fr0k, and so it can swing all the way around the bottom of the bot (no doubt ripping off the entire bottom plate in the process). To prevent this, I’ll add some things that stick out of the fr0k towers. While I could easily limit the travel in software, a hardware backup is good for preventing self-eating disasters.

So Ãœberclocker is ready to be wired up and programmed. The fr0k, with the chain tightened (by removing one pitch with an offset link), successfully powerlifted 30 pounds, so I know torque isn’t a problem. Maybe there will be a drive test soon…

Nuclear Kitten 5

NK went from 0 to about 50% done in a day due to the “snap-together” chassis. The only thing I needed to build for that were some nutstrips ( 1/4″ aluminum squares with regularly spaced tapped holes), which was tedious but trivial. Past that, I had to machine up the weapon motor and drive wheels.

I specifically bought a 4-40 spiral-tipped tap so I could powertap all the holes, 7 each in 12 nutstrips. Sadly enough, I’m short about 4 inches worth of 1/4″ square aluminum stock to make the last of the nutstrips. This is within range of just biting the proverbial bullet and machining down some bigger stock.

Blurry ass-picture showing some frame bits and the nutstrips. Ignore the obvious non-trusses that populate the inner rails. My excuse is that it was 5AM Joltgineering – I’m not sure why I didn’t just link the corners with triangles instead of making an ugly V shape.

I like this “Chinese Puzzle” frame – I think I’ll keep the tricks in mind for future projects.

While the waterjet pump was still primed, I tossed on a plate of 1/4″ 4140 and cut out the blades.

Because the blades are now steel, they are thinner in profile. This should be more than enough for 3lber duty, especially after heat-treating (famous last words).

After discovering that the grungy MITERS horizontal bandsaw cut much faster when I dropped a weight on the end of it, I started on the disc motor. The motor itself is almost identical in structure to my wheelmotor and much simpler in construction. I also didn’t have a stiff and consistent tool holding device when I built the wheelmotor. Overall, this resulted in a very fast build of the disc motor structure.

I made two side plates out of 3″ aluminum round and the center axle out of 1″. A steel pipe was turned into the magnet ring. This steel pipe appeared fine on inspection, but upon contact with a cutting tool, turned to powder on the inside. Fortunately, the rust wasn’t deep enough to affect the final ring dimensions.

I also made all four drive wheels. Each wheel consists of a stock SDP (redundancy?) pulley, an aluminum “rim”, and an O-ring “tire. The process was fast, since each rim only had radial features that could all be made by selective parting tool use. The drive motors themselves are in transit and should arrive Monday. Previously, I ordered a few Speed 300 size RC motors off Ebay to retain the absurd speed and maneuverability of NK4, which featured those motors spliced into the aforementioned gearboxen.

Upgrading the wheel size the morning before I ordered all my parts (more 5AM  Joltgineering), I failed to account for the fact that one of the frame connector pieces now interfered with the front wheels. Something will probably be sanded down.

After taking a Taco Bell break, I put the disc motor together for a test fit. This motor has a very tight airgap to maximize torque, and I was worried about the tolerances adding up and causing the stator to grind against the magnets. To my surprise, it ran concentric and true – with no rubbing. Cheers for the robot gods. I then went back and preliminarily installed all 28 magnets (in groups of 2) with ultra-thin CA glue. The empty spaces will be filled in with epoxy.

So, here’s a picture of NK in that “well, it LOOKS done” pose.

Old NK is undergoing the scrapping process to extract the goodies (there’s not much left).

Only a few spacers here and there remain to be done on NK.

So the summary of things to do is:

Ãœberclocker

  1. Wire up!
  2. ???
  3. Profit!
    1. Make bot carrier

NK5

  1. Weapon pivot axle and spacers
  2. Wind motor
  3. Tune drivetrain for belt tension
  4. Wire up

PQ2

  1. Wait for giant plate of titanium (est. Tuesday)
  2. Cut blades out of Ti
  3. Machine a blade retaining collar
  4. Integrate receiver and mixer into a single module
  5. Think of how to get reception

A week remains…

 

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