Tangled Marionette Status Report
My wife at 8:30pm two days before Bash
Well, one of my stated goals for this year was to stay in the weight
class I'd designed for. Despite careful planning down to weighing
every component and putting it into an Excel spreadsheet, there were
just too many things I had left to do and not enough time to do it.
So, with only 12 hours before I was supposed to start packing the car
to leave for Bash, I realized I was nearly a pound over weight (quite a
bit for a 12.9lb bot!), and I wasn't going to have time to do what needed
to be done to drop the weight. So, rather than face being outclassed
AGAIN with a bot in the wrong weight class, I hurried to finish implementing
the plan 'C' that I'd had in the back of my head all along. Perhaps I knew
that I wasn't going to make weight...
||Despite starting nearly 6months ago, I still somehow managed
to not be really FINISHED until checkin-night at Bash. Last minute
wiring and other prep took me right to the end. At least this time
I got some sleep thursday night, which was good since we were taking
the WRX Fraggin' Waggin' this year and my wife can't drive stick.
The spikes on the front were originally the forks I made for the
business end of the lifting arm. I wanted to try something other
than a wedge on a box, so I just drilled and tapped them onto the
drive tubes. They worked really well for keeping an opponent in
front of me, rather than letting them skirt around the sides too much.
|In this rear view you can just barely make out the
"biscuit plates" crafted to prevent being stood on end
a la "War Machine" at Battlebots Las Vegas 2000. They're
the round discs that were left over after I cut the motor
holes in the drive pods. This is why I never throw anything
away; after 2 minutes on the mill and another minute in the
drill press I had two "D" shaped plates that bolted into the
back end making it rounded.
||The span between the drive pods were skinned with 2-mil
Carbon Fiber sheet from Kinetic
Composites, Inc.. This is my first time working with
composites, and I'm greatful for the tips from Dan Danknick
and Jason Bardis on working with it. This stuff is really
killer as a high performance to weight ratio product.
I'll be spending a lot of time at KCI in the future,
because I just can't think of too many reasons to use
Aluminum over this stuff when I have the choice. I'd
also like to extend a big thanks to Richard Blethen for
showing me around KCI's operation and giving me a clue
as to what could be accomplished with this stuff.
| Another peek at the chain drive system. I used another
of my surplus sprockets and a bearing to make an ultra low
profile idler sprocket that mounted to the outside face of the
tubes. This helped route the chain so that I had better tooth
contact on the driven sprockets. To tension the chain, I took
advantage of the fact that the Pittman motors have their output
shaft off-center from the gearbox. By turning the motor in the
concentric mount, I could bring the chains into tension or
relieve the tension for servicing.
||This worked great except
for one thing: With the capacitor clamp motor mounts, I couldn't
quite get enough pressure on the motors to keep them from
loosening slightly after HEAVY loads. The fight I lost to
Jason Bardis' "Hell on Wheels" was probably at least partially due
to the fact that I was slipping chain during the last 30 seconds
of the fight. The same thing happened in the rumble, but at least
in that case I had good chain tension when going in reverse, so I
spent the last 45 seconds backing into "Carbon Conflict". I know
how to fix this now, if I decide to pursue this design again.
|Here's a shot of the fully implemented "Plan C". I removed
the Team Delta RCE220's and replaced the Vantec, only this time
bolted to the rear bulkhead (which was more protected by the
biscuit plates). Where the lifter motor was I installed a third
battery in extruded-channel clamps. You can also see the similar
clamp I made for the electronics. My receiver and Team Delta
RCE85 battery eliminator are housed in the black project box
you can see at the bottom. Its nice having a small receiver
like the Hitec Micro555 because its much easier to package and
||I've been in deep love with these genderless Anderson
connectors ever since I got these batteries with them installed.
I can easily add/delete/reconfigure battery packs for series or
parallel running and for easy charging. My only advice with
these is to tape the connectors together, since the "lock" is
only mildly mechanical and wouldn't hold if the battery started
flopping around inside. My wife got very good at cutting a
few short strips of electrical tape just the right length as
I pulled the Astroflight 112D off and started bolting the
Marionette back up for a fight.
|A closer look at the mount for the third battery. I'd originally
intended to put velcro straps in to strap the battery into the clamp,
but it seemed secure enough on tension alone. After a couple of
my last fights this battery had popped loose, so in the future I'll
follow through with strapping everything down. Also, off to
the right, notice, under
the protective electrical tape, that the wires coming into my
Vantec come in from the "top", rather than at a 90 degree angle
to the unit.
||My local surplus place had replacement header blocks
that had the funky D-shaped plug that the vantec header uses, except
that they turned the wires to a more convenient approach. This
allowed me to use the screwdriver from the top and have the wires run
directly along the length of the 'bot, rather than having them come
in from the top and then having to bend them over and having to adjust
the screws with the screwdriver down in the body of the machine. I'm
going to see if I can get extras of these and re-sell them as a service
to Vantec users everywhere. Oh, they also shorten the height of the Vantec by nearly 1/4" also.
|Since the Marionette was basically a large box of Aluminum
and Carbon Fiber (neither radio transparent), I was worried about
getting decent radio signal to it. Here's my solution, I made a
plug from Nylon to fit one of the lightening holes in the drive
tube, and bolted it up. A small hole fits one of the "disposable"
flexible antenna masts that R/C cars use. I brought a spare, sort
of wondering if it would get messed up in a fight, but truth be
told the only damage it suffered was from me setting the thing
on the table upside down too many times. However, the nearby
scratches are from my fight with Jerome Miles' Hyper Active.
More on that in the deployment report.
On to Part 3
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