reverse knee style aesthetic that I felt was important for
capturing the feel of the Mech. I quickly assembled a
set of legs based on the MicroRaptor and started
plugging away at getting them to
walk. Figure 4 shows a photo of the
leg design.
Many painstaking hours later
and after watching Jon’s videos
dozens upon dozens of times, my own
prototype started taking its first steps
forward. One thing I was very mindful of while
doing this testing was the payload capability. I closely
monitored the temperatures of all the servos (another
great function readily available with the AX-12s) and had
the distinct feeling that while they would be sufficient to
carry the components required to compete, I would end
up wanting to do more with this project than just the
bare minimum. With that in mind, I moved
towards building my proof of concept.
Hagetaka v1.0
Armed with a solid vision of the
project in mind, I started on the
first revision of Hagetaka. Why
build the robot on a smaller
scale when we’ve already
verified that the design is
functional and can walk?
Well, one can plan all
they want on paper,
but having a real
world scale model of
your final version is
invaluable for trial and
error. My other reason
for building the robot
on a smaller scale was
budget. I knew my
ultimate goal
would be to
move this over
to a custom
aluminum chassis
with much
higher torque
servos, but the
cost for that would
be considerable. For the
time being, I could at
least build a smaller
version to experiment with,
and use what I learned
from that to move
forward with the larger,
final version.
With the legs more or
less taken care of, I started to plan
out what else would need to
be added: an upper
torso to carry the
electronics, wireless
camera, battery, and
a method of mounting
the weapons as well
as aiming them, all
the while keeping payload
considerations in mind. I
decided on a pan/tilt
arrangement for the waist
which would be the simplest
solution for aiming and looking
around. The airsoft weapons
and camera would then be
mounted in a stationary
fashion to the upper torso,
allowing me — in theory —
to shoot whatever my
camera was aimed at. I do
most of my CAD work in
Autodesk Inventor 2008,
so I started drawing up a
simple ‘roll cage’ style
Figure 5
upper torso design that
would protect the
electronics and provide
a means of mounting the
weapons. Pololu Robotics ( www.pololu.com) offers
a fantastic, low cost laser cutting service that I have
used on more than one occasion. I recommend them
because of their customer service, pricing, and quality
of work.
I’ve always been a big fan of building a chassis
using flat frame pieces connected with standoffs: it’s
inexpensive, easy to design, and quite effective. I also
added Lynxmotion SES compatible mounting holes to
the sides of the torso chassis to provide a mounting
point for my weapons. Check out Figure 5 for a shot
of Hagetaka v1.0.
I learned quite a bit from building the first version.
For armament, I ended up using airsoft weapons intended
for an R/C tank due to their light weight and small
form factor. Mounting the weapons was fairly
straightforward using some Lynxmotion tubing
and hubs. While I did encounter a few challenges
getting my original onboard micro, battery,
wireless camera, and other supporting
electronics mounted within the chassis, I would
classify my prototype as a great starting point.
Figure 4
Hagetaka v2.0
Upgrading the servos in version 2.0 would not only
increase the payload capacity to allow for a higher end
video system and better weaponry, but it would also
increase the overall size of the robot by a substantial
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