I
had a lot of ideas in regards to the wedge/plow design. with my highest
priority being to protect the robot against high mass spinners by
blocking and absorbing kinetic energy. I played around with having two
separate plows one maximized for horizontal absorption, and another
focused on vertical absorption,. in a eureka moment I figured I could
design a single shield capable of absorbing energy in all directions by
simply using springs.
I
Started by cutting a piece of 1-1/2 x 1/16' thick angle aluminum down to
6', measuring and marking my shape and drill points. It was rather heavy
at start so I new I would have to lighten it up with multiple drill
holes. Using the band saw I cut down the corners, and using the drill
press I drilled pilot holes for all weight reduction holes. afterwards I
did a second pass with the larger drill bit, the pilot holes made sure
the larger drill bit did not wander, and made all of the holes fairly
evenly spaced.
I built two Wedge/Plows one out of 1/16th" and another out of 1/8th" stock. The 1/8" plow was an inch shorter and only 1-1/4 wide, but still it was far heavier then the larger coverage plow made out of 1/16th. Feeling fairly confident that 1/16 anodized aluminum would be just strong enough I settled on the 1/16th thick Plow.
Mounting the springs to the back of the plow was fairly easy, I just shaped a bit of the left over cutting board materiel with a "V" to hold the Plow, and then drilled out a hole behind the "V" for the spring to slide into. I then locked the spring and the plow into place with a few miniature wood screw.
While I was working on the plow the second set of motors came in and I was able to quickly mount them onto the fiberglass and then mount the plow onto the robot by threading the spring through the plastic at the front of the robot. At this point everything was coming together nicely but I was a robot without armor.
I ended up jumping the gun a bit and started cutting into a nice piece of Garolite before I sat down and weighed how much I was going to need for both the top and the bottom piece and the side armor pieces.
When I was done, the cut and fit looked rather sharp and well fitted
to the robots internal structure, unfortunately a quick drop of
everything on the scale told me I was in trouble. And this weigh in did
not include the plow and a few other bits of wire and hardware, so I was
at least a whopping 3 oz over weight if not more.
At this point I had no choice, I had to order some carbon fiber or face a re-design far to late in the build to start over in time for the upcoming event. after a bit of math I figured I could save a lot of weight by moving from 1/16" garolite to 1/32" carbon fiber. After the new materials showed up and I had it cut down using the original cuts as templates the two CF parts weighed in at .35 less than a single piece of the 1/16 garolite, so this alone was a savings of 2.15oz over all.
I also re cut the bits of side armor out of the left-over's from the carbon fiber sheet helping to reduce weight a bit more. putting it all together it was starting to really look sleek,.. but I still had internal wiring and lots of little details to work out, including still being at least .6 oz over weight and needing to add a switch and wanting to add some rare earth magnets for added traction.
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