FIGURE 10. The weapon assembly is installed in
the frame and the drive motors are test fitted.
FIGURE 11. All of the components are
mounted and wiring has begun.
• Tank steering
• Minimum drivetrain speed of 6 mph
• Minimum 1/4” ground clearance
• Five minute run time
• As small a size as possible in all
dimensions
• Importance of subsystems
• 40% weapon
• 15% armor
high current draw the weapon would have. However, my
drive required much less current so I used 12 gauge wire
for it. Every connection was crimped and soldered for
maximum strength and conductivity. I used Anderson
power poles at each major connection point because of
their high current carrying capacity and ease of use. After
mounting all of the components and wiring the robot, it
was finished! The completed robot — dubbed Papercut —
can be seen in Figure 12.
• 20% drive train
• 25% reliability
• Comply to all of the Robot Fighting League’s and BotsIQ rules
Papercut met all of these requirements, and even with
its high powered weapon system weighed in at 117 pounds
— 3 lbs underweight. After testing, I found that Papercut
could be improved in one area. The wheel configuration
was very long and narrow; this led to the robot having a
hard time turning unless it was already moving. To alleviate
this problem, in future designs I need to ensure the robot’s
wheel base is at a minimum as wide as it is long.
Testing and Analysis
In Conclusion
Part of building a robot is analyzing how well it meets
its goals and design specifications. After comparing the
completed robot against the design specifications from
the first article of this series, I would say that we were
successful in meeting all of our requirements. To refresh
your memory, those requirements were:
• Combat robot for fighting in national competitions
• Middleweight weight class (120 pound maximum weight)
• Four-wheel drive
• Inboard wheels
In this four part series of articles, we have covered a lot
of material! We have discussed every part of building a custom
robot from scratch. Starting with a simple idea, we developed
and quantified that idea. Next, we came up with a number
of different options and analytically compared them,
choosing the best one. We decided upon a frame type and
components, along with the best way to lay them out. Taking
all of this information, we designed the robot using CAD.
Next, we discussed a number of tools and techniques that are
useful when building a robot. Using this new construction
knowledge, we applied it towards
building a robot using the CAD as the
instructions. We successfully built the
robot and analyzed how well it
matched the design specifications
along with identifying its weaknesses.
I hope you enjoyed this series of
articles and that the information
presented will be useful in your future
robotic projects! For more information
on myself or my robots, or if you have
any questions, please visit
www.robotic-hobbies.com. SV
FIGURE 12. Papercut is completed and
is ready to do battle!
40 SERVO 06.2008