Build Your Own Combat Robot

222 Build Your Own Combat Robot
Strategy
Saw Bots
While a powerful spinner is the most destructive form of kinetic-energy
weapon in the competition, this destructiveness comes with a price. The powerful
kinetic impacts that the spinner delivers are felt as much by it as by its opponent;
many spinners have crippled the opposing robot only to be themselves knocked
out by the same impact. A spinner needs to be built as ruggedly as possible to avoid
this fate. Many of the fully enclosed shell-type spinners use rings of rollers on the
inner frame to allow the spinner to ride smoothly even if it becomes bent or dented.
A fully enclosed spinner has an additional difficulty not faced by other robots:
when the weapon is running, it can be difficult for the robot’s driver to see which
way the base inside is facing! Methods of dealing with this include having a tail
trailing out underneath the shell, having a non-rotating flag or arrow sticking up
through the center of the shell, making part of the spinning shell out of transparent
materials, or cutting windows in the shell to allow the interior to be partially visible.
The reaction torque of spinning the shell will produce a strong turning force on
the base of the robot, which will make the bot want to swerve to the side when
driving. A four-wheeled base is recommended to give some straight-line stability.
Many spinner drivers also use R/C helicopter rate gyroscopes in their control electronics
to compensate for the effects.
For optimum damage, the spinner weapon should be large and should have its
mass concentrated as much as possible at the outside of its radius. Many spinner
weapons are made of disks or domes with weights at the edges and holes in the
middle, to maximize the rotary inertia of the weapon. Of course, more inertia in
the weapon means a greater spin-up time.
Ideally, a spinner wants to knock out its opponent in as few hits as possible. A
spinner’s worst possible opponent is a solidly built ram or wedge, which can take
repeated impacts until the spinner breaks itself. A high-speed collision with a
wedge can cause some spinners to flip themselves over. Spinners fare better
against lifters, clamp bots, or hammers—exposed weapon parts that can be bent
or broken off of an opponent help a spinner win.
The saw bot was first used in The Master (Robot Wars, 1994). Examples of saw
bots include Ankle Biter and Village Idiot. Saw bots feature an abrasive or toothed
disk that is spun by a powerful motor, which is intended to cut or rip the opponent
on contact.