Build Your Own Combat Robot

218 Build Your Own Combat Robot
FIGURE 10-6
Thwack bot
schematic of the
rotational motion.
Strategy
periodically varying the drive power in sync with the rotation, causing a slow
wobble toward its opponent while spinning at nearly full speed.
A thwack bot’s impact force comes from stored kinetic energy in the rotation of
it’s body. Its angular momentum is proportional to the body’s moment of inertia
times the speed of rotation. The faster it spins, the harder it hits. The robot’s moment
of inertia can be increased by moving its weight away from its center; however,
this will also increase the time it takes to spin up.
A powerful thwack bot has proven to be an effective robot against the lifter—a
strong spinning attack can keep the lifter from getting its arm in a position to pick
up the thwack bot, and the open-wheeled design and powerful drive of most
thwack bots makes them difficult to keep a grip on. A clamp bot that gets a firm
grasp on a thwack bot will render it helpless, but a powerful thwack bot can make
it difficult and dangerous to get such a grasp. Wedge bots are difficult to fight
against with a thwack bot, with the victory often coming down to speed and
maneuverability.
Drums and vertical spinners can also be very dangerous customers for a thwack
bot to fight, as the long weapon boom of a thwack bot can get hit and tossed upward
violently, disrupting the thwack bot’s spin as its wheels lose contact with the