Bipedal Bike Riding Robot
Robot creator Masahiko Yamaguchi has demonstrated a robot which can
balance, steer and correct itself while riding a fixed-gear bike.
"A
feature of this robot is, it pedals the bike with its own feet, and
keeps its balance just by using the handlebars. I think this is probably
a world first."
"I'm interested in artificial
intelligence, and in that context, I think intelligence and skills have
equal value. So my purpose in creating this robot was to pursue
intelligence from the skills side. While I was thinking of suitable
topics, my local science museum demonstrated a cycling robot. So I decided to consider cycling as the skill, and build a bicycle robot."
This
robot system consists of a commercially available two-legged robot and a
bicycle made by Yamaguchi. To detect how much the robot is tilting, the
TAG201 gyro from Tamagawa Seiki is used. Based on the tilt data, a
method called PID control is used to control the robot's balancing
motion.
"There's a control board in the backpack.
That needed to have a high processing speed, so I made my own board
using the SH7125 CPU core."
"PID control is a
classical control method. It's used to calculate how far to turn the
handlebars when the frame tilts. By calculating proportional, integral,
and differential components for the tilt, and adding them, the system
calculates how far to turn the handlebars when the frame tilts. Also,
the robot needs to decide which direction to go in, so we use a remote
control to instruct it."
The system has two speeds. Because there
aren't any brakes, the robot stops by taking its feet off the pedals and
placing them on the ground.
"With an ordinary
bicycle, the rear wheel keeps turning even when you stop pedaling. But
in a fixed-gear bike, there's no ratcheting, so when you stop pedaling,
the rear wheel stops, too. Ordinarily, that makes riding difficult, but
with this robot, it also has a braking effect, so a fixed-gear bike is
more convenient."
"From now on, I'd like to link
this robot's skill to its intelligence. I personally don't like using a
remote control for the robot. I'd like to make the robot intelligent
enough to ride by itself. This system is the first step toward doing
that."
