24 SERVO 12.2017
WEAK IN THE KNEES
Roboticists working on quadrupedal locomotion usually
spend a lot of time developing control
strategies to make their robots more
robust and adaptable. The idea is that
an advanced controller will let your
robot do things on its own more
effectively, such as choosing the
proper gait for a given task or terrain.
Researchers from Osaka
University in Japan are experimenting
with a different approach — one that
relies on interactions between the
body of a quadruped and its
environment to generate gaits without
any sensors or controllers or really
much of anything besides some
deliberately weak leg motors.
During experiments, the only
thing being changed is the input
voltage to the four DC motors
driving the robot’s legs. The gaits that
the robot generates arise
spontaneously from the interaction
between the ground and the robot’s motors.
The motors are weak enough that they slow
down a bit when there’s a lot of force pushing
on them, causing the robot’s limbs to converge
on a type of movement where the motors are all
synced up with each other. The patterns in which
the motors sync depend on their speed, with
different speeds resulting in different gaits.
WHO LET THE NEW DOG OUT?
Of all the legged robots built in labs all over the world, few inspire more awe and reverence
than Boston Dynamics’ quadrupeds.
Chinese roboticist, Xing Wang has long been a
fan of BigDog, AlphaDog, Spot, SpotMini, and other
robots that Boston Dynamics has famously
introduced over the years.
Now Wang (with funding from a Chinese angel
investor) has founded his own robotics company,
called Unitree Robotics; it’s based in Hangzhou,
outside Shanghai. Wang says his plan is making
legged robots as popular and affordable as
smartphones and drones.
Unitree’s first robot is a four-legged robodog
called Laikago, which the company announced
earlier this year.