Track C teams had to compete to earn a spot in the
challenge. Over 100 teams entered to compete with the
track B teams in the Virtual Robotics Challenge. The
Challenge was held in June of this year. The winners were
awarded a state-of-the-art Atlas robot developed by Boston
Dynamics. Nine teams were chosen as winners and will
continue on the physical challenge.
Track D teams have no funding. They need to compete
against the fully funded top research groups on the planet.
Team “Walk Like A Man” is one of the track D teams
that have taken the challenge. Our biped WATSON
(Without A Tether Stereoscopic Omni-Navigation) was
started six years ago. Early versions were covered here in
SERVO in Dec 2007, and again in a four-part article in the
February through May 2011 issues.
This early model could stand but had problems
walking. This was due to two major design flaws. First —
and very important — is the need to create mechanical
stiffness in all joints. Instability in the system prevented the
original center of mass algorithm from achieving enough
balance necessary to walk. The new rebuild of the platform
has reduced the mechanical slop by a factor of five.
Mechanical springs have been added to reduce the
necessary holding torque in specific positions.
Second is the need for enough torque. The hobby
servos available five years ago did not have enough torque
and control. Newer servos boast three to six times the
torque of our original units. However, in practice, these
numbers vary, and the most optimistic torque values tend
to be when the DC motor is spinning at its rotational
velocity sweet spot.
In the first model, only load cells provided feedback for
the balancing algorithm. This has been augmented with a
nine-axis IMU and a vision system. A neural network is now
in development with our smaller test platform. These
smaller bipeds have learned to stand and walk on their
own. WATSON is bigger, heavier, and prone to more
damage when mishaps occur. Our goal is to have the neural
net learn rudimentary movements with the smaller bipeds
that can be passed on to WATSON.
In December of this year, the DRC Trials will begin.
Eight challenges will be given to each team’s robot. After
each challenge, each team will be able to recharge, repair,
or reprogram as necessary. In the final showdown which
will be held in December 2014, all eight of these challenges
will need to be performed as a single continuous scenario
without any breaks. The challenge is meant to mimic a
disaster scenario, with the robots coming to the rescue!
The robots will enter a utility vehicle and drive around
barrels and barriers to get to the staged disaster scene. This
will include climbing in, releasing the hand brake, putting it
in drive, and working the brake and accelerator pedals
while steering around obstacles. Once at the site, putting
the vehicle back in park and climbing out will complete the
task. To eliminate the requirements for fine motor control,
the keys will already be in the ignition and turned on. Also,
it will be an automatic. No stick shift!
SERVO 09.2013 59