bots IN BRIEF
SERVO 05.2015 23
TOSS ME A SUPER BALL BOT
NASA’s Super Ball Bot has to be one of the weirdest, yet most effectively innovative robot designs yet. It’s a tensegrity structure: nothing more than a
bunch of rods connected by a bunch of cables. It’s almost certainly not what you
would picture when you think of a robot — much less one that’s intended to
head into space. They’ve been working on this project at NASA Ames Research
Center, through NASA’s Innovative Advanced Concepts (NIAC) program.
The primary advantage of tensegrity structures is that they are excellent at
distributing forces. Since there is no rigid connection between any of the
structure elements of the robot, they’re easy to pack, easy to unpack, and
extraordinarily resilient to external forces — since any external stress gets
absorbed across the entire structure of the robot. This means you can drastically
reduce the mass of the robot and still end up with something strong enough to
meet your mission requirements.
Super Ball Bot also features tunable stiffness. By increasing or decreasing the
tension on the cable network, the bot can transform from a nearly rigid
structure to a squishy and compliant pile of interconnected sticks. The sticks are the muscles of the robot,
containing motors that wind and unwind the cables. By making the right cables at the right lengths at the right
times, the sticks can make the robot move.
Saying that Super Ball rolls might be a bit optimistic, but it can move in any direction, has no problems with
rough terrain, and can even make its way up hills. If you do somehow manage to break something on the robot, it
can keep itself going even after 75 percent of
its actuators are non-functional, or even if a
For the last year or so, NASA has been
working on a much larger and more complex
version of the robot, called SUPERball.
SUPERball has 12 actuators (the final robot
will have 24) — enough to really explore
how to make the robot move effectively. It’s
also large enough that a scientific payload can
be suspended inside to see how it fares, and
modular to be able to test out different
Long term, a robot like this could be
perfect for exploring a place like Titan
(Saturn’s largest moon) where the
atmosphere and relatively low gravity
means that you could drop the robot as-is from orbit without any additional
descent paraphernalia, and it would make
it to the ground completely unscathed.
The photos to the left show a few
other intriguing applications.