bots IN BRIEF
8 SERVO 12.2015
JUMPING ISSUE LICKED
It doesn’t seem like the most exciting form factor
for a robot would be a cube, but recently, cube robots
have been where it’s at. Balancing cubes, jumping
hedgehog cubes, even self-assembling cubes. Somehow,
cubes can do it all, and if you give them springy metal
tongues with which they can elastically lick surfaces
like MIT did (for some reason), they can jump, bounce,
and roll.
Seriously. You did not misread that. This robot has
metal tongues that it uses to jump.
Inside of the robot there are two motorized
rotors, each connected to one end of four flattened
loops of spring steel. Activating the rotors causes the
spring steel loops (tongues) to get pulled through
rectangular openings (mouths) into a round cavity
inside the body of the robot, compressing them. As
the rotors continue to turn, eventually the
compressed tongues get pulled all the way around back to the mouths — at which point they spring out, releasing that
elastic energy all at once and causing the robot to jump.
As long as you keep the rotor turning, you can get the robot to keep jumping more or less continuously. Directional
control (to the extent of two possible takeoff angles) is possible by using different mouths at different orientations, and
driving the rotor either forward or backwards to take advantage of them.
MIT tested two different designs for the jumping cube: one hard and one soft — each seven centimeters on a side
with a mass of 200 grams. The jumping performance of both was identical ( 20 centimeters vertical), but the soft robot
was able to bounce along flat surfaces after landing, basically doubling the distance it was able to travel.
The cubes are completely self-contained with
integrated controllers, sensors, and rechargeable
batteries, offering a substantial amount of mobility
in a very small form factor, with a minimum of
complexity.
Future work will give the cubes more power
to get them jumping even higher and farther.
While the soft cube seemed to perform better
than the hard cube, the researchers will also be
trying different soft material to see what works
best. Ultimately, they’d like to design a closed-loop
controller that will enable the robot to jump and
bounce autonomously over rough terrain. Adding
more sensors could lead to some interesting
With some lightweight payloads such as
miniature cameras, the robot can be used for
exploration tasks. Moreover, a wireless sensor network
can be automatically deployed and reconfigured for
outdoor surveillance by using a group of our jumping
robots.
Image: MIT.
