| Why legged robots?
| Legged systems provide some key performance
advantages compared to wheeled systems. In a legged system the feet
are not continually in contact with the ground, whereas wheels require
a continuous path of support. This enables legged organisms and
robots to traverse challenging terrain. Some legged systems
(biological and man-made) can overcome obstacles that are more than
three times taller than the hip height of the system while wheels are
limited to obstacles no higher than one radius. Finally, and perhaps
most interesting is the dynamic behavior of legged organisms seen in
nature. Many legged animals exhibit dynamically, self-stabilizing
behavior. That is, the passive mechanical properties of the systems
are tuned to naturally reject disturbances which might otherwise cause
unstable behavior in the system. |
Recent
Results
| OctoRoACH:Dual Drive MilliRobot (Sep. 2011)
The OctoRoACH robot has a mass of less than 30 grams, and includes
the ImageProc CPU with gyro, accelerometer, radio and camera, is
capable of locomotion in rough surfaces. Robot designed by A. Pullin.
|
|
CLASH:
Climbing loose vertical cloth (Sep. 2011)
The CLASH robot has a
mass of 15 grams, and is capable of climbing a loose cloth surface at
15 cm per second using a simple passive claw mechanism and a coupled
in-plane leg drive system. (Birkmeyer et al. IROS 2011)
|
|
MEDIC Millirobot with body-supported climbing
(Dec. 2010)
The Medic robot has a
mass of 5.5 grams, and is capable of positioning within
1 mm using static SMA drive. The robot includes camera and wireless.
(Kohut et al. ICRA 2011.)
|
|
Dynamic turning by modulating leg stiffness
(Sep. 2010)
The dynaRoACH robot has
mass of 24 grams and is capable of running at 14
body lengths per second. By changing leg stiffness, the robot can
execute a 90 degrees turn in 5 leg strides.
BioRob 2010
Movie (slow
motion)
Movie (real time)
|
|
RoACH 2.0 and DASH on
Granular Media (Apr. 2010)
Joint work with Goldman
lab at GeorgiaTech to measure cost-of-transport on granular media shows
5-30 J/kg-m at 6-10 body lengths per second. SPIE 2010 |
|
|
DASH 16 gram Hexapedal
Robot (Oct. 2009)
Using compliant fiber board as
structural material, and a single main driver motor, the DASH robot is
capable of 15 body lengths per second on flat surfaces. The structure
is resilient and survives ground impact at terminal velocity of
10
meters per second.
DASH: A Dynamic 15g Hexapedal Robot, IROS 2009.
Video
(Youtube).
|
|
|
The RoACH Robot
In
the Biomimetic Millisystems Lab we have combined our expertise in
building millirobots with an interest in legged systems to build what
we believe is the smallest untethered, legged robot to date - a 2.5
gram legged robot called the Robotic Autonomous
Crawling Hexapod
(RoACH). This robot makes use of the Smart Composite
Microstructures fabrication process
and integrated shape memory alloy (SMA) wire actuators. All power,
control, and communication electronics are carried onboard and the
entire robot is powered with a 20maHr Lithium-polymer battery from the
Full River corporation.
|
 |
|
Scaled prototyping of a legged millirobots
Using
commonly available, inexpensive
materials, it's possible to create folded prototypes of legged robots
with as many as 60 joints in about 1 hour. The prototypes can then be
actuated with DC motors or other types of actuators such as shape
memory alloy wire as shown in the photo to the right. Folding Prototyping
Fast
scale prototyping for folded millirobots, ICRA 2008
|
 |
|
