Inspired by the biomechanics of cheetahs, researchers have developed a new type of soft
robot that is capable of moving more quickly on solid surfaces or in the water than previous
generations of soft robots.
The new soft robotics are also capable of grabbing objects delicately - or with sufficient
strength to lift heavy objects.
Recently, soft robotics have attracted tremendous research interest because of their safe and
adaptive interaction with humans and harsh environments, enabling a wide range of new
functionalities that can rarely be achieved by conventional rigid robots, including manipulation
of delicate objects, navigation through a confined space, and actuation with multiple
degrees of freedom . Despite these advances, it remains challenging to achieve high performance
in soft robots, e.g., high-speed locomotion and high-strength manipulation, because of
the intrinsic limitations of their soft bodies.
Cheetahs are the fastest creatures on land, and they derive their speed and power from
the flexing of their spine.
The researchers from North Carolina State University were inspired by the cheetah to
create a type of soft robot that has a spring-powered, 'bistable' spine, meaning that the robot has
two stable states.
They can switch between these stable states rapidly by pumping air into channels that
line the soft, silicone robot.
Switching between the two states releases a significant amount of energy, allowing the
robot to quickly exert force against the ground.
This enables the robot to gallop across the surface, meaning that its feet leave the ground.
Previous soft robots were crawlers, remaining in contact with the ground at all times.
This limits their speed.
The fastest soft robots until now could move at speeds of up to 0.8 body lengths per second
on flat, solid surfaces.
The new class of soft robots, which are called "Leveraging Elastic instabilities for Amplified
Performance" (LEAP), are able to reach speeds of up to 2.7 body lengths per second - more
than three times faster - at a low actuation frequency of about 3Hz.
These new robots are also capable of running up steep inclines, which can be challenging
or impossible for soft robots that exert less force against the ground.
These "galloping" LEAP robots are approximately 7 centimeters long and weigh about 45 grams.
The researchers also demonstrated that the LEAP design could improve swimming speeds
for soft robots.
Attaching a fin, rather than feet, a LEAP robot was able to swim at a speed of 0.78
body lengths per second, as compared to 0.7 body lengths per second for the previous fastest
swimming soft robot.
By tuning the force exerted by the robots, the researchers were able to lift objects
as delicate as an egg, as well as objects weighing 10 kilograms or more.
The researchers note that this work serves as a proof of concept, and are optimistic
that they can modify the design to make LEAP robots that are even faster and more powerful.
Potential applications include search and rescue technologies, where speed is essential,
and industrial manufacturing robotic.
For example, imagine production line robotics that are faster, but still capable of handling
fragile objects.