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 robots are also capable of grabbing objects delicately — or with sufficient strength to lift heavy objects.
Cheetahs derive their speed and power from the flexing of their spines. The researchers 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. Switching between these stable states is achieved by rapidly 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.
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, 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 3 Hz. 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. The 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, compared to 0.7 body lengths per second for the previous fastest swimming soft robot. They also demonstrated the use of several soft robots working together, like pincers, to grab objects. By tuning the force exerted by the robots, they were able to lift objects as delicate as an egg, as well as objects weighing 10 kilograms or more.
Potential applications include search and rescue technologies in which speed is essential and industrial manufacturing robotics.