The new gripper can be used to hold a variety of objects with better control.
The agile gecko is one of nature's best climbers – and his secret lies in the adhesive pads on his feet. Now researchers have combined the adhesive properties of gecko toes with air-powered soft robotics to achieve unprecedented grip sensitivity.
On a gecko toe, there are millions of microscopic hairs that are about 20 to 30 times smaller than a human hair. These hairs interact with molecules on the surface that the gecko tries to grab at the atomic level, creating so-called van der Waals forces that allow the toes to easily attach and release when the gecko wants it ,
The University of California, San Diego, has developed an artificial version of the microscopic features of gecko toes using synthetic materials and a technique called photolithography. In a three-step process, the researchers first made a masterpiece of the millions of microscopic structures that line the gecko's toes. Later, copies of the master form were made using a low cost, scalable method. A process called spin coating allowed researchers to make as many copies of the wax form as they wanted at a rate of 10 to 20 sheets per hour. The soft robot gripper itself was cast in 3D printing form from a silicone rubber.
The team, working with NASA's Jet Propulsion Laboratory, coated the 3D-printed fingers of a soft robotic gripper with the artificial gecko adhesive.
During a series of experiments, the gecko-inspired adhesive allowed an air-powered robot hand to grab a wide range of objects, from pipes to beakers. The adhesive was also strong and versatile enough to enable the robot to grasp objects at many different angles. The grapple also manipulated volcanic rock, whose porous and rough texture was always challenging for gecko-type adhesives.
Because Van der Waals forces are most effective on a larger surface area, researchers had to develop control algorithms that distribute the correct force along the length of the finger. Thanks to the optimal control and distribution of the load, the gripper can lift various objects in different positions with a weight of up to 20 kg.
"We found that these two components, Soft Robotics and Gecko Adhesives, really complement each other well," said Paul Glick, the first author of the thesis and a Ph.D. Student at the Bioinspired Robotics and Design Laboratory at the Jacobs School of Engineering at UC San Diego
There are several applications that could facilitate this research. As NASA is involved, one obvious area is the exploration of space. Gecko-inspired adhesives could enable janitorial botsters to collect garbage, or new grippers can attach themselves better and safer than ever to objects outside the International Space Station. The upcoming research will further explore the potential of the adhesive for zero gravity operation.