Soft robotic gripper is inspired by twining plants

The team, led by associate professor Mable Fok, UGA College of Engineering, claim that their soft robotic gripper offers several advantages over existing robots thanks to its twining motion inspired by pole beans.

While pole beans and other twining plants use their touch-sensitive shoots to wrap themselves around supports like ropes and rods to grow upward, the team’s robot is designed to firmly but gently grasp objects as small as 1mm in diameter.

“Our robot’s twining action only requires a single pneumatic control, which greatly simplifies its operation by eliminating the need for complex coordination between multiple pneumatic controls,” said Fok. “Since we use a unique twining motion, the soft robotic gripper works well in confined areas and needs only a small operational space.”

In their study, published in the journal Optics Express, the researchers explain how the spiral gripper – a little more than three inches long and fashioned from silicone – proved effective in gripping objects such as pencils, paintbrushes and even objects as small as thin wire paperclips. The device was also said to achieve ‘excellent repeatability, high twining sensing accuracy and precise external disturbance detection’.

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Fok explained that the robot features an embedded sensor, providing real-time feedback, which is located in the middle of its elastic spine and can sense the twining angle, the physical parameters of the target and any external disturbances that could cause the target to become loose.

The team, which includes PhD candidates in engineering Mei Yang and Ning Liu; computer systems engineering undergraduate Liam Paul Cooper; and associate professor Xiangiao Wang, believe that their soft robotic gripper could be useful in settings such as agriculture, medicine and research.

Applications could include selecting and packaging products that require a soft touch such as plants and flowers, surgical robotics, or selecting and holding research samples in fragile glass tubes during experiments.

Next steps for the researchers include continuing work to improve the automatic feedback control based on the readings of the fibre optic sensor and exploring miniaturising the design to serve as the foundation of a biomedical robot.