Hold it softly like an elephant would

Engineers in Australia have gone back to nature in the quest to design a robotic gripper that can deal with tight spaces and delicate situations.

Their soft fabric prototype, described in a paper in the journal Advanced Materials Technologies, behaves like an elephant’s trunk to pick up and release objects without breaking them.

“Animals such as an elephant, python or octopus use the soft, continuum structures of their bodies to coil their grip around objects while increasing contact and stability: it’s easy for them to explore, grasp and manipulate objects,” says senior author Thanh Nho Do, from UNSW Sydney.

“These animals can do this because of a combination of highly sensitive organs, sense of touch and the strength of thousands of muscles without rigid bone… So, we wanted to mimic these gripping capabilities.”

A prototype weighing 8.2 grams could lift an object of 1.8 kilograms while one 13 centimetres long could wrap around an object with a diameter of 30 millimetres.

It can even work in confined space. During testing, lead author Trung Thien Hoang and colleagues were able to lift a pen from inside a tube, for example.

“We used a manufacturing process involving computerised apparel engineering and applied newly designed, highly sensitive liquid metal-based tactile sensors for detecting the grip force required,” says co-author Nigel Lovell.

The key is the enhanced real-time force sensor which, the researchers say, is 15 times more sensitive than conventional designs and detects the grip strength required to prevent damage to objects it’s handling.

A thermally-activated mechanism can change the gripper body from flexible to stiff and vice versa, enabling it to grasp and hold objects of various shapes and up to 220 times its own mass.

The researchers now plan to optimise the integrated materials, develop a closed-loop control algorithm, and integrate the gripper into the ends of robotic arms for gripping and manipulating objects autonomously.

“If we can achieve these next steps, there will be no need to manually lift the gripper which will help for handling very large, heavy objects,” Do says.

“We are also working on combining the gripper with our recently announced wearable haptic glove device, which would enable the user to remotely control the gripper while experiencing what an object feels like at the same time.”

Please login to favourite this article.