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Robotic Snake Demonstrates Dexterity

Nature has inspired engineers at UNSW Sydney to develop a soft fabric robotic gripper which behaves like an elephant’s trunk to grasp, pick up and release objects without breaking them.

The researchers say the versatile technology could be widely applied in sectors where fragile objects are handled, such as agriculture, food and the scientific and resource exploration industries – even for human rescue operations or personal assistive devices.

Dr Thanh Nho Do, Scientia Lecturer and UNSW Medical Robotics Lab director, said the gripper could be commercially available in the next 12 to 16 months, if his team secured an industry partner. He is the senior author of a study featuring the invention, published in Advanced Materials Technologies this month.

Dr Do worked with the study’s lead author and PhD candidate Trung Thien Hoang, Phuoc Thien Phan, Mai Thanh Thai and his collaborator Scientia Professor Nigel Lovell, Head of the Graduate School of Biomedical Engineering.

“Our new soft fabric gripper is thin, flat, lightweight and can grip and retrieve various objects – even from confined hollow spaces – for example, a pen inside a tube,” Dr Do said.

“This device also has an enhanced real-time force sensor which is 15 times more sensitive than conventional designs and detects the grip strength required to prevent damage to objects it’s handling.

He added that there is a thermally-activated mechanism that can change the gripper body from flexible to stiff and vice versa, enabling it to grasp and hold objects of various shapes and weights – up to 220 times heavier than the gripper’s mass.

The researchers found inspiration in nature when designing their soft fabric gripper.

Dr Do shared that 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.

“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 – for example, an elephant’s trunk has up to 40,000 muscles. So, we wanted to mimic these gripping capabilities – holding and manipulating objects are essential motor skills for many robots.” He added.

The researchers’ new soft gripper was an improvement on existing designs which had disadvantages that limited their application.

Lead author Trung Thien Hoang said the researchers’ fabrication method was also simple and scalable, which allowed the gripper to be easily produced at different sizes and volumes – for example, a one-metre-long gripper could handle objects at least 300 millimetres in diameter.

During testing, a gripper prototype weighing 8.2 grams could lift an object of 1.8 kilograms – more than 220 times the gripper’s mass – while a prototype 13 centimetres long could wrap around an object with a diameter of 30 mm.

Dr Do has filed a provisional patent for the new gripper, having successfully tested and validated the technology as a complete device. He expects the gripper to be commercially available in the next 12 to 16 months, if he finds an industry partner. [APBN]