Nature inspired engineers at the University of New South Wales in Sydney to develop a soft fabric robotic gripper that behaves like an elephant's trunk, capable of grasping, picking up, and releasing objects without damaging them.

Researchers state that this versatile technology can be widely used in industries handling fragile items, such as agriculture, food, science, and resource exploration, as well as for human rescue operations or personal assistive devices.

Scientia Lecturer and Director of the Medical Robotics Laboratory at the University of New South Wales, Dr. Thanh Nho Do, stated that if his team secures support from industry partners, the gripper will reach the market within the next 12 to 16 months. He is the senior author of the study featuring this invention, published in Advanced Materials Technologies.

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

"Our new soft fabric gripper is thin, flat, and lightweight, capable of grasping and retrieving various objects even from narrow hollow spaces, such as a pen inside a tube," said Do.

"The device also features enhanced real-time force sensors with sensitivity 15 times greater than conventional designs, allowing it to detect the required gripping force to prevent damage to handled objects."

"There is also a heat-activated mechanism that transitions the gripper body from flexible to rigid and vice versa, enabling it to hold objects of various shapes and weights, up to 220 times heavier than the gripper's own mass."

Nature-inspired robotics

Do stated that researchers drew inspiration from nature when designing the soft fabric gripper.

He said, "Animals such as elephants, pythons, or octopuses utilize their soft, continuous structures to grasp objects while increasing contact and stability, making it easier for them to explore, grip, and manipulate objects."

"These animals are able to do this due to the combined effect of highly sensitive organs, tactile sensation, and the strength of thousands of muscles without rigid skeletons—for example, an elephant's trunk has up to 40,000 muscles."

"Therefore, we aimed to mimic this gripping capability—grasping and manipulating objects are essential motor skills for many robots."

Improvements over existing soft robotic grippers

Do stated that the researchers' new soft robotic gripper is an improvement over existing designs, which have limitations that restrict their applications.

"Many soft grippers are based on claw-like or hand-like structures with multiple inwardly curving fingers, but this makes them unsuitable for grasping oddly shaped, heavy, or bulky objects, or objects smaller or larger than the gripper's opening," he said.

"Many existing soft grippers also lack sensory feedback and adjustable stiffness features, meaning they cannot be used with fragile items or in confined environments."

"Our technology can grasp slender objects and retrieve them from narrow, confined spaces, and can also hook into holes on objects to pick them up, such as a cup handle."

Lead author Trung Thien Hoang stated that the researchers' manufacturing method is also simple and scalable, allowing for the easy production of grippers in different sizes and volumes—for example, a one-meter-long gripper can handle objects with a diameter of at least 300 mm.

During testing, a gripper prototype weighing 8.2 g could lift objects weighing 1.8 kg, more than 220 times the gripper's mass, while a 13 cm long prototype could wrap around objects with a diameter of 30 mm.

Lovell said, "We employed a manufacturing process involving computer garment engineering and applied a newly designed high-sensitivity liquid metal-based tactile sensor to detect the required gripping force."

"The flat continuum of the gripper also allows it to form excellent contact with the surface while wrapping around objects, thereby increasing the gripping force."

"Furthermore, the entire heating and cooling cycle for the gripper to transition its structure from flexible to rigid takes less than half a minute, which is the fastest reported to date."

Integrated robotic arm and haptics

Do has successfully filed a provisional patent for the new gripper and has successfully tested and validated the technology as a complete device.

He expects that, if industry partners are found, the gripper will be commercialized within 12 to 16 months.

"Our current goal is to optimize the integrated materials, develop closed-loop control algorithms, and integrate the gripper into the end of the robotic arm for automatic grasping and manipulation of objects," said Do.

"If we can achieve these subsequent steps, there will be no need to manually lift the gripper, which will help in handling very heavy objects.

"We are also working on combining the gripper with our recently announced wearable haptic glove device, which will allow users to remotely control the gripper while experiencing the sensation of the object."