An elephant’s trunk holds a timeless fascination for children and adults alike. This unique appendage allows the animal to breathe, smell, make sound, drink, bathe, and grasp. Comprising up to 40,000 muscles, the trunk has the strength to lift heavy tree branches and even its younger offspring, which can weigh around 200 lbs on average. Yet its complex musculature can also grasp delicate objects as small and light as a single blade of grass.
Seeking to design a superior robotic gripper, a team of engineers from the University of New South Wales (UNSW), Sydney, turned to the anatomy of the elephant’s trunk, snakes, and octopuses for inspiration. These animals can explore and manipulate objects by curling their body parts around them in a firm yet gentle grasp. The team found this to have advantages over existing grippers based on claws or human hands. Such devices have limitations because they can’t make fine adjustments in force or grip to lift awkward, bulky, or fragile objects.
The resulting gripper contains sensitive tactile sensors made of liquid metal within a fabric matrix. When approaching an object, these sensors determine the amount of force needed to grasp and lift the object. The flat fabric strip provides full contact as the gripper wraps around the object.
The gripper can also transform from flexible to stiff via a heat-activated internal mechanism, allowing it to grasp objects of different sizes, shapes, and weights. More sensitive than existing fabric grippers, the UNSW device’s flexibility and force precision enable it to lift fragile items and to work within confined environments. The gripper prototype lifted objects up to 220 times its own mass during testing.
With a patent already filed, the team’s next step is to affix the gripper to robotic arms and other types of robotics, then work towards bringing the device to market. The UNSW team sees the potential for wide-reaching applications across many industries.
From a medical perspective, the new gripper could assist individuals living with conditions that limit motor control and agility. Examples include nervous system disorders such as Parkinson’s disease, other conditions that affect muscle control, or paralysis due to spinal cord injuries. It could also enhance the capabilities of prosthetic limb devices.