October 30, 2018

12:25 pm

Could Elephant Trunks Hold The Key To Robotics?

Elephant trunks are infinitely fascinating. They can lift up to 770 pounds. They can be used as an elephant's personal snorkel. They contain 40,000 muscles. And now, according to a new study in the Journal of the Royal Society, they may hold the key to solving a longstanding problem in robotics: developing a robot gripper.

“It is very difficult to develop a gripper that is flexible enough to pick up a variety of objects, for example a single pen or a pile of pens, or a cube of Jell-O,” Scott Franklin, a professor of physics at RIT said in a statement. “The elephant trunk is a single thing; it doesn’t change shape at all, but it is able to pick up food of different sizes, weights and masses, so the idea is that this will give us insight and information into how nature has solved this problem of how to pick up multiple things and then we can try to reproduce it.”

The goal of the study was to better understand elephant dexterity. How do they manipulate two things at once? How can they just as comfortably lift something that's one pound versus lifting something that's 400? How do elephants pick up granular materials, such as dirt or sand, that even humans would have difficulty picking up effectively?

Time sequence of elephant trunk sweeping and grabbing a pile of wheat bran. (a) The trunk locates the force plate. (b) The trunk tip sweeps for about 5 s to compact the bran. (c) The trunk tip pushes downward to jam the bran using both finger-like extensions on the trunk tip. (d) The trunk detaches from the force plate, carrying food to the mouth. (Credit: Royal Society Publishing)
Trunk configuration when jamming food for (a) 32 mm cubes, (b) 16 mm cubes and (c) 10 mm cubes and (d) bran granules of diameter 2 mm. Note the carrot cubes are orange and the rutabaga cubes are red. The red dashed line is tangential to the top 50% of the trunk above the joint. Note that the trunk is straight when grabbing cubes with a side length of 32 mm, but then forms a joint when grabbing smaller pieces. When grabbing bran, the vertical part is the longest, reaching up to 11 cm. (Credit: Royal Society Publishing)

So what do the findings tell us?

"In this study, we investigate how elephants pick up piles of objects. The challenge in performing this task is that compressive forces must be applied to the objects so that they do not slip away. Using mathematical models, we showed that the greater the number of objects, the more compressive force must be applied. We test this idea in our experiments by providing elephants with food items varying from four to 40 000 in number. Elephants accordingly can vary the forces they apply by a factor of four, from 7 to 47 N. Using synchronized force platforms and video cameras, we show that the application of this force is accompanied by the formation of a kink or joint in the elephant trunk. The distal end of the trunk forms a pillar which provides up to 28% of the applied force. Forming joints may help reduce the energy required to reach for and grab food items, a task they perform for 18 h every day. The joint formation may also have application in elephant-inspired robots."