Danish scientists have developed an origami snake robot that could one day search for survivors at disaster sites, or even explore other planets. The device moves via rectilinear locomotion, just like real snakes often do.
When most people think of a snake moving along the ground, they likely picture the reptile undulating its body in a horizontal S-shaped pattern. The fact is, though, that form of locomotion – known as serpentine – is just one of four that snakes commonly use.
When a snake has to pass through a narrow gap, swishing its body from side to side just isn't an option. Instead, the animal keeps its body straight while sequentially contracting and relaxing a series of muscles, starting at its head and running down to its tail.
Because the skin on the snake's underside is more flexible than the skin along its sides, that underside skin stretches more than the side skin with each muscle contraction. This causes the underside skin to repeatedly shift forward (relative to the sides) and grip against the ground like the treads on a tire, pulling the snake's body forward.
That form of movement, called rectilinear locomotion, is utilized by the new robo-snake. It was created at the University of Southern Denmark, by a team led by engineering PhD student Burcu Seyidoğlu and Prof. Ahmad Rafsanjani.
The robot's body consists of linked segments made of a lightweight composite textile that incorporates the world's strongest synthetic fiber, ultra-high molecular weight polyethylene (UHMWPE). That textile is laser-cut and folded like origami, then heat-pressed so that each segment forms a bellow.
Inside the bottom of each segment is a small semi-air-permeable pouch, made of the same textile. A silicone hose running along the inside of the robot delivers pulses of pumped air into those pouches, causing them to sequentially expand and then deflate as the air leaks back out of them. As the pouches repeatedly go through this process, they move the robot forward.
As compared to most other snake robots we've seen, the Danish one is said to be considerably lighter and less costly to build, plus the soft and pliable nature of its textile body should allow it to squeeze through tight spaces better. And, of course, it can move forward while keeping its body straight.
The researchers are now working on incorporating the air pump into the robot's body, along with increasing the bot's speed and allowing it to turn to either side. It is hoped that someday an untethered, autonomous, sensor-equipped version of the robot may find use locating survivors trapped under rubble at disaster sites – or in other snaky applications.
You can see the robo-snake in action, in the video below. A paper on the research was recently published in the journal Device.
Source: University of Southern Denmark
