February 15, 2024

Snakes are remarkably agile. They can move on land by pushing against rocks, branches and other physical objects. They can swim and climb. Some can even glide through the air. 

As a result, they’re found in a variety of environments: in sand and on stone, in trees, in oceans and in freshwater, and in narrow passages. And, as an added bonus, they can wrap around objects like trees. 

Because of these capabilities, snakes are increasingly providing inspiration for robot design. Snake robots imitating this wide array of actions could do a variety of things, such as explorations of earthquake-hit areas, inspections for the oil and gas industry, fire-fighting operations and search-and-rescue (SAR) activities. 

Introducing the snake cobot

In emergency situations, snake robots could be outfitted with sensors and specialized equipment.  But their usefulness goes beyond that. Rather than viewing snake robots as tools or mobile sensor carriers, they can be viewed as team members, especially in unpredictable environments such as disaster zones, and in emergency circumstances.

Collaborative  robots, cobots for short, represent the idea of Human-Robot Teaming (HRT). This implies that humans and robots team up to tackle tasks that neither can complete on their own. When considering this paradigm, working steps are simultaneous, working spaces are shared, working tasks are dependent, and physical contact is possible, often desired. This represents a fundamental shift from traditional robots, which were not sharing spaces nor forces with humans.

A snake cobot can integrate technologies like augmented reality, digital twinning, and artificial intelligence to foster more effective control and actuation, yielding enhanced problem-solving abilities, adaptability, and efficiency, particularly in dynamically changing environments like disaster zones.

How Snake Cobots Navigate the World

When a snake robot moves through a cluttered environment by pushing against walls or other external objects (anything but flat ground), we refer to that as obstacle-aided locomotion (OAL).  But the ability to map and perceive the world is of fundamental importance. When robots use a sensory-perceptual system to exploit its surrounding operational space, we call this perception-driven, obstacle-avoidance locomotion (POAL). 

Achieving POAL requires precisely identifying potential push-points and accurately applying the force necessary to move the robot. Accomplishing this with traditional rigidly-actuated robots is exceedingly demanding because they are not supple and flexible.

One such snake cobot, known as Serpens, has been designed to be cost-effective, open-source, and highly flexible. It uses a technology called a “series elastic actuator” to accomplish POAL, which was previously challenging with rigid robots.

How Snake Cobots Could Be Used

In the aftermath of earthquakes, accidents, avalanches, or explosions, snake cobots can work with human counterparts to increase the possibility of rescuing people.

Because of the way they move, snake cobots enable unique capabilities in places that humans might find too difficult or too dangerous to reach. In particular, snake cobots could enlarge passages around victims by grabbing things or pushing them out of the way to allow rescuers to gain access. Or they could pass through areas that would also be blocked to human rescuers for search purposes. They could bring first aid supplies or medicine to the trapped people.

How People React to Snakes

One question facing the makers of snake robots is whether people being rescued want to confront anything in snake form. Numerous studies have examined how humans view and react to robots, as well as how robots should interact with people. Techniques exist to estimate people’s behavior in specific circumstances. The way a snake cobot interacts with humans must take several factors into account. It is crucial to study how a snake cobot might approach a person and convey its intentions through nonverbal clues. During emergency situations, nonverbal cues may be more appropriate and less stressful compared to verbal communication or other forms of communication that rely heavily on language or speech. These nonverbal cues can be achieved through different robot gaits or by employing a multi-modal feedback system involving auditory, visual, and tactile stimuli. In particular, snake cobots could convey critical tactile information by using haptics, such as pressure, vibrations, or textures, to improve communication and comprehension between the robot and potential victims, or between the robot and first responders. This tactile feedback could help snake cobots and people establish trust, provide guidance, and promote successful HRT in critical circumstances.

Filippo Sanfilippo is an IEEE Senior Member whose work focuses on robotics and machine learning. He is a member of the IEEE Public Visibility Committee and a former chair of IEEE Norway Section.


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