In the trenchesSnake-like robots dispose of IEDs

Published 28 July 2010

Snakes are flexible, and they can crawl, slither, swim, climb, or shimmy through narrow spaces; the U.S. military wants to emulate these characteristics in snake-like robots that can replace soldiers in dangerous search and rescue missions, surveillance operations, and IED disposal

A robotic tentacle during testing; scaleable and combineable with others // Source:

IEDs are the main killer of U.S. and allied troops in Afghanistan — and, before that, in Iraq — and the U.S. military has been trying many different methods to deal with them: man-made lightning, bomb-handling robots, radio frequency jammers, microwaves that detonate a bomb before the enemy does, and more.

Robots built to dispose of IEDs may also perform other tasks. The U.S. Army is now developing a new, snake-like robots for battlefield action that could include search and rescue missions, opening doors, as well as handling IEDs (for earlier uses of snake-like robots, see “IDF to use serpent surveillance robot,” 10 June 2009 HSNW; “Snake-like robots to help in search and rescue missions,” 6 March 2008 HSNW; and “Mechanical mole seeks out disaster survivors under collapsed buildings,” 19 September 2007 HSNW).

Researchers at the U.S. Army Research Laboratory (ARL) have developed a prototype Robotic Tentacle Manipulator. The snake-like technology is moving the U.S. military toward sending more autonomous systems instead of soldiers on search-and-rescue missions, a top priority in the most dangerous mission areas.

The Robotic Tentacle Manipulator is a developmental project that expands on snake robotics research introduced at Carnegie Mellon University’s Robotics Institute, an ARL-funded effort through its robotics Collaborative Technology Alliance initiative. This new work has resulted in the arrangement of the bases of several snakes in a circular array that functions like a team using multiple parts of their bodies to manipulate an object, scan a room, or handle IEDs.

This snake-robot is scalable; it can be built however large or small as a subsystem to a larger platform like iRobot’s rugged system Warrior, which travels over rough terrain and climbs stairs. The number of tentacles or snakes determines the breadth or scope of its search capabilities. The number of links on each of those tentacles supports each snake’s length or reach into an area, as well as its ability to crawl, swim, climb, or shimmy through narrow spaces — all while transmitting images to the soldier who is operating the system. The subsystem comes equipped with sophisticated electronic sensors, among them laser detection and ranging (LADAR) to render 3-D representations of object shapes and physical properties like faces, mass, and center of mass.

The technology is leading to more than just the very tip of the snake being used in the object manipulation effect,” said Derek Scherer, a researcher who works within ARL’s Vehicle Technology Directorate. “Consider that snakes push off rocks or roots to propel their bodies. We are using this same concept in development.”

Scherer said that with increased manipulator dexterity, soldiers can offload more tasks to the robotic platform. “When the platform is tasked with inspecting a potential IED threat, the extreme adaptability of the tentacle manipulator will allow the platform to rummage with precision,” he said.

Its “touch sensitivity” allows the snake-robot to balance objects and feel where forces are being applied as it rotates devices. “It allows it to lift and reposition objects, including IEDs, for examination, and do so in a controlled fashion that is unlikely to detonate any ordnance,” Scherer noted. “These same capabilities would improve inspections during cargo and checkpoint missions.”

Researchers predict the technology may one day solve the “opening a door” problem, which has been a consistent obstacle in robotics, Scherer said.

High levels of articulation in the manipulator could prove to be effective for grasping and rotating different types of door handles using knobs, handles, levers, and bars. “Solving the door problem would greatly improve indoor robot missions,” Scherer added.

The developmental hardware includes a large-screen laptop, which presents a simple user interface. Each 24-centimeter tentacle is directed by a master controller system, which communicates with the motors that are embedded in each of the links found on the tentacles. The motors essentially direct individual tentacle movement and the master controller directs the entire amalgamation of snakes, or tentacles.

This is a distributed intelligence framework that permits advanced manipulation algorithms to run on a complex but affordable hardware platform,” Scherer said.

Tim Hornyak writes that labs around the world are working on snake bots for civilian and military purposes. The Israeli army is refining a six-foot-long camouflaged robot serpent with a camera eye. It could be sent to spy on enemies and plant explosives.