Illustration of the Exobiology Extant Life Surveyor (EELS) idea. This versatile, snake-like robotic is being designed to autonomously discover uncharted terrains in house and on Earth with out real-time human enter. Credit score NASA/JPL-CalTech
A flexible robotic that will autonomously map, traverse, and discover beforehand inaccessible locations is being put to the check at NASA’s Jet Propulsion Laboratory.
How do you create a robot that can go places no one has ever seen before – on its own, without real-time human input? A team at NASA’s Jet Propulsion Laboratory that’s creating a snake-like robot for traversing extreme terrain is taking on the challenge with the mentality of a startup: Build quickly, test often, learn, adjust, repeat.
Called EELS (short for Exobiology Extant Life Surveyor), the self-propelled, autonomous robot was inspired by a desire to look for signs of life in the ocean hiding below the icy crust of Saturn’s moon Enceladus by descending narrow vents in the surface that spew geysers into space. Although testing and development continue, designing for such a challenging destination has resulted in a highly adaptable robot. EELS could pick a safe course through a wide variety of terrain on Earth, the Moon, and far beyond, including undulating sand and ice, cliff walls, craters too steep for rovers, underground lava tubes, and labyrinthine spaces within glaciers.
Team members from JPL test a snake robot called EELS at a ski resort in the Southern California mountains in February. Designed to sense its environment, calculate risk, travel, and gather data without real-time human input, EELS could eventually explore destinations throughout the solar system. Credit: NASA/JPL-Caltech
“It has the capability to go to locations where other robots can’t go. Though some robots are better at one particular type of terrain or other, the idea for EELS is the ability to do it all,” said JPL’s Matthew Robinson, EELS project manager. “When you’re going places where you don’t know what you’ll find, you want to send a versatile, risk-aware robot that’s prepared for uncertainty – and can make decisions on its own.”
The project team began building the first prototype in 2019 and has been making continual revisions. Since last year, they’ve been conducting monthly field tests and refining both the hardware and the software that allows EELS to operate autonomously. In its current form, dubbed EELS 1.0, the robot weighs about 220 pounds (100 kilograms) and is 13 feet (4 meters) long. It’s composed of 10 identical segments that rotate, using screw threads for propulsion, traction, and grip. The team has been trying out a variety of screws: white, 8-inch-diameter (20-centimeter-diameter) 3D-printed plastic screws for testing on looser terrain, and narrower, sharper black metal screws for ice.
EELS is tested in the sandy terrain of JPL’s Mars Yard in April. Engineers repeatedly test the snake robot across a variety of terrain, including sand, snow, and ice. Credit: NASA/JPL-Caltech
The robot has been put to the test in sandy, snowy, and icy environments, from the Mars Yard at JPL to a “robot playground” created at a ski resort in the snowy mountains of Southern California, even at a local indoor ice rink.
“We have a different philosophy of robot development than traditional spacecraft, with many quick cycles of testing and correcting,” said Hiro Ono, EELS principal investigator at JPL. “There are dozens of textbooks about how to design a four-wheel vehicle, but there is no textbook about how to design an autonomous snake robot to boldly go where no robot has gone before. We have to write our own. That’s what we’re doing now.”
JPL’s EELS (Exobiology Extant Life Surveyor) was conceived of as an autonomous snake robotic that will descend slender vents within the icy crust of Saturn’s moon Enceladus to discover the ocean hidden under. However prototypes of have been put to the check to arrange the robotic for quite a lot of environments. Credit score: NASA/JPL-Caltech
How EELS Thinks and Strikes
Due to the communications lag time between Earth and deep house, EELS is designed to autonomously sense its atmosphere, calculate threat, journey, and collect information with yet-to-be-determined science devices. When one thing goes fallacious, the objective is for the robotic to get better by itself, with out human help.
“Think about a automobile driving autonomously, however there aren’t any cease indicators, no visitors alerts, not even any roads. The robotic has to determine what the street is and attempt to observe it,” mentioned the mission’s autonomy lead, Rohan Thakker. “Then it must go down a 100-foot drop and never fall.”
Members of JPL’s EELS workforce decrease the robotic’s sensor head – which makes use of lidar and stereo cameras to map its atmosphere – right into a vertical shaft referred to as a moulin on Athabasca Glacier in British Columbia in September 2022. The workforce will return to the placement in 2023 and 2024 for extra assessments with variations of the complete snake robotic. Credit score: NASA/JPL-Caltech
EELS creates a 3D map of its environment utilizing 4 pairs of stereo cameras and lidar, which is analogous to radar however employs quick laser pulses as a substitute of radio waves. With the info from these sensors, navigation algorithms determine the most secure path ahead. The objective has been to create library of “gaits,” or methods the robotic can transfer in response to terrain challenges, from sidewinding to curling in on itself, a transfer the workforce calls “banana.”
In its remaining kind, the robotic will include 48 actuators – primarily little motors – that give it the flexibleness to imagine a number of configurations however add complexity for each the {hardware} and software program groups. Thakker compares the actuators to “48 steering wheels.” Lots of them have built-in force-torque sensing, working like a type of pores and skin so EELS can really feel how a lot pressure it’s exerting on terrain. That helps it to maneuver vertically in slender chutes with uneven surfaces, configuring itself to push in opposition to opposing partitions on the identical time like a rock climber.
The screws that propel EELS whereas offering traction and grip are lined up in a lab at JPL. At left is the black aluminum screw for testing on ice. The remaining 3D-printed plastic screws – with various lengths, lead angles, thread heights, and edge sharpness – have been examined on looser snow and sand. Credit score: NASA/JPL-Caltech
Final yr, the EELS workforce obtained to expertise these sorts of difficult areas after they lowered the robotic’s notion head – the section with the cameras and lidar – right into a vertical shaft referred to as a moulin at Athabasca Glacier within the Canadian Rockies. In September, they’re returning to the placement, which is in some ways an analog for icy moons in our photo voltaic system, with a model of the robotic designed to check subsurface mobility. The workforce will drop a small sensor suite – to observe glacier chemical and bodily properties – that EELS will finally have the ability to deploy to distant websites.
“Our focus to date has been on autonomous functionality and mobility, however finally we’ll have a look at what science devices we will combine with EELS,” Robinson mentioned. “Scientists inform us the place they wish to go, what they’re most enthusiastic about, and we’ll present a robotic that can get them there. How? Like a startup, we simply should construct it.”
The EELS system is a cell instrument platform conceived to discover inside terrain buildings, assess habitability and finally seek for proof of life. It’s designed to be adaptable to traverse ocean-world-inspired terrain, fluidized media, enclosed labyrinthian environments, and liquids. Credit score: NASA/JPL-CalTech
Extra Concerning the Challenge
EELS is funded by the Workplace of Expertise Infusion and Technique at NASA’s Jet Propulsion Laboratory in Southern California by way of a know-how accelerator program referred to as JPL Subsequent. JPL is managed for NASA by Caltech in Pasadena, California. The EELS workforce has labored with quite a lot of college companions on the mission, together with Arizona State University, Carnegie Mellon University, and the University of California, San Diego. The robotic just isn’t presently a part of any NASA mission.
