It’s not going to dance Gangnam Style any time soon. But in order to help sailors extinguish shipboard fires, the Navy’s newest robot has to learn how to move as awkwardly as real people do.
This is the Autonomous Shipboard Humanoid, or ASH, the latest robotic creation from Dennis Hong’s team at Virginia Tech. ASH is based on Hong’s award-winning (and Gangnam-dancing) CHARLI-2, a highly mobile, 4-foot-tall ‘bot. Only ASH is going to have a major upgrade from CHARLI-2: titanium springs in his legs and butt that act like human muscles. No more will robots amble stiffly like, er, robots.
The reason they do is that they’re designed that way. Humanoids typically have rigid limbs, an approximation of the bones of their human creators. That’s good for robotic durability, but it has limitations for mobility. Approximating the tendons and musculature of homo sapiens “has been a no-no for some time” among robot engineers, says Hong, who displayed ASH — well, his lower half at least; that’s all Hong’s built so far — for the first time at the Office of Naval Research’s biennial science and technology expo. “He’s a significant departure from the traditional humanoid robot.”
There hasn’t really been a reason for humanoid robot design to approximate the more complex ambulatory systems of a human’s lower body. Most robots only have to walk across the flat surfaces of laboratories, stages and convention floors, Hong explains. But ASH is part of a program, funded by the Office of Naval Research, called SAFFiR, an effort to create an autonomous robot that can help human sailors deal with shipboard disasters like firefighters. And a regular humanoid robot wouldn’t be able to maintain its balance aboard a rolling deck, climb through “knee-knocker” passageways or ascend the ladders and stairs that define shipboard life. To do that, Hong had to design ASH according to “biological principles.”
That means ringing its legs and hindquarters with “compliant linear actuators,” Hong says — i.e., titanium springs. “You don’t walk like a robot,” Hong explains, somewhat generously, as he exaggerated his own gait as if he were walking on the moon. “You store potential energy, and then you reset [your leg], like a spring… It helps you keep your balance after you’re knocked off it. It’s more energy-efficient.”
It’s somewhat similar to Boston Dynamics’ PETMAN, a headless robot that walks more naturally than most humanoid machines. And it’s a bit counterintuitive: By making ASH’s legs springy, and seemingly more wobbly than the average robot, Hong is betting he can better stabilize ASH’s mobility, plus allow him to climb — a traditional robotic difficulty.
ASH got his share of gawkers as Hong and other Virginia Tech engineers suspended him near the exhibition floor — understandably, since the robot doesn’t have a body from the waist up. Hong programmed the robotic leg set to move about, demonstrating its hydraulics and titanium springs. It was the first time Virginia Tech brought ASH out to meet his public. But since the robot is unfinished, it can’t yet march, let alone climb, and his tethered ambling was a bit awkward.
The Navy will start testing him aboard a ship next year, Hong says. But there’s no word yet on when ASH will hit the dance floor.