A rare bird has landed at the University of Michigan. It has no feathers, no arms, and no head. Its two knees appear to face backwards. The bird’s odd gait seems part amble, part trot, and part swagger. Say hello to Cassie, the walking robot.
Engineers at Agility Robotics built Cassie. The bot is an example of biomimicry—imitating designs from nature to solve human problems. (See “Biomimicry Copies Perfect Design” in May/June 2017 WORLDteen.) Scientists have made cockroach-bots that squeeze into tight places, bee-bots that pollinate flowers, turtle-bots that swim underwater, and more. But they have yet to master a two-legged, walking robot. Bird-bot Cassie is coming close.
To construct Cassie, engineers imitated one of God’s strikingly unusual designs. The cassowary (CASS-uh-ware-ee) is a flightless bird similar to an ostrich. Its long legs are so powerful that Guinness World Records labels it the “World’s Most Dangerous Bird.”
Like the cassowary, Cassie’s long legs are powerful. It has a short torso that holds motors, computers, and batteries. Cassie weighs about 66 pounds and stands a bit over 3.25 feet tall, fully extended. Multi-jointed legs, ankles, and feet allow the bot to traverse rough and uneven terrain all while keeping its balance . . . usually.
Jessy Grizzle is director at University of Michigan Robotics. He and his team are giving Cassie a road test. They take it to a sidewalk. At first, Cassie ambles along a grassy, sloped surface. But then it takes a serious tumble and face-plants on the concrete. Ouch. Good thing this bird’s really a bot.
Cassie lies in a heap. It’s slightly nicked and scratched but not seriously damaged. “Well, I think that’s the end,” Grizzle tells the team about this particular test.
Two-legged man-made bots still struggle with certain tasks, like climbing stairs and staying upright on moving surfaces. God’s design of human and bird legs, joints, feet—not to mention the ability to balance that involves frame, muscles, brain, and even inner ear construction—is still unsurpassed. Still, researchers hope this bot will lead to many more—ones that can someday navigate disaster sites to help find survivors.
Agility Robotics CEO Damion Shelton predicts that a robot capable of walking around the border of an area and taking 3-D scans is no more than two years away. But he says search-and-rescue “is a hard problem” with many random variables.
