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MIT's Cheetah Robot Runs Untethered
An anonymous reader writes: It's easy to make a robot walk, but hard to keep it from falling over. We've seen a number of crazy robot prototypes, but they're usually tethered and/or stuck on a treadmill. Now, researchers from MIT have developed an algorithm that allows their giant robot cheetah to run around outdoors at up to 10mph. They expect the robot to eventually hit speeds of 30mph. "The key to the bounding algorithm is in programming each of the robot's legs to exert a certain amount of force in the split second during which it hits the ground, in order to maintain a given speed: In general, the faster the desired speed, the more force must be applied to propel the robot forward. ... Kim says that by adapting a force-based approach, the cheetah-bot is able to handle rougher terrain, such as bounding across a grassy field." The MIT cheetah-bot also runs on a custom electric motor, which makes it significantly quieter than gas-powered robots. "Our robot can be silent and as efficient as animals. The only things you hear are the feet hitting the ground."
That article is written as if that crowd invented running using force control. Of course you use force control. Everybody in the field knows that by now. I patented that 20 years ago. The Scout II robot at McGill, developed by Prof. Martin Buehler, used that approach. Buehler went on to become the designer of BigDog, but never got much public credit for it and quit to work for iRobot.
The key to legged running in non-trivial situations is careful management of ground traction. Traction is first priority, then balance, then foot placement. Historically, everybody worried about foot placement first, but that turns out to be backwards. As soon as you get off flat surfaces with good traction, traction control dominates.
The next unsolved problem in that area is not going fast. It's starting, stopping, and turning fast. Most of the legged robots accelerate very slowly, and don't make abrupt high-speed turns. Big Dog starts by trotting in place, then extending the gait out. Starting fast, stopping fast, and turning fast are all facets of the same problem. You have to take one stride using completely different control algorithms than you use for normal locomotion. That's all I'm going to say about this for now.
If this is an implementation of a cheetah's running locomotion, it is a complete fail.
- When running, a cheetah's spine flexes. Not this robot.
- When running, a cheetah's hind legs land in front of its forelegs. Not this robot.
- When running, a cheetah's legs land with a full pacing stagger, ie left first then right. The feet on this robot land simultaneously.
Check out a real cheetah running. It's like they didn't do any research at all.
When our name is on the back of your car, we're behind you all the way!
One of the things that makes US reasearch strong is the ability of it's universities to attract te best and brightest from all around the world. This is nothing new - it has always been thus - though perhals this is incresingly so as the state of secondary education seems to be in decline compared to opter parts of the world.
When researchers stop coming to the US, the state of
research there will go into rapid decline.The US isn't alone though - it's the same story in Australia too.
Given the already established centres for excellence in the US, it's a favoured destination for smart and motivated people from India and Asia, as well as other parts of the world to further their education and opportunities.
Half the world's population is Asian or India/Bangadesh/Pakistan, so naturally you are going to see many from those regions. Be glad for it - or they would be busy innovationg wherever they came from instead of the US.