Robot cheetah demonstrates efficient new motors

MIT researchers built a 70-pound robot "cheetah" meant to demonstrate the high efficiency of a new electric motor design. Among other improvements, the design enables the impact energy of the robot's leg hitting the ground to be captured and fed into the robot's battery. Soon, they expect the motors to enable the cheetah-bot to gallop at 35 mph which, of course, is still just half the speed of a real cheetah. However, it will hit those speeds much more efficiently than other running robots.

From MIT:
Sangbae Kim, the Esther and Harold E. Edgerton Assistant Professor in MIT’s Department of Mechanical Engineering, says achieving energy-efficiency in legged robots has proven extremely difficult. Robots such as Boston Dynamic’s “Big Dog” carry heavy gasoline engines and hydraulic transmissions, while other electrically powered robots require large battery packs, gears, force sensors and springs to coordinate the joints in a robot’s leg. All this weighty machinery can add up to significant wasted energy, particularly when a robot’s legs need to make frequent contact with the ground in order to trot or gallop.
"MIT ‘cheetah’ robot rivals running animals in efficiency"

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  1. kpkpkp says:

    MIT aka Ng Security Industries

  2. I'm pretty sure that these are the cats that Ng's dogs will be chasing in the dystopian anarco-capitalist future...

  3. Only when they have doggy brains

    I'd say they're a long way from implanting a pit bull's brain!

    "the design enables the impact energy of the robot's leg hitting the ground to be captured and fed into the robot's battery."

    Isn't it better to capture the energy in a spring like the much debated prosthetics of the amputee runner Oscar Pistorius? It was said they stored the impact energy more efficiently than human tendons, enabling him to maximize his momentum.

  4. I assume that the spring gives you better efficiency (a motor driven backwards is a generator; but not necessarily a good one, and battery charging doesn't help); but motors have the advantage of being exquisitely controllable. Unless you are talking some retro brushed job or something, you can control the current flow through each segment of coil as your application requires, moving between near-zero resistance and maximum torque(in either direction) at lightning speed.

    Springs have simplicity and efficiency; but if you really want to be pushing off now and the spring in your joint insists that it is going to be soaking up all your effort until it reaches it's set tension, not much to be done.

    Now, a system capable of dynamically modifying the springiness of materials, or of engaging/disengaging elastic components from the limb on demand... That would be quite a toy.

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