Animal Robots

hamlet2600 writes "The New York Time is running an article all about how animal like robots [Soul Sucking registration required] are beginning to become more imporant in furthering research. For years reseachers have been trying to make humanoid robots, Honda's ASIMO, MIT's M2 are some notable ones. It seems that more and more researchers are turning to the animal kingdom for "simpler" means of locomotion."

Comments

Efficiency

[devilsadvoc8]

Bipedal movement is more efficient than quadrapeds. It takes less energy to move the same mass at the same speed using two legs vs four. The problem lies in the inherent instability of bipedal movement. Thankfully, evolution has blessed us with the means to account for this instability. Roboteers don't have the benefit of millions of years and thus an easier solution would be to revert to the less efficient mode of movement involving more than two legs.

M2

[Xeo2]

I actually spent this last summer working on M2, so I can tell you a little about how it works. M2 was designed to make use of two nifty ideas, the first being Series-Elastic Actuators (photo)and the other being Virtual Model Control link to pdf journal article).

The series elastic actuators are meant to simulate the interaction of a human muscle-tendon-bone system, and to allow for the design of a low-impedance system. M2 is designed to actually mimic the inherent low-impedence (low-stiffness) mechanical system that people represent. People are really awful at position based/high-impedance control, which is what most traditional robots use. This is useful for manufacturing, when you want the robot arm to always put the bolts in the same place, but leads to stereotypical "robot" movement (like the guy spastically jerking around on the dance floor). People are pretty good at force control though (there are all sorts of biological reasons for this). So M2 was built to be low-impedance like a person by using these S-A Actuators.

Virtual Model Control is supposed to allow more a more intuitive control of a robot by simulating it as a mechanical system. VMC lets you basically define springs and dampers at different points which are then simulated by the actuators. So to keep M2 standing, you might make a granny-walker out of springs, and to make it walk you could "attach" a spring to its chest pulling it forward. VMC has been implemented in simulation (where it works great), but it's not quite ready in real life.

The really cool thing about M2 is its potential. It already moves much more fluidly and naturally than any other robot out there, and its not nearly done yet. Once its working properly, it'll be able to walk essentially blindly (becuase its low impedance) like a person, rather than needing to know exactly where to place each foot (*cough*ASIMO*cough*) to keep from shattering itself.

If anyone has any other questions about how M2 actually works, I'd be happy to answer them.

-Zach