A working human body requires more than just hooking up muscles and nerves, as poor Doctor Frankenstein found out. But researchers of humanoid robots are finding that sometimes the original design is the best. Swapping out muscles and arteries for pulleys and motors, they’ve come up with a robot that’s not afraid to flex its muscles.
Kenshiro Robot Gets New Muscles and Bones
by Angelica Lim
Why try and mimic the human body? It turns out that getting a robot’s weight right is a tricky problem. Yuto Nakanishi, the head of the project, spoke about the weight problems of Kenzoh, Kenshiro’s tendon-driven upper-body robot ancestor. Kenzoh was a hearty 45 kg, just for the upper body. Scaling up, they projected that a full-body Kenzoh could weigh as much as 100kg!
That was a lot of weight for a relatively small robot. So they decided to design a robot with the same weight ratios of a human. For example, a 55 kg boy would have about a 5 kg thigh and 2.5 kg calf. Kenshiro copies that ratio, with a 4 kg thigh and 2.76 kg calf. Balance is key.
Weight was one thing, but the researchers also tried to mimic the muscle torque and joint speeds. Kenshiro’s total power output is 5 times greater than Kojiro’s, allowing it to do things like the gymnastics-like leg lift in the video above. Kenshiro can get almost the same amount of joint torque as a human, with joint angular speed not quite at human level, at 70-100 degrees per second. It’s a trade-off in weight and power: bigger and stronger motors are often heavier.
Read the full article at IEEE Spectrum. What are some industrial applications that could benefit from a humanoid robot’s flexibility? On the other hand, what are some applications that robots are better at because they don’t have to adhere to a human-like design?