Hacker News Reader

> bike brake cable

Funny you mention that, this guy [1] made an actuator/arm recently doing that technique. Does work but accuracy/flex can be a problem.

[1] https://www.youtube.com/watch?v=ahSS5HUylT8

View on HN

Curious, could one apply fancy control theory and modern computing at the problem and fix most of the accuracy and flex problem? Position feedback with integrated sensors can be very compact and highly accurate, and human muscle seem to also use feedback control for holding position..

The human system doesn't use single-muscle feedback for holding position though; it requires flexing both the push and pull muscles and coordinating the strength between them; positional information is relayed not just from the muscles, but the surrounding skin as well.

The constant muscle tone is largely to help bones stay in ball-and-socket joints. Presumably, such tone wouldn't be necessary with other kinds of joints.

Rather than control theory you can use geometry to reduce the problems with cable driven robots. There are more but I like the Ambidex: https://youtu.be/aLaqMreVj9o

Reply on news.ycombinator.com