Why isn't passive dynamic walking used more?

[chi-young]

I was researching movement models for bidpedal locomotion and when I stumbled across this amazing video of passive dynamic walking from 1990. But all the papers now I find are about neural oscillation. I do not find a mention of passive dynamic walking anywhere. Was there some kind of fatal flaw that prevented this model from extensive use?

 

[Bobbywhy]

Do you have access to Google Search? I do. When I used these search terms: “knee design for a bipedal walking robot based on a passive-dynamic walker” about 73,000 results appeared. I did not find any mention of a “fatal flaw” among the designs, but maybe you could.

 

[chi-young]

ouch.

Okay. Why are there not more quasi passive dynamic lower extremity active orthosis' or exoskeletons in comparison to fully actuated versions?

What is holding passive dynamic exoskeleton design back?

 

[256bits]

Perhaps as computational power progressed from the 90's it became able to simulate, in real time, the walking motion through methods of electrical excitation. Do realize that walking is a combination of forced and passive oscillation, so perhaps both are being researched as one towards the same goal.

 

[tedjan]

I have been working on a physics based mathematical model of a bipedal runner, not a walker, for several years. It uses two models; a spring mass model first developed by Blickhan in ‘89 and a similar swing leg model. Both models use RK4 algorithms controlled by Newton-Raphson drivers to solve Newton’s and Euler’s equations . I was interested in using the combined model to understand how a runner's specific power expenditure (w/kg) depends on their velocity (speed).

I thought that there would be some research in the biomechanics groups (Biomch-L) in this area, but I have been disappointed. I don't know why this is so, but I think it may be because most biomechanics people are well founded in biology and human physiology, and not math/physics and mathematical modeling

There are a few who work in this area. McGeer's work was produced in 1990. As far as I can tell, it has not been built upon. Regarding PDR you might take a look at the PDR400 on Yourtube.com by Owaki. There are several interesting videos that may be of values.

Please post here if you find anyone who is working on a similar math/physics based approach to understanding the PDR model.