Keep on trippin'...

June 20, 2019 5:02 PM

First step towards a better prosthetic leg? Trip people over and over. The aim of "stumble recovery" research being carried out at Vanderbilt University is to "construct a model of which factors determine the nature of the stumble response, so when a stumble occurs, we can use the various sensors on a robotic prosthetic leg to artificially reconstruct the reflex." From the Journal of NeuroEngineering and Rehabilitation: A novel system for introducing precisely-controlled, unanticipated gait perturbations for the study of stumble recovery.
posted by mandolin conspiracy (10 comments total)

This is super cool, I just wrote it up. Some further info I got from the researcher:

What specific types of motions or reactions was the study on the hunt for, and what did it find that you think might be useful?

An individual who stumbles will perform different actions depending on various factors, not all of which are well known. The response changes, because the strategy that is most likely to prevent a fall is highly dependent on the “initial conditions” at the time of stumble. We are hoping to construct a model of which factors determine the nature of the stumble response, so when a stumble occurs, we can use the various sensors on a robotic prosthetic leg to artificially reconstruct the reflex in order to provide a response that is effective and consistent with the biological reflex loop.

How do you envision prosthetics reacting to a trip or fall informed by this data? Currently there's basically no allowance for this kind of case at all, right?

Ideally a robotic prosthesis will react in concert with the biological reflex loop, which is still intact, but is incomplete (i.e., lacks information from the missing limb). Current prosthetic legs are highly susceptible to stumble. A very limited number of “high-tech” devices include a singular “stumble response” in which the knee will “stiffen” when encountering a stumble; this may be the correct response in a limited number of cases, but most often is not the correct response. As mentioned in the response to the first question, the “right” response will vary depending on the conditions of stumble, as determined by the reflex loop. As such, in some case, the singular “stiffening” response is exactly the wrong response, and may increase the likelihood of falls.

Could these motions or reactions also be useful for autonomous locomotion, like a bipedal robot?

Sure, the model could be used directly to program reflexes in a biped.

(Oh, my article is in the post! Thanks for linking!)
posted by BlackLeotardFront at 5:40 PM on June 20, 2019 [6 favorites]

This is so cool. There are so many amazing applications for this, obviously first and foremost helping people with prosthetics but it just spirals out from there! I would love to be involved in research like this, but they wouldn't need obstacles, I can trip just as well with nothing in my way at all.
posted by gloriouslyincandescent at 5:57 PM on June 20, 2019 [1 favorite]

(Oh, my article is in the post! Thanks for linking!)

Thanks for writing that up!

This was also on CBC's As It Happens this evening - interview with Maura Eveld starts at 33:45.
posted by mandolin conspiracy at 6:39 PM on June 20, 2019 [1 favorite]

Why should a mechanical leg have to respond with the limitations of a flesh and bone leg? It could, for example, shoot out supporting rods create support in the event of the stumble. Or other totally unanimal-like but save-from-stumble things it might do. Why think within the flesh box when you're wearing a robot leg?!
posted by hippybear at 8:35 PM on June 20, 2019

I am amused by the dude who kind gives up on recovering after he flails a bit, and just hangs in the harness.
posted by tavella at 9:23 PM on June 20, 2019

Why think within the flesh box when you're wearing a robot leg?!

Asking the important questions! Just take that train of thought a few stops down the line and we'll be Moravec bushes in no time.
posted by Halloween Jack at 9:58 PM on June 20, 2019

unanticipated gait perturbations

IDM album title.
posted by Foosnark at 5:45 AM on June 21, 2019 [1 favorite]

Oh, sure, but when Boston Dynamics does it with their robots, everyone gets all upset...
posted by biogeo at 7:08 AM on June 21, 2019 [3 favorites]

This is cool!
posted by freethefeet at 6:43 PM on June 21, 2019

Haha, gloriouslyincandescent, I was going to say the same thing - I trip over my own toes all the time (I have the shoe scuffs to prove it!)
posted by batter_my_heart at 2:11 PM on June 22, 2019