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Category: Brands

Bad Hand Day V - will the mobile app actually start?

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Bad Hand Day V - will the mobile app actually start?; published January 23, 2018, 23:01; URL: https://www.swisswuff.ch/tech/?p=8150.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Bad Hand Day V - will the mobile app actually start?}}, month = {January},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8150}}


As I was lucky tonight, the app for the Touchbionics iLimb actually started after the 8th attempt. That is better than it was, there were times when it did not start at all.

So first, one spends a bit of time "warming the system up".

Time lapse video loop (2x), exuding serene obsolescence:

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Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]; published January 4, 2018, 14:29; URL: https://www.swisswuff.ch/tech/?p=8066.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]}}, month = {January},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8066}}


 


This is a blog post of one of the rare focused and well based scientific journal articles that really explains how real work, body powered and myoelectric arms relate and go together for a unilateral right below elbow amputee in a physically demanding work environment.

The prior presentation of this paper [poster at Cybathlon symposium 2016], which had been more pragmatically worded (with me thinking people would know anyway), this was now written up as article and published. During that process, the reviewers clearly made great points of all kinds of aspects I never knew were not sky clear to everyone.

So maybe, writing a ~ 30 page case study with > 210 references does clarify stuff, at least potentially and for those that actually read it. But possibly, it still requires attention to even just read it.

Knowledge does not come easy, Highlander! (Nakano, in: Highlander III The Final Dimension)

 

If you are more interested in visionary posts, read about the gadget features of the prosthetic arm in Kingsmen: The Golden Circle [link]. And technically, myoelectric control did have it coming. That technology remained uncool for four decades [link].

Publication [link]

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Scientific approach taken for implementing a successfully marketable microprocessor-controlled knee - history of Otto Bock C-leg [lessons for prosthetic arms?]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Scientific approach taken for implementing a successfully marketable microprocessor-controlled knee - history of Otto Bock C-leg [lessons for prosthetic arms?]; published January 2, 2018, 15:10; URL: https://www.swisswuff.ch/tech/?p=7790.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Scientific approach taken for implementing a successfully marketable microprocessor-controlled knee - history of Otto Bock C-leg [lessons for prosthetic arms?]}}, month = {January},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=7790}}


This blog post takes a few relevant observations, and assumptions, throws them up in the air and sees if they turn into sunshine.

  • If anything has brought us forward, it is also the ability to find relevant short cuts. We do not always have to invent the wheel when really we just want a variation of it.
  • If there is any acutal success story where academic research was required to leverage consumer market for a prosthetic limb, it is that of Otto Bock's C-leg.
  • If we can understand what the concepts are for getting a C-leg successfuly built, marketed and sold, we should be able to take generalized aspects of it to formulate success elements for prosthetic hands, grippers or arms.

Background

While the idea of a microprocessor controlled knee was created earlier [link], no marketable solution was available in due course. "In the early 1990s, Kelly James, an engineer at the University of Alberta, Edmonton, Canada, developed the C-Leg, the first leg with microprocessor-controlled swing and stance phases. Buying the rights from the university, he traveled around the world to interest prosthetic manufacturers in his invention ("A Leg Up," by Isabelle Gallant, U of A Engineer, Spring 2011). However, he didn't receive any commercial interest until German manufacturer Ottobock bought the patent in 1992 and launched the groundbreaking technology.".

Then, based on work betweeen 1995 and 1998, a doctoral thesis at the ETH Zurich described an intelligently, microprocessor controlled knee for above knee prostheses built from available and affordable materials [1].

That research was performed 1995 to 1998, financially supported by Otto Bock, and Otto Bock presented its first C-Leg in 1997.

The rest is history. If ever there was a leap in performance of prosthetic function, ever, it was the C-Leg. No prosthetic hand ever came close to achieving this level of success.

So this particular doctoral thesis seems to contain some possibly interesting ingredients worthwhile looking at. As any doctoral thesis here is public record, and a copy of it must be made available at the public library, I borrowed a copy for further information.

There are some other prosthetic developments, however, nowhere else is academic research anywhere near that successful as in the instance of the C-leg:

  • Otto Bock Michelangelo hand; the mechanism seems to come from American DARPA or other army research and probably was just built, the first glove was a great design work. So there is no analytical approach comparable to the C-Leg. It is too heavy, it does not work with prosthetic gloves really, it is not sturdy.
  • i-Limb: This cannot possibly have suffered too much analytical thought. The device looks more like it was born out of something else. While it does not always function as maybe intended, it is really lovable. It does not have a reliable precision grip, it is really weak, it tears up its paper thin gloves within minutes.
  • TRS prosthetics: Bob Radocy as end-user himself developed by far the greatest useful solutions. But they are not the result of extensive academic efforts, so they cannot be compared to the C-Leg. They are extremely good though and any analysis must start there.
  • Toughware PRX: These devices are extremely well made, mechanics wise - but we lack an analytical model that precedes the engineering there as well, comparing this to the C-leg approach.
  • Becker Mechanical Hand: Also the Becker hand was clearly built by someone with great practical and pragmatic understanding. No analytical effort of the magnitude of a C-Leg preceded it though.
  • Hosmer hooks: they came out of a practical development, no scholarly work appeared to be prepared for these either.

 

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[1] D. Zlatnik, "Intelligently controlled above knee prosthesis," PhD Thesis, 1998.
[Bibtex]
@phdthesis{zlatnik1998intelligently,
  title={Intelligently controlled above knee prosthesis},
  author={Zlatnik, Daniel},
  year={1998},
 school={ETH Zuerich, Switzerland}
}

Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - first approach [technical right below elbow amputee core focus work / bike adaptation]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - first approach [technical right below elbow amputee core focus work / bike adaptation]; published December 3, 2017, 15:11; URL: https://www.swisswuff.ch/tech/?p=7816.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Modifying Shimano Ultegra road bike setup on a Colnago C40 for left handed use - first approach [technical right below elbow amputee core focus work / bike adaptation]}}, month = {December},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7816}}


I got myself a Colgnago C40 carbon road bike / race bike / Rennrad for leisure amateur purposes. That is, for the colloquial ride. With that, I am not a professional or competitive racer. Modifying my Shimano Ultegra road bike setup for left handed use therefore aims towards leisure purposes.

How to go about riding a road bike as arm amputee. This is the first approach and test. If you are after the improved set-up, head over to the page with the second approach [link] because that really worked a lot better.

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Toughware Equilux - new VO (voluntary opening) / VC (voluntary closing) body powered device - industrial grip pads [concept, beta]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Toughware Equilux - new VO (voluntary opening) / VC (voluntary closing) body powered device - industrial grip pads [concept, beta]; published August 17, 2017, 20:15; URL: https://www.swisswuff.ch/tech/?p=7569.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Toughware Equilux - new VO (voluntary opening) / VC (voluntary closing) body powered device - industrial grip pads [concept, beta]}}, month = {August},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7569}}


Read about the Toughware Equilux here. All prosthetic hooks, prehensors or grippers lack the option of using industrial grip pads. Pads that are readily available, cheap, durable and that the user can easily switch.

And grip pads and grip gloves are a real issue. As posted before, grip pads must be soft,  possible to clean, easy and cheap to replace and convenient. These requirements are in part mutually exclusive. With the knife holding issue of the Equilux, what easier than to mount some standard bike rim brake pads and take it from there.

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Toughware Equilux - new VO (voluntary opening) / VC (voluntary closing) body powered device - first usage report [NEW PRODUCT]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Toughware Equilux - new VO (voluntary opening) / VC (voluntary closing) body powered device - first usage report [NEW PRODUCT]; published August 13, 2017, 20:06; URL: https://www.swisswuff.ch/tech/?p=7462.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Toughware Equilux - new VO (voluntary opening) / VC (voluntary closing) body powered device - first usage report [NEW PRODUCT]}}, month = {August},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7462}}


I was offered the privilege to provide a first usage test and report for a new body powered device. This device allows an "on the fly" switch between VC (voluntary closing) and VO (voluntary opening) control mode.

If you use a prosthetic arm recreationally, for fun, for "the little things that count", such as opening the odd envelope, holding the odd water bottle while filling it with tap water, or pushing the odd knob on your coffee machine, then it probably does not matter what device you wear, or how it would hold up. But if you usually demand performances of your prosthesis that are in the domain of the "unreal", the difficult to cover for existing devices, then having a terminal device that allows on the fly switching between these two control modes really is a big thing. It means that I can switch between the most popular passive grasp mode (VO) - used to carry or hold on to items without thinking - and the most powerful dynamic and forceful grasp mode that ever exists for prosthetic arms (VC).

The device is called "Equilux" and it is (or will be) manufactured by Toughware PRX.

Toughware PRX
2514 West 104th Circle
Westminster, Colorado 80234-3508
Telephone:303-635-1619
FAX:303-635-1621
E-mail: info@toughwareprx.com

An outstanding feature is that the device also provides for the fact that normally, VO works better with slightly longer control cables, whereas the VC system requires mildly shorter ones. This device's flip / switch design does away with this by way of clever design. So with one good control cable length, you are set.

As a further feature, it contains an interface for exchangeable grip pads. As we will see, this is a relevant aspect, that will have to be followed up in the future.

QR code for this post:

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TRS Prehensor [grip surface tweaking II]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - TRS Prehensor [grip surface tweaking II]; published May 25, 2017, 13:43; URL: https://www.swisswuff.ch/tech/?p=7381.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - TRS Prehensor [grip surface tweaking II]}}, month = {May},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7381}}


The TRS Adult Grip Prehensor is a bit like an American car. You may want to tune it, even try to tune it well, before you cant take it out  to really shine. Not literally "shine", though. Proverbially! Really I do not need this here to actually shine. It is totally OK if it just makes me look less bad, like, by supporting me, grip wise.

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Fotoserie - Herstellung und Aufbereitung einer Serie von Passteilen für PMCTA-Sets [photos]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Fotoserie - Herstellung und Aufbereitung einer Serie von Passteilen für PMCTA-Sets [photos]; published April 4, 2017, 15:55; URL: https://www.swisswuff.ch/tech/?p=7322.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Fotoserie - Herstellung und Aufbereitung einer Serie von Passteilen für PMCTA-Sets [photos]}}, month = {April},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7322}}


Herstellung von 3D gedrucktem PMCTA Equipment. Alle Teile wurden von mir selbst entworfen und gedruckt. TRS Prehensor im Einsatz.

Fotoserie für die Einreichung zum bgw-Wettbewerb.

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Grip 5 Evolution Prehensor TRS - Cybathlon winning device - first bike ride test [video / 1:1]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Grip 5 Evolution Prehensor TRS - Cybathlon winning device - first bike ride test [video / 1:1]; published January 21, 2017, 18:01; URL: https://www.swisswuff.ch/tech/?p=7119.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Grip 5 Evolution Prehensor TRS - Cybathlon winning device - first bike ride test [video / 1:1]}}, month = {January},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7119}}


2 Comments

I use the voluntary closing (VC) Grip 5 Evolution Prehensor by TRS on my body powered prosthetic arm - the terminal device that Bob Radocy used when winning both heat and final of the Cybathlon prosthetic arm race - for a first bike ride. No modifications of bicycle, handlebar or prosthetic arm necessary whatsoever.

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Grip strengths (measured results)

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Grip strengths (measured results); published January 18, 2017, 20:09; URL: https://www.swisswuff.ch/tech/?p=7085.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Grip strengths (measured results)}}, month = {January},year = {2017}, url = {https://www.swisswuff.ch/tech/?p=7085}}


Using a Camry EH101 electronic hand dynamometer, I went through a few prosthetic terminal devices for my arm to see just how strong they were. And I added a baseline for my (human) left hand and my (bare) stump.

This certainly provides a base for a range of discussions later. Or previous ones ; )

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Towards Extreme Cyborging (EC) microworks: very small things [grip mechanics theory, parametrization and then testing side by side - Trautman hook, Hosmer Mod 5 hook, TRS Prehensor, Touch Bionics iLimb revolution]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Towards Extreme Cyborging (EC) microworks: very small things [grip mechanics theory, parametrization and then testing side by side - Trautman hook, Hosmer Mod 5 hook, TRS Prehensor, Touch Bionics iLimb revolution]; published December 28, 2016, 17:52; URL: https://www.swisswuff.ch/tech/?p=7010.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Towards Extreme Cyborging (EC) microworks: very small things [grip mechanics theory, parametrization and then testing side by side - Trautman hook, Hosmer Mod 5 hook, TRS Prehensor, Touch Bionics iLimb revolution]}}, month = {December},year = {2016}, url = {https://www.swisswuff.ch/tech/?p=7010}}


Small things to be picked up, side by side demo with other prosthetic devices.

Yes, very small things.

"It is the little things that count", they said. "The little things are important", they said. They all said that. But behold, their "bionic" apparatus cannot handle little things! "Why is a hook not evil", they wondered. And a storm of little demo videos came upon them. Deep into the myriad of grip mechanics this went.

"Get a grip on grips", he said.

This totally bypasses the fact that after laying down real life consequences for what I call Extreme Cyborging, I just finished building my first own steel Trautman hook, and all just with shape information from the internet. Yeah, you read that right. I did not build yet another one of the ubiquitous funny hands that promises to change my life or what it is these 3D printed hands now do - no. I sit on the demand and I sit on the technology and what is it that I do? See? This is what should really disturb you - because given the current signs of the times, it should feel deeply wrong on many levels. To you. But then, we were likely living on different planets all along, and maybe it is time you realize that too ; ) After we knew since years in detail what the Cybathlon showed us yet again, with glory but not with any improvement, it is yet again up to us, the users, to push further into what is, what can be, and what matters. And honestly? We have seen far enough funny hand videos.

What we have not seen is the Rebirth of The Cool. The Rebirth of an absolutely insane gripper. Physically. In 3D printed steel. The Trautman hook is such a device. And I went for it just because I can.
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Casio wrist watch wrist band swap [technical, EC microworks]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Casio wrist watch wrist band swap [technical, EC microworks]; published November 24, 2016, 19:44; URL: https://www.swisswuff.ch/tech/?p=6851.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Casio wrist watch wrist band swap [technical, EC microworks]}}, month = {November},year = {2016}, url = {https://www.swisswuff.ch/tech/?p=6851}}


I switched the old used up Casio watch wristband against a new one. I used a prosthetic hook to do it.

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Grip planning and carrying out [TRS Prehensor vs. iLimb Ultra Revolution - theory and practice]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Grip planning and carrying out [TRS Prehensor vs. iLimb Ultra Revolution - theory and practice]; published October 17, 2016, 17:49; URL: https://www.swisswuff.ch/tech/?p=6764.

BibTeX: @MISC{schweitzer_wolf_1571789151, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Grip planning and carrying out [TRS Prehensor vs. iLimb Ultra Revolution - theory and practice]}}, month = {October},year = {2016}, url = {https://www.swisswuff.ch/tech/?p=6764}}


To reliably plan and successfully carry out a grip using a prosthetic hand or gripper, it helps having a few requirements met.

This is obviously not clear at this moment, as recent experiences at the Cybathlon show. All the same, others and myself have addressed various related grip aspects previously so this is something we can come back to.

So let us start by watching the iLimb hand trying to grasp a clothespin.

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