This post is directed mainly toward the “old-timers” of PCT. In Bill Powers’ “Little Man” demo, Version 2 modeled Level 1 system used to control muscle length and force. (These were not modeled in Version 1). However, to simplify the computations Bill chose to model the pairs of opposing (retractor versus extensor) muscles – each of which is capable only of pulling – as if they were a single muscle capable of both pulling and pushing. Unfortunately, this simplification eliminates the possibility for isometric contraction (in which the extensor and retractor muscles oppose each other’s actions).
My question is, to anyone’s knowledge, did Bill ever work on a model in which opposing muscles are represented separately, so that isometric contraction becomes possible?
There is the byte article from '79 with Basic source code, models three muscles that can only pull. It is possible to set total tendon tension to make isometric contractions, or to set central point position to make isotonic contractions. http://www.livingcontrolsystems.com/enclosures/byte_aug_1979.pdf
I’ve ported it to Processing a year or two ago, but I’m afraid I’ve lost the source code. I’ll see on my old laptop, maybe there is a folder…
This post is directed mainly toward the “old-timersâ€? of PCT. In Bill Powers’ “Little Manâ€? demo, Version 2 modeled Level 1 system used to control muscle length and force. (These were not modeled in Version 1). However, to simplify the computations Bill chose to model the pairs of opposing (retractor versus extensor) muscles – each of which is capable only of pulling – as if they were a single muscle capable of both pulling and pushing. Unfortunately, this simplification eliminates the possibility for isometric contraction (in which the extensor and retractor muscles oppose each other’s actions).
Â
My question is, to anyone’s knowledge, did Bill ever work on a model in which opposing muscles are represented separately, so that isometric contraction becomes possible?
Thanks, Adam, I had totally forgotten about the Byte article! Happy new year!
Bruce
···
From: Adam Matic [mailto:adam.matic@gmail.com] Sent: Thursday, December 31, 2015 12:36 PM To: csgnet@lists.illinois.edu Subject: Re: Little Man Demo’s model of the arm
Hi Bruce, happy new year!
There is the byte article from '79 with Basic source code, models three muscles that can only pull. It is possible to set total tendon tension to make isometric contractions, or to set central point position to make isotonic contractions. http://www.livingcontrolsystems.com/enclosures/byte_aug_1979.pdf
I’ve ported it to Processing a year or two ago, but I’m afraid I’ve lost the source code. I’ll see on my old laptop, maybe there is a folder…
This post is directed mainly toward the âold-timersâ? of PCT. In Bill Powersâ âLittle Manâ? demo, Version 2 modeled Level 1 system used to control muscle length and force. (These were not modeled in Version 1). However, to simplify the computations Bill chose to model the pairs of opposing (retractor versus extensor) muscles – each of which is capable only of pulling – as if they were a single muscle capable of both pulling and pushing. Unfortunately, this simplification eliminates the possibility for isometric contraction (in which the extensor and retractor muscles oppose each otherâs actions).
My question is, to anyoneâs knowledge, did Bill ever work on a model in which opposing muscles are represented separately, so that isometric contraction becomes possible?
Bruce A.
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7294 / Virus Database: 4489/11295 - Release Date: 12/31/15
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7294 / Virus Database: 4489/11295 - Release Date: 12/31/15