[From Wayne Hershberger]
(Bill Powers 920312)
There was a big breakthrough this week [re: little stick man].
To explain it, I have to describe the basic spinal-cord part of
the model. I won't go into every detail.
Pulling on the load point will cause the muscle to shift the
load point in the direction of the pull (one muscle will pull in
the direction of the load while the other relaxes). As a result,
the sensed force in the tendon will remain the same. This system
reduces the effective mass of the arm nearly to zero. It will
apply the specified force regardless of the position of the
load.
Congratulations on your breakthrough! This is VERY important
work. Could you please expand upon your explanation? I am not
sure that I understand your use of the terms _load point_, nor
your expressions _pulling on the load point_ and _to shift the
load point_. Nor do I understand your parenthetical expression
above; which muscle relaxes?.
What values are you using as reference inputs for the gama
system?
What is the magnitude of the error signal in the position loop
when the arm comes to a stop ; does the magnitude of this error
signal vary systematically with the eccentricity of the arm's
position?
Warm regards, Wayne
Wayne A. Hershberger Work: (815) 753-7097
Professor of Psychology
Department of Psychology Home: (815) 758-3747
Northern Illinois University
DeKalb IL 60115 Bitnet: tj0wah1@niu