Little Man Version 2

[From Bill Powers (921027.1400)]

A paper by Bill Powers and Greg Williams, "A control-system model of
human pointing behavior," has been submitted to Science magazine as a
Research Report; it went off in the mail on Oct. 26. It is a review of
the Little Man program, Version 2, and contains a comparison of motion
trajectories with some human data from an article by Atkeson and
Hollenbach.

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The Little Man Version 2 is now available for distribution. It
includes a 31-page writeup giving some details of the program, with
block diagrams of the major aspects of the model.

The program includes two levels of kinesthetic control and one level
of visual control. The kinesthetic control systems can be run in a
test mode with square-wave reference signals at level 2 or level 1.
All main parameters of the control systems are adjustable by the user.
There are two modes of visual control: direct and mapped. In the
mapped mode, a correction matrix is placed between the visual control
outputs and the kinesthetic level 2 reference inputs. This map slowly
adapts while the arm tracks the target (one operational mode makes the
target jump randomly about in space). After an hour on a 486-33
computer, the map is essentially complete. After than, the
trajectories of arm movement for large jumps of the target become very
close to the way real arms move.

There is plenty of room for improvement at the visual control level.
At the lower levels, Joe Lubin said "You've got it nailed." I hope
that Joe will become active in carrying this model forward at
Princeton.

The 360-K or 720-K disk contains full C source code with all necessary
auxiliary modules and object files to compile under Turbo Pascal C
version 2.0 (in addition to the runnable object code). The files are
all contained in a self-extracting zipped file. There is an "install"
batch file that creates a directory on drive C: with the necessary
subdirectories and does all the necessary expansions. You can install
from any floppy drive.

Prices:

For institutions and professional use: $100
For members of the Control Systems Group: $ 20

Send check and shipping address to:
William T. Powers
73 Ridge Place, CR 510
Durango, CO 81301

Specify 5-1/4 or 3-1/2 inch disk.

I encourage you to get your institution to buy the disk at full price.
Note that if you join the CSG ($45 per year, $5 for students), you can
get the disk for $20, at a total outlay considerably under the direct
cost of the disk -- and you will also get 4 issues of Closed Loop. If
you can't afford a copy for yourself, we will not object to copying
the program from a legal owner. Strictly honor system, friends. Just
remember that this is the sort of income that supports my work and
Greg's. Don't ask me for a free copy unless you include a formatted
disk in a self-addressed adequately stamped mailer and tell me a very
sad story about how you live on even less income than Greg and I do.
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Best to all,

Bill P.