Hi. I've been reading an otherwise interesting article "Multisensor
Integration and Fusion in Intelligent Systems", Ren C. Luo and Michael G.
Kay, IEEE Trans. System Man and Cybernetics, 19:5, pp. 901-931, 1989.
What struck me was a description of the Sensory and Control Hierarchy build
by the National Bureau of Standards in their Automated Manufacturing
Research Facility, which has been implemented by a guy named Albus, and
bears on uncanny similarity to PCT.
It's a robotic environment which seemingly consists of a hierarchy of
perception and feedback. Each level takes input from a lower level sensory
signal (ultimately the environment), and compares it to the output of a
"world model" at that level, and finally passes it on to an action
subsystem at that level, which feeds to a lower level action system (also
ultimately the environment).
The levels are:
Level Input Output
----- ----- ------
1 Joint position, velocity Servo velocities
2 X,Y,Z position, force Action primitive (X,Y,Z)
3 Proximity edges Elemental move
4 Part-position orientation Simple task
5 Part-identity relationships Complex task
Here's a quote from the paper:
"Raw sensory data from the environment enter the system at the bottom. At
this lowest level, most of the required sensory processing will be
continuous monitoring of the robot's joint positions. Any deviation between
the actual and expected data is sent as feedback information to the servos,
and as summary information to the next level in the sensory processing
hierarchy. More complex data, like that from vision sensors, is sent
through to higher levels unmodified. At the very highest level of the
system, the complex task and top-level world model filter down to lower
levels in the hierarchy both expected and desired information values. It is
at the intermediate levels where both of these information flows meet and
interact. Based upon current sensory information, the world models are
updated. The updated world models can then serve to modify the desired task
control actions until, at the lowest level, the necessary drive signals are
sent to the robot to initiate actions in the environment."
The main reference for all this is JS Albus, _Brains, Behavior and
Robotics_, Peterborough, NH, Byte Books, 1981.
Do any of you know anything about this?
O----------------------------------------------------------------------------->
Cliff Joslyn, Cybernetician at Large, 327 Spring St #2 Portland ME 04102 USA
Systems Science, SUNY Binghamton NASA Goddard Space Flight Center
cjoslyn@bingsuns.cc.binghamton.edu joslyn@kong.gsfc.nasa.gov
V All the world is biscuit shaped. . .