LYONS%cs.umass.edu@CSNET-RELAY.ARPA.UUCP (07/28/86)
Hi: I know I'm a bit late on posting this; however, I would welcome
comments from interested persons out there:
July 25th, 1986.
Dept. of Computer and Information Science.
University of Massachusetts at Amherst.
Amherst, MA.01003.
RS: A Formal Model of Distributed Computation
For Sensory-based Robot Control.
Damian M. Lyons
Robot systems are becoming more and more complex, both in terms of
available degrees of freedom and in terms of sensors. It is no longer
possible to continue to regard robots as peripheral devices of a computer
system, and to program them by adapting general-purpose programming
languages. This dissertation analyzes the inherent
computing characteristics of the robot programming domain, and formally
constructs an appropriate model of computation. The programming of a dextrous
robot hand is the example domain for the development of the model.
This model, called RS, is a model of distributed computation: the basic
mode of computation is the interaction of concurrent computing agents. A
schema in RS describes a class of computing agents. Schemas are instantiated
to produce computing agents, called SIs, which can communicate with each
other via input and output ports. A network of SIs can be grouped atomically
together in an Assemblage, and appears externally identical to a single SI.
The sensory and motor interface to RS is a set of primitive, predefined
schemas. These can be grouped arbitrarily with built-in knowledge in
assemblages to form task-specific object models. A special kind of
assemblage called a task-unit is used to structure the way robot programs
are built.
The formal semantics of RS is automata theoretic; the semantics of an
SI is a mathematical object, a Port Automaton. Communication, port
connections, and assemblage formation are among the RS concepts whose
semantics can be expressed formally and precisely. A Temporal Logic
specification and verification methodology is constructed using the automata
semantics as a model. While the automata semantics allows the analysis of
the model of computation, the Temporal Logic methodology allows the top-down
synthesis of programs in the model.
A computer implementation of the RS model has been constructed, and used
in conjunction with a graphic robot simulation, to formulate and test
dextrous hand control programs. In general RS facilitates the formulation
and verification of versatile robot programs, and is an ideal tool with
which to introduce AI constructs to the robot domain.