(Georgia Institute of Technology, 2011-07)
Dantam, Neil; Stilman, Mike; Egerstedt, Magnus B.
Using both formal language and differential
equations to model a robotic system, we introduce a calculus
of transformation rules for the symbolic derivation of
hybrid controllers. With a Context-Free Motion Grammar,
we show how to test reachability between different regions
of state-space and give several symbolic transformations to
modify the set of event strings the system may generate.
This approach lets one modify the language of the hybrid
system, providing a way to change system behavior so that
it satisfies linguistic constraints on correct operation.
(Georgia Institute of Technology, 2011-06)
Dantam, Neil; Stilman, Mike
We present and analyze the Motion Grammar: a
novel unified representation for task decomposition, perception,
planning, and control that provides both fast online control of
robots in uncertain environments and the ability to guarantee
completeness and correctness. The grammar represents a policy
for the task which is parsed in real-time based on perceptual
input. Branches of the syntax tree form the levels of a hierarchical
decomposition, and the individual robot sensor readings are given
by tokens. We implement this approach in the interactive game
of Yamakuzushi on a physical robot resulting in a system that
repeatably competes with a human opponent in sustained gameplay
for the roughly six minute duration of each match.
(Georgia Institute of Technology, 2011)
Dantam, Neil; Stilman, Mike
We present a new Inter-Process Communication (IPC) mechanism and library. Ach is uniquely suited for coordinating perception, control drivers, and algorithms in real-time systems that sample data from physical processes. Ach eliminates the Head-of-Line Blocking problem for applications that always require access to the newest message. Ach is efficient, robust, and formally verified. It has been tested and demonstrated on a variety of physical robotic systems. Finally, the source code for Ach is available under an Open Source BSD-style license.