Certainty Equivalence, Detectability, and the Control of Uncertain Systems

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DARPA 20 OCT 99
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REACTIVE SWITCHING STRATEGIES FOR THE CONTROL
OF UNINHABITED AIR VEHICLES Yale
University Peter Belhumeur Paul Hudak
A. Stephen Morse
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OVERVIEW
The fielding of reliable, fast-moving,
autonomously functioning vehicles, in the sea, on
land or in the air will require much
more advanced control concepts in which
switching and logic will play a major role.
Control Research Needed are methods for
synthesizing/designing such logic-based
switching or hybrid control algorithms. Morse
Software Research Needed are verification and
simulations tools for validating such
algorithms. Needed also are high level
programing languages think of numerical control
of machine tools for implementing such hybrid
algorithms. Hudak
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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Although the complexity of guiding an object
robot through a cluttered environment was
worked out more than a decade ago, the problem
addressed did not take into account
uncertainty, the evolution of the robots
field-of-view with time, or the potential value
of feedback.
To solve visual guidance problems such as the
preceding, it will almost certainly be necessary
to deal with vision not simply as an isolated
sensory process, but rather as an integrated
component of an overall guidance system.
It is not clear at this time which of the many
issues currently being addressed within the
computer vision field,e.g., camera calibration,
the correspondence problem, etc. are relevant
to guidance and motion control problems, and
which are not.
Moreover, while it is likely that most, if not
all, of the tried and true paradigms normally
associated with conventional feedback processes,
are appropriate to visual guidance, it is
unlikely that visual guidance can be effectively
achieved by relying on these paradigms alone.
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Supervisory Control of a Robot Arm Using
Self-Calibrating Stereo Vision Feedback
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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To achieve long flight times and low per unit
cost, there is a desire to field UAVs of
relatively small sizes.
But the smaller an aircraft, the more susceptable
it is to the effects of gusting and other
undesirable weather conditions.
Problem How might we design control systems to
increase the survivability of small aircraft in
the face of large gusts?
Existing paradigm - disturbance attenuation - not
up to the task
But acceleration constraints imposed on
UAVs/UCAVs need not be any where near as severe
as those required for manned aircraft.
So., why not exploit this to deal with
disturbance???
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Use a Go with the Flow Paradigm
Fish feeding
Kayaking
Skiing
Implementation will require high level logic to
manage if and when to switch from conventional
disturbance attenuation control to GWF control
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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hope to leverage results from
Coordinated Motion of Natural and Man-Made Groups
Yale Princeton Harvard
U. of Washington
Develop a robotic fish school testbed for
studying group coordination in three dimensions.
Develop a data base of stereo-video of real
tagged fish school moving in 3-d environment.
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taken at Norwalk, CT
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Peter Belhumeur
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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CONTROL RESEARCH
Vision-Based Guidance and Control
Go With the Flow or GWF Control Objectives
Coordinated Motion of Vehicle Groupings
Reliable Self-Reconfigurable Control Systems
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Why reconfigure switch controllers on the fly?
To compensate for changes in systems dynamics
which are
foreseeable measurable gain scheduling
unforeseeable
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Barron Associates, Siva Bandas WPAFB Group
popular in chem process industry
advantage is can deal with saturation constraints
least-squares estimator
receding horizon control
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GOAL RELIABLE, RECONFIGURABLE UAV FLIGHT CONTROL
Approach provably correct multiple model
supervisory control concept
YALE SMALL HELICOPTER TESTBED
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Robust Performance - in the face of norm-bounded
unmodeled dynamics
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