Transcript Document

Networked Control Systems
Vincenzo Liberatore
Today: Cyberspace

Interact with remote virtual environment
– On-line social activities
 Communicate with co-workers, friends
– On-line search and information gathering
– Disaster Recovery Networks
– Distributed multimedia, games
– E-commerce:
 Buy books, CDs, computers
 Dump stock shares
Tomorrow: Cyber+Physics
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Affect a remote physical environment
– Hazardous environments
– Terrestrial, space exploration
– Distributed manufacturing
– Remote diagnostic and troubleshooting
– Experimental facilities
 E.g., microgravity fluid dynamics
– Home robotics
Enabling Technologies
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Embedded computing
– Embed computers in the physical world
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Pervasive networking
– Interconnect them
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Control theory and robotics
– Physics-software interface
Challenges
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Remove dependency on
– Precise environment models
– Quality-of-Service provisioning
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Software that is
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–
–
–
Distributed
Adaptive and evolvable
Secure and safe (e.g., stability)
Remotely re-programmable
Outline
Remote robotic manipulation
 Foundations for Networked Control
Systems
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Remote Robotic Manipulation
Objectives
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Manipulation tasks
– E.g., collect and manipulate a specimen from
Mars surface
– Contact operations
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Energy exchanged between robot and environment
Results in physical change in environment state
– Safety:
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Force or kinematics constraints
Remote supervision
Distributed Control
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Natural admittance control
– Virtual Attractors
– Locally encapsulates real-time constraints
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Multi-agent distributed system
– Software components, autonomous, adaptable,
knowledgeable, mobile, collaborative, persistent
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Supervisory control and tele-operation
 Evolvable software
Demonstration
VR
The VS then splits the
command into pieces and
send them to the
Virtual Robots (VR’s)
residing on the network.
Engineer, using a
C# interface, loads
a high-level
command into the
Virtual Supervisor
(VS).
VR
VR
Wide-area
Network
VR
VR
VR
VR
Based on
data
obtained by
the other
VR’s, the
robot is
controlled
directly by a
single VR.
Benefits

Supervisory control
– Beyond tele-operation and autonomy
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Dynamic reconfiguration
–
–
–
–
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Task-oriented reconfiguration
Plug-and-play
Fault-tolerance
Survivability
Extensibility
Foundations of
Networked Control Systems
Networked Control Systems
+
-
CONTROL
SYSTEM
Traditional view
+
-
CONTROL
SYSTEM
INTERNET
Networked control system
Foundations

Toward a theory of networked control
– Mathematical underpinnings
– Established operation principles
– Patterns and pitfalls
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Core factors
– System dynamics
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E.g., output of open loop system
– Network dynamics
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E.g., packet forwarding, losses, delays, jitter
Networked control systems
Acknowledgments
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Faculty
– Vincenzo Liberatore, Wyatt S. Newman,
Michael S. Branicky, Steve P. Phillips
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Students
– Adam Covitch, Ahmad Al-Hammouri
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Alumni
– David Rosas
More info?
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Demos
– Internet Robotics
– Scalable Data Dissemination
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URL
http://vorlon.cwru.edu/~vxl11/netlab/