Networked Control Systems

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Networked Control Systems

• Vincenzo Liberatore

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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

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Tomorrow CyberPhysics

• 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

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Enabling Technologies

• Embedded computing
• Embed computers in the physical world
• Pervasive networking
• Interconnect them
• Control theory and robotics
• Physics-software interface

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Challenges

• Remove dependency on
• Precise environment models
• Quality-of-Service provisioning
• Software that is
• Distributed
• Adaptive and evolvable
• Secure and safe (e.g., stability)
• Remotely re-programmable

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Outline

• Remote robotic manipulation
• Foundations for Networked Control Systems

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Remote Robotic Manipulation
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Objectives

• Manipulation tasks
• E.g., collect and manipulate a specimen from Mars
  surface
• Contact operations
• Energy exchanged between robot and environment
• Results in physical change in environment state
• Safety
• Force or kinematics constraints
• Remote supervision

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Distributed Control

• Natural admittance control
• Virtual Attractors
• Locally encapsulates real-time constraints
• Multi-agent distributed system
• Software components, autonomous, adaptable,
  knowledgeable, mobile, collaborative, persistent
• Supervisory control and tele-operation
• Evolvable software

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Demonstration
VR
The VS then splits the command into pieces and
send them to the
VR
Wide-area Network
VR
VR
Virtual Robots (VRs) residing on the network.
VR
VR
VR
Engineer, using a C interface, loads a
high-level command into the Virtual Supervisor
(VS).
Based on data obtained by the other VRs, the
robot is controlled directly by a single VR.
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Benefits

• Supervisory control
• Beyond tele-operation and autonomy
• Dynamic reconfiguration
• Task-oriented reconfiguration
• Plug-and-play
• Fault-tolerance
• Survivability
• Extensibility

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Foundations ofNetworked Control Systems
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Networked Control Systems

CONTROL
SYSTEM
-
Traditional view
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Foundations

• Toward a theory of networked control
• Mathematical underpinnings
• Established operation principles
• Patterns and pitfalls
• Core factors
• System dynamics
• E.g., output of open loop system
• Network dynamics
• E.g., packet forwarding, losses, delays, jitter
• Networked control systems

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Acknowledgments

• Faculty
• Vincenzo Liberatore, Wyatt S. Newman, Michael S.
  Branicky, Steve P. Phillips
• Students
• Adam Covitch, Ahmad Al-Hammouri
• Alumni
• David Rosas

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More info?

• Demos
• Internet Robotics
• Scalable Data Dissemination
• URL

http//vorlon.cwru.edu/vxl11/netlab/