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

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

Outline Remote robotic manipulation Foundations for Networked Control Systems

Remote Robotic Manipulation

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

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

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

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

Foundations of Networked Control Systems

Networked Control Systems Traditional view CONTROLSYSTEM + - Networked control system INTERNET CONTROLSYSTEM + -

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

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

More info? Demos – Internet Robotics – Scalable Data Dissemination URL