Integrated Control and Scheduling Anton Cervin - Artes

24 Pages·2001·1.13 MB·English

Integrated Control and Scheduling
Anton Cervin
Department of Automatic Control
Lund Institute of Technology
Joint work with Dan Henriksson, Bo Lincoln, Johan Eker,
and Karl-Erik Årzén
Objective
“Squeeze the most out of limited resources”
Main Thesis
Dynamic scheduling based on feedback
;
Higher resource utilization
Better control performance
A Classical Control System
Reference
Control Output
Controller Process
Feedback
Process: Continuous dynamics (differential equations)
Controller: Continuous or discrete dynamics
A Computer Control System
Computer
A/D Controller D/A Process
Controller: Piece of code executing in an operating system
A Distributed Computer Control System
Process
Sensor Actuator Sensor Actuator
Node Node Node Node
Network
Control Other Other
Computer Node Node
Controller: Distributed among different nodes in the network
Key Problems
•
Limited computer resources
– Cheap, embedded micro-controllers
– Networks with limited bandwidth
•
The control computer and the network are shared
resources, which must be scheduled
•
The delays in the computer system degrade the control
performance
Control System Development Today
Control Department Software Department
Requirements
Functional Test
Control Unit/Structural Test
Algorithm Design
Design
− plant/algorithm
models
Software Design
Project Goals
Understand the relationship between scheduling and control:
•
How do the delays in the computer system affect the
control performance?
•
How should limited resources be allocated among different
tasks?
Develop dynamic scheduling and control techniques:
•
Use scheduling theory to reduce delays
•
Use control theory to compensate for delays
•
Introduce feedback in the computer system itself:
– Operate “closer to the edge”
– Handle variations in the load
– Reallocate resources dynamically
Project Goals, Cont’d
Develop design tools:
•
T T : Simulation of real-time control systems
RUE IME
– Matlab/Simulink
•
J : Analysis of real-time control performance
ITTERBUG
– Matlab