1.  Candidate NCSs  Control Strategies Introduction DCS Structure
Why NCSs ?
Factors Affecting NCSs Performance
Modeling of NCSs with Network–Induced Delay
 Delay / Sampling Time Ratio Effect
 NCSs Design Approaches
 Candidate NCSs
 Control Strategies
 Results
 Conclusion & Future Trends 1

2. Introduction  What is Networked Control Systems ?
Control Network
 Data Networks Versus Control Networks
 Concept of Distributed Control Systems 2

3. DCS Structure
Local Data Links 3

4. • Pervasive Flow of Mixed Data
Why NCSs ?
• Easy Problem Diagnostic
• Less Expensive
• Complexity Management
• Pervasive Flow of Mixed Data
• Attractive Features of Serial Communication Network 4

5. Factors Affecting NCSs Performance
Delay
Mis-Sync
Buffer Saturation
NW Architecture
Sampling Time
Noise 5

6. Modeling of NCSs with Network-Induced Delay
Delay Models
• Constant
• Random 6

7. Delay/Sampling Time Ratio Effect
 Delay < Sampling Period
 Longer Delays 7

8. NCSs Design Approaches
Begin
NW To
Be Designed
Existing NW
Select
Communication
Protocol
Delay is A Given Condition
Control Strategies
Minimize Delay 8

9. Candidate NCSs Small Data Large Data 58% 98% Best Okey Worst C.E 0.5 5
10-100
Data Rate (Mbps)
More
Less
O.H
0-8 B
0-510 B B
Data Size
47 bit
7 byte
26 byte
Overhead
CSMA/AMP
Token Bus
CSMA/CD
MAC
DeviceNet
ControlNet
Ethernet 9

10. Simulation of a Real Dial-Up Internet Connection 10

11. Control Strategies Results
• Phase Lead & Phase Lag
• Pole Placement
• State Estimator
• Deadbeat
Results 11

12. Conclusion  Concept of NCS  Focus on Delay Problem
 Proposed Solutions
Candidate Networks
Design Control Strategies
Phase Lead Works Well
Pole Placement is Delay Dependent
State Estimator is the Best for Loss
Deadbeat is the Fastest One 12

13. Future Trends  Hardware Implementation DC Motor
Applying a Control Strategy
 Simulation on IUG Network 13

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15. Thank You For your Good Listening15