Royal Institute of Technology KTH Wireless Control Systems - from theory to a tool chain Aalto University Department of Communications and Networking Control Engineering Group KTH Radio Communication Systems Group Automatic Control Group Mikael Björkbom Wireless Sensor and Actuator Networks for Measurement and Control Phase II
37
Embed
Wireless Control Systems - from theory to a tool chain, Mikael Björkbom, Aalto University
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Royal Institute of Technology KTH
Wireless Control Systems
- from theory to a tool chain
Aalto University
Department of Communications and Networking
Control Engineering Group
KTH
Radio Communication Systems Group
Automatic Control Group
Mikael Björkbom
Wireless Sensor and Actuator Networks for Measurement and Control
Phase II
Royal Institute of Technology KTH
Wireless Automation: Control
Communication affects control performance
-> Control should be robust to problems in the network
Royal Institute of Technology KTH
Nordite WISA Project
Quality of service
Increase robustness
Decrease jitter
Requirements for
current control algorithms
Performance of
current wireless networks
Increase jitter margin
and tolerance to errors
Data fusion
PID Controller tuning
New control algorithms
Coexistence protocols
Multi-path routing (mesh)
Synchronization
Wireless automation systems
Royal Institute of Technology KTH
Workpackages
• WP1: Reliable and secure communication protocols for
wireless automation
• WP2: Communication constrained reliable control
• WP3: Implementation of WiSA toolchain
• WP4: Project management
Aalto KTH
Royal Institute of Technology KTH
WISA Phase I & II
WISA Phase I WISA Phase II
Tool chain
Control, data fusion and networking algorithms,
testbeds and simulation tools Control and
data fusion
Wireless
networking
Design
tools
WISA Phase I WISA Phase II
Tool chain
Control, data fusion and networking algorithms,
testbeds and simulation tools Control and
data fusion
Wireless
networking
Design
tools
Cro
ss-layer
desig
n
Royal Institute of Technology KTH
Results: Toolchains
• PiccSIM – Simulation of wireless control systems
• WirelessTools – Planning of wireless network schedule
• PROSE – Node and simulated network
Royal Institute of Technology KTH
WP 1: Reliable and secure communication
• T1.1. Interference avoidance and dynamic spectrum
management
– Time and frequency domain methods
– Adaptive frequency hopping
• T1.2. Reliable networking
– SIRP, Antenna switching
– Tools for scheduling
• T1.3. Sensor and network monitoring, fault detection,
and fault recovery
– Fault detection part is partly missing
– Fault recovery: Code dissemination tool
Royal Institute of Technology KTH
WP2: Communication constrained reliable control
• T2.1. Communication-aware data fusion and control
– New data fusion schemes
– Network jitter aware PID tuning rules
• T2.2. Control structures, architectures and scalability
– Impact of MAC on control and data fusion were analyzed
– Tuning of PID controllers for distributed MIMO systems
• T2.3. Adaptive and robust control
– Delay adaptive Internal Model Control based tuning
– Network performance adaptive controller
Royal Institute of Technology KTH
WP3: Implementation of WiSA Tool Chain
• T3.1. Automated implementation of routing protocols
– This was not accomplished! There is no automation in the
development of routing protocols
– PROSE tool for hardware in the loop simulation
• T3.2. Automated control algorithm implementation
– Part of PiccSIM
• T3.3. Design tools and interfaces for the WiSA tool chain
– Part of PiccSIM
• T3.4. Demonstrator development
– Several demo sessions were arrange (including NORDITE
workshop)
Royal Institute of Technology KTH
WP 1/T1.1-T1.2: Results
• Objective: wireless sensor nodes should be able to
communicate in a reliable fashion despite bad channel
conditions (interference, fading).
• We aim at improving reliability by means of:
– Interference Avoidance through Dynamic Spectrum Access
– Frequency Hopping
– Channel Coding
RELIABILITY
Dynamic Spectrum Access
Frequency Hopping
Antenna Switching
Receiver diversity
Channel Coding
Hybrid ARQ
Royal Institute of Technology KTH
WP 1/T1.1: Dynamic Spectrum Access
• An Example: Experimental Comparison of DSA schemes:
Spectrum Holes in the Time domain
Spectrum Holes in the Frequency domain
Performance of DSA in the time domain depends heavily on
channel conditions:
Energy increased
of up to 5 times for
high interference!
DSA in the frequency domain (channel selection) requires larger
energy for spectrum sensing but allows to avoid interference:
By selecting the
communication channel
effects of interference
can be mitigated
Royal Institute of Technology KTH
WP 1/T1.2: Spatial diversity
-90 -85 -80 -75 -70 -650.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
Mean RSSI (dBm)
Packet
Deliv
ery
Ratio
Time Diversity Approaches for 0.1km/h and 1km/h
Pure Time Diversity (0.1km/h)
Piggybacking (0.1km/h)
Switch if No Acknowledgement (0.1km/h)
Piggybacking (1km/h)
Pure Time Diversity (1km/h)
Switch if No Acknowlodgement (1km/h)
12
Elektrobit’s: Channel Emulator PropSIM-c2
TABLE I
CHANNEL PARAMETERS
Tap CHANNEL 1 CHANNEL 2
Relative
tap delay
[ns]
Relative tap
amplitude
[ns]
Relative tap
delay [ns]
Relative tap
amplitude
[ns]
1 0 0 0 -0.1
2 20 -0.9 20 -0.6
3 30 -2.6 50 -2.9
4 40 -3.5 100 -5.8
5 100 -6.7 150 -8.7
6 300 -17.9 200 -11.6
Multiple receiving antennas:
26% increase in packet delivery ratio
Royal Institute of Technology KTH
• Antenna switching and receiver selection diversity
WP 1/T1.2: Spatial diversity
1 2 3 4 5 6 7 80
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Links (1-8)
PA
CK
ET
DE
LIV
ER
Y R
AT
IO
Bridge 23.3m, Receiver sensitivity = -94 dBm
Receiver Array
• 10 packets/s
• Dual Antenna System
• Receivers Array (4)
Royal Institute of Technology KTH
Performance of Multi-Channel MAC Protocols
• Performance of G-McMAC analyzed and compared to other existing
protocols
• G-McMAC outperforms other protocols with respect to delay
regardless of the used parameters
• G-McMAC achieves the highest throughput in many cases.