Structural Control II - Smart Structures Technology Laboratory
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Transcript Structural Control II - Smart Structures Technology Laboratory
Asia-Pacific Student Summer School on Smart Structures Technology
KAIST, Daejeon, Korea
August 1, 2008
Day 2.
Lecturers: H.-J. Jung, H. Myung, KAIST, Korea
Assistants: S.H. Park, D.D. Jang, KAIST, Korea
Lab. Schedule
Time
8/1 (Fri)
13:00-17:00*
Topics
Demonstration: MR damper-based semi-active
control
Lab.: Active control using piezo-actuator
Introduction to student competition:
Project II: Structural Control
*Group 1: 13:00-15:00
Group 2: 15:00-17:00
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MR Damper-based Semiactive Control System
Experimental Setup
3
MR Damper-based Semiactive Control System
Control Algorithm: Modal Neuro Control
4
MR Damper-based Semiactive Control System
Experimental Test Results
5
MR Damper-based Semiactive Control System
Experimental Test Results
6
Active Control Using PiezoActuator
Experimental Setup
PZT actuator
PZT sensor
Notebook
DAQ Terminal block
Power Amplifier
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Active Control Using PiezoActuator
Experimental Setup
Structure
Cantilever beam made of aluminum (500(L) ⅹ 50(W) ⅹ 0.8(t) (mm))
Sensor, Compensator & Exciter
Piezoceramic patch
Data Acquisition & Real Time Control
Hardware: NI DAQCard-6062E for PCMCIA & Terminal Block BNC-2110
Software: MATLAB Real Time Workshop
Other Equipments
Power Amplifier (or High Voltage Amplifier)
Control Algorithm for active control
Positive Position Feedback (PPF) Control (sample controller)
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Active Control Using PiezoActuator
Sample Control Algorithm: PPF Control
The equation of motion of the beam:
My Cy Ky Lu
where,
(1)
M, C, K : mass, damping, stiffness matrix of the beam
y(x,t) : displacement at the position y and time t
u : control input
L: the location defining vector for u
The y(x,t) can be rewritten as the product of mode shape φ(x) and modal coordinate q(t).
M q C q K q Lu
→
T M q T C q T K q T Lu
Since, it is orthogonal among the modes, the equation of motion can be written as follows:
qi 2 ii qi i2 qi Leui
where,
,
: damping ratio and natural frequency of the beam.
(2)
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Active Control Using PiezoActuator
Sample Control Algorithm: PPF Control
The control input u is generated by the PPF control scheme as
u H ̂
Where,
̂
(3)
is the output vector from a set of PPF filters described as
ˆ 2 ccˆ c2ˆ c2 q
where,
(4)
c , c : the PPF filter frequency and damping ratio.
Then, the equation (2) can be rewritten as
qi 2 ii qi i2 qi Le Hˆ
Since, Le H is square matrix, let’s define a new signal
gi2 Le Hˆ
where, g is the control gain.
(5)
, which satisfies
(6)
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Active Control Using PiezoActuator
Sample Control Algorithm: PPF Control
The resultant closed-loop system can be written as
qi 2 ii qi i2 qi gi2
(7)
2 cc c2 c2 q
(8)
qi 2 ii qi qi 0
2
i
g
qi
structure
2
i
c2
2 cc c2 0
compensator
< The block diagram of PPF controller >
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Active Control Using PiezoActuator
MATLAB Simulink Block for Experiment
1
Analog
Input
2
Analog Input
National Instruments
DAQCard-6062E [auto]
PZT sensor
-K-
x' = Ax+Bu
y = Cx+Du
control gain
4
PPF control
3
5
PZT actuator
Sine Wave1
0
Constant
Analog
Output
0
Clock3
0
Clock2
0
Clock1
Analog Output
Switch3
National Instruments
DAQCard-6062E [auto]
Switch2
Sine Wave
Switch1
6
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Active Control Using PiezoActuator
MATLAB Simulink Block for Experiment
① The voltage generated by PZT sensor is acquired through the DAQ card.
② PPF controller, which calculates the required control voltage.
③ If 0≤ time ≤ 20s, sine wave, else zero voltage will be provided.
④ If time ≤ 45s, the voltage determined by ③, else sine wave1 voltage will be provided.
⑤ If time ≤ 60s, the voltage determined by ④, else the voltage calculated by PPF
controller will be provided.
⑥ The voltage determined by ⑤ will provided to the PZT actuator through the DAQ card.
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Asia-Pacific Student Summer School on Smart Structures Technology
KAIST, Daejeon, Korea
July 28-August 16, 2008
Student Competition
Project 1: Structural Monitoring
Lecturers: J.-J. Lee, Sejong Univ., K.Y. Koo, KAIST, Korea
Assistants: H.J. Park, H.J. Kim, KAIST, Korea
Student Competition
Project 1: Structural Monitoring
Problem Description
Problems
Prob. 1
Prob. 2
Description
Damage detection on a steel beam
- All data sets including baseline and 3 unknown
states will be provided.
- Identify damage existence, location and severity if
possible.
- You CAN use ANY algorithm and software, not
limited to the peak-picking method and IDIS.
Monitoring of model structures
- Make each team’s own structure using pieces of
steel beams which are provided.
- Establish monitoring strategies fit to each structure.
- Introduce damages
- Perform vibration tests and damage identification
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Student Competition
Project 1: Structural Monitoring
Evaluation Criteria*
Problems
Prob. 1
(50%)
Evaluation Criteria
Damage identification results for 3 unknown data sets
Programming skills for demonstration
New methodologies (probably) will get additional points
Prob. 2
(50%)
Novelty of problem definition (structure, damage type,
algorithms, etc.)
Completeness of procedures
Presentation/Demonstration skills
Teamwork
* Final evaluation criteria will be announced on 8/6 (Wed).
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Asia-Pacific Student Summer School on Smart Structures Technology
KAIST, Daejeon, Korea
July 28-August 16, 2008
Student
Competition
Prjoect 2: Structural Control
Lecturers: H.-J. Jung, H. Myung, KAIST, Korea
Assistants: S.-H. Park, D.-D. Jang, KAIST, Korea
Student Competition
Project 2: Structural Control
Problem Description
Problems
Prob. 1
Prob. 2
Description
Vibration control of cantilever beam using
piezo-actuator
- Strain-rate feedback (SRF) control algorithm
- SRF control algorithm can be obtained by slightly
modifying PPF control algorithm.
Vibration control of cantilever beam using
piezo-actuator
- Any control algorithm can be used
- Neuro-control and fuzzy control are recommended
* New specimens for student competition will be distributed on 8/6 (Wed).
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Student Competition
Project 2: Structural Control
Evaluation Criteria*
Problems
Prob. 1
(40%)
Evaluation Criteria
Damping ratio (50%)
Settling time (5% of the initial value) (30%)
Overshooting (20%)
Prob. 2
(40%)
Completeness of control algorithm (40%)
Damping ratio (30%)
Settling time (5% of the initial value) (20%)
Overshooting (10%)
Presentation
(20%)
Presentation and demonstration skills
Teamwork
* Final evaluation criteria will be announced on 8/6 (Wed).
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