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CONTENTS Introduction Semi-Active Control Proposed Control Algorithm

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Presentation on theme: "CONTENTS Introduction Semi-Active Control Proposed Control Algorithm"— Presentation transcript:

0 지진 하중을 받는 구조물의 수정된 분산뱅뱅 제어기법을 이용한 MR Damper 제어 한국지진공학회 츤계학술발표
연세대학교 2002년 3월 23일 지진 하중을 받는 구조물의 수정된 분산뱅뱅 제어기법을 이용한 MR Damper 제어 조 상 원* : KAIST 건설·환경공학과 박사과정 김 병 완 : KAIST 건설·환경공학과 박사과정 김 운 학 : 한경대학교 토목공학과 교수 이 인 원 : KAIST 건설·환경공학과 교수

1 CONTENTS Introduction Semi-Active Control Proposed Control Algorithm
Numerical Example Conclusions and Further Studies Structural Dynamics & Vibration Control Lab., KAIST, Korea

2 Introduction Recent Earthquakes Kobe, Japan (1995)
5,400 of death and 1.5 trillion won of damage Gebze, Turkey (1999) 14,491 of death and 13 trillion won of damage Chi-Chi, Taiwan (1999) 2,161 of death and 9.2 trillion won of damage  To increase the safety and reliability, structural control is required Structural Dynamics & Vibration Control Lab., KAIST, Korea

3 Structural Control Strategies
Active control Use external control force to reduce the responses Large external power The problem of reliability under earthquake Active Mass Damper (AMD) Passive control Increase the capacity of energy dissipation of structure No external power No adaptability to various external load Lead Rubber Bearing (LRB) 능동제어기법은 외부제어력으로 구조물의 응답을 감소시키는 ‘방식’이다. 따라서 대규모의 외부 전력이 필요하다 그러므로 지진시에 전력차단과 같은 신뢰성에 문제가 있다. 이에 비해서 수동제어 방식은 구조물의 에너지 소산능력을 증가시키는 방식이다. 따라서 외부입력전원이 필요가 없다. Structural Dynamics & Vibration Control Lab., KAIST, Korea

4 Change the characteristics of control devices Small external power
Semi-active control Change the characteristics of control devices Small external power Reliability of passive system with adaptability of active system Variable-orifice damper, MR/ER damper Structural Dynamics & Vibration Control Lab., KAIST, Korea

5 Semi-Active Control Devices
Variable-orifice damper Feng and Shinozuka (1990), Kawashima et al. (1992) Variable-friction damper Akbay and Aktan (1990), Kannan et al. (1995) Semi-active impact damper Masri and Yang (1973), Papalou and Masri(1996) Structural Dynamics & Vibration Control Lab., KAIST, Korea

6 Controllable fluid damper Electrorheorogical fluid damper (ER damper)
Ergott and Masri(1992) Magnetorheorogical fluid damper (MR damper) Carlson et al. (1994) Table 1 Properties of MR and ER Fluids Property MR Fluids ER Fluids Response Time milliseconds Operable Temp. Range -40 to 150°C +10 to 90°C Stability Unaffected by most impurities Cannot tolerate impurities Structural Dynamics & Vibration Control Lab., KAIST, Korea

7 Without Magnetic Fields
MR Damper Characteristics of MR fluid With Magnetic Fields Without Magnetic Fields Wires to Electromgnet Diaphragm MR Fluid Voltage dependence 강조 Coil Accumulator Bearing & Seal Structural Dynamics & Vibration Control Lab., KAIST, Korea

8 Model of the parallel-plate MR damper (Jansen et al. 2000)
Modeling of MR damper Model of the parallel-plate MR damper (Jansen et al. 2000) x (1) f c0 Voltage dependence of the damper parameters (2) v : commanded voltage Indirect control command is used Structural Dynamics & Vibration Control Lab., KAIST, Korea

9 Objective and Scope To develop an efficient semi-active control strategies considering the characteristics of MR damper Structural Dynamics & Vibration Control Lab., KAIST, Korea

10 Semi-Active Control Semi-Active Control Algorithms
Karnopp et al. (1974) “Skyhook” damper control algorithm Feng and Shinozukah (1990) Bang-Bang controller for a hybrid controller on bridge Brogan (1991), Leitmann (1994) Lyapunov stability theory for ER dampers McClamroch and Gavin (1995) Decentralized Bang-Bang controller Structural Dynamics & Vibration Control Lab., KAIST, Korea

11 Modulated homogeneous friction algorithm for a
Inaudi (1997) : Modulated homogeneous friction algorithm for a variable friction device Sack et al. (1994), Dyke (1996) : Clipped optimal controllers for semi-active devices Structural Dynamics & Vibration Control Lab., KAIST, Korea

12 Clipped-Optimal Control (Dyke et al. 1996)
Optimal control with clipped algorithm Optimal control State-space equation Cost function (3) (4) Structural Dynamics & Vibration Control Lab., KAIST, Korea

13 Optimal control algorithm K : solution of Ricatti equation
(5) (6) Control force is linear to the state of structure - No consideration of saturation Structural Dynamics & Vibration Control Lab., KAIST, Korea

14 Indirect control command to MR damper
Clipped algorithm Indirect control command to MR damper Control voltage v , instead of control force (7) fc : calculated optimal control force fi : control force of MR damper H : Heaviside step function vi : control voltage Structural Dynamics & Vibration Control Lab., KAIST, Korea

15 Proposed Control Strategy :
Clipped Decentralized Bang-Bang Control (CDBBC) Decentralized Bang-Bang Control To use full capacity of MR damper To consider the saturation of MR damper High speed switching control command Clipped algorithm Indirect control command Structural Dynamics & Vibration Control Lab., KAIST, Korea

16 Decentralized Bang-Bang Control (McClamroch and Gavin, 1995)
Based on Lyapunov stability theory Lyapunov function V(z) Derivative of Lyapunov function (8) (9) Structural Dynamics & Vibration Control Lab., KAIST, Korea

17 Control law which minimize Eq.(9)
Approximate sign function Modified decentralized bang-bang control (10) (11) (12) where Structural Dynamics & Vibration Control Lab., KAIST, Korea

18 Indirect control command to MR damper
Clipped algorithm Indirect control command to MR damper Control voltage v , instead of control force (13) fc : calculated CMBB Control force fi : control force of MR damper (nonlinear) H : Heaviside step function vi : control voltage Structural Dynamics & Vibration Control Lab., KAIST, Korea

19 ` Block diagram of proposed control algorithm
Structure MR Damper ` Clipped Algorithm Modified DBB Control Clipped Modified Decentralized Bang-Bang Control (CMDBBC) Structural Dynamics & Vibration Control Lab., KAIST, Korea

20 Numerical Examples Six-Story Building (Jansen and Dyke 2000) f2 v2 f1
MR Damper f2 v2 LVDT f1 v1 LVDT Control Computer Structural Dynamics & Vibration Control Lab., KAIST, Korea

21 Mass of each floor : 0.277 N/(cm/sec2) Stiffness : 297 N/cm
System data Mass of each floor : N/(cm/sec2) Stiffness : 297 N/cm Damping ratio : each mode of 0.5% Structural Dynamics & Vibration Control Lab., KAIST, Korea

22 Damper modeling and parameters
Value coa Nsec/cm a 8.66 N/cm cob Nsec/cmV b 8.86 N/cmV A 120 300 cm-2 n 2 190 sec-1 x F-f , Bouc-Wen Model Structural Dynamics & Vibration Control Lab., KAIST, Korea

23 3 Modes of MR damper Passive-off : input Voltage = 0 V
Passive-on : input Voltage = 2.5 V Semi-Active : switching on and off according to control algorithm Structural Dynamics & Vibration Control Lab., KAIST, Korea

24 Structural responses by CMDBBC
(Under El Centro Earthquake, at 3rd floor) Uncontrolled CMDBBC Structural Dynamics & Vibration Control Lab., KAIST, Korea

25 Modified Decentralized
Unsaturated condition under El Centro earthquake Control Strategy J1 J2 J3 J4 Passive-Off 0.862 0.801 0.904 Passive-On 0.506 0.696 1.41 0.0178 Lyapunov A 0.686 0.788 0.756 Lyapunov B 0.326 0.548 1.39 Clipped Optimal A 0.631 0.640 0.636 Clipped Optimal B 0.405 0.547 1.25 Modified Decentralized Bang-Bang 0.567 0.673 1.18 0.0119 0.591 0.618 1.24 0.0115 Structural Dynamics & Vibration Control Lab., KAIST, Korea

26 Discussions Maximum measured control forces : 24.03 N
Capacity of MR damper : 29N (1.8% of total weight) Unsaturated condition !! Structural Dynamics & Vibration Control Lab., KAIST, Korea

27 Modified Decentralized
Saturated condition under magnified El Centro earthquake Control Strategy J1 J2 J3 J4 Passive-Off 19.84 19.817 20.034 0.0036 Passive-On 19.108 17.8 19.775 0.0217 Lyapunov B 18.816 18.401 18.191 Clipped Optimal B 19.112 17.814 18.864 Modified Decentralized Bang-Bang 19.623 19.577 19.56 0.0122 Structural Dynamics & Vibration Control Lab., KAIST, Korea

28 Conclusions Proposed Clipped modified decentralized bang-bang
control reduce the structural responses from the uncontrolled value Performance of proposed is not better than clipped optimal control under unsaturated condition For the strong earthquake (i.e. saturated condition), clipped optimal control is not better than others Structural Dynamics & Vibration Control Lab., KAIST, Korea

29 Further Studies Clipped Modified Decentralized Bang-Bang Control
Improve the performance Apply to full-scale MR damper Experimental Studies Shaking table test Full-scale MR damper test Structural Dynamics & Vibration Control Lab., KAIST, Korea


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