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í•œêµì§€ì§„공학회 ì¸¤ê³„í•™ìˆ ë°œí‘œ ì—°ì„¸ëŒ€í•™êµ 2002 ë…„ 3 ì›” 23 ì¼. 지진 í•˜ì¤‘ì„ ë°›ëŠ” êµ¬ì¡°ë¬¼ì˜ ìˆ˜ì •ëœ ë¶„ì‚°ë±…ë±… ì œì–´ê¸°ë²•ì„ ì´ìš©í•œ MR Damper ì œì–´. ì¡° ìƒ ì›* : KAIST 건설 · 환경공학과 ë°•ì‚¬ê³¼ì • ê¹€ 병 완 : KAIST 건설 · 환경공학과 ë°•ì‚¬ê³¼ì • ê¹€ ìš´ í•™ : í•œê²½ëŒ€í•™êµ í† ëª©ê³µí•™ê³¼ êµìˆ˜ ì´ ì¸ ì› : KAIST 건설 · 환경공학과 êµìˆ˜. CONTENTS. Introduction Semi-Active Control
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한국지진공학회 츤계학술발표 연세대학교 2002년 3월 23일 지진 하중을 받는 구조물의 수정된 분산뱅뱅 제어기법을 이용한 MR Damper제어 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
CONTENTS • Introduction • Semi-Active Control • Proposed Control Algorithm • Numerical Example • Conclusions and Further Studies Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
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) Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
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
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 Structural Dynamics & Vibration Control Lab., KAIST, Korea
MR Damper • Characteristics of MR fluid With Magnetic Fields Without Magnetic Fields Wires to Electromgnet Diaphragm MR Fluid Coil Bearing & Seal Accumulator Structural Dynamics & Vibration Control Lab., KAIST, Korea
x (1) • Modeling of MR damper • Model of the parallel-plate MR damper (Jansen et al. 2000) f c0 • Voltage dependence of the damper parameters (2) v : commanded voltage Indirect control command is used Structural Dynamics & Vibration Control Lab., KAIST, Korea
Objective and Scope To develop an efficient semi-active control strategies considering the characteristics of MR damper Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
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
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
(5) • Optimal control algorithm K : solution of Ricatti equation (6) • Control force is linear to the state of structure- No consideration of saturation Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
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
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
(10) • Control law which minimize Eq.(9) • Approximate sign function • Modified decentralized bang-bang control (11) (12) where Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
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
Numerical Examples • Six-Story Building (Jansen and Dyke 2000) f2 MR Damper v2 f1 LVDT v1 LVDT Control Computer Structural Dynamics & Vibration Control Lab., KAIST, Korea
System data • Mass of each floor : 0.277 N/(cm/sec2) • Stiffness : 297 N/cm • Damping ratio : each mode of 0.5% Structural Dynamics & Vibration Control Lab., KAIST, Korea
x • Damper modeling and parameters F-f , Bouc-Wen Model Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
Structural responses by CMDBBC (Under El Centro Earthquake, at 3rd floor) Uncontrolled CMDBBC Structural Dynamics & Vibration Control Lab., KAIST, Korea
Unsaturated condition under El Centro earthquake Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
Saturated condition under magnified El Centro earthquake Structural Dynamics & Vibration Control Lab., KAIST, Korea
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
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