Robust Hybrid Control System for a Seismically-Excited Cable-Stayed Bridge

2003년도 대한토목학회 정기 학술대회 2003. 10. 25. Robust Hybrid Control System for a Seismically-Excited Cable-Stayed Bridge 박규식, 한국과학기술원 건설 및 환경공학과 박사과정 정형조,세종대학교 토목환경공학과 조교수 김운학,한경대학교 토목공학과 교수 이인원,한국과학기술원 건설 및 환경공학과 교수

CONTENTS • Introduction • Robust hybrid control system • Numerical examples • Conclusions

INTRODUCTION • Hybrid control system (HCS)  A combination of passive and active control devices • Passive devices: offer some degree of protection in the case of power failure • Active devices: improve the control performances  However, the robustness of HCS could be decreased by the active control devices.

Objective of this study Apply robust control algorithms to improve the controller robustness of HCS

ROBUST HYBRID CONTROL SYSTEM • Control devices  Passive control devices • Lead rubber bearings (LRBs) • Design procedure: Ali and Abdel-Ghaffar (1995) • Bouc-Wen model  Active control devices • Hydraulic actuators (HAs) • actuator capacity: 1000 kN • The actuator dynamics are neglected.

Robust hybrid control system • Control algorithm  RHCS I • Primary control scheme · Linear quadratic Gaussian (LQG) algorithm • Secondary control scheme · On-off type controller according to LRB’s responses

Robust hybrid control system Bridge Model LRB MUX Sensor LQG HA On/Off Block diagram of RHCS I

Robust hybrid control system  RHCS II • H2 control algorithm with frequency weighting filters • Frequency weighting filters

Robust hybrid control system Bridge Model R Wu Wz kg Wg Q DM LRB MUX H2 HA Sensor K Block diagram of RHCS II  RHCS III • H control algorithm with frequency weighting filters

NUMERICAL EXAMPLES • Analysis model  Bridge model • Bill Emerson Memorial Bridge · Benchmark control problem · Under construction in Cape Girardeau, MO, USA ·16 Shock transmission devices (STDs) are employed between the tower-deck connections.

Numerical examples 142.7 m 350.6 m 142.7 m 4+3 2+3 4+3 2+3 2+3 4+3 2+3 4+3 Configuration of control devices (HAs+LRBs)

Numerical examples  Historical earthquake excitations PGA: 0.348g PGA: 0.143g PGA: 0.265g

Numerical examples • Analysis results  Control performances Mexico City El Centro Gebze Max.

Numerical examples  Controller robustness • The dynamic characteristic of as-built bridge is not identical to the numerical model. • To verify the applicability of RHCS, the controller robustness is investigated to perturbation of stiffness parameter. where : nominal stiffness matrix : perturbed stiffness matrix : perturbation amount

Numerical examples Max. variation of evaluation criteria for variations of stiffness perturbation

Numerical examples • •Maximum variations of evaluation criteria for all three • earthquake (%, 5% perturbation)

Numerical examples • •Maximum variations of evaluation criteria for all three • earthquake (%, 20% perturbation)

CONCLUSIONS • Hybrid control system with robust control algorithms  has excellent robustness for stiffness perturbation without loss of control performances  could be used to seismically excited cable-stayed bridges This research is supported by the National Research Laboratory (NRL) program (Grant No.: 2000-N-NL-01-C-251) from the Ministry of Science of Technology (MOST) and grant for pre-doctoral students (Grant No.: KRF-2003-908-D00050) from the Korea Research Foundation (KRF) in Korea.

Robust Hybrid Control System for a Seismically-Excited Cable-Stayed Bridge