Sliding mode fuzzy control(SMFC) algorithm is presented for vibration reduction of large structures. Rule-base of the fuzzy inference engine is constructed based on the sliding mode control, which is one of the nonlinear control algorithms. In general, fuzziness of the controller makes the control system robust against the uncertainties in the system parameters and the input excitation, and non-linearity of the control rule makes the controller more effective than linear controllers. A distinctive feature in vibration control of a large civil infrastructure is the existence of large disturbances, such as wind, earthquake, and sea wave forces. SMFC uses not only the structural response measurement but also the external environmental load measurement. By direct utilizing the external environmental load data, SMFC can reduce the structural vibration more efficiently. However the external environmental load cannot be precisely measured in many cases, hence, an adaptive disturbance estimation filter is introduced to estimate a disturbance at each time instance based on the measured structural response and the stochastic information of the disturbance. The structure of the filter is constructed based on an auto-regressive model. For verification of the present algorithm, numerical studies are carried out on the two benchmark problems initiated by the ASCE Committee on Structural Control. One is the aseismic control using active tendon system, and the other is the wind-induced vibration control using active tuned mass damper. To achieve a high level of realism, various aspects are considered such as actuator-structure interaction, sensor noise, actuator time delay, precision of the A/D and D/A converters, magnitude of control force, and order of control model. Performance of the SMFC is examined in comparison with those of other control algorithms such as $H_{mixed}2/\infty$, optimal polynomial control, neural networks control, linear quadratic Gaussian control, frequency domain optimal control, quadratic stability control, continuous sliding mode control, and $H_\infty/\mu$ control, which were reported by other researchers. The results indicate that the present SMFC is efficient and attractive, since the vibration responses of the structure can be reduced very effectively and the design procedure is simple and convenient. The results also show that most of the performance indices improve as the adaptive disturbance estimation filter is introduced, which indicates that the wind force estimation using the disturbance estimation filter makes the control algorithm more effective.
본 논문에서는 대형 기반 구조물의 진동제어를 위한 슬라이딩 모드 퍼지 제어기법을 제안하였으며 제안된 기법의 타당성과 적용성을 검증하기 위하여 지진하중과 바람하중에 대한 베치마크 문제에 대해 수치 예제 해석을 수행하였다. 본 논문에서 제안된 슬라이딩 모드 퍼지제어기법은 비선형 구조물의 진동제어에도 응용 가능하며 피드포워드 루프를 포함하여 제어 효율이 뛰어난 슬라이딩 모드 제어기법을 퍼지화 함으로써 기존의 슬라이딩 모드의 슬라이딩 면의 설계를 편리하고 체계적으로 수행할 수 있게 한 기법이다. 슬라이딩 면의 수직한 성분 뿐 아니라 평행한 성분도 고려함으로써 실제적인 슬라이딩 면의 미세설계가 가능하도록 하였다. 또한 바람에 의한 진동제어와 같이 외부 하중의 측정이 용이하지 않은 경우를 위하여 외란 예측을 위한 필터를 설계하여 측정된 신호로부터 가상의 피드포워드 루프를 구성하도록 하였다. 제안된 기법은 벤치마크 문제를 통하여 다른 연구자들에 의해 제안된 기법들과 비교하였으며 그 결과로부터 본 논문에서 제안한 슬라이딩 모드 퍼지제어기법이 구조물의 진동제어에 매우 효율적임을 확인하였다.
