| Summary: | 碩士 === 淡江大學 === 土木工程學系碩士班 === 93 === As earthquakes had brought terrible losses all over the world in every year, the use of control devices to improve dynamic characteristic of civil structures has become widely accepted in civil engineering. In this research, an hybrid tuned mass damper (HTMD) was constructed and equipped at the top floor of the scaled model of a 3-story frame building to verify its applicability using the shaking table in the department of Civil Engineering, Tamkang University.
Firstly, a mathematical model called full-order-system was identified to simulate the dynamic behavior of the 3-story model equipped with an HTMD under the excitations of the actuator command and shaking table. In this system, the possible control-structure interaction induced by the actuator has been taken into account. Through the balanced-state reduction and the choice of the appropriate physical quantities for feedback, the LQG (Linear Quadratic Gaussian) control law was used to design the controllers. For implementation, the discrete dynamic output feedback equation was formed and directly used for calculating the controller command in real time. The control purpose is to reduce the adjacent drifts between floors and the absolute acceleration of building floors.
The LQG controllers designed were implemented on the 3-story building equipped with an HTMD by conducting shake table tests. The time scaling factor was considered in the tests. A passive tuned mass damper (TMD), which is corresponding to HTMD with no control command, and another type of active devices – active mass driver (AMD) were both installed on the same building model for the comparisons of their control effectiveness. In designing the controllers for the building with an AMD, the LQG strategy following the same procedures as in the HTMD case was employed.
From the time domain and frequency domain analyses of the experimental results, we found that the HTMD has a remarkable effect on reducing the response if the weightings were appropriately adjusted. It is also shown that the application of LQG strategy to the building with AMD or HTMD can achieve good performance. Furthermore, the hybrid control using acceleration feedback was demonstrated to be a promising way for response reduction of buildings.
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