Implementation Of Active Mass Damper Control Systems For Flexible Structures: Some Related Methods

Flexible buildings are developing rapidly with the development of the national economy. However, the structural responses under strong wind, such as accelerations of high-rise buildings and inter-story displacement angle, are too large to meet comfort requirements in relevant codes, so stiffness of the structure need to be increased generally, which results in a substantial increase in the cost. Active Mass Damper （or Active Mass Driver, AMD） is a potential solution to the above questions because of its good control effect, great control bandwidth in frequency and high performance-to-price ratio. Although AMD control system has been widely studied, while its applications in civil engineering are fewer than the other control devices, such as Tuned Mass Damper （TMD）. There are still many questions should be solved in engineering applications, including establishment of accurate numerical model to the structure, observer design of full state feedback control system based on partial floor’s accelerations, influence of time delays of AMD control system on the system performances, effective compensator design to compensate time delays and other issues. In response to those problems, the following work has been done.The order of a control system is reduced based on comparative analysis of several commonly used methods. The optimal method will be improved combined with characteristics of high-rise buildings. Comparative analysis of original model and reduced model are obtained using the improved method, which includes structural responses in time domain and frequency domain, pole distribution of the two systems, etc. A reduced-order controller is designed based on the low-order model. Lastly, numerical analysis of a high-rise building with an AMD control system and experimental analysis of a four-layer frame with an AMD control system are carried out to verify the accuracy and validity of low-order model and controller.For an AMD control system with full state feedback, two observers with partial floor’s accelerations as input are designed, where the system state equations and fuzzy neural network are used for two observers separately. To proof the accuracy and validity of the proposed method, numerical analysis of a high-rise building with an AMD control system and experimental analysis of a four-layer frame with an AMD control system are both given. Finally, to take the average observation error as objectives, the locations of accelerometers in high-rise buildings are determined by the minimum value of average observation error.To reduce the influence of noise in feedback signal in control system and to meet the requirements of real-time control of AMD control system, a LMI-Kalman filter is designed based on Kalman filtering theory and linear inequalities （LMI） theory. Furthermore, the effectiveness of the filter is certified based on a numerical model of a high-rise building and experimental four-layer frame model with an AMD control system.Influence of time delay on pole position and stability for AMD control systems with single degree or multi-degree of freedom is analyzed in theory. According to the analysis results, the maximum time delay to ensure stability of the system is calculated, as following, the influence of control gain and structural parameters on system stability is analyzed. Then a time-delay compensation controller is designed based on the pole assignment algorithm to an actual high-rise building with an AMD system.Based on the input-output formula of servo motor, numerical model of an AMD control system is established, which includes the model without CSI effect, the model with low-order CSI effect and the model with high-order CSI effect, respectively. Based on these three models, mechanism of CSI effect and the influence of structural parameters on CSI effect are analyzed, while the result shows that essence of CSI is equal to a time-varying time lag. To reduce the influence of this effect on the control system, a H∞controller is designed. At last, effectiveness of compensator is verified.Based on the relationship between auxiliary mass stroke and its relative speed, a calculation formula of feedback gain based on auxiliary mass stroke is established to achieve computing time-varying feedback gain step by step or continuously. Analysis on how AMD strokes change with gains step by step or continuously is carried out using an actual project. In addition, procedures and methods of design and implementation of AMD control systems is introduced briefly based on a four-layer frame with an AMD control system.