Active Vibration Control of Buildings against Earthquakes Using Quadratic Optimal Approach

摘要

Vibration control of structures and hence minimizing their damage due to earthquakes is becoming increasingly important. This paper proposes the quadratic optimal control algorithm to design active control system for buildings subjected to earthquake excitations. The original dynamic equation is reduced to first order using state space approach and the algorithm works on full-state feedback system. Active Tuned Mass Damper (ATMD) is used as the control mechanism. The efficiency of the designed system has been verified against El-Centro earthquake. Active control gives nearly 32% more reduction in response of the structure over that obtained by passive control. The mass of the dam per has appreciable effects on response parameters than its stiffness. A flexible damper proves to be more effective than a stiffer one, but at the cost of actuating forces required. Performance of the active control system is found to be optimum, when the mass damper is tuned to the fundamental frequency of the structure. The stability of the structure is also enhanced by the intelligent Active Control system. A SDOF building is presented for illustration. The theory has also been applied to an eight-storey building and its response was found to be improved as compared with that of Yang et al for the same building.