Active Vibration Control For Seismic Excited Building Structures

Building structures are usually vulnerable to seismic hazard,it is essential to protect these structures and human occupants from the seismic threat by reducing excessive structural vibration response.For alleviating the vibration of building structures,some sensors are generally required to be installed in the building structures so as to acquire structural responses and transmit the measurement information to vibration controllers.Afterwards,the controllers calculate the control command and drive the actuator to perform control force thus the overall structure responses will be mitigated.However,the following considerable issues are still not fully investigated in the most existing literatures.i)For obtaining the state information,some drift,velocity and acceleration sensors are usually necessary.However,the types,numbers,locations and coupling relations of the sensors with the building structures play important role in mitigating of the vibration yet these factors are not systematically investigated.ii)The measurement errors of sensors usually encounter in practice and they are capable of reducing the control performance.Besides,the controllers are commonly capable of digital calculation and implemented through hardware,therefore,the analog measurement signals will be encoded to digitals then transmitted to the controllers for decoding and further calculating.The above en-and de-coding processes inevitably introduce quantization errors in the measurement signals.iii)When the control commands are calculated,they will be further transmitted to the actuators for performing real-time control of building structures.Unfortunately,the physical actuators can only accept limited input signals and produce restricted outputs in practice.Therefore,if the required control force exceeds its limit,the actuator can only perform its maximum output.If the above discussed three factors are not fully addressed or neglected,the vibration mitigating performances will be reduced even the stability of the closed-loop system will be threaten.For investigating effective active vibration reduction strategy as well as enriching and completing vibration mitigation theory and implementation,the following key issues will be thoroughly and sequentially investigated in this paper.i)Considering the influences of soft,medium and dense intensity soils that on underground storey,types and locations of the sensors and actuators,the building structure,sensors and actuators will be organically integrated and the corresponding control system model will be proposed.Afterwards,taking the measurement stochastic noise into consideration,a robust observer based active vibration control law will be proposed for the seismic excited building structures to guarantee the stability and achieve a pre-specified_?/_?index.Moreover,the choosing the numbers and locations of the sensors and actuators,the vibration of the building structure can be mitigated in different levels.ii)The active vibration controllers are placed in some storeys,meanwhile,some active tuned mass dampers are also installed at the top floor and oscillating under their control forces.By considering measurement noise,quantization and actuator saturation,an observer-based feedback active vibration control law is proposed and the stability in mean square sense of the closed-loop system as well as a pre-regulatable_?/_?index can be simultaneously guaranteed.Moreover,the choosing some sensors and in presenting of measurement stochastic noise,quantization and actuator saturations,some effective active vibration control laws will be proposed;iii)Some active vibration controllers are placed in building structures;meanwhile,some acceleration sensors will be installed to acquire the acceleration measurement information of the building structure.Afterwards,considering the actuator saturation,an acceleration based feedback activation vibration control is investigated for the building structure to guarantee the stability of the closed-loop system and achieve a pre-specified_?index.