Research On The Theory And Application Of A New Semi-active Controlled Base-isolated Structure

At present,the semi-active controlled isolation system is still mainly in the theoretical analysis and physical tests.There are no ideal solutions about control devices and control algorithms.In this paper,a new type of semi-active isolation system is proposed,and a relatively complete theoretical and experimental studies are carried out.The main innovative research results are as follows:(1)A new type of Tunable Friction Pendulum System(TFPS)bearing is proposed.It combines the new structural vibration control technology with the advantages of the conventional FPS,friction damping and continuous adjustability of active control technology,so that the friction force can be adjusted online.The theoretical analysis is conducted.(2)Based on the design concept of the proposed TFPS bearing,a small TFPS specimen is designed and manufactured for single concaved surface type,and its experimental study is carried out.The theoretical analysis and adjustability of TFPS bearing are verified by using different displacement amplitudes and oil pressure grades.The theoretical calculation is consistent with the experimental results,and the horizontal friction force can be adjusted by changing the distribution of pressure force on the slider surface.(3)Based on the proposed TFPS,a semi-active controlled isolation system is established,and several conventional control algorithms are applied in the numerical simulations.The results show that the proposed TFPS bearings can be effectively used for seismically structural control,which meets the needs of multi-objective seismic resistance demand and provides theoretical basis and technical support for further research and application.(4)Aiming at the problem of parameter uncertainties in the controlled structure,a new Optimal Model Reference Adaptive Control(OMRAC)algorithm is proposed based on the Lyapunov-MRAC algorithm and Linear Quadratic Regulator(LQR).The stability and robustness is proved.The corresponding design method is put forward and the control parameters are analyzed.The OMRAC algorithm is applied to control a base-isolated structure equipped with TFPS bearings.Considering the parameter uncertainty in base isolation layer,numerical simulations are carried out under different earthquakes.The results demonstrate the effectiveness and stability of OMRAC algorithm.(5)For base-isolated structures with unknown time-various nonlinear disturbances,the OMRAC algorithm mentioned above still has some limitations.Based on the linear quadratic optimal control(LQR),a new type of nonlinear Robust Optimum Control(Robust Optimum Control-ROC)algorithm is proposed by combining and designing a nonlinear robust compensator.The proof,parameter analysis and design method are presented.The ROC algorithm is applied to the semi-active controlled base-isolated structure with TFPS bearings.Considering the time-various nonlinearity in the isolation layer,numerical simulations are carried out,which proves the availability and effectiveness of the proposed ROC algorithm for the nonlinear disturbance problem.