The Hybrid Control Theory And Experimental Research Of Structural Vibration Based On Magnetorheological Damper

Structural vibration control technology is an effective method which using some controldevices working together with structures to resist the dynamical loads by seismic, wind andothers. The semi-active and hybrid control based on using the smart materials open a new doorfor developing theory and engineering application of this theory. Magnetorheologica (MR)dampe is a semi-active control device, which has illustrated a good application prospects in thefield of vibration control for civil structures. This type of damper has many obvious advatanges,such as its small cubage, rapid response, low power requirement, simple structure, largedamping force capacity, and so on.Appling the theory of electromagnetism, a new-style composite MR damper is developedmaking use of the material characteristic of MR liquid in this dissertation. Based on thecomposite MR damper, a study on the theories and experimentes of passive control, semi-activeand hybrid control using the Linear Quadratic Gaussian (LQG) and Generalized PredictiveControl (GPC) is performed. The main work of this thesis can be concluded as:(1) The basic principle and the internal mechanism of a new-style composite MR damperare introduced first. Based on the theory of electromagnetism, the mechanical model of thedamper is established, and is simulated by the commercial package ANSYS. The results haveshown the validity of the magnetic circuit for the design of MR damper.(2)A new-style composite and valve mode MR damper is designed and constructed. Themaximum force is 5500N, the maximum controllable force is 4680N, and the dynamiccharacteristics of the damper are investigated through experimental study. Considering theadvantages and disadvantages of existing models, a modified nonlinear hysteretic biviscousmodel is presented, which is very reasonable for this damper.(3) The Linear Quadratic Gaussian(LQG) algorithms control theory and GeneralizedPredictive Control(GPC) theory are adopted to investigated the passive control, semi-active andhybrid control system, which is composed of lead plug laminated rubber bearings and thecomposite MR damper. The LQG only required the acceleration responses of structure for thefeedback, while the GPC has the function of time delay self-compensation. Based on themodified nonlinear hysteretic biviscous model, the numerical simulation using powerful software-MATLAB/SIMULINK on a three-storey steel frame is performed. The numericalresults have proved the validity of the control scheme.(4) Under two different seismic input (El-Centro,Taft), three control systems are adopted,which are semi-active control system, passive and hybrid control system respectively. Thesemi-active control systems is based on the Linear Quadratic Gaussian(LQG) and GeneralizedPredictive Control(GPC), the four passive control is carried out at the value of-0.5A(Passive-on1), 0A(Passive-off), 2A(Passive-on2) and only use lead plug rubber bearings,respectively, and the hybrid control system consist of semi-active control and the base isolation.On the real-time control platform of WINCON/SIMULINK, a series of shaking table tests of thecontrol systems on a one-fourth scaled steel frame model installed the composite MR damperand lead plug rubber bearings are carried out. The test results indicate that the control systemsbased on the composite MR damper are very effective. The four passive control situations,semi-active control and hybrid control are all able to significantly reduce the seismic responsesof the model structure. The effect of the passive control system under 0A current demonstratesthat the composite MR damper applied in the vibration control for civil engineering is morereliable, practical and economic than the conventional MR damper. The GPC theory, which hasthe function of time delay self-compensation, achieves a better control effect than the LQGalgorithms control theory in the testing, besides, both the GPC theory and the LQG algorithmsachieve a better control effect with less control forces compared with passive control. From thepoint of view of control strategy, test results indicate that the control effect with eitherhybrid-passive control or hybrid-semi-active control are better than the passive control onlyinstalled lead plug rubber bearings, the composite MR damper and the semi-active control onlyinstall the composite MR damper, respectively. Compared the numerical simulation with thetested results, the foregoing controlling algorithms are proved to be effective. Consequently, itprovided reliable basis for applying the semi-active control systems and hybrid controls usingthe composite MR damper to civil engineering.