Shaking Table Cascade Control And Predictive Control For Structure’s Anti-seismic Method

In recent years,earthquakes frequently occurred in the worldwide scale,whose negative impact on human society has induced many new seismic problems,and the demand for structural seismic testing is increasing,especially the research on seismic simulation shaker testing and structural seismic control technology has become a hot issue.The shaking table is the most important test equipment in structural seismic testing,which has a complex structure,strong nonlinearity and low damping ratio.The traditional TVC has the disadvantages of difficult adjustment of control parameters and low accuracy of waveform reproduction,while the general iterative learning vibration control cannot solve the problems of time-varying and uncertainty of system parameters.In addition,the shaking table is expensive,and its state is influenced by the dynamic characteristics of the shaking table itself and the load specimen on the table,leading to a problem of online debugging with load,so it is necessary to establish a dynamic model that can reflect the full physical characteristics of the shaker,and debug and verify the control strategy through simulation.What’s more,most of the traditional seismic designs of building structure aim to modify the material of the structure itself,therefore,in order to reduce the damage caused by the earthquake,besides the modification of the material of the structure,an active seismic control system needs to be built to strengthen the seismic resistance of the building structure under the vibration condition.To this end,this thesis focuses on shaking table and active structural seismic control strategies.For the shaking table control,a large 5m × 5m three-way six-degree-of-freedom electro-hydraulic servo shaking table is the object of study;for the structural seismic control,the study is mainly focused on the building structure equipped with active anchor system.Firstly,after analyzing the working mechanism of each component of the shaking table(control system,hydraulic source system,exciter system,table and support system,etc.),and the dynamic characteristics of the three-stage servo valve,hydraulic cylinder and accumulator,the mathematical models of the shaking table’s physical components,such as three-stage servo valve,hydraulic cylinder and accumulator,are created based on Pascal’s principle and Newton’s second law.Subsequently,the dynamic simulation model of the electro-hydraulic shaking table is constructed on this basis.Secondly,the shaking table cascade control strategy is designed,and the inner loop proposes a particle swarm optimization algorithm-based velocity positive feedback three-parameter control method.At first,the PSO algorithm is used to rectify the six variable of the three-variable controller.Then the negative velocity feedback in the traditional three-parameter feedback control is replaced with positive velocity feedback,and the system open-loop gain and system damping ratio are increased by appropriately reducing the system inherent frequency,to improve the accuracy of waveform recurrence.At the same time,the outer loop proposes a shaking table vibration control strategy based on adaptive iterative learning control,which uses an adaptive algorithm to rectify the time-varying parameters in the shaker test,and then compensates the waveform tracking error through iterative learning control.Thirdly,to improve the seismic resistance of building structures in different seismic environments,a model predictive structural active seismic control strategy based on acceleration feedback is proposed,which uses Kalman filtering to estimate the real state of the system from structural acceleration feedback,and then performs seismic control of building structures through model predictive control,in order to reduce actuator energy consumption while improving structural seismic resistance.The velocity positive feedback TVC method based on PSO algorithm proposed in this thesis expands the operating bandwidth of the shaking table system to 161 Hz while allowing3 d B attenuation,improves the dynamic characteristics of the system,lays a solid foundation for the outer-loop vibration control,and improves the seismic wave reproduction accuracy while reducing the controller parameter adjustment time.In addition,the vibration control strategy based on adaptive iterative learning proposed in this thesis can accurately reproduce seismic waves,and the correlation coefficient between the reproduced waveform and the desired waveform reaches 0.9994,which meets the control accuracy requirements of the national standard GBT21116-2007 for shaking table.Finally,the active seismic control strategy of the model predicted structure based on acceleration feedback in this thesis reduces the maximum inter-story displacement of the building example under seismic excitation by76% for the second floor and 80% for the second floor,and avoids the building structure from entering the plastic domain,which improves the seismic performance of the building structure.