Research Of Control Algorithm For Seismic Simulation Shaking Table

Seismic simulation shaking table tests are used to evaluate structural performance in earthquake engineering.The development trend of shaking table test is the equipment with large-scale,multi-directional and multi-degree of freedom,and the control systems with high accuracy.Because of the simplification of the model,the nonlinearity of the drive system,the dynamic response of the specimen,and the change of the structure state behavior,it is difficult for control systems to achieve accurate tracking performance for different reference input signals under different payloads.The output accuracy of the shaking table system will affect the reference value of the experimental results.Therefore,it is very important to study whether the control systems can make the seismic simulation shaking table accurately reproduce the target seismic wave.This study establishes and analyzes the models for the system composition,working principle,and control algorithm of seismic simulation shakeing table.The main results are as follows:1.By analyzing the seismic simulation shaking table system and studying the hydraulic components in the electro-hydraulic servo system and the motor components in the electric dynamics system,this study built mathematical models for both types of shaking tables,and use MATLAB/Simulink to build a numerical simulation model of a hydraulic servo-type seismic simulation shaking table.2.A two-loop control method is proposed by combining three-variable control and model reference adaptive control based on Lyapunov stability theory.The outer-loop controller uses model reference adaptive control instead of offline iterative control to reduce the tracking error and avoid causing premature damage to the specimen,model reference adaptive control can adjust its parameters online to improve the robustness of the system dynamics,while the inner-loop controller can accelerate convergence of the adaptive algorithm to improves the initial poor transient response of model reference adaptive controller.3.Numerical simulations of the electro-hydraulic servo-type shaking table are used to verify the effectiveness of the two-loop control method.To study the robustness against the control-stucure interaction effects and the specimen uncertainties of the proposed method,the numerical simulation results are compared with the performance of model reference adaptive controller and that of three-variable controller,reapectively.According to the results,the performance of the two-loop controller is better than that of the three-variable controller and adaptive law converges to the optimal solution more quickly than model reference adaptive controller,which not only improves the output accuracy of the electro-hydraulic servo-type shaking table,but also significantly reduces the tracking error of the controlled plant.The two-loop control method has better robustness than the cases only using three-variable controller or model reference adaptive controller.4.MATLAB/Simulink and the software and hardware of dSPACE are used to perform the rapid control prototyping simulation experiment of the two-loop control method for the electric dynamic shaking table.The performance of the proposed controller is compared with that of the three-variable controller to verify the effectiveness.For the electric dynamic type shaking table,the output of two-loop controller has better accuracy than the output of three-variable controller.The values of two-loop control parameters vary with time during the experiment process and adaptively change with the different payloads under same initial values.Therefore,the results of experiment demonstrate that the two-loop control method can have good control performance and robustness for electric dynamic shaking table.