Research On The Control Algorithm Of Electrohydraulic Seismic Simulating Shaking Table

The seismic simulating shaking table experiment is the most accurate method to test the seismic performance of building structures.Researchers put the scale model of building structure on the top of shaking table and input seismic wave signals to the shaking table to simulate the real seismic environment through the vibration of the table.The research and development of seismic simulating shaking table started relatively late in China and its core technology is insufficient.Therefore,the development of high-precision seismic simulating shaking table is of great significance for the development of national defense and disaster reduction in China.The core of seismic simulating shaking table research is to design reasonable control algorithms so that the acceleration waveform of shaking table can accurately reproduce the input reference waveform in time domain.Due to the low damping ratio and strong nonlinearity of seismic simulating shaking table,servo and vibration control algorithms are usually applied to improve dynamic characteristics and control accuracy of the system respectively.In addition,it is also very important for designing control algorithms to analyze the internal mechanism and nonlinear factors and establish an accurate nonlinear model of shaking table system.Therefore,the model and control algorithm of the seismic simulating shaking table are deeply studied in this paper,including the following work:(1)Research on the servo control algorithm of seismic shaking table.This paper analyzes the internal composition and operating mechanism of seismic simulating shaking table and obtains an approximate model of system by linearization method.Regarding the low bandwidth and small damping ratio problem of hydraulic servo system,this paper designs the three-variable control algorithm to improve dynamic characteristics of the system.Regarding the randomness problem of three-variable parameter tuning,this paper applies the inverse method to tune the three-variable parameters fast.(2)Research on vibration control algorithms of seismic shaking table.This paper analyzes the non-linear factors of hydraulic system and points out that friction is the main influencing factor.Regarding the discontinuity problem of the traditional friction model,this paper introduces a continuously differentiable friction model to correct the friction characteristics of system.Regarding the model uncertainty in the system,the error integral robust control algorithm is designed to control the vibration of system and the Lyapunov stability of system is proved.Regarding the randomness of robust gain value,the adaptively adjusting robust gain method is proposed,which can adjust the robust gain in real-time.(3)Verification of seismic simulating shaking table system.The control algorithm is tested on the seismic simulating shaking table and the error sign integral robust control algorithm is applied for experiments to analyze the relationship between the actual motion signal and the reference signal of the table.The results show that the adaptive error sign integral robust control algorithm based on the continuously differentiable friction model can greatly improve the control accuracy of the system and it can meet the requirements of the national standard GB T 21116-2007.