| Earthquake simulation oscillators are now very important test equipment in the field of seismic safety of buildings.It directly observes and measures the failure mechanism of the earthquake and the seismic strength of the building by inputting the expected seismic waveform to the seismic simulation shaking table,so as to further take corresponding measures to improve the seismic strength of the building and protect the safety of human life and property.At present,most of the domestic and foreign seismic simulation shakers use electro-hydraulic servo as the excitation resource,which is expensive,has the poor high-frequency capability and covers a wide area,etc.However,as the vibration test tends to develop in the direction of streamlining,so small and medium-sized electrodynamic shakers will be more and more widely used in the future.Therefore,it is important to design a cost-effective and stable electrodynamic shaker system to reduce the cost of structural seismic testing and to broaden the application of shakers.In this paper,a high-precision seismic accelerated waveshape reproduction electrodynamic shaker system is developed independently according to the actual requirements and the basic principle and design index of the shaker.The upper computer of the system is PC,the lower computer is STM32 development board,and the actuator is AC servo motor.This shaking table has the characteristics of stable and reliable performance,high precision of waveform reproduction,low maintenance cost and strong practicability.This paper will study the mathematical model construction and control algorithm optimization of electric shaking table,data processing of seismic acceleration signal,design of STM32 controller,interface design of control system and waveform reproduction performance test.Firstly,the accuracy of the displacement signal after secondary integration of the seismic acceleration signal is improved using a time-frequency hybrid integration algorithm,which combines an improved low-frequency decay algorithm with the proposed algorithm for removing constants and linear terms to provide a stable and reliable displacement input signal for electrodynamic shakers;second,the proposed mathematical model of the electrodynamic shaker is derived,and the three-parameter control model is used to effectively improve the accuracy of the output signal of the electrodynamic shaker.The three parameters are displacement,velocity and acceleration signals,and the feedforward and feedback parameters of the three parameters are obtained by using the fast rectification method,while the corresponding velocity signals are estimated by combining the acceleration and displacement signals with the Kalman filter algorithm in the actual experiment,in order to overcome the quantization noise of the velocity signals obtained directly by using the displacement differentiation or acceleration integral the noise.Then,the STM32-based electrodynamic shaker lower computer is designed.In accordance with the actual control requirements of the vibration shaker,the hardware circuit is designed and the corresponding lower computer program is written,whose main function is to accept the transmitted data from the upper computer and ensure the stability of the driver;then,the QT architecture is used to design the interactive interface of the vibration shaker design,which is mainly to process and output the initial input signal of the vibration shaker,obtain and display the acceleration and displacement signals of the vibration shaker table,and perform analysis.Lastly,the control system of the electrodynamic seismic simulation shaker is built as a whole and the performance of key aspects of the control system is verified through the related performance tests.At the same time,the accuracy of the seismic waveform reproduction of the shaker under two different operating conditions,no load and loaded,is verified using real seismic acceleration as the excitation signal,thus verifying the accuracy and reliability of the whole control system.At the same time,the errors generated in the tests are analyzed and summarized. |
