Design And Control Method Research Of Small Low-frequency Vibration Test-platform

Geophone is the key instrument to acquire the field seismic data.It is a prerequisite to ensure the data accuracy by calibration or test in time to eliminate failed ones.Focusing on the needs for low-frequency vibration test equipment to calibrate and test geophone,as well as the disadvantages of low-frequency vibration test platform in labs such as complexity and heaviness,high energy consumption,high cost and inability to perform field operations,this paper adopts the voice coil motor as the actuator to design a small low-frequency vibration experimental platform with the advantages of low waveform distortion and high economy.Meanwhile,it also designs a comprehensive vibration control algorithm based on adaptive inverse control and speed feedback to improve the tracking performance of the sinusoidal waveform as well as the system rapidity and stability.In this paper,the CATIA modeling software is adopted to design the mechanical structure of the vibration platform.Then,the ANSYS finite element simulation software is adopted to determine the structural resonance frequency and lateral vibration ratio,so as to ensure no harmful resonance within the working frequency and the lateral vibration ratio within the allowable range.Firstly,the hardware is selected as per the needs to complete the whole hardware system.Secondly,the working principles of the established vibration test platform and the voice coil motor are analyzed and studied,so as to build the electromechanical coupling mathematical model of the small low-frequency vibration test platform,laying the foundation for the design of control algorithm.Thirdly,this paper studies the control algorithm for the fast and accurate reproduction of sine waveform in the vibration test platform,and establishes an adaptive inverse vibration control strategy based on the NLMS algorithm.With regard to the problem of slow response speed and low stability,this paper also proposes the adaptive inverse vibration control strategy based on speed feedback,so as to establish the relevant control parameters of the algorithm through the strategy simulation and verify the validity of the control algorithm.Finally,the system software is designed to verify the control algorithm on the low-frequency vibration test platform.The performance of the low-frequency vibration test platform is tested to complete the calibration experiment of the geophone.The results show that the low-frequency vibration test platform designed in this paper can achieve satisfactory sinusoidal vibration control with the advantages of low distortion and high tracking accuracy which can achieve geophone calibration within the range of 0.5Hz～80 Hz.