Research On Detection Technology Of Weak Vibration For Ultra-Static Platform

The measurement and calibration of high-precision sensors require a vibration isolating platform with good performance.The vibration isolation level of the platform determines the accuracy of sensors.In-depth study of the vibration detection technology of the ultra-static platform is of great significance for the improvement of the vibration isolation effect.After a series of vibration isolation means,the ultra-static platform still has vibration which has the characteristics of low frequency,tiny amplitude and six degrees of freedom.In order to solve these problems,a system is developed for real-time detection of ultra-static platform's six-degree-of-freedom weak vibration and the low-frequency geophone array is used as the sensor in this paper.The main contents of this paper are as follows:1)Research on the low frequency compensation method of the geophone.The vibration frequency band of the ultra-static platform is close to the natural frequency of the geophone.The sensitivity of the geophone is rapidly attenuated as the frequency decreases.Therefore,the geophone needs to be compensated for low frequency.After comparing the commonly used compensation methods,the digital compensation method is selected.In this paper,transfer models are established based on the geophones used.A compensation scheme is developed and verified through the simulation tool.2)Research and implementation of noise suppression methods for high-precision weak vibration detection systems.In order to achieve high-precision measurement of weak vibration signals,it is necessary to analyze and calculate the influencing factors of system noise.On this basis,the noise suppression method is studied,and the design of low-noise circuit is completed.Experiments are conducted to verify the function and short-circuit noise of each channel.3)Research and implementation of six-degree-of-freedom solution method for the platform's vibration.By studying the six-degree-of-freedom method based on velocity sensor array,the installation position and sensitive direction of the geophone array are designed,and the relationship equation between speed and six degrees of freedom is established.The least squares method is used to solve the problem.And the vibration model of platform is established in the simulation tool in order to verify the solution.Finally,the measurement and verification of the weak vibration detection system are completed on the ultra-static platform.The functions and indicators of the system are evaluated,and the design goals are achieved.