Research And Design On Low Frequency Ultra Low Frequency Vibration Excitation System

Inertial sensor (displacement sensor, accelerometer sensor, gyro, etc.) is a kind of sensor that used frequently in the aviation and aerospace field, the level of precision calibration of sensors is the key for measuring the development level of sensor, especially the calibration for the inertial sensor with ultra-low frequency characteristics is one of the most important indicators to measure a country's vibration metering technology. Thus, the calibration research of inertial sensor with ultra-low frequency characteristics is extremely significant. As the core equipment of vibration measurement, ultra-low frequency vibration excitation system is not only one of the signs to measure the development level of vibration equipment, but also the core equipment of sophisticated inertial sensors. A large number of sensors applied in aviation and aerospace must undergo rigorous testing then can be put into use, it is a kind of indispensable test equipment for the national defense industry. The structural dynamics, early warning of earthquake prediction and detection waves, geological exploration and new energy development, advanced precision processing and manufacturing, nuclear explosion monitoring and other fields have strong demand on it.A vibration platform was designed and fabricated, which was characterized with a simple structure, convenience for use and a 1.2m length of travel. The movement forms of sinusoidal velocity curve, half-sine velocity curve, trapezoidal velocity curve and step would be simulated in this system. Otherwise, it can achieve sweeping frequency to some extend. The long length of travel of the system can make up for the distortion of the velocity of ordinary low-frequency electromagnetic vibration tables. It can made Low-frequency vibration table with a more precise motion accuracy. The prototype tests show the better velocity curve when the system runs at the higher speed. By contraries, the velocity curve distorts with the decrease of velocity. The distortional curve arises from the Coulomb friction of guide rail. With the improvement of the control algorithms and the decrease of friction force, the distortion will be reduced effectively. Preliminary tests showed that the movement of the vibration system maximum distortion was 10%, the amplitude of stability was less than 1%.