Design And Research Of Permanent Magnet Sensor

It is an important technical indicator for the flight speed of projectile to ensure that the performance can meet the design requirement. A new permanent magnetic inductive speed sensor has been proposed aiming at improving the signal-noise ratio of coil targets used before and preventing affected by mains fluctuation. The new sensor provide a new equipment for testing projectile velocity.The principle of the permanent magnetic inductive speed sensor was introduced. On the basis of magnetic dipole theory and law of electromagnetic induction, the model of the sensor was built.Choose the NdFe35 provide the magnetic field. Space magnetic field distribution model was deduced for cylindrical permanent magnet based on molecular circulation hypothesis. was applied to research how the dimension parameter of permanent magnet affects on magnetic field distribution and determine the shape of permanent magnet. Besides, the parameters of configuration and the permanent magnet count were analyzed by using finite element simulation software-Ansoft.The equivalent radius model of the induction coil was established. Using the model, the influence law of sensitivity affected by the equivalent radius was researched. Based on the equivalent circuit model of the sensor system, the influence law of the induction coil resistance, inductance and distributed capacitance affected by the wire parameters was analyzed. The paper determines the parameter of the induction coil by orthogonal experiment which based on range analysis. According to the analyzed results, the sensor was made.The device of testing projectile velocity is designed.The experimental data of the firing test proved that the sensor meet the performance requirement. Compared with the coil target, the new sensor improved the signal to noise ratio and the measurement accuracy. Due to the advantages of stable performance and without environmental impact such as power source,.