Research And Realization Of Test Control Technology For Air Tightness Test Bench

In short-range air-to-air missiles,most of them use pneumatic steering gear,which uses highpressure air as air source to control the movement of the rudder surface.Therefore,the air tightness of steering gear is one of the factors affecting the quality and performance of the missile.The process of quantitative air tightness detection method is to fill high pressure gas into the measured parts,and then hold the pressure for a certain time.The leakage amount is calculated by the change of the gas pressure in the measured parts before and after the pressure is held,so as to achieve the purpose of the air tightness detection of the tested parts.Therefore,in the quantitative air tightness detection method,the main problem lies in the measurement of the pressure change before and after pressure preservation of the tested parts.Because of the influence of environmental temperature,inflation process and other factors,how to improve the measurement accuracy of the pressure change before and after pressure preservation of the tested parts is a key engineering problem.In this paper,based on the reference of air tightness testing equipment at home and abroad,analyzes the direct pressure and differential pressure air tightness detection principle and process,by means of the differential pressure tightness test method to establish the charge process and pressure maintaining process simulation mathematical model,the measured piece at the time of high voltage test,the change rule of temperature and pressure in the understanding of the main factors that affected the accuracy of detection.the method of differential pressure air tightness detection is adopted to design and implement the embedded air tightness detection platform from the two aspects of leak judgment and leak detection,including the design of differential pressure air tightness detection pipeline,embedded hardware control system and upper computer air tightness detection software.When the leakage is obvious and the pressure holding process exceeds the range of the differential pressure sensor,the detection platform will give the detection result of the leakage of the tested part qualitatively.When the leakage is small,the testing platform will give a quantitative amount of leakage.The joint commissioning results show that the designed air tightness detection platform can effectively detect leakage,with a resolution of 1Pa and a repetition accuracy of 1.542KPa/3σ.