Small Caliber Barrel Straightness Test System

The processing technology and metal smelting directly affects the straightness of the gun barrel, In addition, in the course of the collision, rapid changes of temperature and other factors also make the gun barrel unrecoverable bent. If the degree of bending was lighter, it will affect the gun barrel’s firing precision. If the degree of bending was sharper, it will affect the shells in flight and cause the gun barrel scrapped. At worst, it will cause explosion in bore. Therefore, the straightness of the gun barrel must be high precision detected. This paper designed a perfect straightness measurement system of gun tube.The measurement system used a position sensing detector (PSD) as sensors to measure the linearity of a minor-caliber tube. First, this paper describes the design of hardware system. By comparing the advantages and disadvantages of all hardware, appropriate components are selected. Part of the components must be assembled and fixed. Then a software system is designed for the test system using LabVIEW programming language. The software system mainly used to collect the coordinates of PSD signal, which includes of a series of content, like human-computer interaction, testing, data processing and display. Last, this paper uses five methods to evaluating the straightness error, which are two endpoints link line algorithm, least square algorithm, pole searching algorithm, subdivision approximating algorithm and convex polygon algorithm. From the data of the PSD coordinate, it obtains the last result of straightness error evaluation. Besides, this paper also analyzes the cause of the error, and gives measures to reduce the error.The related experiment shows that all the technique targets of this straightness measurement system of gun tube meet the performance demands. The method can meet tangible needs; carry out rabid and accurate measurement.