Research on the inner bore profile detecting system of railgun

•Measuring the inner bore profile of the railgun based on non-contact method.•The three-dimensional inner bore profile can be measured online.•Achieving the location of the azimuth and the origin.•Realizing the precise point positioning of axial displacement. In the process of electromagnetic launching, there is much inner damage containing wear, corrosion, gouging, and transition in the rail. After several launchings, the damage has an enormous influence on the accuracy of launching and rail lifetime. In order to protect the rail and research on the damage mechanism, this paper provides an insight into the methods of measuring the inner bore of the electromagnetic rail launcher based on the optical vision measurement principle. Applying this optical method, the apparatus is designed and divided into three subsystems. These three subsystems provide global alignment information, the axial depth information, and inner surface profile information respectively. In this way, the 3D model of the rail can be precisely rebuilt. The feasibility of the method was confirmed in the experiment. And this method may have significant implications for the further research on the on-line measurement of electromagnetic rail launchers.