A High Reliability 3D Scanning Measurement of the Complex Shape Rail Surface of the Electromagnetic Launcher

Abstract

After an electromagnetic railgun launch, a series of damage phenomena may cause the inner bore surface to become complex, such as gouging and deposition. Furthermore, the rail surface will be uneven and blackened by oxidation. To understand these forms of rail degradation, many previous studies have mentioned several surface scanning methods, but none of these can be used in the complex inner bore. Therefore, we present a 3D scanning system based on binocular stereovision technology combined with the active illumination, which can be used to obtain the rail surface topography under a complex inner bore environment. The laser dot projection is applied as the active illumination. In contrast with other active illumination, laser dot projection has high reconstruction reliability. By combining laser dot projection with binocular stereovision, the object can be completely reconstructed. In addition, an image acquisition method which can improve image signal-to-noise ratio is proposed. The proof-of-principle experiment of the system is done under dim light conditions. Through the experiment, the 3D depth map of the rail surface is obtained and the gouge crater is scanned out. Meanwhile, system evaluation and measurement uncertainty analysis have also been carried out.

Investigation of the Distribution Problem in the Operating State of an Electromagnetic Railgun: Radio Fuse Disturbance, Field Characteristics, and Susceptible

“…From a quantitative perspective, based on the mechanism of the pulse discharge generated by the breakdown and the accompanying characteristic phenomena of pulse discharge described above, discharge at extremely high voltage belongs to the type of spark discharge [12], generating discharge voltage pulses with a width of ns. Based on the basic characteristics of spark discharge and the gap breakdown characteristics of high voltage [13][14][15][16][17], we have determined that the time-domain width of the generated nanosecond width discharge pulse is within tens of nanoseconds (20-60 ns), with a characteristic value of 40 ns. Spark discharge is based on the streamer theory.…”

Numerical 3D Simulation of a Full System Air Core Compulsator-Electromagnetic Rail Launcher

“…The current flowing in the rails (and in the armature) produces a flux density distribution in correspondence of the armature, where the interaction with its current produces a thrust force that accelerates the armature. The main drawbacks affecting the rail launchers are a consequence of the Velocity Skin Effect (VSE) which is caused by the limited diffusion rate of the current in the rails as the armature moves; VES produces a concentration of the current in the rear portion of the armature near the rails [15][16][17][18]. The importance of VSE increases with the speed and it is one of the causes which may prevent the use of rail launchers at very high speed.…”