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Electromagnetic coil launcher (ECL) is a specific application of electromagnetic launching technology and has broad prospects in the fields of new weapon systems and launching microsatellites. The acceleration force of the projectile in the ECL depends on the current of the driving coil and the projectile together with the mutual inductance between them, and to maximize the launch coefficient, each drive coil should be energized according to the projectile’s movement position. In order to realize the closed-loop control of the ECL and improve the energy utilization, a new position detection system (PDS) based on fiber optic sensor (FOS) is designed in this article, which can obtain the armature displacement and velocity in real time during the launch process. Then, the main factors influencing the detection results are analyzed and studied. Finally, after experimental verification, the PDS designed in this article has an error of 4.2% and 1.41% in the measurement of the armature position and velocity, respectively. The results are of great significance to the realization of ECL engineering. [ABSTRACT FROM AUTHOR]

A mathematical electromechanical model of the multistage induction coil launcher was established based on the current filament model. According to the model, the armature force is determined by the current of the drive coil and the armature together with the mutual inductance gradient between them. Except that the current waveform of the drive coil is determined by the given electrical parameters, the current waveform induced by the armature and the mutual inductance gradient waveform is determined by the position of the drive coil and armature. Therefore, after simulating and comparing, the acceleration performance and efficiency of the matching situation of drive coil current waveform and the mutual inductance gradient waveform can be obtained under limit conditions, and the following results are concluded: 1) the current pulse time is much longer than the mutual inductance gradient time and 2) the current pulse waveform is much smaller than the mutual inductance gradient waveform. Therefore, the current pulse time shall be consistent with the mutual inductance gradient time to achieve smoother acceleration curve and higher efficiency. According to the above-mentioned principles, the current pulse time and mutual inductance gradient time were calculated quantitatively, and the position of drive coil and armature were considered; thus, the armature trigger formula of the multistage induction coil launcher was given, which would lay a theoretical foundation for the performance optimization of the multistage induction coil launcher. [ABSTRACT FROM AUTHOR]