The research of the detecting the armature position in the electromagnetic launcher bore

In order to optimize the performance of the rapid fire rail gun, it is necessary to detect the armature position in the real time. The B-dot probe is the basic method to detect the armature position in the bore. The induced voltage signal of the probe is generated by the current of armature. This signal is affected with the current and velocity of the moving armature. The probe is invalid for the discontinuous current in the rapid fire rail gun. So another measurement should be developed. Some laser detectors are installed in the insulator along the armature moving direction. The output signal of the optical receiver is rising when the armature arrives at the laser position. So the velocity can be calculated by two signals. In the same time, the signal can be used as the control signals by shaping in rapid fire rail gun. The detecting principle, hardware portion of the system is described in this paper. The test results show that this system can detect the armature position and the response time is less than 216ns. The output signals can be used as the real time control signals.