Velocity Precision Analysis With the Small Caliber Electromagnetic Launch

The armature between the two rails can get the huge electrical force by the high pulse driving current. It can be accelerated to high velocity within several ms. The high muzzle velocity is an advantage of the electromagnetic launcher. The precision has been researched in the developing of the rail gun for these years. The dispersity of the muzzle velocity is affected by static and dynamic parameters in the launching process, such as initial position, preload method and force, mass of the armature, driving current, the performance of the sliding electrical contact about the resistance and friction between the rails and armature, and so on. In order to study the precision of the velocity, some experiments have been done with the small caliber rail gun. The experimental setup and velocity measurement are described in detail. According to the analysis of the load and mass, it is obvious that the velocity can be affected by the armature mass. The whole launching consists of three phases: good electrical contact, pseudotransition, and slow transition. According to the product of muzzle voltage (U) and driving current (I), the loss is different in these phases, so the armature moving velocity may be changed largely. So the muzzle velocity precision can be controlled with a little change of the muzzle velocity. Finally, the results of different initial positions of the armature show that the armature initial position is a key parameter for the muzzle velocity.