Research on the energy control law of universal electromagnetic launch

• Novel 3-stage electromagnetic launch models analyze energy-mass relationship. • System efficiency peaks then declines with mass under fixed input energy. • Constant stage efficiencies (33%, 50%) achieved at fixed exit velocity. • Clear projectile mass-input voltage relation enables velocity control. • Input voltage adjustment maintains constant velocity across varied masses. Under the background condition of universal electromagnetic launch, to obtain the variation law of input energy when the mass of the projectile varies, mathematical models of three 3-stage systems, namely sleeve armature, induction coil armature, and direct-feed coil armature, were established. Through numerical calculation, the variation of the first stage output efficiency of the system within the effective mass range of 0 kg-85 kg was analyzed and studied. Assuming a constant exit velocity of 45 m/s, the initial voltage of the capacitor corresponding to different projectile masses in the direct-feed coil armature system was solved through experimental methods. Based on the experimental data, the relationship between input voltage and projectile mass was determined, and the accuracy of the relationship was further verified through experiments. The data showed that under constant input energy conditions, the output efficiency of the system first increases and then decreases with changes in mass. Under constant exit velocity conditions, the first stage and second stage efficiencies of the direct-feed coil armature system remain constant at 33% and 50%, respectively. The relationship between input voltage and projectile mass is clear and accurate. It is proven that under constant energy conditions, the larger the mass, the lower the output efficiency. Under constant exit velocity conditions, the system has a constant overall efficiency, and the input energy can be controlled by controlling the input voltage, thereby controlling the projectile with different masses to have a constant exit velocity.