A Control Method of Projectile Spinning Speed Based on Magnetic Field Vector Transformation in a Railgun

This article studies the spinning speed control method of projectile in a railgun. The core idea is to adjust the current in extra rails to produce a controllable magnetic field and rotational torque. Then, the spinning speed and direction can be accurately controlled. Based on the Biot–Savart law, a model is established to analyze the rotating characteristics affected by the current waveform in the extra rails. Results show that this method is feasible since the spinning speed is linear and controllable. It can achieve a high speed to meet the fly spinning stability. It is also found that the increase of spinning speed is at the expense of muzzle velocity, and the launching system cannot achieve the maximum spinning speed and maximum muzzle velocity at the same time. The greater the energy given to the inner rails, the higher the muzzle velocity, and the faster the spinning speed. Without a large muzzle velocity, it may not achieve a high spinning speed. Finally, the influence of different parameters on the consistency of spinning speed is analyzed. The method proposed in this article can control the spinning speed accurately, which is of reference significance for the development of electromagnetic launch technology.