中文摘要：

大口径火炮输弹过程中弹丸卡膛行程不一致会导致火炮发射药室容积、弹丸起动压力差异，影响火炮射击初速和射击精度。为了提高某臂式自动输弹机的弹丸定位精度，首先通过高速摄影发现弹丸在人膛后会产生在重力方向的振动，消耗弹丸动能造成卡弹力不一致。通过分析臂式输弹机工作机理，明确输弹过程中各个部件的运动关系，对输弹机构在静止状态和运动状态进行受力分析，确定造成弹丸振动激励源的位置，利用激光位移传感器测试了该点振动的幅值及频率。最后提出了输弹机的改进方案以消除振动对输弹稳定性的影响。

英文摘要：

During the ramming process of large caliber gun, the inconsistency of bayonet-chamber process will cause difference about the volume of gun emission＇s anther chamber and the starting pressure of projectile,which can affect projectile＇s firing initial velocity and accuracy. In order to improve the positioning accuracy of automatic ramming mechanism＇s projectile,firstly,we use the high speed photography to find out that after the projectile was pushed into chamber, it will cause vibration along gravity direction. The vibration leads to inconsistency of the jamming of cartridge force by consuming some projectile＇s kinetic energy, through analyzing about the working mechanism of arm type ramming device,we not only can clearly understand the motion relationship of all parts in ammunition ramming process, but also we can carry out the force analysis about the static or dynamic feed transfer mechanism. So we can pinpoint the position of excitation source which cause the projectile＇s vibration. Furthermore,we can find out the position＇s amplitude and frequency with the help of laser displacement sensor. At last,we will propose a improvement scheme which can eliminate the influence of vibration on stability of ramming mechanism.