弹丸锥形运动对半捷联稳定平台稳定性的影响分析

Analysis of the Effect of Projectile Conical Motion on the Stability of Semi-strapdown Stabilized Platform

为解决弹丸锥形运动的存在导致半捷联稳定平台摆动角速率增大的问题,对带动稳定平台发生摆动的轴承摩擦力矩变化规律进行分析。以SKF轴承摩擦力矩计算模型为基础,用龙格-库塔法对弹丸锥形运动情况下的轴承摩擦力矩进行仿真,结合文献[1]分析的稳定平台工作原理得到锥形运动情况下半捷联稳定平台摆动角速率的理论值。为了对理论分析验证,进行了地面半物理试验,将试验数据与理论仿真数据的频谱分析结果对比,发现二者都存在频率与幅值相一致的高低频段角速率,且低频角速率的频率恒定,高频角速率的频率与弹丸滚转角速率的频率一致。从而说明半捷联稳定平台摆动角速率的增加是由于弹丸锥形运动导致稳定平台俯仰角以及轴承所受压力发生变化,引起轴承摩擦力矩随弹丸滚转角速率同频变化,最终使稳定平台叠加高频角速率所致。

In order to solve the problem of that the swing angular velocity of the stabilized semi-strapdown platform is increased due to the coning motion of projectile,the variation law of friction torque of bearing driven by the semi-strapdown stabilized platform is analyzed. Based on the novel calculation model of SKF,the friction torque of bearing under the coning motion of projectile is simulated by the Runge-Kutta method. The theoretical value of swing angular rate of semi-stapdown stabilized platform under conical motion is obtained based on the working principle of the stabilized platform. The ground semi-physical test is conducted to verify the theoretically analyzed results. The experimental results are compared with the theoretically simulated results. It shows that there both exist high and low frequency angular rates whose frequency and amplitude are consistent,and the angular rate of low frequency is constant. The frequency of high frequency angular rate coincides with that of projectile roll angular rate. It indicates thatthe increase in the swing angular velocity of semi-strapdown stabilized platform is due to the changes of its pitch angle and the pressure on bearing resulting from the coning motion of projectile,which causes the friction torque of bearing to change with the roll angular rate of projectile at same frequency,and finally superimposes the angular rate of high frequency on the stabilized platform.