自转旋翼机的纵向稳定性研究

Research of Autogyro Longitudinal Stability Characteristics

为研究自转旋翼机的纵向稳定性,首先应用配平分析法求出各个飞行状态的旋翼转速,求出转速后用列文伯格-马夸尔特算法对旋翼机的姿态和操纵进行配平,得到各个飞行状态的姿态角和操纵量。运用五点中心差分法求纵向稳定导数,从而得到状态矩阵以及纵向运动模态,然后建立旋翼机纵向稳定性分析模型,利用所求得的一些模态分析旋翼机的稳定性。研究结果表明,旋翼转速随前飞速度的变化不明显,旋翼机的操纵主要是纵向的,旋翼转速主要取决于桨盘的倒角;在速度范围内,除了旋翼转速模态,旋翼机的其他纵向模态是稳定的,旋翼自由度与旋翼机机体存在耦合,重心相对推力线的垂直位置对稳定性有明显的影响,重心位于推力线上方具有更好的稳定性。

To investigate the longitudinal stability of gyroplane, a method of trim analysis was to solve the rotorspeed in primarily. Then, the Levenberg-Marquardt algorithm was applied to gyroplane＇ s trim, thus acquire the gyroplane＇ s attitude and manipulated variable. The five center difference method was used for the longitudinal stability derivative, so that we can get the state matrix and the longitudinal modes, then the analysis model of the gyroplane＇ s longitudinal stability was established and was used to research the gyroplane＇ s stability. The results indicate that the change of rotorspeed is not obivious.The manipulate of gyroplane is longitudinal mainly, and the rotorspeed depend on rotor disc＇ s chamfer largely. Except rotorspeed modes, the other longitudinal modes are stability in range speed, and the degree of rotorspeed is coupling with the body degrees of freedom. In a word, the center of gravity relative thrust line of vertical position has obvious influence on the stability, center of gravity is above in the line of thrust have better stability.