研究蜜蜂悬停飞行的控制问题。用数值求解N-S方程的方法计算拍动翅体的控制导数;用特征模态分析方法分析控制特性。文中δu,δw,δq和δθ分别为水平方向速度,垂直方向速度,俯仰角速度和俯仰角度的扰动量;δΦ和δφ^-为拍动幅度和拍动平均角增量;δα1表示上、下拍迎角同时增加的增量;δα2表示下拍迎角增加(或减小)而上拍迎角减小(或增加)的增量。获得以下结果:(1)悬停飞行时,改变Φ和α1主要产生垂直力的变化;改变φ^-主要产生俯仰力矩的变化;改变α2主要产生水平力及俯仰力矩的变化。(2)蜜蜂悬停飞行的纵向扰动运动由3个特征模态构成:不稳定振荡模态,快衰减模态和慢衰减模态;为实现稳定的悬停飞行,不稳定振荡模态和慢衰减模态需要控制。为控制不稳定振荡模态,以δφ^-(或δα2)反馈δu,δq和δθ这3个量的某种组合便可;为控制慢衰减模态,以δΦ(或δα1)反馈δw便可。这就是说,该昆虫只需用控制变量δΦ和δφ^-(或δΦ和δα2,δα1和δφ^-,δα1和δα2),便可稳定地悬停(当然也可4个控制变量都用)。
The stabilization control of the longitudinal motion of a hovering honeybee is studied using the method of computational fluid dynamics to compute the control derivatives and the modal decomposition method to analyze the control properties. At hovering flight, a change in the stroke amplitude (δФ), or an equal change in the geometrical angles of attack of the down- and upstrokes (δα1) , mainly produces a change in vertical force, a change in the mean stroke angle (δφ^-) mainly produces a change in pitching moment, and a differential change in the geometrical angles of attack of the down- and upstrokes (δα2) mainly produces changes in pitching moment and horizontal force. The hovering flight can be stabilized by feeding back δu, δq and δθ to produce δφ^- or δα2 (δu, δw, δq and δθ represent the disturbances in horizontal velocity, vertical velocity, pitching rate and pitching angle, respectively).