熊蜂用于控制飞行的气动力和力矩

Control of Flight Forces and Moments by the Flapping Wings of a Model Bumble-bee

采用计算流体力学方法研究熊蜂用于控制飞行的气动力和力矩.结果表明,悬停时,每1个翅膀运动参数主要控制1个或2个气动力和力矩.当左右翅运动学参数对称变化时,改变拍动幅角(或拍动频率)主要可使垂直力改变.改变平均拍动角主要可使俯仰力矩改变.改变拍动攻角,上拍和下拍攻角等值同向变化时,主要可使垂直力改变;等值反向变化时,主要可使水平力改变.改变转动模式,当翅膀前拍靠近昆虫腹部和后拍靠近昆虫背部的转动模式相同变化时,主要可使垂直力改变;当翅膀前拍靠近昆虫腹部和后拍靠近昆虫背部的转动模式相反变化时,主要可使水平力和俯仰力矩改变.改变转动时间对气动力和力矩几乎无影响.当左右翅运动学参数反对称变化时,改变拍动幅角(或拍动频率)主要可使滚转力矩改变.改变拍动攻角,上拍和下拍攻角等值同向变化时,主要可使滚转力矩改变;等值反向变化时,主要可使偏航力矩改变.改变转动模式,当翅膀前拍靠近昆虫腹部和后拍靠近昆虫背部的转动模式相同变化时,主要可使侧向力和滚转力矩改变;当翅膀前拍靠近昆虫腹部和后拍靠近昆虫背部的转动模式相反变化时,主要可使偏航力矩改变.改变翅膀运动参数可分别控制3个方向的力矩及垂直力.改变拍动角可以改变垂直力;改变拍动角的平均位置可以改变俯仰力矩;反对称改变左右翅的拍动攻角可以改变滚转力矩;反对称改变拍动起始时刻可以改变偏航力矩.通过对翅膀运动参数的适当调整熊蜂即可实现快速转弯飞行.

The control of flight forces and moments by the flapping wings of a model bumble-bee is studied using the method of computational fluid dynamics. Hovering flight was taken as the reference flight： wing kinematic parameters are varied with respect to their values at hovering flight. Moments about （and forces along） x, y, z axes that pass the center of mass were computed. Changing stroke amplitude （ or wingbeat frequency） mainly produces a vertical force. Changing mean stroke angle mainly produces a pitch moment. Changing wing angle of attack, when down- and up-strokes having equal change, mainly produces a vertical force, and when down- and up-strokes having opposite changes, mainly produces a horizontal force and a pitch moment. Changing wing rotation timing, when dorsal and ventral rotations having the same timing, mainly produces a vertical force, and when dorsal and ventral rotations having opposite timings, mainly produces a pitch moment and a horizontal force. Changing rotation duration has very small effect on the forces and moments. Anti-symmetrically changing stroke amplitude （or wingbeat frequency） of the contralateral wings mainly produces a roll moment. Anti-symmetrically changing the angles of attack of the contralateral wings, when down- and up-stroke having equal change, mainly produces a roll moment, and when down- and up-stroke having opposite changes, mainly produces a yaw moment. Anti-symmetrically changing wing rotation timing of the contralateral wings, when dorsal and ventral rotations having the same timing, mainly produces a roll moment and a side force, and when dorsal and ventral rotations having opposite timings, mainly produces a yaw moment. Vertical force and moments about the three axes can be separately controlled by separate kinematic variables. Very fast rotation can be achieved with moderate changes in wing kinematics.