Stabilization control of a hovering model insect: lateral motion

Abstract

Our previous study shows that the lateral distur- bance motion of a model drone fly does not have inherent stability (passive stability), because of the existence of an un- stable divergence mode. But drone flies are observed to fly stably. Constantly active control must be applied to stabilize the flight. In this study, we investigate the lateral stabiliza- tion control of the model drone fly. The method of compu- tational fluid dynamics is used to compute the lateral control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that al- though inherently unstable, the lateral disturbance motion is controllable. By feeding back the state variables (i.e. lateral translation velocity, yaw rate, roll rate and roll angle, which can be measured by the sensory system of the insect) to pro- duce anti-symmetrical changes in stroke amplitude and/or in angle of attack between the left and right wings, the motion can be stabilized, explaining why the drone flies can fl ys ta- bly even if the flight is passively unstable.