The effects of dihedral angle on hover rigidity and planar maneuvers in rotary-wing UAVs

Abstract

Purpose Any consensus about the effects of dihedral angle on hover rigidity of rotary-wing unmanned aerial vehicles (RW-UAVs) does not exist in the literature. There are researchers who state that the dihedral angle has an effect on flight stability and researchers who claim the opposite. The discord stems from the different approaches of these groups to the concept of “stability,” the fact that they conduct experiments whose measurements are largely influenced by environmental conditions, and the physical assumptions are not similar. On the other hand, there is no study examining the effect of dihedral angle on the maneuverability of drones either. This study aims to analytically reveal the consequences of dihedral angles in RW-UAVs in terms of flight agility and maneuverability. Design/methodology/approach Dihedral angle examinations on both hover rigidity and maneuverability are carried out analytically. Equations of motions for a multicopter’s rigid body with a dihedral angle under two different conditions (zero and nonzero dihedral angles) are derived. Numerical simulations are conducted by defining the simulation parameters, and then displacement graphics for the center of mass are interpreted. Findings The presence of a dihedral angle makes the multicopter platforms behave like a pendulum, and this pendulum motion affects the disturbance rejection and the planar maneuver capabilities of multicopters. Since deflections can be spread to the orthonormal axes thanks to rotation about a pivot, net deflections of the geometric center may be diminished. Besides, pendulum motion eases the maneuvers with yaw rotations since the required rotation might occur without rotors’ revolution per minute changes. Practical implications Proposed dihedral angle implementation may enhance the hover stiffness and maneuverability capabilities of multicopters which, in turn, raise the performance of the drones. Originality/value This paper presents the analytical basis for the dihedral angle's effects on flight stability and agility.