Unravelling quadcopter frame dynamics: A study on vibration analysis and harmonic response

Abstract

Quadcopters are widely used rotorcraft members of UAV family. Since they have four motors and four propellers, they are exposed to dynamic loads and vibratory motion. This study presents vibration analysis of a well-known F450 quadcopter frame. Modal analysis was performed to identify the natural frequencies and mode shapes, followed by harmonic response analysis to observe the dynamic behaviour under a periodic force. Harmonic response analysis frequency range covered all critical frequencies obtained by modal analysis. Two additional axes in addition to hovering direction were considered in order to simulate propeller imbalance case. Numerical solution of analysis was performed by finite element method. Critical frequencies were examined in terms of motor angular velocities and compared with real life motor rpm values.