  Unmanned aerial vehicles (UAVs), specifically quadrotors, have revolutionized
various industries with their maneuverability and versatility, but their safe
operation in dynamic environments heavily relies on effective collision
avoidance techniques. This paper introduces a novel technique for safely
navigating a quadrotor along a desired route while avoiding kinematic
obstacles. We propose a new constraint formulation that employs control barrier
functions (CBFs) and collision cones to ensure that the relative velocity
between the quadrotor and the obstacle always avoids a cone of vectors that may
lead to a collision. By showing that the proposed constraint is a valid CBF for
quadrotors, we are able to leverage its real-time implementation via Quadratic
Programs (QPs), called the CBF-QPs. Validation includes PyBullet simulations
and hardware experiments on Crazyflie 2.1, demonstrating effectiveness in
static and moving obstacle scenarios. Comparative analysis with literature,
especially higher order CBF-QPs, highlights the proposed approach's less
conservative nature. Simulation and Hardware videos are available here:
https://tayalmanan28.github.io/C3BF-UAV/
