Quadrotors in Smart Cities Avoiding Helicopters

Drones are the first robots to arrive in smart cities, and collision avoidance with helicopters is among the first barriers to widespread drone use. In this paper, we develop control designs and vehicle models to analyze collision avoidance between quadrotors and helicopters, and use them to derive the ranges required for sensing or communication radios used for collision avoidance. The models account for rotational inertia and drag. Our controllers consider both horizontal and vertical avoidance strategies and show that the vertical avoidance strategy can be better than the horizontal one, though it does entail a loss of altitude. Preliminary use of our models show that at one second delays, communication and sensing ranges need to be about 500 m, which is viable for communication radios on small drones but challenging for lightweight radar or lidar.