Navigation of an unmanned helicopter in urban environments

When employing autonomous vehicles, it is desirable to use controllers which can be rigorously shown to always ensure safety is maintained. In this manuscript we compare two approaches for the problem of navigation through environments containing obstacles. The first uses boundary following to maintain an avoidance distance to obstacles, and the second uses a MPC-type algorithm to plan short range trajectories around detected obstacles, while ensuring the vehicle can be brought to a halt within the sensor radius. The controllers are subjected to analysis for robustness, and simulations are carried out with both a simple second order linear model and a realistic helicopter model for verification. The controller that planned ahead was found to give significantly better trajectories.