A Fuzzy Approach to the Guidance of Unmanned Air Vehicles Tracking Moving Targets

This paper presents the development of a fuzzy guidance system for unmanned aircraft based on waypoints described in a 5-D space: position in 3-dimensions, desired crossing heading, and speed. The aircraft is assumed to be auto piloted in speed, heading, and flight path angle. The proposed system uses standard Takagi-Sugeno fuzzy controllers that provide speed, heading, and flight path angle references for the autopilots. In particular, the heading guidance law results in a pipeline of two fuzzy controllers depending on the relative distance between aircraft and waypoint. A trajectory optimization algorithm is used to yield a long-distance guidance law blended with a short-distance guidance law as the waypoint approaches. The system handles sets of not directly flyable waypoints, driving the aircraft on flyable trajectories that try to cross the waypoints at a prescribed altitude and heading.