Minimum-time Approach to Obstacle Avoidance Constrained by Envelope Protection for Autonomous UAVs
Jongki Moon, J. V. R. Prasad · 2009
An integrated approach is needed for combining path planning for obstacle avoidance with envelop protection to ensure that a UAV is operated within its safe operational limits while maneuvering in obstacle fields. This paper presents a minimum-time approach to this problem by treating obstacle avoidance and envelope protection as inequality constraints in a state space formulation. The approach is used to study the guidance of a rotary wing UAV for aggressive maneuvering in avoiding an obstacle while staying within its operational envelope. The Nonlinear trajectory generator (NTG) is used as a real-time optimization solver, and load factor and rotor flapping angle are considered as limit parameters. A nonlinear simulation model of the GTMax rotary wing test bed within the Georgia Tech Unmanned Aerial Vehicle Simulation Tool (GUST) is used to evaluate the proposed approach.