minimum-time approach to obstacle avoidance constrained by envelope protection for autonomous uavs

  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 a rotary wing test bed within the georgia tech unmanned aerial vehicle simulation tool (gust) is used to evaluate the proposed approach.