Three-Dimensional Trajectory Optimization Design of Parafoil System Obstacle Avoidance Based on Switched System Method

摘要

We research on a problem for three-dimensional trajectory optimization design of parafoil systems obstacle avoidance. Since open-loop control lacks of robustness in practical engineering applications, to ensure the robustness of system, by devising a new piecewise state feedback controller, we convert previous problem to the closed-loop switched systems optimal control problem with state inequality restrictions. Due to the unknown switching instants and the existence of such restrictions, we have difficulty in handling this problem by employing classical optimization methods. To address faced dilemma, time-scaling transformation and smoothed penalty approach are applied. Finally, an unconstrained parameter optimization problem is derived, and an improved conjugate gradient algorithm is introduced for addressing this problem. Simulation experiment indicates proposed algorithm is valid, and a desired three-dimensional trajectory of parafoil is obtained and avoids terrain obstacles to reach the landing point more precisely.