微小型无人直升机避障最优轨迹规划

针对无人直升机在低空复杂环境下避障飞行问题，提出了一种基于非线性最优控制理论的求解策略.以避障机动飞行时间为优化目标，无人直升机六自由度非线性动力学方程为等式约束，直升机飞行性能限制以及三维空间中障碍物限制等因素为不等式约束，建立了避障机动飞行的最优控制模型.然后利用高斯伪谱法（GPM，Gauss Pseudospectral Method）将轨迹规划问题转化为非线性规划（NLP，Non-Linear Programming）问题，并采用序列二次规划算法进行求解.在此基础上研究了障碍物尺寸对最优轨迹的影响.计算结果表明，该方法能够以较高的精度生成真实可行的避障飞行轨迹，最优机动动作取决于障碍物纵横向尺寸比.

Optimal trajectory planning for small-scale unmanned helicopter obstacle avoidance

Obstacle avoidance for unmanned helicopter safely flying in complex-low environments was investigated. A solving strategy based on nonlinear optimal control theory was developed. The computation of optimal obstacle avoiding maneuvers was viewed as an optimal control problem, where the solution minimized the maneuvering duration subjected to the 6-freedom nonlinear dynamics equations and limitations of helicopter flight performance, in which the obstacles in 3D space were formulated as inequality constraints by using 1-norms. Gauss pseudospectral method (GPM) was employed to transform the trajectory planning problem to non-linear programming(NLP) problem, which can be solved using a sequential quadratic programming algorithm. Moreover the influence of obstacles sizes to the planned trajectory was investigated. Simulation results show that the proposed method can generate feasible trajectories with high accuracy, and the optimal maneuver depends on the ratio of obstacle height and weight.