Optimal trajectory planning for small-scale unmanned helicopter obstacle avoidance
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摘要: 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.Abstract: 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.
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[1] Pettersson P O, Doherty P.Probabilistic roadmap based path planning for an autonomous unmanned helicopter[J].Journal of Intelligent and Fuzzy Systems, 2006, 17(4):395-405 [2] 于振中, 闫继宏, 赵杰, 等.改进人工势场法的移动机器人路径规划[J].哈尔滨工业大学学报, 2011, 43(1):50-55 Yu Zhenzhong, Yan Jihong, Zhao Jie, et.al.Mobile robot path planning based on improved artificial potential field method[J].Journal of Harbin Institute of Technology, 2011, 43(1):50-55(in Chinese) [3] Tsenkov P, Howlett J K, Whalley M, et al.A system for 3D autonomous rotorcraft navigation in urban environments[R].AIAA 2008-7412, 2008 [4] 梁宵, 王宏伦, 李大伟, 等.基于流水避石原理的无人机三维航路规划方法[J].航空学报, 2013, 34(7):1670-1681 Liang Xiao, Wang Honglun, Li Dawei, et al.Three-dimensional path planning for unmanned aerial vehicles based on principles of stream avoiding obstacles[J].Acta Aeronautica et Astronautica Sinica, 2013, 34(7):1670-1681(in Chinese) [5] Hurni M A, Sekhavat P, Ross I M.Autonomous path planning using real-time information updates[R].AIAA 2008-6305, 2008 [6] Moon J, Prasad J V R.Minimum-time approach to obstacle avoidance constrained by envelope protection for autonomous UAVs[J].Mechatronics, 2011, 21(5):861-875 [7] Koo T J, Sastry S.Output tacking control design of a helicopter model based on approximate linearization[C]//Proceedings of the 37th IEEE Conference on Decision & Control.Tampa:IEEE, 1998:3635-3640 [8] Gavrilets V, Mettler B, Feron E.Nonlinear model for a small-size acrobatic helicopter[R].AIAA 2001-4333, 2001 [9] Gatzke B T.Trajectory optimization for helicopter unmanned aerial vehicles[D].Monterey:Naval Postgraduate School, 2010 [10] 陈功, 傅瑜, 郭继峰.飞行器轨迹优化方法综述[J].飞行力学, 2011, 29(4):1-5 Chen Gong, Fu Yu, Guo Jifeng.Survey of aircraft trajectory optimization methods[J].Flight Dynamics, 2011, 29(4):1-5(in Chinese) [11] Benson D.A Gauss pseudospectral transcription for optimal control[D].Bostom:Massachusetts Institute of Technology, 2004 [12] Gill P E, Murray W, Saunders M A.SNOPT:an SQP algorithm for large-scale constrained optimization[J].Society for Industrial and Applied Mathematics, 2005, 47(1):99-131
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