Hurdle-Hop Simulation of Tilt-Rotor Aircraft Based on Optimal Control Theory

Jinhe Chen,Hongyuan Tian,Zhengzhong Wang

doi:10.1051/jnwpu/20203861266

Abstract

Aiming at simulating the hurdle-hop of tilt-rotor aircraft in forward flight near the ground, two models of numerical simulation and analysis based on optimal control theory were proposed. Firstly, Longitudinal flight dynamic model for tilt-rotor was modified considering the influence of ground effect. Secondly, the first model is combined with predicted trajectory from inverse simulation method, the inverse model of hurdle-hop of tilt-rotor is established based on optimal trajectory, and the second model is the optimal control model of unpredicted trajectory, which is formulated from the reasonable function of objective, path and boundary constraints for hurdle-hop with detailed analysis, solved two models by direct multiple shooting method and nonlinear programming algorithm. Finally, XV-15 as the sample vehicle. Two models for hurdle-hop based on optimal control theory was calculated, the history of optimal flight trajectory and control are given.

Highlights

线性的代数方程组,直接求解此代数方程组就可得到未知量,该方法是由 Thomson 和 Bradley[8] 率先提出,随后 WHalley[9] 利用该方法进行了人在环的飞行仿真研究。积分方法,在每个时间步长上初始状态和控制量已知,基于 Newton 迭代或优化算法消除时间步长末端的预定轨迹和计算轨迹误差,该方法由 Hess[10] 提出。
Hurdle⁃Hop Simulation of Tilt⁃Rotor Aircraft Based on Optimal Control Theory
Aiming at simulating the hurdle⁃hop of tilt⁃rotor aircraft in forward flight near the ground, two models of numerical simulation and analysis based on optimal control theory were proposed

Summary

Introduction

线性的代数方程组,直接求解此代数方程组就可得到未知量,该方法是由 Thomson 和 Bradley[8] 率先提出,随后 WHalley[9] 利用该方法进行了人在环的飞行仿真研究。积分方法,在每个时间步长上初始状态和控制量已知,基于 Newton 迭代或优化算法消除时间步长末端的预定轨迹和计算轨迹误差,该方法由 Hess[10] 提出。轨迹优化方法,考虑飞行器整个运动过程的飞行轨迹,Lee 和 Kim[13] 将逆仿真问题转化为等式约束的最优控制问题。 Celi[14⁃15] 提出了基于最优化理论的逆解方法,以飞行轨迹或机动约束( 限制条件) 建立无约束增广目标函数最优控制模型,该方法的优势在于不依赖于既定的飞行轨迹和具有良好的通用性,但对于路径中的约束处理偏弱。水平位移;h 为高度;Iy 为倾转旋翼机俯仰惯性距; FxR,FzR 和 MyR 分别为旋翼纵向、垂向的力和俯仰力矩;Ff ,FW ,FHT ,FVT 和 Mf ,MW ,MHT ,MVT 为机身、机翼、平尾、垂尾的气动力和力距;m 为倾转旋翼机总部件的气动力和力矩系数来自于 XV⁃15 的吹风数据[23] 。图 6 给出了 4 种跃障飞行过程中的倾转旋翼机需用功率 Pr 曲线,从图中可以看出,预定轨迹方式随着飞行完成时间 T 的减小,倾转旋翼机的需用功率的峰值在增加,甚至超出倾转旋翼机发动机的输出功率 Pmax,如需进一步考虑功率限制,则 XV⁃15 倾转旋翼机完成跃障飞行需至少 12 s。

Results

Conclusion