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对于一大类时间最省(单次推进)和燃料最省(多次推进)的中等推力水平持续推进地球轨道转移问题,本文给出了一种系统的直接优化方法。首先,对于具有倾角和偏心率的目标轨道,我们介绍了一种惯性坐标转换方法得到更具一般性的末端约束条件。这个转换避免了逆行赤道轨道对春分点轨道根数引起的奇异,同时也提高了求解优化问题的收敛性。多次打靶法在本文中也得到了应用,给出了针对不同形式的轨道转移如何分配多次打靶变量的方法。基于惯性坐标转换和多次打靶法,最优控制问题转换为利用非线性规划法求解的参数优化问题。本文给出了单次推进时间最省以及多达12次推进燃料最省的轨道转移仿真结果,所有收敛结果均以简单定义的初值迭代得到。最后,我们讨论了利用模型预测控制进行自主制导的潜在方案。
For a large class of middle-lift levels with the most time-saving (single-propulsion) and fuel-saving (multiple propulsion) levels, the system directly optimizes the orbit transfer problem. First, for a target orbit with dip and eccentricity, we introduce a more general end-of-pipe constraint on the inertial coordinate transformation method. This conversion avoids the singularities caused by the retrograde equatorial orbit at the vernal equinox orbit number, and also improves the convergence of the solution to the optimization problem. Multi-shot method has also been applied in this paper, given how to assign multiple shooting variables to different types of orbital transfer. Based on the inertial coordinate transformation and multiple shooting methods, the optimal control problem is transformed into the parameter optimization problem solved by nonlinear programming. This paper presents the simulation results of the orbital transfer with the single least propulsion time and up to 12 propulsion fuels. All the convergence results are obtained by iteratively starting with a simple definition. Finally, we discuss potential solutions for autonomous guidance using model predictive control.