【作者】 闫旭；

【导师】 孙兆伟；

【作者基本信息】 哈尔滨工业大学 ， 飞行器设计， 2010， 硕士

【摘要】 航天器进行轨道机动或转移往返于空间站与平台、卫星之间,它们的变轨可用冲量或连续推力方式,但是耗能比较大,而气动力辅助轨道转移可成为节省燃料的变轨方案。本文所研究的气动力辅助变轨方式由于有效的利用了航天器环绕星球上的大气这种自然资源,减少燃料消耗,从而使航天器获得了较大的有效载荷比。因此,研究气动力辅助变轨具有重要的意义。本文分析了气动力辅助变轨飞行器的特点,研究了影响气动力变轨过程中的因素,确定了升阻比和滚转角作为主要的控制参数,燃料最省作为目标。首先,建立了大气层内运动学微分方程,并对方程进行了简化和无量纲化处理。其次,在同面HEO-LEO的气动辅助变轨过程中,根据大气边界条件和最优目标确定性能指标,通过引入哈密顿函数,利用庞特里压金极大值方法,对性能指标进行分析,设计出关于升阻比的控制律,代入轨道运动学方程中进行最优控制。分别对升力系数受约束和不受约束两种不同情况进行仿真,并改变转移轨道近地点高度进行仿真。再次,在异面HEO-LEO的气动辅助变轨过程中,分别以升阻比和滚转角控制参数,进行控制律设计,在大气飞行段对轨道倾角进行寻优,分别对不同的轨道倾角进行仿真分析。最后,通过对同面辅助变轨和异面辅助变轨两种情况大量的仿真,分析了升力系数受约束和不受约对同面变轨的影响,同时分析转移轨道近地点高度对同面变轨的影响和轨道倾角的变化对异面变轨的影响,并与霍曼变轨进行对比,结果验证了本文算法的有效性和合理性。更多还原

【Abstract】 Spacecraft commit to maneuver or transfer to and from the space station, platform and the satellites with thrust impulse or continuous mode, but consuming large energy, while aeroassisted orbit transferring can be efficient program for fuel saving. By using the planet’s atmosphere surrounding this natural resource, the way of aeroassisted orbital transfer can reduce fuel consumption, which makes the vehicle gain a larger payload. Therefore, it is of great significance to study aeroassisted orbital transfer.This paper analyzes the characteristics of the aeroassisted orbital transfer vehicle, studies the influence factors in orbit transferring, identifies lift-to-drag ratio as the main control parameters, minimum fuel consumption as the target. First, to establish the atmospheric kinematics equations and the equations have been simplified and non-dimensional quantities.Second, with the process of the coplanar HEO-LEO aeroassisted orbital transfer, according to atmospheric boundary conditions and the optimal target it determines performance index, this paper analyzes performance index by introducing the Pontryagin maximum method and using the Hamiltonian function, it obtained the optimal control law of the lift coefficient, which is substituted into orbit kinematics control law equation, to commit the optimal control. To simulate when the lift coefficient is fettered and unfettered respectively, and change the transfer orbit perigee altitude to simulate.Third, with the process of the nonplanar HEO-LEO aeroassisted orbital transfer, this paper designs the control law with the control parameters of the lift-drag ratio and roll angle. To find good of the orbital inclination in atmospheric flight segment, it is to simulate when the orbital inclination is different.Finally, with a large number of optimization simulation experiments on both of the coplanar and nonplanar orbit transfer, this paper analyzes the impacts of the lift coefficient when it is fettered and unfettered respectively, and analyze the impacts of transfer orbit perigee height to the coplanar orbital transfer and the orbit inclination changes to the nonplanar orbital transfer, it presents the verification of the algorithm effective and reasonable.更多还原