【作者】 郭鹏；

【导师】 秦子增；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2012， 博士

【摘要】 回收着陆过程对航天器回收系统的安全性和可靠性提出了很高的要求。降落伞作为回收系统的重要组成部分，在设计时必须对其工作性能进行全面的分析与评定。本文以航天器回收系统降落伞为研究对象，针对大型伞充气过程及伞舱盖弹射分离后拉伞包过程进行研究，主要研究内容如下：针对大型伞空投试验地面录像的特点，提出了一种模块化的录像分析方法。通过分析，得到了大型伞拉直过程伞绳伞衣非直线的运动特征，明确了伞衣拉出过程中的“无控”状态以及伞包与返回舱之间较大的速度差是拉直结束后伞衣顶部出现剧烈横向运动的主要原因。采用录像分析方法，首次得到了大型伞拉直结束后伞衣顶部运动信息，大型伞充气过程伞衣投影面积变化曲线以及物伞系统姿态变化信息，为大型伞开伞过程的理论研究及工程设计改进提供了重要的数据。针对空投试验舱上录像特点，提出一种通过伞衣外部轮廓求解投影面积的录像分析方法。在对伞衣轮廓中受遮挡及缺失部分进行识别并恢复后，采用封闭轮廓计算录像中伞衣区域投影面积。利用该方法得到了大型伞充气过程伞衣投影面积变化曲线及物伞之间相对运动信息，弥补了试验测量手段的不足。基于录像分析结果对大型伞充气过程进行了深入研究。提出了大型伞充气过程阻力面积及附加质量计算方法，分析了充气过程中开伞力各主要影响因素的变化规律，研究了质量比与开伞力之间的关系。研究表明，附加质量及其变化率对开伞力有着重要影响，而一定的质量比则是大型伞解除收口过程出现两个开伞力峰值的重要原因。与其他文献方法的对比表明，基于录像分析建立的物伞系统动力学模型充气阶段的仿真精度得以全面提高。地面弹盖试验中曾观察到伞舱盖弹出后伞包追赶伞舱盖的现象，但目前尚无文献能够对其进行合理解释。针对这一问题，建立了伞舱盖弹射分离拉伞包过程动力学模型，复现了试验中观察到的伞包追赶伞舱盖现象，比较了地面静止弹盖条件及飞行条件下拉伞包过程的异同，分析了主要设计参数对拉伞包过程的影响。研究表明，对于伞舱盖与伞包之间采用连接绳连接的弹盖系统，追赶现象必然出现。该部分研究为伞包追赶伞舱盖现象的机理分析提供了理论依据，具有重要的工程应用价值。推导了空间绳索动力学方程，提出一种能够分析应力波在绳索间断面反射透射问题的数值方法，分析了应力波在两段具有不同广义波阻抗的相连绳索中传播的特点和规律。在此基础上，将伞包连接绳与伞包视为相互连接绳索，建立了伞舱盖弹射分离后拉伞包过程连续模型，研究了冲击载荷作用对拉伞包过程的影响。仿真结果表明，由于冲击加载较小，应力波在伞包连接绳及伞包中的反射透射对拉伞包过程的影响有限。更多还原

【Abstract】 The process of recovery and landing makes great demands on the safety andreliability of the spacecraft recovery system. As an important part of the recoverysystem, the parachute’s operational performance must be analyzed and evaluatedentirely in the design phase. The dissertation studies on the opening process of the largeparachute and the phenomenon of the pulled-out parachute pack chasing the parachutecontainer cover. The main contents and conclusions are listed as follows:According to the features of the videos from ground-based cameras, a modularimage processing method is proposed. The non-linear motion characteristics of thecanopy and the ropes are analyzed via the videos, and uncontrolled state of the canopyand the velocity difference between the pack and the spacecraft in deployment areshowed to be the principal cause of the canopy vent’s rapidly swing after deployment.By using the image processing method, the motion information of the canopy vent afterdeployment, the projection area of the canopy and the attitude of the parachute areacquired for the first time in our nation. The experimental data from the videos isnecessary for the large parachutes’ theoretical research and engineering designimprovement.Considering the features of the videos from on-board cameras, an image processingwhich is used to measure the canopy’s projection area via its contour in the video isproposed. The missing and occluded part of the contour could be identified and berepaired, and then the projection area could be calculated. By using this method, theprojection area of the canopy and the relative motion information between the canopyand the spacecraft are acquired. The results could make up for the traditionalmeasurement limitation.Based on the video analysis, the inflation process of the large parachutes is studiedintensively. Formula and algorithms for calculating the drag area and added mass aregiven. The changing characteristics of the main influencing factors of the opening forceare analyzed, and the relationship between mass ratio and opening shock are discussed.The research shows that the added mass has an important effect on the opening force,and the specific mass ratio is the major cause of double force pulse during disreefing.Comparison with the model in the literature indicates that the new method has higherprecision. The new model has been applied to the spacecraft recovery system simulationsoftware successfully.In terms of the lack of research on the phenomenon of the parachute pack chasingthe parachute container cover, a discrete analytical model is established, and thesimulation result could reproduce the chasing phenomenon observed in the tests, thenthe influence of the major design parameters are discussed. The study shows that the chasing phenomenon inevitably appears when the cover separation unit uses an elasticbelt connecting the cover and the pack. The research supplies the theoretical basis forthe mechanism analysis of the phenomenon.The dynamic model of a spatial rope is deduced. An approach for analyzing theshock wave reflection and transmission in a rope with discontinuity is provided andvalidated by numerical simulation of simple examples. The features of propagation ofshock wave in two connected ropes with different general wave impedance is analyzed.By taking the belt and the parachute pack as interconnected ropes, a continuous modelof the parachute pack pulling process is established. The results shows that the impactloading has no significant effect on the force and velocity during the parachute pack’spulling process for its low level.更多还原