【作者】 韦文书；

【导师】 荆武兴；

【作者基本信息】 哈尔滨工业大学 ， 航空宇航科学与技术， 2013， 博士

【摘要】 航天器携带着质量特性未知的物体(称为质量体附着航天器)进行轨道机动和姿态稳定跟踪控制是未来高级空间任务经常遇到的问题。例如航天器将空间垃圾清理到废弃轨道或送入大气层、航天器从外天体采样返回等，均需要姿轨耦合控制操作。与传统任务的航天器不同，质量体附着航天器构型和质量特性参数变化较大、轨道动力学和姿态动力学强烈耦合、姿态控制系统的稳定跟踪控制面临巨大挑战。因此，对质量体附着航天器这类复杂非线性不确定系统的动力学和控制问题进行研究具有重要的理论意义和实际应用价值。本文以附着未知质量体的航天器变轨推进过程中的姿态跟踪稳定控制为背景，重点研究这一复杂系统的数学模型建立、质量特性参数辨识和姿态跟踪耦合控制等问题，主要包括以下几部分：研究质量体附着航天器的数学模型问题。任何系统的研究分析都是基于正确描述系统的数学模型开展的，建立质量体附着航天器的数学模型是本文研究工作的基础和关键所在。针对质量体附着航天器的特点，本文将其抽象为一个平台和附着在平台周围的子体组成的多体系统。针对航天器和子体为常质量或变质量、子体相对平台运动或锁定等情况，给出了质量体附着航天器的一般数学模型。分析了质量体附着航天器参数干扰和输入干扰的产生机理，此二种干扰对姿态的稳定跟踪会产生严重影响。针对参数干扰问题，采用辨识理论估计大范围变化的质量特性参数，以便在控制中进行补偿。质量体附着航天器的质量特性参数均未知，而这些参数的联合辨识目前尚未完全解决。通过对数学模型中待辨识参数和可选信号源的分析，选取摇摆发动机的摆动运动为信号源、角速度和加速度为观测量，在此基础上，提出了质量特性参数辨识方案。鉴于质量体附着航天器参数变化大，为确保算法收敛，基于敏感器测量数据，并考虑初始角动量可能不为零和数据存在噪声等情况提出一套质量特性参数初值解算方法。基于解算的参数初值，采用Levenberg-Marquardt算法对质量特性参数进行迭代估计。利用数值仿真手段分析影响辨识精度的因素如仪器误差、发动机摆动周期、发动机摆动幅值和发动机与航天器的质量比等，验证质量特性参数联合估计问题的解决方法。研究质量体附着航天器在变轨推进过程中的姿态跟踪耦合控制问题。针对参数干扰问题，通过构造拟欧拉角和拟欧拉角速度将参数确定后的质量体附着航天器动力学模型转换为摄动双积分系统，采用滑模变结构理论设计了控制律，分析了输入干扰以及辨识偏差情况下闭环姿态控制系统的稳定性。针对变轨过程中轨控发动机带来的强输入干扰问题，提出利用发动机摆动使得推力方向穿过航天器质心以消除推力干扰的策略，建立了发动机摆动指令与航天器质心位置之间的关系。为确保推力方向指向变轨要求方向，根据发动机相对平台的状态和制导方向，利用四元数理论建立了变轨过程中航天器的耦合控制指令姿态。数值仿真结果验证了文中提出的策略和控制系统能够克服参数变化带来的强干扰，解决质量体附着航天器的姿态跟踪耦合控制问题。更多还原

【Abstract】 For future advanced space mission, it would be a general problem for spacevehicle which carries unknown characteristic body (can be called as Mass BodyAttached Spacecraft MBAS) to implement orbit maneuver and attitude tracking. Forexample, during the missions of cleaning space junk to derelict orbit or atmosphere,executing samples return; spacecraft vehicles all need orbit maneuver to implementmissions. Different from the traditional spacecraft, these attached masses willchange the spacecraft system characters on its configuration and parameters,resulting in strong couple between orbit and attitude dynamics, and bringingenormous challenges for the control system to stay stable. Hence, it’s of importanttheoretical significance and wide application prospects to implement research onthe dynamics and control of such complicated nonlinear uncertain system as MBAS.Based on background of the attitude tracking stability control during the orbitpropulsion of the MBAS, this dissertation focuses on the mathematical model, masscharacteristic parameters identification and attitude tracking coupled controlproblem. The major contents of this dissertation are consisted the following parts.Firstly, the mathematical model of the MBAS is studied. As is known, anyresearch and analysis to system should be stretched out under correct mathematicalmodel. Hence, to establish the mathematical model of the MBAS is the basis andkey to the science research. According to the characteristics of the MBAS, thispaper abstract it as a multi-body system which considered the spacecraft as theplatform and the attached mass bodys as daughter bodys around the platform. Thegeneral mathematical models of the MBAS are proposed, in case that the quality ofthe spacecraft is constant or variable, and the relative movement of the attachedmass bodys is motorial or locked and etc. The mechanism of two interference suchas parameter interference and input interference caused by the attached mass bodysare analyzed in this paper, which will impact the stability of the attitude trackingcontrol system.Secondly, for parameter interference problem, the identification theory isadopted to estimate the mass characteristic parameters for the compensation in thecontrol system. The mass characteristic parameters of the MBAS are all unknown,and the perfect approach to identify these parameters is still studied. Through theanalysis of the unknown parameters and the optional signal source in themathematic models, the swing motion of the swivel engine is choosed as the signal source, angular velocity and acceleration are considerd as observed quantity. Onthis basis, the scheme for mass characteristic parameters identification is proposed.Because of the large change in parameters of the MBAS, a set of initial valuecalculating method is proposed to make the results convergence, considering theinitial momentum maybe not zero and noise in measured data. With the calculatedinitial value, the Levenberg-Marquardt algorithm is used for estimation of the masscharacteristics parameters. Furthermore, the numerical simulation is used to analyzethe affected factors to the accuracy of estimation, such as instrument error, engineoscillation time, engine oscillation amplitude and engine mass ratio, etc; andvalidate the algorithms and theory to solve the union identification problem for themass characteristic parameters.Finally, the attitude tracking coupled control problem during the propulsion ofthe MBAS is studied. For the parameters interference, the quasi-Euler angles andquasi-Euler angular velocities are proposed to convert the dynamics system of theMBAS with identified parametes into a perturb double-integral system. The controllogic is designed by the slide variable structure control theory. The stability of theclosed loop control system is anyalyed with input interference and identificationerrors. For the input interference problem caused by the engine during the orbitpropulsion, a strategy is proposed by using the swing of engine to make the thrustpoint to the platform centroid to avoid thrust interference. The command angles ofthe engine during the swing motion are derived. To make the thrust point theguidance direction, the coupled control attitude is establied with the quaterniontheory; on account of the relative state between the swivel engine and platform andthe guidance direction. Numerical simulation has verified that the proposed strategyand control logic can overcome the strong coupling interference and solve attitudetracking coupling control problem of the MBAS during the orbit propulsion.更多还原