绳系卫星系统动力学与展开规划问题研究

发布时间：2019-03-17 07:38

【摘要】：绳系卫星系统是指由绳系连接两颗或多颗卫星而组成的航天器系统,绳系卫星在空间环境探测、空间碎片清除等领域有着广阔的应用前景。考虑到复杂的空间摄动环境及其自身的姿轨耦合运动特性,绳系卫星系统的动力学及控制问题具有一定的难度,其中绳系卫星的释放及回收策略一直是该领域内的研究重点。在绳系卫星释放及回收过程中,绳系长度的变化会导致系统姿态出现大幅的轨道面内外振荡,因此,结合绳系卫星系统的动力学及运动学特性,合理的规划系统展开释放过程并保证系统的稳定,是绳系卫星在轨运行的关键。本文针对绳系卫星系统的释放展开任务需求,调研了国内外已有绳系卫星系统项目,总结了绳系卫星系统的动力学分析与控制策略设计方法,在已有成果的基础上,进一步开展了绳系卫星系统动力学建模、分析及释放规划问题研究。论文的主要研究内容包括:首先,采用Lagrange方程建立了二体及多体绳系卫星系统的动力学模型;在二体系统的建模过程中,通过将绳系视为质量均匀分布的线弹性体得到了较为通用的系统模型;然后将二体系统拓展为多体系统,并在模型中对比了考虑主星姿态和不考虑主星姿态的状况,分析了辐射式及串珠式多体系统的动力学特性。在二体动力学模型的基础上,引入绳系形变系数得到接近真实绳系的数学模型和精确计算张力的方法,结合绳系张力力矩和重力梯度力矩研究了系统匀速、匀加速、幂指数展开时绳系和主星姿态的运动。通过数值仿真分析了不同展开策略下绳系和主星姿态收敛速度及稳定性,并给出幂指数展开稳定的约束条件。随后,结合二体绳系系统建模及分析结果,研究了绳系姿态变化条件下的电绳系离轨过程的轨道参数变化。根据洛伦兹力作用下的姿态动力学模型和高阶国际地磁场模型分析绳系运动过程中洛伦兹力和洛伦兹力矩的计算方法;结合高斯摄动方程,建立了电动绳系离轨数值仿真模型,在分别考虑无摆角、仅有面内摆角、有面内外摆角的条件下,对电动绳系离轨过程进行仿真对比。最后,将二体系统的释放规划问题拓展到多体系统,研究了辐射开环绳系卫星系统的展开动力学特性及展开完成后的振动抑制。针对不考虑主星姿态的辐射系统设计了匀速、变加速展开策略,分析了展开效率与末端振动的关系,并通过数学仿真进行了验证。对于考虑主星姿态及几何尺寸建模的辐射系统,设计了重力梯度补偿及无补偿时的展开控制策略,针对展开完成后绳系的振荡,提出分阶段展开的开环、闭环振动抑制控制方法,使系统展开完成后稳定运行。通过搭建仿真模型验证提出展开控制策略的有效性。
[Abstract]:Tethered satellite system is a spacecraft system composed of two or more satellites connected by tethered satellites. Tethered satellites have broad application prospects in space environment detection and space debris removal. Considering the complicated space perturbed environment and its attitude-orbit coupling motion characteristics, the dynamics and control of tethered satellite system are difficult to some extent. The release and recovery strategy of tethered satellite has always been the focus of research in this field. In the process of release and recovery of rope satellite, the change of rope length will lead to large-scale oscillation in and out of orbit of the system. Therefore, combined with the dynamics and kinematics characteristics of tethered satellite system, Rational planning of the release process and stability of the system is the key to the on-orbit operation of tethered satellites. In this paper, according to the requirements of the release mission of tethered satellite system, the existing projects of tethered satellite system at home and abroad are investigated, and the methods of dynamic analysis and control strategy design of tethered satellite system are summarized. The dynamics modeling, analysis and release planning of tethered satellite system are further studied. The main contents of this thesis are as follows: firstly, the dynamic models of two-body and multi-body tethered satellite systems are established by using Lagrange equation; In the process of modeling the two-body system, a general system model is obtained by taking the rope system as a linear elastomer with uniform mass distribution. Then the two-body system is extended to a multi-body system, and the dynamic characteristics of the radiative and beaded multibody systems are analyzed by comparing the two-body system with and without the master star attitude in the model. On the basis of the two-body dynamic model, the mathematical model close to the real rope and the method of accurately calculating the tension are obtained by introducing the deformation coefficient of the rope. The uniform velocity and uniform acceleration of the system are studied in combination with the tension moment and the gravity gradient moment of the rope system. The motion of the rope system and the attitude of the master star in exponential expansion. The convergence rate and stability of rope and star attitude under different expansion strategies are analyzed by numerical simulation, and the constraints of power exponential expansion stability are given. Then, combined with the modeling and analysis results of the two-body rope system, the orbit parameter variation of the electric rope deorbiting process under the condition of the rope attitude change is studied. According to the attitude dynamics model under Lorentz force and the high-order international geomagnetic field model, the calculation method of Lorentz force and Lorentz moment in the process of rope movement is analyzed. Combined with Gao Si's perturbation equation, a numerical simulation model for derailment of electric rope system is established. Under the conditions of no swing angle, only in-plane swing angle and inside-out swing angle, the simulation and comparison of the deorbit process of electric rope system are carried out. Finally, the release planning problem of the two-body system is extended to the multi-body system. The unfolding dynamic characteristics of the radiative open-loop tethered satellite system and the vibration suppression after the deployment are studied. A uniform and variable acceleration deployment strategy is designed for the radiation system without considering the attitude of the master star. The relationship between the deployment efficiency and the terminal vibration is analyzed and verified by mathematical simulation. For the radiation system considering the attitude and geometric dimension of the master star, the control strategy of gravity gradient compensation and non-compensation is designed. For the oscillation of the unfolded rope system, a phased open-loop expansion is proposed. The closed-loop vibration suppression control method makes the system run stably after completion. The effectiveness of the proposed deployment control strategy is verified by building a simulation model.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V448.2

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