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1.
胡洁  杨萱 《微计算机信息》2012,(4):155-156,71
研究了大型太阳帆航天器展开机构的柔性动力学建模问题。首先对结合模态综合法和混合坐标法介绍了太阳帆展开机构柔性动力学一般模型建立过程。根据工程需要对展开机构进行模态分析,给出了工程实用的各耦合系数的计算表达式,并计算出各耦合系数。  相似文献   

2.
针对柔性航天器振动影响飞行器姿态稳定性和精度.为了解决上述问题,提出了多柔体航天器的动力学建模.首先,根据工程实现的假设振型法,采用拟坐标拉格朗日方程,推导出带有刚体模态的二阶系统刚柔耦合动力学模型,其中,为了减少模型计算量,通过坐标变换将刚体模态和柔性模态解耦,利用一种刚体模态解耦的二阶不稳定系统的模型降阶方法,并对航天器多柔体系统动力学方程进行了仿真分析,结果飞行姿态稳定,满足了精度要求,表明了动力学建模与模型降阶法的有效性和正确性.  相似文献   

3.
本文采用柔性多体系统单向递推组集的建模方法,基于速度变分原理建立了带Stewart平台、柔性帆板和CMG组件的航天器刚柔耦合动力学模型.由于该模型自由度较大,无法满足实时控制的需求,因此建立了简化的Stewart平台等效模型,并通过与柔性Stewart平台完整模型对比,验证了所建立的动力学简化模型的正确性与高效性.分析了星体平台运动及柔性帆板的振动对有效载荷动力学响应的影响,指出了设计Stewart平台的微振动抑制方案时不能忽略下平台的运动及柔性附件的振动.本研究为带Stewart平台的航天器的微振动减振设计与高精度指向提供了有效的技术支撑.  相似文献   

4.
在Pro/E4.0的软件平台上建立航天器太阳能电池帆板的虚拟样机模型,简单介绍电池帆板的三种常见结构:弯曲主振动梁武结构、弯曲组合振动板式结构和一般多体结构.并且对弯曲主振动梁式结构和一般多体结构类型的电池帆板进行展开过程的比较仿真和动力学分析,为航天器帆板的设计提供一定的依据.  相似文献   

5.
对于机器人、航天器和车辆悬架部件等一些多体系统来说,其中一些部件的大尺寸、轻型化趋势使得传统的刚性体建模已经难以准确地模拟实际的工况,将部件所具有的柔性特性加入到多体系统模型中进行柔体动力学仿真,由于考虑了部件弹性变形与大范围刚性运动之间的耦合,故可以得到部件更为真实的动力学行为.文中通过与基于Lagrange法的刚体动力学基本方程进行对比研究,详细说明了柔体动力学方程中上述的耦合作用.以某大型雷达可展开天线为例,分别在刚体和柔体的假设下对其展开运动进行动力学仿真,结果表明采用柔性体仿真更能真实反映其动力学特性.  相似文献   

6.
本文讨论了航天器太阳帆板展开过程中航天器姿态的最优控制问题,在控制算法中用小波函数逼近控制输入规律,提出了太阳巾帆板展开过程最优控制的遗传算法,数值仿真表明,小波逼近和遗传算法联合求解最优控制问题是有效的。  相似文献   

7.
柔性臂动力学模型中单杆的质量—弹性杆简化模型的讨论   总被引:3,自引:0,他引:3  
多自由度串联柔性臂是强非线性系统 ,动力学模型往往很复杂 .这样的动力学模型对控制系统很难提供有效的设计依据 .因此系统模型降阶问题是柔性臂研究的热点问题 [1~ 3] .模态展开法是模型降阶中常采用的方法 .模态的求解及截断问题较复杂 .本文针对特定构型的柔性臂提出了一种简化的集中质量 -弹性杆动力学建模方法 ,并与模态展开法进行了比较 .结果表明 ,在类似的结构中这种方法有很好的精度  相似文献   

8.
组合体太阳帆板遮挡分析是航天器在轨能源持续性评估的重要依据.针对电能效率与光照有关,提出一种太阳光线与航天器体素的各个面一一求交点的算法,即“穿点判断法”.算法具有数据输出和可视化特点.首先通过几何学的方法建立了组合体太阳帆板遮挡简化数学模型,并对太阳帆板采用四叉树递归划分,考虑了组合体本体对帆板以及帆板对帆板的遮挡情况,然后应用一元二次方程求根法来判断帆板是否被遮挡,最后通过设定帆板最小粒度来计算帆板的遮挡面积,并用OpenGL对遮挡情况进行可视化显示.仿真结果表明,方法能够有效地解决方程可以描述的任何体素如圆柱、圆台、圆锥、球以及用标准化的体素构造复杂的几何形体等航天器的太阳帆板遮挡问题.  相似文献   

9.
利用MSC Adams软件的参数化建模和二次开发功能,建立专为航天器太阳翼展开分析设计的仿真模块,为用户提供自动、快速的建模环境,使得进行航天器太阳翼展开过程的运动学和动力学分析工作效率更高、扩展方便,通过优化设计为设计者提供最优的设计参数.  相似文献   

10.
从工程的角度出发,采用拉格朗日方程建立一类挠性多体航天嚣方程。将滑动模态变结构控制和PI反馈控制有机地结合起来,针对一类航天器提出了一种新型的PI反馈控制方案。该方法主要针对变结构控制应用过程中的抖动问题,采用频率形式的性能指标设计滑动模态切换面来使系统中的高频和低频模态振动最小。整个设计方案简单而又系统化,对于减小抖动。直至抑制一类柔性航天器的各种模态的抖动是有效的。  相似文献   

11.
The subject of this work is the dynamics of a rotating spacecraft. The spacecraft is modeled as a main rigid body connected to two flexible solar panels. The orbital motion of the whole spacecraft with a constant angular velocity is considered, interacting with small rigid motions of the main body, and small elastic deformations and infinitesimal vibrations of the solar panels. A continuum approach based on the Rayleigh–Ritz discretization is used to describe the distributed flexibility in the spacecraft. Rayleigh–Ritz discretization functions used are the clamped modes of the solar panels. This method enables us to construct the impedance matrix of the whole system relating to the displacement of the main body and the external torque. A spectral expansion of this impedance matrix, in terms of these clamped modes is obtained in the frequency domain. The numerical results presented show that for small values of orbital angular velocity, the vibration motion frequencies of the flexible parts (solar panels) are not perturbed substantially. Moreover, when great values of orbital angular velocity are simulated, these frequencies change considerably. The present investigation based on the Rayleigh–Ritz discretization shows the effect of the interaction between the orbital motion of the whole spacecraft and the vibration motions of the flexible parts.  相似文献   

12.
Simulation of Deployment of a Flexible Solar Array   总被引:5,自引:0,他引:5  
The deployment of a solar array is simulated three-dimensionally using the multibody program SIMPACK. The analyses are performed for 500 real-time seconds, which contain the three deployment phases, (I) jump-out, (II) steering phase and (III) deployed phase. The goal of the simulations is to check the influence of the flexibility of the solar array on the solar generator motions during these three phases against results obtained by a rigid body model simulation.The modelling of flexible bodies is based on the widely used method of floating frame of reference formulation applying global shape functions (Ritz method). The preparation of a proper set of shape functions to represent the flexibility of the yoke and the six solar panels is one of the main objectives of thispaper. For each of the components, eigenmodes and static modes forvarious boundary conditions are computed using the finite elementprogram NASTRAN.For a good convergence of the Ritz approximation with a smallnumber of shape functions, the shape functions are selected usingmodal participation factors, that are computed for various load casesprior to the time simulations. The load cases are obtained, for example,by a rigid body simulation of the deployment phases. The proposed methodof shape function selection using modal participation factors isdemonstrated by examples.  相似文献   

13.
本文提出了一种基于显式参考管理与模态观测器的挠性航天器姿态机动控制方法. 首先, 采用改进的罗德里格斯参数建立了航天器的运动学和动力学模型, 分析了存在的控制约束和角速度约束. 在此基础上, 设计了基于显式参考管理的约束挠性航天器姿态重定向控制算法. 由于挠性模态不能直接测量, 内层设计了模态观测器, 并将观测器观测得到的模态坐标作为内层无约束控制器的输入. 随后, 外层导航模块根据所需满足的约束条件设计了相应的动态路径, 该路径可以根据当前状态以合适的速率收敛到最终状态, 通过跟踪该路径, 航天器姿态就可以在满足约束的情况下快速到达期望位置. 通过构造合适的李雅普诺夫函数, 严格证明了该挠性航天器显式参考管理姿态控制算法的稳定性. 最后, 仿真结果进一步验证所设计算法的约束处理效果与振动抑制能力.  相似文献   

14.
Output attitude tracking for flexible spacecraft   总被引:2,自引:0,他引:2  
In this work a class of nonlinear controllers has been derived for spacecraft with flexible appendages. The control aim is to track a given desired attitude. First, a static controller based on the measure of the whole state is determined. Then, a dynamic controller is designed; this controller does not use measures from the modal variables, and the variables measured are the parameters describing the attitude and the spacecraft angular velocity. Finally, it is shown that a relaxed version of the tracking problem can be solved when the only measured variable is the spacecraft angular velocity. Simulations show the performances of such control schemes.  相似文献   

15.
太阳帆利用太阳辐射压力提供太空航行的必要动力,由于具有理论上的无限速度和无需消耗任何燃料等优势,被认为是完成未来深空探测任务的有效技术途径之一.柔性太阳帆航天器的动力学模型包括多体动力学、刚柔耦合动力学和太阳辐射光压模型,复杂的动力学特性导致其姿态控制设计具有很强的挑战性.针对带有控制杆的柔性太阳帆航天器,本文采用拉格朗日方程和有限元法,给出了面向控制的解析式动力学模型.所推导的刚柔耦合动力学模型,刻画了太阳帆航天器的本质动力学特性,即双框架控制杆的短周期运动,姿态与柔性太阳帆的耦合效应,以及在太阳光压恢复力矩下的姿态静稳定性和长周期运动.基于带控制杆的太阳帆航天器的双时间尺度特性,提出了双回路控制结构,用于实现航天器俯仰轴和偏航轴的姿态控制.将内回路设计为PD控制器,用于实现质心位置的调整.将外回路设计为PID控制器,用于阻尼姿态运动,并实现在平衡太阳光压力矩下的姿态保持.从而将柔性太阳帆航天器的复杂姿态控制问题转化为两个低阶子问题,实现了在不同频带上的控制设计.仿真结果验证了动力学建模和姿态控制设计方法的有效性.  相似文献   

16.
This research is concerned with the dynamic modeling of satellite with deployable solar arrays equipped with strain energy hinges (SEH). The SEH is a new deployment device consisting of a strip tape measure, which utilizes the buckling behavior of a thin curved shell to produce nonlinear dynamic characteristics during deployment of solar arrays. For dynamic simulation, the SEH is assumed to be a massless-nonlinear elastic member and the solar panels are assumed to be rigid bodies which are connected by the SEHs. The planar deployment is of interest in this study since the deployment of solar arrays mainly occurs in a two-dimensional plane. In deriving the equations of motion, we developed a new systematic approach suitable for the simulation of solar array deployment in space. The simulation results were compared to the ground experimental results obtained at the laboratory of Korea Aerospace Research Institute. In the ground experiments, the hub of the solar arrays was attached to the frictionless rotational bearing, and the solar arrays were hanged by bungee cables. Even though the dynamic model was derived for the space deployment of the solar arrays, the simulation result corresponding to the solar array deployment was similar to the ground experimental results thus validating the simulation model developed in this paper.  相似文献   

17.
This paper presents an algorithm for the terminal synthesis of the orbital orientation for a spacecraft. The algorithm is based on solving the following problems: the analytical determination of the program values for the angular velocity vector components in an orbital coordinate system and the stabilization of the program values for the turn rate vector components and the desired terminal angular position of a spacecraft. The program values of the angular velocity vector components are determined analytically using the method previously proposed by the authors for solving a boundary value problem based on the parameter identification of a discrete model with the use of modal control. The simulation results demonstrating the effectiveness of the proposed algorithm, as well as the high accuracy level of the steady-state control, are presented.  相似文献   

18.
We study cooperative object manipulation control of rigid–flexible multibody systems in space. During such tasks, flexible members like solar panels may get vibrated. Which in turn may lead to some oscillatory disturbing forces on other subsystems and consequently produce errors in the motion of the end-effectors of the cooperative manipulating arms. Therefore, to design and develop capable model-based controllers for such complicated systems, deriving a dynamics model is required. However, due to practical limitations and real-time implementation, the system dynamics model should require low computations. So, first, to obtain a precise compact dynamics model, the rigid–flexible interactive dynamics modeling (RFIM) approach is briefly introduced. Using this approach, the system is virtually partitioned into two rigid and flexible portions, and a convenient model for control purposes is developed. Next, a fuzzy tuning manipulation control (FTMC) algorithm is developed for a simple conceptual model for cooperative object manipulation. In fact, a suitable setup is designed for practical implementation of this controller. After that, a wheeled mobile robot (WMR) system with flexible appendages is considered as a practical case that necessitates delicate force exertion by several end-effectors to move an object along a desired path. The WMR system contains two cooperative manipulators, appended with two flexible solar panels. To reveal the merits of the developed model-based controller, the maneuver is deliberately planned such that flexible modes of solar panels get stimulated due to arms motion. The obtained results show an effective performance of the proposed approach as will be discussed.  相似文献   

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