共查询到18条相似文献,搜索用时 156 毫秒
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可变构型复合柔性结构航天器动力学建模研究 总被引:2,自引:0,他引:2
针对中心刚体加复合柔性结构类航天器采用混合坐标法和子结构模态综合法,建立了可变构型复合柔性结构航天器低阶动力学模型。获得的柔性动力学方程及其各类耦合系数矩阵,适用于全星级可变构型系统和部件级复合柔性附件系统的控制系统设计与仿真,该模型具有阶数低和工程实用的特点。 相似文献
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针对现代航天器中包含复合柔性结构的特点,本文通过将柔性航天器动力学建模的混合坐标法与结构动力学分析的模态综合法相结合,提出了模态综合—混合坐标建模方法。此方法拓宽了混合坐标法的应用范围,使其适用于包含刚体和复合柔性结构的航天器的动力学建模。 相似文献
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研究基于Stewart平台主动基座的挠性结构振动控制。首先,建立含Stewart平台主动基座的柔性梁刚柔耦合动力学模型;随后,在模态空间上分别针对挠性结构的一阶和二阶模态设计由线性扩张状态观测器(LESO)和PD控制器组成的自抗扰控制器(ADRC);最后,基于独立模态控制(IMSC)中的模态滤波器从物理坐标中提取模态坐标,建立振动主动控制实验系统,基于模态空间的自抗扰控制方法完成挠性结构的前两阶模态振动主动控制实验。研究结果表明,利用Stewart平台作为主动基座,采用自抗扰控制方法实现挠性结构的振动抑制是一种高效的振动主动控制方法,在空间振动主动控制领域具有广阔的应用前景。 相似文献
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中心刚体-柔性梁系统是一个典型的刚柔耦合动力学系统,对其动力学与控制的研究一直是国内外的研究热点问题之一。采用一次近似简化模型对中心刚体-柔性梁系统的旋转运动控制进行研究,其中控制律采用变结构控制方法进行设计。切换面的设计采用最优化方法而得出,控制律的设计采用指数趋近律方法。因为所设计的控制律是模态坐标的函数,而模态坐标不可能通过物理测量直接获得,因此给出一个从物理测量中提取模态坐标的滤波器方法。数值仿真结果显示,模态滤波器能够较好地提取出控制律所需的模态坐标;变结构控制能够使得系统达到所期望的运动状态,并可使柔性梁的残余振动得到抑制。 相似文献
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空间柔性臂的解耦动力学模型及其控制 总被引:1,自引:0,他引:1
提出了一种空间柔性结构通过关节电机同时实现轨迹控制和振动抑制的方法。针对单连杆空间柔性臂,采用非约束模态法建立了刚柔解耦动力学模型;提出了基于应变反馈的PID控制策略,并设计了PID/应变反馈复合控制器,同时实现对柔性臂末端运动轨迹的定位控制和弹性振动抑制控制;仿真结果验证了该控制策略的可行性。 相似文献
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用于惯性完备性降价的模态恒等式研究 总被引:2,自引:0,他引:2
《航天器工程》2003,(2)
从P.C.Hughes的研究成果出发,对柔性航天器的模态恒等式及其用于动力学模型降阶的惯性完备性准则进行了严格证明和应用研究。全文详细阐述了柔性核、动量系数、角动量系数、约束模态和非约束模态等物理概念及其相关恒等式的物理意义;并对主要模态恒等式给出了完整证明;推导了航天器基频的估算公式;同时通过算例深入探讨了这些恒等式的工程应用。 相似文献
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非接触光学测量方法,可作为空间站太阳电池翼等大型航天器柔性部件在轨模态分析的一种潜在手段。为合理布置相机的拍摄工位及视角,有效捕捉靶标运动的位移及方向,提出了利用轨控或姿控激励下柔性附件瞬态响应的结构动力学仿真结果,结合计算机图形学仿真技术,预示虚拟靶标运动过程成像及其位移重构效果,从而对测量有效性做出判断的实验方案评价方法,并通过仿真实验对其可行性进行了验证。该方法可发展为航天器在轨模态测量的计算机辅助优化工具,能充分利用结构动力学仿真成果,弥补大型柔性部件地面实验的不足。 相似文献
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On orbit maneuvering of flexible space manipulators requires a special caution. In fact the task of reaching the desired configuration, and at the same time safely preserving the structure integrity and not perturbing the overall spacecraft attitude, is complicated by the extreme flexibility of the structure itself. For studying this problem, an experimental test bed is designed and realized at the Guidance and Navigation Laboratory at La Sapienza, University of Rome. In this paper, visual based techniques are considered as a valid option for the dual purpose of evaluating the control signals and monitoring the flexible behavior of the controlled structure. In fact the joint motors are controlled in order to reach a desired target taking the image of the target as acquired by a mobile camera mounted on the end effector of the manipulator, into account. The Image Based Visual Servoing is introduced together with the simple adaptive algorithm used for processing the acquired images. With respect to a more traditional terrestrial visual servoing, a control system based on a moving camera (a typical configuration in space applications) is particularly sensitive to the flexible vibrations of the arm links. In fact in the closed loop control scheme, an oscillating movement of the camera influences the image processing, which in turn influences control actions. Instability could arise if the flexible dynamics is not separated from the rigid motion. This paper shows that it is possible to evaluate the elastic properties of the complex multibody manipulator (flexibility of the link, elastic behavior of the joints, effects of nonstructural masses) thanks to the analysis of the image acquired. 相似文献
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Vibrations represent one of the most important topics of the engineering design relevant to flexible structures. The importance of this problem increases when a very flexible system is considered, and this is often the case of space structures. In order to identify the modal characteristics, in terms of natural frequencies and relevant modal parameters, ground tests are performed. However, these parameters could vary due to the operative conditions of the system. In order to continuously monitor the modal characteristics during the satellite lifetime, an operational modal analysis is mandatory. This kind of analysis is usually performed by using classical accelerometers or strain gauges and by properly analyzing the acquired output. In this paper a different approach for the vibrations data acquisition will be performed via image-based technique. In order to simulate a flexible satellite, a free flying platform is used; the problem is furthermore complicated by the fact that the overall system, constituted by a highly rigid bus and very flexible panels, must necessarily be modeled as a multibody system. In the experimental campaign, the camera, placed on the bus, will be used to identify the eigenfrequencies of the vibrating structure; in this case aluminum thin plates simulate very flexible solar panels. The structure is excited by a hammer or studied during a fast attitude maneuver. The results of the experimental activity will be investigated and compared with respect to the numerical simulation obtained via a FEM-multibody software and the relevant results will be proposed and discussed. 相似文献
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针对航天器上太阳帆板这种悬臂外伸薄板结构的挠性附件 ,在存在建模参数不确定及外部扰动条件下所引起的振动 ,本文采用压电致动片作为执行器 ,将变结构控制应用于板的主动振动控制。通过仿真研究结果与应变律反馈控制比较 ,可知变结构控制具有较强的鲁棒性 ,同时控制器结构简单 ,易于实现 相似文献
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