摘要：Inflatable space structures may undergo the vibration of a long duration because of their features of dynamic deployment,high flexibility,and low-frequency *** this paper,a topology optimization methodology is proposed to reduce the vibration of a spinning inflatable *** the first step,a variable-length shell element is developed in the framework of arbitrary Lagrange-Euler(ALE)and absolute nodal coordinate formulation(ANCF)to accurately model the deployment dynamics of the inflatable *** the help of two additional material coordinates,the shell element of ALE-ANCF has the ability to describe the large deformation,large overall motion,and variable length of an inflatable *** nonlinear elastic forces and additional inertial forces induced by the variable length are analytically *** the second step,a topology optimization procedure is presented for the dynamic response of an inflatable structure through the integration of the equivalent static loads(ESL)method and the density *** ESL sets of the variable-length inflatable structure are defined to simplify the dynamic topology optimization into a static one,while the density-based topology optimization method is used to describe the topology of the inflatable structure made of two materials and solve the static optimization *** order to obtain more robust optimization results,sensitivity analysis,density filter,and projection techniques are also ***,a benchmark example is presented to validate the ALE-ANCF modeling *** deployment dynamics and corresponding topology optimization of a spinning inflatable structure are studied to show the effectiveness of the proposed topology optimization methodology.

摘要：How nonlinear joints affect the response of large space structures is an important problem to *** this paper,a multi-harmonic equivalent modeling method is presented to establish a frequency-domain model of planar repetitive structures with nonlinear ***,at the local level,the nonlinear joint is modeled by the multi-harmonic describing function *** element of the hybrid beam is obtained by the dynamic condensation of the beam-joint ***,at the global level,the displacement-equivalence method is used to model the multi-harmonic Euler continuum beam equivalent to the planar repetitive ***,the pseudo-arc-length continuation method is applied to track the multi-harmonic trajectory of ***,an experiment is conducted to validate the correctness of the modeling method,considering the effect of hanging rope and air *** the numerical studies,several simulation results indicate the similarity of response between a single-degree-of-freedom system with a single nonlinear joint and the system of the planar repetitive structure with a large number of nonlinear ***,the component of higher-order harmonics is shown to be important for predicting the resonance frequencies and amplitudes.

摘要：堆叠卫星入轨后分离再重构是构建大型空间结构的有效手段之一.使用自然坐标法建立堆叠卫星系统的动力学方程,具有方便处理卫星组装中固定约束的优点.设置合适的堆叠卫星分离策略和组装策略,采用自旋分离实现了卫星以堆叠状态入轨后的无碰撞分离,使用PD控制结合势函数方法实现了卫星的逐步组装.另外,采用优化算法计算了卫星之间的最小距离,用以精细确定排斥势的大小.基于以上方法,仿真实现了卫星由堆叠状态分离到分段组装的全部过程,证明了所设计的分离和组装策略是有效的.

摘要：软体材料作动器具有良好的目标抓取适应性,为实现软作动器结构的轻量化,保证抓取与承载能力,采用形状记忆合金丝作为驱动元件,设计出一种可变刚度的软作动器。首先,基于形状记忆合金(shape memory alloy,简称SMA)一维本构关系建立了作动器的弯曲变形力学模型;其次,通过实验对力与变形之间的关系进行了验证,弯曲变形与理论结果一致;最后,通过回弹结构的动力学设计,使得该作动器能够在恢复阶段快速回到初始形态。实验结果显示,加热用于变刚度的形状记忆合金丝可显著提升作动器的负载能力,从而达到变刚度的效果。

摘要：弹性波/声波超材料具有许多超常力学性质,为航空、航天和船舶等领域的装备减振降噪提供了新途径。本文介绍多胞局域共振型超材料的减振实验研究。该研究基于局域共振元胞的频散分析、波动传递率分析和周期结构的振动响应计算,讨论了超材料在带隙频率区内外的波动传播。设计制造了具有低频带隙的轻质周期性局域共振超材料构型,并用于空间桁架结构的振动抑制实验。实验结果表明,在15~45 Hz的带隙频率区间,多胞超材料减振装置可使振动传递率降低30 dB以上,展现出良好的减振效果。

摘要：以交流伺服电机为作动器实现对绳系单体系统的鲁棒控制,建立绳系单体系统的非线性动力学模型,基于平衡点线性化设计μ控制器,针对系统选取合适的权函数并作降阶处理进行在线鲁棒控制。实验结果表明,初始干扰角度在0.4rad范围内,所设计的μ控制器可有效抑制模型参数不确定性及扰动影响,系统有较好的鲁棒性。

摘要：多星分离是一箭多星成功发射之关键技术,为保障卫星在轨顺利分离,需要在地面开展相关的分离试验及其仿真验证。本文针对带橡胶夹层的卫星自旋分离过程,进行了卫星分离地面试验方案设计和数值仿真。首先,给出了卫星分离地面试验设计方案;其次,采用自然坐标法分别对不带工装和带有工装的在轨卫星分离过程进行动力学建模及动态仿真分析;最后,研究了卫星⁃工装整体动力学建模及分离过程中带工装结构和不带工装结构对卫星分离的影响。

摘要：考虑系绳弹性的影响,建立了绳系卫星系统三维动力学模型,研究了在状态和控制约束下的绳系卫星非线性时间最优控制问题.为缩减系统变量,控制律设计没有采用通常的状态空间模型,而是基于二阶微分包含,将连续时间最优控制问题离散为大规模动态规化问题,最后通过数值模拟验证了该方法的有效性.

摘要：状态观测器设计是大型空间结构主动控制设计中的一项重要内容.由于大型空间结构频率低、模态密集且阻尼小,传统的基于模态截断模型的观测器设计方法容易导致观测溢出问题.直接基于结构的偏微分方程(PDE)模型进行状态观测器设计可以避免上述问题,目前正成为该领域的研究热点.针对具有弱阻尼的空间柔性曲梁,对曲梁在悬臂状态下的面内振动进行状态估计.首先建立考虑剪切变形和转动惯量的曲梁面内振动PDE模型,并通过变量替换将PDE模型转化为Hilbert空间中的抽象状态方程,然后基于Kalman滤波理论构建曲梁的无穷维状态观测器模型,并采用频域下的谱分解方法得到无穷维Kalman滤波器增益函数的解析解.最后通过数值算例对无穷维Kalman滤波器的观测效果进行了验证。

摘要：由于陀螺耦合效应,系统动力学方程的特征值和特征向量皆为复数形式,不便于进行控制力矩陀螺的配置优化和控制律设计。本文基于复模态理论,构造出一种实数域上的伪模态矩阵,从而实现方程解耦。综合考虑结构模态、控制输入能量和传感器接收能量的复合优化准则,获得了控制力矩陀螺的最优配置。结果表明,采用线性二次型最优控制,能够快速将结构的响应振幅降至5%以内,验证了使用伪模态矩阵进行方程解耦的可行性及控制的有效性。