Automatic Generation of Optimally Rigid Formations Using Decentralized Methods

In this paper, decentralized methods of optimally rigid graphs generation for formation control are researched. The notion of optimally rigid graph is first defined in this paper to describe a special kind of rigid graphs. The optimally rigid graphs can be used to decrease the topology complexity of graphs while maintaining their shapes. To minimize the communication complexity of formations, we study the theory of optimally rigid formation generation. First, four important propositions are presented to demonstrate the feasibility of using a decentralized method to generate optimally rigid graphs. Then, a formation algorithm for multi-agent systems based on these propositions is proposed. At last, some simulation examples are given to show the efficiency of the proposed algorithm.

Stiffness identification of four-point-elastic-support rigid plate

As the stiffness of the elastic support varies with the physical-chemical erosion and mechanical friction, model catastrophe of a single degree-of-freedom(DOF) isolation system may occur. A 3-DOF four-point-elastic-support rigid plate(FERP) structure is presented to describe the catastrophic isolation system. Based on the newly-established structure, theoretical derivation for stiffness matrix calculation by free response(SMCby FR) and the method of stiffness identification by stiffness matrix disassembly(SIby SMD)are proposed. By integrating the SMCby FR and the SIby SMD and defining the stiffness assurance criterion(SAC), the procedures for stiffness identification of a FERP structure(SIFERP) are summarized. Then, a numerical example is adopted for the SIFERP validation, in which the simulated tested free response data are generated by the numerical methods, and operation for filtering noise is conducted to imitate the practical application. Results in the numerical example demonstrate the feasibility and accuracy of the developed SIFERP for stiffness identification.

Research on the Structural Rigidity Characteristics of a Reconfigurable TBM Thrust Mechanism

To improve the adaptability of TBMs in diverse geological environments,this paper proposes a reconfigurable Type-V thrust mechanism(V-TM)with rearrangeable working states,in which structural stiffness can be automatically altered during operation.Therefore,millions of configurations can be obtained,and thousands of instances of working status per configuration can be set respectively.Nonetheless,the complexity of configurations and diversity of working states contributes to further complications for the structural stiffness algorithm.This results in challenges such as difficulty calculating the payload compliance index and the environment adaptability index.To solve this problem,we use the configuration matrix to describe the relationship between propelling jacks under reconfiguration and adopt pattern vectors to describe the working state of each hydraulic cylinder.Then,both the dynamic compatible equation between propeller forces of the hydraulic cylinders and driving forces,and the kinematic harmonizing equation between the hydraulic cylinder displacements and their deformations are established.Next,we derive the stiffness analytical equation using Hooke’s law and the Jacobian Matrix.The proposed approach provides an effective algorithm to support structural rigidity analysis,and lays a solid theoretical foundation for calculating the performance indexes of the V-TM.We then analyze the rigidity characteristics of typical configurations under different working states,and obtain the main factors affecting structural stiffness of the V-TM.The results show the deviation degree of structural parameters in hydraulic cylinders within the same group,and the working status of propelling jacks.Finally,our constructive conclusions contribute valuable information for matching and optimization by drawing on the factors that affect the structural rigidity of the V-TM.

广义 Rigid环(英文)

本文定义并研究了广义 Rigid环 。

Discrete time transfer matrix method for dynamics of multibody system with flexible beams moving in space

In this paper, by defining new state vectors and developing new transfer matrices of various elements mov- ing in space, the discrete time transfer matrix method of multi-rigid-flexible-body system is expanded to study the dynamics of multibody system with flexible beams moving in space. Formulations and numerical example of a rigid- flexible-body three pendulums system moving in space are given to validate the method. Using the new method to study the dynamics of multi-rigid-flexible-body system mov- ing in space, the global dynamics equations of system are not needed, the orders of involved matrices of the system are very low and the computational speed is high, irrespec- tive of the size of the system. The new method is simple, straightforward, practical, and provides a powerful tool for multi-rigid-flexible-body system dynamics.

STUDY ON AUTOMATIC BALANCE TECHNOLOGY FOR THE RIGID ROTOR

The theory and application of automatic balance technology for the rigid rotor is re- searched. New analysis about the mechanical model of vibratory system is done in view of feature of automatic balance, and the result is that the accurate model of system can be gained by compensa- tion method and the traditional principle error of balance machines both for soft and hard bearing can be overcome. The automatic balance testing theory for sofi and hard bearing machines is pro- posed. The automatic balance system has been developed and the function and technical key is also introduced in detail.

带柔性部件飞行器刚性耦合系数矩阵优化算法

针对目前飞行器刚性耦合系数矩阵算法中按照单元节点规律排列的质量矩阵数据处理难度大,运算维度高的问题,本文提出一种非离散化方法的刚性耦合系数矩阵优化算法,利用在三维模型中可以直接获取的柔性部件质量特性,替代高维度的质量矩阵参与计算,避免了模型离散化误差,在简化刚性耦合系数计算流程的同时,具有提高计算结果准确度的效果,增强了工程设计中的便利性.

基于分叉传递矩阵法的多跨连续刚构桥桥墩有效长度系数

桥墩的有效长度系数对桥墩的稳定性和强度十分重要。为解决桥墩的稳定性问题,本文建立了一种便于采用传递矩阵法求解的新颖力学模型,并基于该方法计算了多跨连续刚构桥的有效长度系数。首先,建立n跨刚构桥的一般力学模型,并利用传递矩阵法推导了其在考虑自重荷载情况下的平面内稳定特征方程,进而求得弹性屈曲载荷和有效长度系数,并将其与有限元法得到的结果进行对比,从而验证所提理论和方法的正确性。其次,研究了用碳纤维增强聚合物和超高性能混凝土加固桥墩时,桥墩有效长度系数的变化规律。最后,探讨了边跨与中跨之比、桥面梁刚度以及桥墩刚度对桥墩有效长度系数的影响。结果表明,增强整体结构刚度比增强局部刚度对提高稳定性更有效,桥梁边跨和中跨跨度对有效长度系数的影响较大。同时,还观察到碳纤维增强聚合物加固高度改变时,桥墩有效长度系数变化曲线产生了独特的双峰效应。

基于空间变换矩阵编程的变电工程GIM图元合规化研究

针对国内电网信息模型(Grid Information Model,GIM)建模软件众多,数据来源广泛,施工图设计过程中普遍存在图元属性不合规,导致工程模型无法与建筑信息模型(Building Information Modeling,BIM)平台兼容的问题。基于空间变换矩阵的相关理论,利用GIM标准基本图元在三维空间中的刚体特性,通过计算机编程实现变电工程GIM模型文件标准基本图元合规化,对数据来源广泛的变电站GIM文件进行快速图元合规化处理,进而提高变电工程三维设计的效率和成品质量。

三维最优持久编队拓扑生成策略

针对智能体间的通信拓扑优化问题,结合图论知识研究了三维空间中最优持久图的生成算法.首先,利用刚度矩阵生成最优刚性图;然后,根据顶点连通度数的不同分别采取有向化操作方法,通过逐层缩小最优刚性图范围的方式把刚性图持久化,生成了最优持久图;最后,对三维空间中随机分布的智能体进行仿真实验,其结果验证了该算法的可行性和有效性,此算法能降低编队拓扑的通信复杂度,减少通信能量消耗.

Norea矮塔斜拉桥索力优化

为确定柬埔寨Norea三跨双塔单索面混凝土矮塔斜拉桥的最优成桥索力,基于有限元模型,分别采用刚性支撑连续梁法、最小弯曲能法、影响矩阵法对成桥索力进行了分析和优化。结果表明:三种优化方法中以影响矩阵法得到的索力值效果最好,将最终优化索力值与原设计值对比,分析了斜拉桥的内力、位移以及应力变化,在恒荷载或恒荷载+附加荷载组合作用下,优化后的索力分布更加均匀,结构整体的弯矩、位移以及应力均有所减小,矮塔斜拉桥整体受力和线形更加理想。

SiO_2凝胶玻璃中联吡啶S_2→S_0辐射跃迁

联吡啶以分子水平掺入SiO2凝胶玻璃中,显示出独特的光谱性质。其发射光谱除了正常的S1→S0跃迁产生的中心位于400nm的发射峰外,还出现了中心位于454nm的激基缔合物发射峰。经200℃处理后,联吡啶分子受Si—O网络刚性约束,激基缔合发射峰消失,出现了基于S2→S0辐射跃迁产生的325nm高能级发射峰。至550℃处理后,因联吡啶分子基本进入Si—O三维网络的间隙,发射光谱中只剩下振动结构明显的高能级荧光峰。上述结果为表征有机/无机复合材料微结构演变提供了荧光探针工具。

弹性梁刚度矩阵算法及应用

通过实例介绍了一种实用简单的弹性梁结构刚度矩阵计算方法,可广泛应用于含有弹性梁结构的惯性器件如传感器的设计中。最后介绍了该算法的一种应用,并用ANSYS有限元软件分析验证了其正确性。

复杂载荷下变刚度静不定梁程序化求解

对于有复杂载荷的变刚度静不定梁,常用的方法无法求解。建立一种复杂载荷下变刚度静不定梁求解的通用力学模型,从该模型推导出任一截面的转角和挠度变形方程,由变形方程得出静不定梁程序化求解的通用矩阵。用Matlab语言开发出相应的静不定梁求解程序,实现了对复杂载荷变刚度静不定梁的计算机求解。在静不定梁模型建立和求解推导过程中,不需进行载荷和梁结构的简化,对静不定梁两端的支承形式也没有限制,是一种适于应用计算机编程进行求解的通用计算方法,实际应用效果很好。

带刚臂的两节点精确悬链线索元的非线性分析

为解决应用悬链线索元时锚固点的刚性连接问题,在应用悬链线基本方程导出的两节点悬链线索元的切线刚度矩阵基础上,推导出两端带任意刚臂的两节点精确悬链线索元的切线刚度矩阵显式表达式,并且分析了考虑索元初次张拉和成形使用两种条件下切线刚度矩阵的迭代求解技术。分析和算例表明,应用两端带任意刚臂的两节点精确悬链线索元可以很好地解决前述问题,且其有限元分析格式与不带刚臂的悬链线索元完全一致,而且当索元不带刚臂时该切线刚度矩阵可自动转化为相应的刚度矩阵,实用价值较强。

网壳结构节点体对其承载性能的影响

提出用大位移带刚臂杆元来考虑节点大小对网壳结构承载性能的影响，推导出大位移带刚臂元的影响矩阵，修正了Ｃ．Ｏｒａｎ［１］的渠－柱单元切线刚度矩阵，并对类似的支座节点体进行了同样的推导修正．通过对网壳结构算例的分析计算，证明了文中理论的正确、可靠．

自锚式悬索桥的主缆线形计算与误差分析

介绍了基于分段悬链线法和抛物线法的自锚式悬索桥主缆线形计算的原理和步骤,考虑弯矩对加劲梁轴向刚度的影响,提出采用非线性规划方法进行迭代计算,所得计算结果与传统的影响矩阵法结果吻合.典型跨度自锚式悬索桥主缆线形的计算结果表明,抛物线法对成桥恒载状态的计算误差很小,一般可满足工程设计和施工的精度要求,但空缆吊点坐标和索鞍预偏量的计算误差很大.文中还针对不同矢跨比、跨度、边中跨比和主缆应力安全系数的自锚式悬索桥,采用抛物线法进行了主缆线形的误差分析.

橡胶胀形模设计

通过实例介绍了橡胶胀形模的设计方法 ,并详细地叙述了工艺参数的选择计算及模具结构、工作过程和弹性凸模。

多层地基内部作用集中力时Biot固结方程的求解

应用Schiffman位移函数 ,并借助于Hankel变换和Laplace变换 ,建立了单层饱和土的递推矩阵和半空间饱和土的刚度矩阵 利用边界条件 ,用初始函数 -刚度矩阵方法求出了半空间上多层饱和土内部作用集中力时位移、应力和孔压的解答 当多层地基退化为半空间饱和土体时 ,计算结果表明 ,当t→∞时 。

叉桥薄壁箱梁结构的简化分析

以典型人字形薄壁箱梁桥为研究对象,通过增加自由度的分析方法,在初等梁理论的基础上考虑薄壁箱梁主要的受力特点,同时利用空间梁格理论对结构在分析方法上进行简化。另外,以某人字形桥梁工程为例,分别建立空间普通梁模型、空间板壳模型以及简化的分析模型进行比较分析,验证了简化模型的准确性、简便性,同时指出了3种不同理论对人字形桥梁进行分析时存在的优缺点。研究结果表明:本文分析方法能够简便、准确地把握该结构的行为,为求解该结构提供新的途径。