PATH CONTROL OF A 3-DOF ROBOT MECHANISM ACTUATED WITH LOW-PRESSURE AIR POWERED MOTORS

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Rotational equations usable for railway wheelsets

The Euler equation is a correct way for writing rotational moments of solids. But it is simple only if written in rotating frames. Applying it to railway wheelsets is difficult because it necessitates using the Euler angles, or Euler parameters, combined to rotation matrices or, numerically more stable, quaternions. Euler angles can be avoided in railway specific codes, by writing dynamical equations in track frames. However, academic literature [Landau LD, Lifshitz EM. Mechanics (Institute of Physical Problems, USSR Academy of Sciences, Moscow), Vol. 1, Course of theoretical physics. 21st English ed. Oxford (UK): Elsevier; 1960; Shabana AA, Zaazaa KE, Sugiyama H. Railroad vehicle dynamics. CRC Press; 2008.] does not provide simple solutions as to how properly writing equations of gyroscopic moments in no rotating frames. This paper describes how it is possible, owing to an approximation validated for railway applications, to avoid Euler angles and rotation matrices, while correctly taking into account gyroscopic effects. Using a most severe example, emphasising gyroscopic effects, it is demonstrated that a fast specific code using the approximation provides results equivalent to those of an multi body system generalised code with no approximation.     

Codes From Strongly Regular (α,β)-reguli

Strongly regular (α,β)-reguli are a class of incidence structures with given conditions which were introduced by Hamilton and Mathon. We introduce two classes of codes constructed from strongly regular(α,β)-reguli within PG(k-1,q). The codes are related with two-weight codes intimately.     

基于不同规范的连续梁桥确定性及可靠性对比分析

针对分别采用《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG 3362—2018、JTG D62—2004、JTJ 023—1985)设计的满堂支架现浇施工连续梁桥进行确定性和可靠性对比分析,通过有限元程序对成桥阶段选取的典型截面可靠指标进行计算。结果表明,确定性分析和可靠性分析结果有不同规律,不能单从确定性分析结果的大小来判断结构安全储备,需将确定性分析与可靠性分析相结合,才能对结构有合理准确的判断与评价。     

二次扩展复数旋转码及其对偶码

扩展复数旋转的基础上,提出了二次扩展复数旋转码及其对偶码的概念。就它们的特性作了初步的讨论,并给出了它们的生成矩阵的构造方式及主要参数。经过与扩展复数旋转码和其对偶码相比较,可以看出它们也是一类码率高、纠错能力强的差错控制码。     

旋耕机刀轴的优化设计

针对旋耕机刀轴传统设计的不足 ,采用现代机械优化设计方法 ,建立了旋耕机刀轴优化设计的数学模型 ,并给出了计算实例。     

铁路工务日报月报信息管理系统的研究与开发

铁路工务现场作业历史数据的收集、管理和经济评价,是工务信息管理系统的重要基础,须通过工务日报月报的管理来实现.介绍了工务日报月报信息管理系统的设计思路、工务作业编码、系统实现和应用情况.     

高压旋喷桩技术的应用

简要介绍深层高压旋喷桩处理软土地基的加固机理、设计采用的方法、施工工艺及注意事项、以及成桩后的检测,通过万环西路软基处理的工程实践证明,该方法是成功的,可为类似工程提供经验。     

沥青混合料旋转压实与马歇尔击实试件体积特性差异的初步试验研究

该文利用Superpave旋转压实成形机和马歇尔自动击实仪对具有相同级配的沥青混合料进行成形,通过对比两种试件的体积特性来初步分析两种成形方法的差异。研究发现,125次旋转压实成形的试件与75次马歇尔击实成形试件的体积特性差异受细料品质影响很大,研究认为,马歇尔击实和旋转压实成形有着本质的区别,针对马歇尔击实次数建立等效的旋转压实次数是不现实的。     

转阀式内燃机配气机构

设计了一种转阀式内燃机配气机构,可消除发动机气门产生的震动及噪声,易于实现气门开度及正时的连续调节,能简化发动机结构,提高其可靠性。