Digital twin modeling method based on biomimicry for machining aerospace components

High-performance aerospace component manufacturing requires stringent in-process geometrical and performance-based quality control. Real-time observation, understanding and control of machining processes are integral to optimizing the machining strategies of aerospace component manufacturing. Digital Twin can be used to model, monitor and control the machining process by fusing multi-dimensional in-context machining process data, such as changes in geometry, material properties and machining parameters. However, there is a lack of systematic and efficient Digital Twin modeling method that can adaptively develop high-fidelity multi-scale and multi-dimensional Digital Twins of machining processes. Aiming at addressing this challenge, we proposed a Digital Twin modeling method based on biomimicry principles that can adaptively construct a multi-physics digital twin of the machining process. With this approach, we developed multiple Digital Twin sub-models, e.g., geometry model, behavior model and process model. These Digital Twin sub-models can interact with each other and compose an integrated true representation of the physical machining process. To demonstrate the effectiveness of the proposed biomimicry-based Digital Twin modeling method, we tested the method in monitoring and controlling the machining process of an air rudder.     

基于MBD模型的航空发动机零件检测技术

针对当前复杂零件中异型特征位置度无法测量的问题,提出了一种基于MBD模型数字化测量技术.该方法以复杂零件的MBD模型为测量依据,通过模型理论元素与实测元素拟合计算异型特征位置度偏差,并以此为基础进行测量工艺规划、测量程序编制、测量仿真等.可大大减少在机等待时间,避免测量过程中的碰撞与测针干涉问题,解决了不规则特征位置度测量问题,实现了全程的自动测量,提高了检测效率.     

An Efficient Multibody Dynamics Model for Internal Combustion Engine Systems

The equations of motion for the major components in an internalcombustion engine are developed herein using a recursive formulation.These components include the (rigid) engine block, pistons, connectingrods, (flexible) crankshaft, balance shafts, main bearings, and enginemounts. Relative coordinates are employed that automatically satisfy allconstraints and therefore lead to the minimum set of ordinarydifferential equations of motion. The derivation of the equations ofmotion is automated through the use of computer algebra as the precursorto automatically generating the computational (C or Fortran) subroutinesfor numerical integration. The entire automated procedure forms thebasis for an engine modeling template that may be used to supportthe up-front design of engines for noise and vibration targets.This procedure is demonstrated on an example engine under free(idealized) and firing conditions and the predicted engine responses arecompared with results from an ADAMS model. Results obtained by usingdifferent bearing models, including linear, nonlinear, and hydrodynamicbearing models, are discussed in detail.     

The effect of frequent hemodialysis on matrix metalloproteinases,their tissue inhibitors,and FGF23: Implications for blood pressure and left ventricular mass modification in the Frequent Hemodialysis Network trials

Background: Frequent hemodialysis modifies serum phosphorus, blood pressure, and left ventricular mass (LVM). We ascertained whether frequent hemodialysis is associated with specific changes in biomarker profile among patients enrolled in the frequent hemodialysis network (FHN) trials. Methods: This was a post hoc analysis of biomarkers among patients enrolled to the FHN trials. In particular, we hypothesized that frequent hemodialysis is associated with changes in a specific set of biomarkers which are linked with changes in blood pressure or LVM. Results: Among 332 randomized patients, 243 had biomarker data available. Of these, 124 patients were assigned to 3‐times‐a‐week hemodialysis (94 [Daily Trial] and 30 [Nocturnal Trial]) and 119 patients were assigned to 6‐times‐a‐week hemodialysis (87 [Daily Trial] and 32 [Nocturnal Trial]). Frequent hemodialysis lowered phosphate, blood pressures, LVM, log fibroblast growth factor (FGF)23, and tissue inhibitors of metalloproteinase (TIMP)—2 levels. The fall in phosphate was associated with changes in FGF23 (r = 0.48, P < 0.001) [Daily Trial] and (r = 0.55, P < 0.001) [Nocturnal Trial]) and tended to be associated with changes in systolic blood pressure (r = 0.18, P = 0.057) [Daily Trial] and (r = 0.31, P = 0.04) [Nocturnal Trial]. Within the Daily Trial, changes in MMP2 (r = 0.20, P = 0.034) were associated with changes in LVM. In the Nocturnal Trial, changes in TIMP‐1 (r = 0.37, P = 0.029) and MMP 9 (r = ?0.38, P = 0.01) were associated with LVM changes. MMP2 changes were associated with changes in systolic blood pressure. Conclusions: Reduction of serum phosphate by frequent hemodialysis may modulate FGF23 levels and systolic blood pressure. Markers of matrix turnover are associated with LVM changes. Frequent hemodialysis may affect pathological mediators of chronic kidney disease‐mineral bone‐metabolism disorder.     

基于MBD 的产品设计数字化军检研究

针对传统军检技术存在质量监督方式落后的问题,就军事代表在产品设计阶段如何开展基于MBD(model based definition)的数字化军检业务进行分析。梳理产品设计阶段的产出物和相应的军检点,并对军检内容、军检方 式和军检对象进行研究。结果表明：在产品设计阶段开展基于MBD 的数字化军检技术,可提升军事代表对装备质 量的监督能力,适应基于MBD 的装备研制体系,是未来军检技术的发展方向。     

基于Pro/E的三维机加工工艺设计方法研究

基于三维模型机加工工艺设计是当前制造领域研究的热点。针对此问题,在分析三维机加工工艺设计特点的基础上,提出了三维机加工工艺设计方法及实施技术途径,并基于Pro/E平台分析了某零件三维机加工工艺设计过程,验证了方法的可行性和有效性。     

基于三维轻模型的装配MES系统关键技术

针对现阶段产品设计已经实现三维数字化,但在航空等典型离散行业的制造现场仍以二维工程图为产品制造依据的现实,提出了基于三维轻模型的装配MES系统,将产品设计数据向制造过程延伸,并结合MBD( ModelBased Definition,基于模型的定义)技术实现基于三维轻模型的装配工艺定义,以三维轻模型为车间现场装配生产的...     

基于模型诊断的研究进展

通过对诊断对象模型、主要诊断方法和聚焦策略的分析和阐述,系统地总结和综述了近年来基于模型诊断的主要研究内容和方法,介绍和比较了3组诊断对象模型,即定性与定量模型、静态与动态模型、确定与概率模型,并针对近几年的研究热点,重点阐述了分布式系统和2类动态系统--时间驱动型系统和事件驱动型系统的相应诊断方法,同时分析了基于优先序的策略、基于删剪条件的策略、基于层次的策略和基于分治的策略这4类聚焦策略,最后对今后的主要研究方向进行了总结和展望.     

基于UG二次开发的PMI信息快速标注研究

随着技术的快速发展,MBD(Model Based Definition)技术逐渐应用到汽车航天等制造领域。MBD技术的核心思想是用一个集成的CAD三维模型来完整的表达产品定义信息,将三维模型作为信息传递的唯一载体。而三维标注技术就是将产品信息和三维模型关联起来的关键环节。针对目前三维标注存在的问题及缺陷,本文提出一种全新的PMI信息快速标注路线。在MBD技术的基础上,制定模型要素的PMI信息明细表,并对CAD模型中的要素进行定义;以UG11.0为开发平台、利用C/C++编程语言实现了CAD三维模型PMI信息的快速标注。     

基于二自由度PI控制的PMSM的参数整定研究

针对传统单自由度PI控制系统难以兼顾抗扰特性和跟踪特性的缺陷,设计了一种基于误差判断的二自由度控制器并给出了参数整定方法.首先,通过简化电流环的数学模型得到转速环的控制目标;然后,采用多主导极点配置法和时域响应性能指标分别设计出二自由度控制器的PI参数;最后,在Simulink平台上搭建了仿真模型并采用基于模型设计(M...