医院建筑开放体系及其适应性策略研究

本文梳理了自20世纪60年代起,各国对医院建筑应变的探索,分析了医院建筑开放体系的基本理念,并对医院建筑开放体系的应变模式提出了质疑,从而探讨医院建筑开放体系的适应性策略。     

D53K系列径轴向数控辗环机生产线及其控制系统研究

D53K系列径轴向数控辗环机是应用于各种大中型法兰、齿圈、回转支承加工行业的一种先进的、自动化水平较高的生产加工设备。该系列设备完全依靠自主研发,适应国内生产需要,且大大降低设备成本。经过十几年的发展,该系列产品不断完善,为国内的环件加工企业提供广泛支持。通过PLC(下位机)、人机界面(上位机)、各种高精度传感器、直流电机等通用电气元件中央集中控制,实现了该设备高精、高效、柔性化、低成本的控制特性,提高了产品在国内国际市场的竞争力。     

变步距端子切割机构设计及有限元仿真

提出一种变步距端子切割机构,用于端子联的切割压接,可实现端子联进给、夹紧、切割数量在2~6个间柔性可调。通过UG/Modeling功能建立变步距端子切割机构的三维实体模型,利用UG/Motion运动仿真对所设计机构的三维实体模型进行运动学特性分析,验证该机构运动过程无干涉发生。利用UG高级仿真图形分析该机构运动部件的应力与位移变化情况,找出机构中受力最大、最易破坏变形的受力点,进行可靠性分析;通过有限元分析得出运动部件的应力和位移变化趋于线性,远低于机构的许用值,满足设计要求。该机构已授权发明专利,并与合作企业进行了生产性中试,经过试验验证,证明了该机构的可行性。     

S曲线加减速算法研究

S曲线加减速是高档CNC系统中的一项重要功能。本文对S曲线加速度算法进行了深入的研究，给出了加加速度、加速度、速度、位移的计算通式，并对各种情况进行了讨论，通过一个计算实例表明，本文所给出的S曲线加减速算法克服了传统加减速算法中的缺点，速度在变化过程中十分平滑，是一种适合于高速切削的柔性加减速算法。     

6R工业机器人刚度分析

针对6R工业机器人,在机器人连杆刚性的假设下,推导了机器人柔度矩阵。分析柔度矩阵将其划分为四个子矩阵:力—位移柔度矩阵、力—角位移柔度矩阵、力矩—位移柔度矩阵、力矩—角位移柔度矩阵。在非奇异位姿下,单独考虑力矢量(或力矩矢量)对末端线位移(或角位移)的影响,研究使末端产生单位变形时需要在末端施加的作用力,提出机器人力—位移、力—角位移、力矩—位移、力矩—角位移‘刚度椭球’,来表述机器人末端的刚度特性,为机器人刚度研究提供了一种新思路。最后以库卡Kr360机器人为例进行计算。计算表明对于Kr360机器人,在末端作用力矢量、力矩矢量在同一数量级时,可忽略力矩矢量对末端的作用效果。     

UNCERTAINTY AT BOTH DESIGN AND OPERATION STAGES

Process uncertainty is almost always an issue during the design of chemical processes (CP). In the open literature it has been shown that consideration of process uncertainties in optimal design necessitates the incorporation of process flexibility. Such an optimal design can presumably operate reliably in the presence of process and modeling uncertainty. Halemane and Grossmann (1983) introduced a feasibility function for evaluating CP flexibility. They also formulated a two-stage optimization problem for estimating the optimal design margins. These formulations, however, are based implicitly on the assumption that during the operation stage, uncertain parameters can be determined with enough precision. This assumption is rather restrictive and is often not met in practice. When available experimental information at the operation stage does not allow a more precise estimate of some of the uncertain parameters, new formulations of the flexibility condition and the optimization problem under uncertainty are needed. In this article, we propose such formulations, followed by some computational experiments.     

An improved decomposition algorithm for optimization under uncertainty

This paper proposes a modification to the decomposition algorithm of Ierapetritou and Pistikopoulos (1994) for process optimization under uncertainty. The key feature of our approach is to avoid imposing constraints on the uncertain parameters, thus allowing a more realistic modeling of uncertainty. A theoretical analysis of the earlier algorithm leads to the development of an improved algorithm which successfully avoids getting trapped in local minima while accounting more accurately for the trade-offs between cost and flexibility. In addition, the improved algorithm is 3–6 times faster, on the problems tested, than the original one. This is achieved by avoiding the solution of feasibility subproblems, the number of which is exponential in the number of uncertain parameters.     

Effects of Flexibility on Rocking Impedance of Deeply Embedded Foundation

This paper presents a detailed investigation of the influence on the rocking impedance of flexible sidewalls in embedded foundations. The study focuses on vertical and cylindrical foundations embedded in a homogeneous elastic stratum. In order to anticipate the effects of the flexibility, closed-form formulae for rocking impedance are derived based on three-dimensional wave propagation theory and superposition of both the rocking and flexural movements on a single model by assuming complete bonding conditions between the soil and foundations. A function representing the effect of the flexibility is identified from the closed-form formulae, in terms of the height to radius ratio of the foundations and the ratio of the stiffnesses of the ground and foundations. The rocking impedance for a flexible sidewall differs from those evaluated under the assumption of a rigid sidewall. The applicable range of rocking impedance evaluated under the assumption of a rigid sidewall is assessed, and contours to assist in the estimation of the dynamic response of deeply embedded foundations are presented.     

Approaches to uncertainties in facility layout problems: Perspectives at the beginning of the 21<Superscript>st</Superscript> Century

Production uncertainty is one of the most challenging aspects in manufacturing environments in the 21st century. The next generation of intelligent manufacturing is dynamically depending on the production requirements, and success in designing agile facilities is closely related to what extent these requirements are satisfied. This paper presents the most recent advancements in designing robust and flexible facilities under uncertainty. The focus is on exploring the way uncertainty is incorporated in facility design, namely dynamic and stochastic facility layout problems. Recent approaches are explored and categorized in detail, and previous approaches are briefly reviewed in the related categories. Furthermore, research avenues warranting exploration in the emerging field of facility design are also discussed.     

Financial and financial engineering considerations in supply chain and product development pipeline management

Enterprise-wide decision problems are receiving increasing attention in the process systems engineering literature. In particular, the supply chain and product development pipeline management components of this general class of problems have been subjects of intensive research in both their deterministic and their stochastic forms. The supply chain management (SCM) problem has seen work largely focused on the process operations and logistics components while for the product development pipeline management (PDPM) problem much of the attention has been on MILP formulations addressing the consequences of product failure during its development. In their full realization, both are recognized as challenging stochastic multi-stage decision problems. In this paper we discuss three important aspects of these problems that require further research: the realistic representation of the financial components and appropriate criteria for this class of problems, strategic management of supplier and customer relationships through inventory management and option contracts, and innovative approaches to suitably value and integrate a broader range of decisions available to management. We highlight and extend relevant contributions and case examples drawn from the recent literature that are emerging on these topics and use this work to point out further challenges.