Design process for developing a liquid cooling garment hood

A liquid cooling garment (LCG) protects astronauts by providing cooling effects and preventing them from overheating. The objectives of this project were to improve fit and comfort of the original LCG hood of the MACS-Delphi garment and develop a new prototype. The project was conducted by researchers with different backgrounds: apparel design and physiology and psychology. A design process framework developed by LaBat and Sokolowski (1999 LaBat, K. L. and Sokolowski, S. L. 1999. A three-stage design process applied to an industry-university textile product design project. International Textile & Apparel Association to Clothing and Textiles Research Journal, 17: 11–20. [Crossref] , [Google Scholar]) was used in order to help facilitate the process and aid in communication during the multi-disciplinary collaboration. Four crucial problems were identified: 1) the tubing layout that circulates water did not conform to the shape of the head and tubing distribution was not maximised; 2) a difficult stitching method was being used to attach tubing; 3) fabric sources were inconsistent; 4) the hood did not fit properly. Each problem was addressed, improvements implemented and a revised hood was developed. The hood was tested in an environmental chamber and demonstrated effective cooling. Revisions implemented for the LCG hood may be applied to revisions of the whole-body LCG.

Statement of Relevance:The objectives of this project were to improve fit and comfort of the original LCG hood and develop a new prototype. The new prototype will increase safety of the astronauts by providing better heat extraction quality and improved fit and increased wearer comfort.     

Nearly decoupled multivariable control systems design Part 2. Multi-loop control systems design

The design technique proposed in Part 1 is successfully developed to deal with multiloop control systems design. The inner loop is used to extend the frequency range of sensitivity reduction. In the case of a ‘square’ plant this inevitably leads to an excessive noise-response bandwidth. However, it is discovered that the noise response within the inner loop can be reduced considerably by the use of extra output measurements. Again, the standard model-matching problem plays a vital role in the design of a control system with a ‘tall’ plant.     

数据中心制冷系统非线性模型预测控制

数据中心制冷系统具有非线性、强耦合和大滞后特性,目前常用的PID方法无法实现系统整体能效提升,而现有非线性优化算法计算量大,不易工程实现.鉴于此,提出一种数据中心制冷系统模型预测控制策略,上层优化层设计预测控制器,其目标为在满足制冷要求的前提下降低系统能耗,优化层采用神经网络作为反馈控制器,将系统整体优化目标函数作为神经网络控制器优化性能指标,结合变分法与随机梯度下降法,通过滚动优化求取下层各回路被控变量最优设定值,算法占用存储区适中、计算量小;下层现场控制层通过实时控制使各回路被控变量跟踪最优设定值,可以在不破坏原有现场控制系统的情况下实现性能优化.构建Trnsys-Matlab联合仿真平台,针对系统夏季、过渡季和冬季的控制策略进行仿真实验.结果表明,所提出控制策略能够在满足数据中心安全运行的前提下,实现系统整体能效提升,且具有良好的鲁棒性.     

发光服装无线控制单元的设计

简要综述发光服装的用途。设计了含有发光服装的无线控制单元模块,采用C51语言开发了应用程序。实现了上位机与单片机之间的无线数据传输、遥控切换曲目以及乐谱即时同步控制。     

Force control of twisted and coiled polymer actuators via active control of electrical heating and forced convective liquid cooling

For decades, numerous artificial muscles have been proposed in order to implement beneficial features of biological muscles into robotics. Unfortunately, traditional artificial muscles experienced difficulties in imitating properties of the biological muscles due to mechanical and control issues. Recently, twisted and coiled polymer actuators (TCP) have been shown to produce large mechanical power via thermal stimulations and strong linearity. In this paper, a high-performance TCP thermally cycled by electrical heating and forced convective liquid cooling is designed and associated control algorithms are presented. We elaborate the model of the TCP that is simple, yet provides insight into how the electrical heating and the forced convective liquid cooling contribute to the TCP actuation. The proposed model is verified by experimental studies. Based on the proposed model, we design a feedforward–feedback controller and switching laws, which actively control the TCP in both the heating and cooling cycles. Furthermore, we extend our control methodology to agonist–antagonist TCPs. From the experimental studies, the proposed method is shown to be effective in both single TCP and antagonistic TCPs.     

Generalized control systems,boundary control systems,and delayed control systems

We investigate the relationships between the three classes of systems mentioned in the title: we show that systems with delays in control are a special instance of boundary control systems, and a boundary control system produces a generalized control system when projected onto its (unstable) eigenspaces. We use this observation to investigate the action of feedback on the dynamical behavior of systems with boundary controls. In particular, the well-known fact that spectral controllability is necessary and sufficient for a system with delays in control to be stabilizable is derived from a general rather than from anad hoc method. This paper was written according to the programs of the GNAFA-CNR group, with the financial support of the Italian “Ministero della Pubblica Istruzione.”     

Micromachined jets for liquid impingement cooling of VLSI chips

Two-phase microjet impingement cooling is a potential solution for removing heat from high-power VLSI chips. Arrays of microjets promise to achieve more uniform chip temperatures and very high heat transfer coefficients. This paper presents the design and fabrication of single-jets and multijet arrays with circular orifice diameters ranging from 40 to 76 /spl mu/m, as well as integrated heater and temperature sensor test devices. The performance of the microjet heat sinks is studied using the integrated heater device as well as an industry standard 1 cm/sup 2/ thermal test chip. For single-phase, the silicon temperature distribution data are consistent with a model accounting for silicon conduction and fluid advection using convection coefficients in the range from 0.072 to 4.4 W/cm/sup 2/K. For two-phase, the experimental results show a heat removal of up to 90 W on a 1 cm/sup 2/ heated area using a four-jet array with 76 /spl mu/m diameter orifices at a flowrate of 8 ml/min with a temperature rise of 100/spl deg/C. The data indicate convection coefficients are not significantly different from coefficients for pool boiling, which motivates future work on optimizing flowrates and flow regimes. These microjet heat sinks are intended for eventual integration into a closed-loop electroosmotically pumped cooling system.     

热轧带钢层流冷却控制技术

剖析了传统带钢冷却系统存在的冷却效果差、卷取温度不可控等问题。以国内最近投运的两条热轧线的实际经验为前提,阐述了一些新的控制技术。     

Multi-loop design of multi-scale controllers for multivariable processes

Based on the recently proposed (SISO) multi-scale control scheme, a new approach is introduced to design multi-loop controllers for multivariable processes. The basic feature of the multi-scale control scheme is to decompose a given plant into a sum of basic modes. To achieve good nominal control performance and performance robustness, a set of sub-controllers are designed based on the plant modes in such a way that they are mutually enhanced with each other so as to optimize the overall control objective. It is shown that the designed multi-scale controller is equivalent to a conventional PID controller augmented with a filter. The multi-scale control scheme offers a systematic approach to designing multi-loop PID controllers augmented with filters. Numerical studies show that the proposed multi-loop multi-scale controllers provide improved nominal performance and performance robustness over some well-established multi-loop PID controller schemes.     

液体火箭发动机再生冷却槽黏塑性分析

采用Robinson黏塑性模型,利用渐近积分法结合大型有限元程序Marc完成液体火箭发动机再生冷却槽的热结构耦合分析.经验证,Robinson黏塑性模型能够很好地模拟内壁材料NARloy Z高温时的拉伸特性,且在循环载荷下迟滞回环曲线与试验结果符合良好.冷却槽关键点应力分析明确阐释在不同工作阶段内外壁由于材料属性、工况不同导致的应力制约关系;残余应变分析清晰再现冷却槽“狗窝”失效模式及变形情况,同时为定量计算其损伤累积及剩余寿命提供坚实基础.     

多回路网络化控制系统级联反馈调度

针对动态环境下的多回路网络化控制系统，本文基于反馈控制与网络调度协同设计的思想，提出一种级联反馈调度策略．以优化系统整体控制性能为目标，根据可用带宽资源的动态变化，对控制回路采样周期进行在线调节，将截止期错过率控制在期望的较低水平，并对可用带宽进行优化分配．仿真实验结果表明，相对于传统设计方法，该方法能够明显改善整体控制性能．     

热轧带钢层流冷却控制方法

针对热轧带钢层流冷却终冷温度范围的扩大以及控制精度提高的要求,通过分析影响层流冷却过程的关键性因素如,速度、厚度、喷水量对终轧温度的影响,以及各因素之间相互的作用关系,合理制定出层流冷却的初始值,并建立起层流冷却温度控制的数学模型。运用前馈控制、速度补偿控制的思想以及针对层流冷却特点的线性叠加控制对层流冷却过程进行实时控制。所提出的方法成功运用于某层流冷却生产模型中,实现了终冷温度范围扩大以及控制精度提高的目标。     

Evaluation of two cooling systems under a firefighter coverall

Firemen often suffer from heat strain. This study investigated two chest cooling systems for use under a firefighting suit. In nine male subjects, a vest with water soaked cooling pads and a vest with water perfused tubes were compared to a control condition. Subjects performed 30 min walking and 10 min recovery in hot conditions, while physiological and perceptual parameters were measured. No differences were observed in heart rate and rectal temperature, but scapular skin temperature and fluid loss were lower using the perfused vest. Thermal sensation was cooler for the perfused vest than for the other conditions, while the cool pad vest felt initially cooler than control. However, comfort and RPE scores were similar. We conclude that the cooling effect of both tested systems, mainly providing a (temporally) cooler thermal sensation, was limited and did not meet the expectations.     

Supervisory control of switching control systems

In this paper, the problem of designing a switching policy for an adaptive switching control system is formulated as a problem of supervisory control of a discrete-event system (DES). Two important problems in switching control are then addressed using the DES formulation and the theory of supervisory control under partial observation. First, it is verified whether for a given set of controllers, a switching policy satisfying a given set of constraints on the transitions among controllers exists. If so, then a minimally restrictive switching policy is designed. Next, an iterative algorithm is introduced for finding a minimal set of controllers for which a switching policy satisfying the switching constraints exists. It is shown that in the supervisory control problem considered in this paper, limitations on event observation are the factors that essentially restrict supervisory control. In other words, once observation limitations are respected, limitations on control will be automatically satisfied. This result is used to simplify the proposed iterative algorithm for finding minimal controller sets.     

基于衣片网格局部变形的服装多样性研究

针对服装建模过程中,需要反复修改衣片来获得令人满意的虚拟服装模型以及计算复杂度高的问题,提出一种基于多控制点的衣片网格局部变形方法.该方法首先建立衣片网格模型,然后利用OpenGL的选择模式移动服装关键点,进而得到边界控制点,利用控制点对衣片网格模型进行局部变形,最后对衣片建立受力模型,通过虚拟缝合、碰撞检测以及纹理映射建立三维服装模型,展现服装整体效果,得到多样的服装模型.实验结果表明,由于在算法中不需要重新网络化,故具有较低的计算代价,同时也使得到的服装模型更加多样化.     

Acousto-capacitive tomography of liquid multiphase systems

This paper discusses a tomographic approach focusing on ultrasonic measurements to monitor liquid multiphase mixtures. Separately a capacitive tomography low-cost setup is regarded. Both sensor arrays aim for the localization of variable phase boundaries and the physical characterisation of spatially distributed phases. Focusing on a real time processing, a reduced number of transducers in combination with a fast linear modelling and direct image reconstruction methods are used. Experimental results of a layered 3-phase-system validate the potential and limits of physical resolution of both approaches. Finally, the prospectively intended data fusion of both approaches is discussed.     

FIGARMA - Fully integrated garment manufacture: An extension of the concept of flexible manufacturing systems

The techniques of mechanization, automation and communication, inherent in the present state-of-the-art of assembly manufacturing are being projected into a framework for an extension of the concept of FMS into a configuration of sewing assembly automation, featuring a computer-controlled man/machine interaction at three levels of integration within the plant and based on an integrated CAD/CAM application in the form of multipurpose mini/micro computers, distributed at all three levels of plant operation and controlled by a central, mainframe computer via a company-wide dataprocessing network.     

Monotone control systems

Monotone systems constitute one of the most important classes of dynamical systems used in mathematical biology modeling. The objective of this paper is to extend the notion of monotonicity to systems with inputs and outputs, a necessary first step in trying to understand interconnections, especially including feedback loops, built up out of monotone components. Basic definitions and theorems are provided, as well as an application to the study of a model of one of the cell's most important subsystems.