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.     

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。     

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.”     

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。     

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.     

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.     

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.     

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.     

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.     

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.     

General control systems

In this paper we propose a model for interaction between random environments and random automata. To this model we can apply the theory of (generalized) random systems with complete connections (i.e., learning models or dynamic models) in order to describe its behavior. We shall call such a system a general control system. Next criteria and conditions of expediency of a random automaton within such a system are formulated. Finally two special cases are examined.     

Quadratic control systems

We outline a geometric theory for a class of homogeneous polynomial control systems called quadratic systems. We describe an algorithm to compute a minimal realization and study the feedback classification problem. Feedback invariants are related to the singularities of the input-output mapping and canonical forms are exhibited.     

Version control systems

Sane programmers don't write production code without the help of an editor and an interpreter or a compiler, yet the author has seen many software projects limping along without using a version control system. We can explain this contrast if we think in terms of the increased start-up costs and delayed gratification associated with adopting a VCS. We humans typically discount the future, and therefore implementing version control in a project appears to be a fight against human nature. It's true that you can't beat the productivity boost that compilers and editors provide, but four decades after punched-card programming in assembly language has gone out of fashion, we must now look elsewhere for our next efficiency gains. And if you or your project isn't using a VCS, adopting one might well be the single most important tooling improvement you can undertake.     

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.     

TECHNICAL NOTE: Design criteria for microclimate cooling systems

Abstract

This paper identifies and described 25 design criteria that are desirable characteristics for a microclimate cooling system (MCCS). These criteria can be used as a check list by designers when developing an MCCS, and by organizations when evaluating and selecting MCCSs for use by their employees.     

Sampled-data control of networked linear control systems

In this paper, the problem of synthesis and analysis for the networked control systems (NCSs) with time-driven digital controllers and event-driven holders is considered. The NCS is modelled as a sampled-data system with time-delay in its discrete-time subsystem. This model is able to capture many network-induced features, for example, time-delay and packet dropout. Moreover, the model allows different combinations of the time-driven or event-driven mode of the devices, including the samplers, the controllers and the holders. By transforming time-delay in the discrete-time subsystem into its continuous-time subsystem of the sampled-data system, we have also obtained a less conservative time-delay dependent stability result for the NCSs, using a new Lyapunov function and a relaxed condition. Some limitations of the existing literatures on network-induced time-delay and sampling period are removed in the proposed framework. Furthermore, a sampled-data control design procedure is developed for the NCSs. Linear matrix inequality approach has been employed to solve the stability and control design problems. Finally, numerical examples are included to demonstrate the effectiveness of the proposed stability result and the potential of the proposed techniques.     

Modeling and control of a single-phase marine cooling system

This paper presents two model-based control design approaches for a single-phase marine cooling system. Models are derived from first principles and aim at describing significant system dynamics including nonlinearities and transport delays, while keeping the model complexity low. The two approaches investigated are: a baseline design for performance comparison and a nonlinear robust control design. Performance and robustness of performance for the two control designs are evaluated through a simulation example. Both designs show good robustness towards parameter variations, while the nonlinear robust design performs better in terms of disturbance rejection.