Measurement Control System Research Articles

Investigation of heat transfer and pressure drop in an annular channel with heat transfer intensifiers

Results from systematic investigations of heat transfer and pressure drop for water flow in an annular channel using an efficient method for enhancing heat transfer on a convex heating surface are presented. The main technical data of the thermal-hydraulic experimental setup are given together with a brief description of the control, monitoring, and physical parameters measurement and recording systems, as well as primary experimental data processing and storage system. The test section, the enhancement method based on setting up swirl flows, the geometrical characteristics of intensifiers, their schematic design, and installation technology are described. The experimental data are obtained in a wide range of coolant flow parameters under the conditions of single-phase convection with using intensifiers having different shapes. The test measurements carried out on a smooth annular channel showed good agreement with the classic correlations both for heat transfer and pressure drop, thereby confirming reliability of the experimental data. A considerable improvement in heat removal efficiency on the convex heating surface is obtained. The value of heat transfer coefficient is a factor of 1.8 higher than it is for smooth annular channels. The region of the values of intensifier geometrical characteristics and Reynolds numbers for which the growth of heat transfer prevails over the growth of pressure drop is established. It is shown that the maximums of heat transfer and pressure drop are observed at quite definite values of intensifier geometrical characteristics. The primary experimental data are processed and presented as a dependence of the Nusselt number on the Reynolds number for different values of the intensifier’s relative fin height Ḣ. The value of Ḣ at which heat transfer reaches its maximum is found. The experiments were carried out in the pressure range p = 3.0–10.0 MPa and at the constant temperature of liquid at the test section inlet equal to 100°C. The influence of peripheral liquid flow swirling pitch on heat transfer and pressure drop is studied. An empirical correlation describing the dependence of heat transfer on the intensifier geometrical characteristics is obtained.

基于嵌入式机器视觉的激光熔覆成形熔池离焦量在线测控系统

基于嵌入式机器视觉的激光熔覆成形熔池离焦量在线测控系统

Intelligent measurements for monitoring and control of glass production furnace for green and efficient manufacturing

Liquefied petroleum (LP) gas is used as one of the fuel systems for glass production furnaces. This research was conducted to develop an intelligent online measurement system for monitoring and control of LP gas so as to achieve green and efficient manufacturing. LP gas is mixed with air at a desired ratio in order to get a proper specific gravity for glass production. Counterpropagation neural networks (CPNs), which are based on competitive learning, were used in this work. Three inputs, air inlet pressure, air/mixed gas differential pressure, and propane/mixed gas differential pressure, were selected for online measurements of specific gravity for monitoring and control of a glass production furnace. Using a 3 × 12 × 1 CPN yields exceedingly successful results for online measurements of specific gravity. An average error of 1.68 %, a minimum error of 0.08 %, and a maximum error of 4.43 % were achieved for online measurements. Control actions can then be taken to achieve much higher energy efficiency which is very important for glass production for green and efficient manufacturing.

Distance Measurement System using A Stereo Camera and Radial Pattern Target for Automatic Berthing Control

In this paper, we propose a distance measurement system for automatic berthing control using a stereo camera mounted on a rotation control device, and a radial pattern target. Automatically controlling the position and attitude of a ship aims to prevent maritime accidents due to human error. Our goal is to measure the relative distance between a ship and an onshore or offshore target for berthing. Therefore, the distance should be continuously measured while tracking a fixed point on a target. To this end, we developed a stereo camerabased distance measurement system that satisfied these requirements. This paper describes the structure and principle of the measurement system. We validate the distance error for target incline due to the relative position and attitude between a camera and a target in miniature scale. In addition, the findings of an experiment in an outdoor environment demonstrate that the proposed measurement system has accuracy within 1 m at a range of 20-100 m which is the acceptable accuracy for automatic berthing.

Research on Tyred Machinery Chassis Dynamometer

In the tyred machinery chassis dynamometer control system, a fuzzy PID controller was used to adjust the exciting current of a DC dynamometer in order to change the resistance load torque, so the requirement of roller load for simulating the run resistance from the road surface was satisfied. A fuzzy PID arithmetic was designed to control the resistance loads, the system performance was improved by simulation. The software of the detection line measure-control system was designed in VB, the technical parameters of the machinery chassis could the automatically detected.

Development of distributed measurement and control systems for application in electrical energy systems

In this paper LPC1766 microcontroller based network capable application processor (NCAP) system, is described. This system is intended to be used in modern distributed control and monitoring systems for application in power plants and industry, as well as in modern electricity distribution networks. In order to do that it is necessary to analyze different aspects of the system, like signal processing part or communication requirements. The chosen microcontroller has enough resources to satisfy requirements of an transducer interface module (TIM). Beside the realization of NCAp and TIM controllers it is necessary to develop the necessary measurement modules, in order to realize measurement-control systems. The developed layout could be connected to actuators to the local area network (LAN), as well. If the local LAN is connected to the internet it is possible to monitor and configure measurement modules form the remote site. Having in mind the growing complexity in control systems, it has been a real challenge to detect a diagnose problems in today's large scale distributed systems. Implementation of the proposed module could potentially reduce the time necessary to extract necessary information from the abundant quantity of information that are usually provided by the complex distributed systems.

Validation of iGPS as an external measurement system for cooperative robot positioning

External metrology systems are increasingly being used in modern manufacturing to improve the accuracy of industrial robots. In this paper, the problem of achieving absolute accuracy in the positioning and movement of cooperating robots is addressed using the indoor GPS (iGPS) technology as an external position measurement system for real-time feedback and control. This metrology system is presented as an introduction to the iGPS-based 3D Pose Detector and a new concept using generalised measurement systems inspired by iGPS. Attached to the robot end-effectors, the receivers allow coordinate frame measurements to provide spatial information on the robot poses in six degrees of freedom. Experimental results show a strong correspondence between iGPS measurements of cooperating robot end-effector positioning and the control measurements obtained from a double ballbar. Ballbar measurements are further used to determine the relative accuracy between state-of-the-art cooperating manipulators. The iGPS system is validated as an external measurement system using a ballbar device, and its use in the external control of basic robotic tasks is demonstrated. The predicted accuracy achievable for the robots when being controlled or compensated is determined to be at least within 0.3 mm, subject to improvements with continuing research and refinements.

Evaluation of methods for determining food surface temperature in the presence of low-pressure cool plasma

Cool plasma technology is being developed for decontamination and modification of food surfaces. Microwave cool plasmas generated at low pressures, between 0.1 and 2 mbar, are generally believed to induce only weak heating of food surfaces, with effective temperatures below 60 °C, and, therefore, to be suitable for the treatment of thermo-labile materials. Measurement techniques suitable for determining the temperature of product surfaces undergoing plasma treatment are essential to confirm that the temperature is acceptably low, and for effective process control. The harsh environment in the plasma treatment chamber, including the low pressure and the presence of electromagnetic fields, electrons and other reactive species, such as ions, excited molecules and radicals, poses a challenge to establishing reliable and reproducible techniques for surface temperature measurement. This paper compares the performance of fiber-optic probes, thermocouples (with and without sheaths), resistance thermometers, Thermochrons (temperature loggers) and temperature indicators (color changing strips and tapes) under low-pressure microwave cool plasma conditions. Both the reliability of the temperature measurement and the response time are considered. It is found that the fiber-optic probe is the only method that both has an acceptably fast response time and is not susceptible to interference from the plasma environment. Cool plasma technology is being investigated and developed for decontamination of food surfaces. The technology is being considered as very promising alternative to chemical and/or heat processing, particularly for the decontamination of fresh produce and dry food products, such as seeds and nuts, but also powders. The low temperatures on food surfaces, with effective temperatures below 60 °C, make the process suitable for the treatment of thermo-labile materials. Measuring the temperature of product surfaces undergoing plasma treatment is essential to both confirm that the temperature is acceptably low, and for effective process control. The harsh environment in cool plasma, including the presence of electromagnetic fields, electrons and other reactive species, however, poses a challenge to establishing reliable and reproducible techniques for surface temperature measurement. For industrial uptake of the technology not only the process validation from a food safety perspective is important, but also the capability of fast and accurate temperature sensing. The findings of this study allow food and equipment manufacturers to choose the most appropriate temperature measurement system for temperature control in an industrial low pressure cool plasma process.

Designing a unified wireless system for vibration control

This research aims to develop a unified wireless control system which would successfully control the vibration of bridges, and also to evaluate its performance. In this unified wireless control system, a wireless measurement control system is developed independently from the central system, and it controls the structure by feedback on the basis of the measured signals transmitted from the control device. Also this independent control system wirelessly monitors the general performance of the control device on the site and reports to the central control system. Embedded with control algorithm and made into a system with the control device, it continuously controls the vibration by feedback. Since this independently made wireless measurement-control system does not have enough memory space for effective control, all signals can be made to communicate wirelessly with the central control system which has more memory space. When needed, a user can directly intervene in the control process. When the possible disconnection of wires due to earthquake or some other disasters can cause troubles in data transmission or power supply, the wireless control system can safely perform its function. The performance of this unified wireless control system is evaluated in comparison to a wired control system by means of vibration control experiments on bridges. In these experiments, a semi-active control method is selected, and all outputs are quantitatively compared and evaluated. As a result, this unified wireless control system with a central control system is proved to be effective for vibration control and also overcome the shortcomings of the wired system.

실외 주행환경을 고려한 카메라 기반의 RTGC 위치계측시스템 개발

This paper describes a camera-based position measurement system for automatic tracking control of a rubber Tired Gantry Crane (RTGC). An automatic tracking control of RTGC depends on the ability to measure its displacement and angle from a guide line that the RTGC has to follow. The measurement system proposed in this paper is composed of a camera and a PC that are mounted on the right upper between front and rear tires of the RTGC's side. The measurement accuracy of the system is affected by disturbances such as cracks and stains of the guide line, shadows, and halation from the light fluctuation. To overcome the disturbances, both side edges of the guide line are detected as two straight lines from an input image taken by the camera, and parameters of the straight lines are determined by using Hough transform. The displacement and angle of the RTGC from the guide line can be obtained from these parameters with the robustness against the disturbances. From the experiments with the disturbances, we found the accurate displacement and the angle from the guide line that have the standard deviations of 0.95 pixels and 0.22 degrees, respectively.

Initial Design of FAST Engineering Surveying Control Network

The high precision surveying control network provides the positional and orientation datum for the construction and measure-control system of the Five- hundred-meter Aperture radio Sphere Telescope(FAST), which is deployed at the typical Karst depression. The design of the control network is in accordance with the 1:1000 topographic maps. The issues about the control station site selection ,distribution and construction are analyzed and discussed, and the initial results are provided in this paper.

Proposed System for Measuring Project Performance Using Process-Based Key Performance Indicators

Despite some evidence of its usefulness, performance measurement by using Key Performance Indicators (KPIs) in the construction industry also has its critics. Among the shortcomings attributed to existing KPIs is the fact that almost all of them are product oriented. This means that the indicators are mostly used for review purposes after a project is completed and do not provide the opportunity to control the work whilst the project is still in progress. Many researchers have agreed on the need for a new approach that considers the construction process and allows active control. This paper describes the design of a proposed generic system for measuring process performance. As a basis for measuring process performance, the proposed measurement system relies on a series of questions related to both process completeness and process quality. The structure of the measurement system is on the basis of the findings of an earlier stage of the research that had resulted in the development of a number of process-based KPIs and the key issues they encompass. The appropriateness of the proposed measurement system has been tested on two on-going projects. The testing has shown that the proposed system produces relatively accurate indications of actual performance of construction projects. In this research, it was not possible to test the validity or the effectiveness of the proposed measurement system for control in practice. This is because of the long timescales involved in real-life projects and because of the possible influence of control actions taken by project management between the various processes

Multipoint sensor based on fiber Bragg gratings

In some control and industrial measurement systems of physical variables (pressure, temperature, flow, etc) it is necessary one system and one sensor to control each process. On the other hand, there are systems such as PLC (Programmable Logic Control), which can process several signals simultaneously. However it is still necessary to use one sensor for each variable. Therefore, in the present work the use of a multipoint sensor to solve such problem has been proposed. The sensor consists of an optical fiber laser with two Fabry-Perot cavities constructed using fiber Bragg gratings (FBG). In the same system is possible to measure changes in two variables by detecting the intermodal separation frequency of each cavity and evaluate their amplitudes. The intermodal separation frequency depends on each cavity length. The sensor signals are monitored through an oscilloscope or a PCI card and after that acquired by PC, where they are analyzed and displayed. Results of the evaluation of the intermodal frequency separation peak amplitude behavior with FBG stretching are presented.

Real-time stability measurement system for postural control

A method for assessing balance, which was sensitive to changes in the postural control system is presented. This paper describes the implementation of a force-sensing platform, with force sensing resistors as the sensing element. The platform is capable of measuring destabilized postural perturbations in dynamic and static postural conditions. Besides providing real-time qualitative assessment, the platform quantifies the postural control of the subjects. This is done by evaluating the weighted center of applied pressure distribution over time. The objective of this research was to establish the feasibility of using the force-sensing platform to test and gauge the postural control of individuals. Tests were conducted in Eye Open and Eye Close states on Flat Ground (static condition) and the balance trainer (dynamic condition). It was observed that the designed platform was able to gauge the sway experienced by the body when subject's states and conditions changed.

Mathematical model and minimal measurement system for optimal control of heated humidifiers in neonatal ventilation

The control of thermo-hygrometric conditions of gas delivered in neonatal mechanical ventilation appears to be a particularly difficult task, mainly due to the vast number of parameters to be monitored and the control strategies of heated humidifiers to be adopted. In the present paper, we describe the heat and fluid exchange occurring in a heated humidifier in mathematical terms; we analyze the sensitivity of the relative humidity of outlet gas as a function of thermo-hygrometric and fluid-dynamic parameters of delivered gas; we propose a control strategy that will enable the stability of outlet gas thermo-hygrometric conditions. The mathematical model is represented by a hyper-surface containing the functional relations between the input variables, which must be measured, and the output variables, which have to remain constant. Model sensitivity analysis shows that heated humidifier efficacy and stability of outlet gas thermo-hygrometric conditions are principally influenced by four parameters: liquid surface temperature, gas flow rate, inlet gas temperature and inlet gas relative humidity. The theoretical model has been experimentally validated in typical working conditions of neonatal applications. The control strategy has been implemented by a minimal measurement system composed of three thermometers, a humidity sensor, and a flow rate sensor, and based on the theoretical model. Outlet relative humidity, contained in the range 90 ± 4% and 94 ± 4%, corresponding with temperature variations in the range 28 ± 2 °C and 38 ± 2 °C respectively, has been obtained in the whole flow rate range typical of neonatal ventilation from 1 to 10 L/min. We conclude that in order to obtain the stability of the thermo-hygrometric conditions of the delivered gas mixture: (a) a control strategy with a more complex measurement system must be implemented (i.e. providing more input variables); (b) and the gas may also need to be pre-warmed before entering the humidifying chamber.

Measuring the effects of knowledge management practices

Successful managers focus their attention on factors that are critical in establishing and maintaining an organisation's competitive edge. The knowledge and skill of employees is one of those factors and it requires proactive management attention. Conceptually, this is achieved through Knowledge Management, a term that has existed in the mainstream of business lexicon for quite some time. Despite this, there is the conspicuous absence of a common understanding of the term that frustrates many managers. Studies have clearly established that there are three interdependent and complementary pillars that support the concept of Knowledge Management. These are Organisational Learning Management (OLM), Organisational Knowledge Management (OKM) and Intellectual Capital Management (ICM). OLM, which has so far dominated both academic and practitioner debate, concerns itself with the problem of capturing, organising and retrieving explicit knowledge, or information, and has led to the simplistic misconception that Knowledge Management only involves the capture, or downloading, of the content of employees' minds. ICM is dominated by those particularly interested in defining key performance indicators that will measure the impact and the benefits of applying knowledge management practices. If management requires measurement this is an essential task but it can only be undertaken once an organisation has clearly established the strategy‑structure‑process parameters to ensure it accesses, creates and embeds the knowledge that it needs...the OKM pillar of knowledge management. This paper looks more deeply at this pillar and in particular the lack of a general integrative approach to enhancing organisational performance in this key strategic area. It considers to what extent such an approach may help an organisation more effectively manage its most relevant source of competitive advantage. With a greater awareness of the various factors allied to the managing and leveraging of human oriented and system oriented knowledge assets, some proposals are put forward to assist in developing or redefining an organisation's intellectual capital reporting models in search of a planning, control and performance measurement system that accounts for the management of an organisation's intellectual assets.

ENEL PILOT: From a Research Testbed to a Virtual Educational Laboratory

Education in the field of distributed process control and intelligent actuation and measurement (IAM) systems can be greatly enhanced through the use of tools that simulate the behavior of real systems, thus allowing students to test and compare different configurations. In this paper, we present an educational virtual laboratory, called the IAM-Pilot Virtual Laboratory (IPVL), which simulates a physical process consisting of a closed circuit of treated water implementing four regulation loops for pressure, level, flow, and temperature, respectively. This tool is the virtual implementation of a real research laboratory (IAM-Pilot), which was developed a few years ago in the framework of several projects funded by the European Commission, in order to test concepts regarding distributed systems, technologies, and components. The tool allows students to set several different system configurations, both in the control and communication parts, and then assess the resulting behavior. They can also install on the plant different virtual devices, with different features, and monitor their effect on the system. The tool produces graphs that allow students to evaluate the performance offered by the control system. This paper describes the architecture and implementation of the IPVL and reports on its usage in the context of the distributed process control network course at the Faculty of Engineering, University of Catania.

Radio Frequency Measurement and Control Network for a Cable Equipped with the Magnetorheological Damper

The paper is devoted to an investigation of a Radio Frequency (RF) measuring-control system equipped with sensors and actuators distributed along the cable. Displacement, acceleration and strain sensors together with an actuator and PWM type control signals can be used. This system is configured to operate with the experimental setup specially developed to study MR damper performance for vibration suppression of cables. The RF measuring-control system structure, transmission protocol and radio disturbances problem are discussed. The experimental results for the cable laboratory system are presented.

Quality Control of Food Products using Image Analysis and Multivariate Statistical Tools

Visual appearance is an important feature in the quality assessment of food products, since it plays a key role in the decisions made by consumers. Frequently, its evaluation is carried out by a panel of experts from the quality department who analyze, by visual inspection, samples of product taken from the process. It is well-known that such methodologies of assessment suffer from several drawbacks, such as subjectivity, limited precision, and lack of stability over time, even for well-trained personnel, although extensive training programs can improve assessment performance. In this context, we present in this paper results regarding the development of an automated methodology for assessing the visual appearance of cereal flakes, in what concerns a particular quality feature, relative to the existence of regions where cereal coating is inadequate. The proposed procedure is able to extract the necessary information from images taken from product samples, leading to an objective, stable, and quantitative quality control measurement system for this property. The developed algorithm essentially consists of implementing a supervised classification methodology, based on the estimated Mahalanobis distance for assessing proximity in the color space, while incorporating the natural variability and color correlations found in cereal flakes. This procedure also integrates fuzzy logic reasoning for samples falling under regions closer to the classes’ boundaries. Results obtained from a real industrial plant indicate that it is indeed possible to classify different samples of flakes according to classes previously defined. They also provide a sound basis for further developments, in particular regarding the generation of metrics for quality assessment and the implementation of a similar procedure online and in situ.

Schneider Electric Argentina: Beyond Budgeting

Nowadays, Schneider Electric is the world leader of electrical distribution, industrial control, and automation - at both product and service levels. Worldwide, Schneider consists of 105.000 employees in 190 countries, 25 research and development centers, 207 production plants, 60 logistic centers, 15.000 sales outlets and consolidated revenues of euro 14 billion. In 2003, Schneider Electric Argentina ceased to use the budget as a control tool - a cornerstone foreseen in the Managerial Performance Project (MAP). This Project promoted by headquarters and implemented in the whole company, implied the joint use of three tools: rolling forecast, consolidated accounting and balanced scorecard instead of the traditional budgeting and local profitability concepts. Three years later, it is time to make a management balance and questions about advantages and future fears arose. The case allows deepening into advantages and problems appeared when implemented a model aligned to the Beyond Budgeting concept. The discussion lets know the alternative model to the traditional budget considering problems and advantages; analyze the existent alignment between compensation, control and performance measurement systems; deal the issue of slacks creation and think about the impact generated by variable and fix compensations. To write this case was used information provided by the company and interviews to leading actors of the case.