Internet-based monitoring and controlling of real-time dynamic systems

The study in this report mainly focuses on the Internet-based Monitoring and Controlling of a Real-Time Dynamic System interfaced via a dedicated local computer. The main philosophy behind this study is to allow the remote user to conduct an Internet-based Remote Operation (I-bRO) for the dynamic system. The dynamic system has been defined as the system which has its parts interrelated in such a way that a change in one part necessarily affects other parts of the system [I]. In order to achieve this goal, the study has been conducted in a form of an on-line and real-time Virtual Laboratory (VL). Through this form of laboratory, a user can carry out the experiment, perform real-time monitoring and controlling operations of the experiment and collect real and live data from the experiment through the network link as the user was physically in the laboratory. The dynamic system that has been selected for the test-rig of this study is a 3-phase Induction Motor (IM) which is mechanically coupled with a DC-Dynamometer that acts as a variable load to the IM. This system is a common laboratory experiment in the study of the Electrical Engineering for both undergraduate and postgraduate students. The study covers both sides of the I-bRO; the hardware and the software. The hardware side includes the design and the development of a load control box that has been used to interface the DC-Dynamometer and consequently control it from the local computer. The software side covers the design and the development of the Virtual Instrumentation System (VIS) that has replaced successfully the physical Measurement and Test (M&T) instruments of the test-rig. Beside that, the software side includes the development of the internet remote front panel for the remote operation.Furthermore, the software side includes the development of the software that has been used to analyse the system during the I-bRO. In this study, the LabVTEW7 program has been used to design and develop the VIS and the Matlab program has bee used to aualyse the system performance for the remote operations. This study also addresses the issues and problems related to the intranet or the internet to be used as the network for data communication between the test-rig and remote users. This study has been carried out in different stages as follows: 1. Designing and development of the VIS. 2. Interfacing the test-rig apparatus with a local computer. 3. Upload the system from the local computer to the network. 4. Study the performance of the system on the network for the purpose of the remote operations controlled over the internet. The developed system of this study has been used for data acquisition, network communications, instruments monitoring and controlling applications. A user can execute on-line and in the real-time the developed VIS from any point in the university. Due to the fact that the university network is directly integrated to the main internet server. a remote user through the main internet server is able to perform I-bRO of the selected dynamic system. There are many factors associated with the network, the internet or the intranet, and have direct influences on the control system performance throughout the remote operations. The most dominant factors are the random time-delays and the data losses.These factors among others have to be addressed for a proper application of the I-bRO. For this reason, different cases and scenarios of the I-bRO have been investigated and simulated to study the affection of the network on the control system performance. The system is analysed under two control cases, closed loop with random time-delays and open loop when the internet server is disconnected and no communication between the input and the output of the system. In the first case, the closed loop, the internet server is assumed to be closed and subjected to random time-delays. In the second case, the internet server is subjected to random cut-off and thus opens the control loop. The results of both cases have been analysed and discussed. It has been found that, if the control system without the time-delays is stable, it remains stable even with small time-delays up to twenty seconds. This result is different from what has been shown in the literature

Estruturação de um sistema de simulação de instrumentos de medição

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Tecnológico. Programa de Pós-Graduação em Engenharia MecânicaGarantir confiabilidade metrológica é uma necessidade nos sistemas da qualidade; avaliar incertezas de medições é imprescindível no processo de garantia da confiabilidade metrológica. A metodologia de avaliação de incertezas proposta pela ISO - International Organization for Standardization é a do "Guide to the Expression of Uncertainty in Measurement". Sua aplicação exige perfeita caracterização do processo metrológico e é bastante trabalhosa, mesmo que sejam poucos os instrumentos de medição envolvidos. Cada vez mais, os instrumentos são eletrônicos e modulares. Nas medições feitas com cadeias modulares, a caracterização dos processos requer conhecimentos simultâneos de metrologia e de instrumentação eletrônica. Nesses casos, a falta de pessoal especializado tem sido o maior fator limitante à obtenção da garantia da confiabilidade metrológica. A atividade experimental pode contribuir de forma muito significativa, tanto para se conhecer o comportamento metrológico de processos de medição quanto para formação de recursos humanos. Porém a experimentação, além de ter alto custo, esbarra na impossibilidade prática de variação controlada de muitos dos parâmetros envolvidos. Identifica-se aí um cenário apropriado para aplicação de simuladores. Neste trabalho está estruturado um sistema de simulação digital de instrumentos, congregando o estado-da-arte em metrologia, instrumentação, qualidade industrial e informática. O sistema consiste de ambientes, modelos e procedimentos de simulação direcionados à análise do comportamento metrológico de cadeias modulares de medição formadas por instrumentos elétricos. São propostas alternativas inéditas, empregadas no desenvolvimento em Labview de ambientes de simulação e de modelos de características metrológicas estáticas e dinâmicas

Modelo de referencia de laboratorios virtuales y aplicación a sistemas de teleeducación

El origen de esta tesis es encontrar respuestas a la siguiente pregunta: ¿De que forma se puede optimizar el uso de los equipos de laboratorio para que puedan ser utilizados por el máximo número de personas? La opción básica que se ha elegido es el control remoto de los instrumentos a través de internet. Con ello se consigue una accesibilidad total del laboratorio: a cualquier hora, en cualquier día, se pueden realizar medidas sencillamente con disponer de una conexión a internet. Partiendo de esta situación, se ha realizado un estudio de la evolución y situación actal de la instrumentación, de internet y de la teleeducación, los tres pilares en los que se apoya este trabajo. Se observa cómo la instrumentación está tendiendo a la conectividad global al comenzar a incorporar una conexión a red, y la posibilidad de transferir directamente resultados de medida o incluso el control directo del equipo a través de un navegador. Comienza una colaboración que se prevé estrecha entre internet y la instrumentación. La educación a distancia también está tomando un camino similar. El nuevo canal de comunicación que supone la red y la evolución de los ordenadores está permitiendo que se puedan conseguir entornos de trabajo para educación que incorporan desde el sencillo texto con hiperenlaces, herramienta básica del web, hasta transmisión en directo de clases, con vídeo, audio, transparencias e intercomunicación entre los usuarios. De esta forma, la distancia que separa al profesor de los estudiantes y a los estudiantes entre sí, queda minimizada por las capacidades de colaboración y diálogo existentes. A partir de aquí en la tesis se ha pasado al estudio de los instrumentos virtuales, las piezas básicas para el montaje de un laboratorio virtual. Se ha hecho una extensa investigación y clasificación de unos y otros lo cual ha permitido hacerse una idea de los elementos necesarios para la realización de un laboratorio virtual.Rodrigo Peñarrocha, VM. (2003). Modelo de referencia de laboratorios virtuales y aplicación a sistemas de teleeducación [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/7221Palanci