Dressing monitoring with a digital signal processor

Grinding is a finishing process in machining operations, and the topology of the grinding tool is responsible for producing the desired result on the surface of the machined material The tool topology is modeled in the dressing process and precision is therefore extremely important This study presents a solution in the monitoring of the dressing process, using a digital signal processor (DSP) operating in real time to detect the optimal dressing moment To confirm the monitoring efficiency by DSP, the results were compared with those of a data acquisition system (DAQ) and offline processing The method employed here consisted of analyzing the acoustic emission and electrical power signal by applying the DPO and DPKS parameters The analysis of the results allowed us to conclude that the application of the DPO and DPKS parameters can be substituted by processing of the mean acoustic emission signal, thus reducing the computational effort

Noise reduction in speech signals using a TMS320C31 digital signal processor

This paper describes a speech enhancement system (SES) based on a TMS320C31 digital signal processor (DSP) for real-time application. The SES algorithm is based on a modified spectral subtraction method and a new speech activity detector (SAD) is used. The system presents a medium computational load and a sampling rate up to 18 kHz can be used. The goal is load and a sampling rate up to 18 kHz can be used. The goal is to use it to reduce noise in an analog telephone line.

Digital signal processing implementation for near real-time wavelet transformation system for binary images

Communication has become an essential function in our civilization. With the increasing demand for communication channels, it is now necessary to find ways to optimize the use of their bandwidth. One way to achieve this is by transforming the information before it is transmitted. This transformation can be performed by several techniques. One of the newest of these techniques is the use of wavelets. Wavelet transformation refers to the act of breaking down a signal into components called details and trends by using small waveforms that have a zero average in the time domain. After this transformation the data can be compressed by discarding the details, transmitting the trends. In the receiving end, the trends are used to reconstruct the image. In this work, the wavelet used for the transformation of an image will be selected from a library of available bases. The accuracy of the reconstruction, after the details are discarded, is dependent on the wavelets chosen from the wavelet basis library. The system developed in this thesis takes a 2-D image and decomposes it using a wavelet bank. A digital signal processor is used to achieve near real-time performance in this transformation task. A contribution of this thesis project is the development of DSP-based test bed for the future development of new real-time wavelet transformation algorithms.

Desenvolvimento de um Controlador com DSP para um Motor CA de 30 kW para o CEPIUM

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

On the Analysis and Control of a Linear Synchronous Servomotor with a Flexible Load

Industry's growing need for higher productivity is placing new demands on mechanisms connected with electrical motors, because these can easily lead to vibration problems due to fast dynamics. Furthermore, the nonlinear effects caused by a motor frequently reduce servo stability, which diminishes the controller's ability to predict and maintain speed. Hence, the flexibility of a mechanism and its control has become an important area of research. The basic approach in control system engineering is to assume that the mechanism connected to a motor is rigid, so that vibrations in the tool mechanism, reel, gripper or any apparatus connected to the motor are not taken into account. This might reduce the ability of the machine system to carry out its assignment and shorten the lifetime of the equipment. Nonetheless, it is usually more important to know how the mechanism, or in other words the load on the motor, behaves. A nonlinear load control method for a permanent magnet linear synchronous motor is developed and implemented in the thesis. The purpose of the controller is to track a flexible load to the desired velocity reference as fast as possible and without awkward oscillations. The control method is based on an adaptive backstepping algorithm with its stability ensured by the Lyapunov stability theorem. As a reference controller for the backstepping method, a hybrid neural controller is introduced in which the linear motor itself is controlled by a conventional PI velocity controller and the vibration of the associated flexible mechanism is suppressed from an outer control loop using a compensation signal from a multilayer perceptron network. To avoid the local minimum problem entailed in neural networks, the initial weights are searched for offline by means of a differential evolution algorithm. The states of a mechanical system for controllers are estimated using the Kalman filter. The theoretical results obtained from the control design are validated with the lumped mass model for a mechanism. Generalization of the mechanism allows the methods derived here to be widely implemented in machine automation. The control algorithms are first designed in a specially introduced nonlinear simulation model and then implemented in the physical linear motor using a DSP (Digital Signal Processor) application. The measurements prove that both controllers are capable of suppressing vibration, but that the backstepping method is superior to others due to its accuracy of response and stability properties.

Comparação entre métodos digitais de linearização de sensores

Na era de sistemas embarcados complexos, a interface direta de dispositivos e sistemas integrados para o mundo real demanda o uso de sensores e seus circuitos analógicos de suporte. Desde que a maioria das características físicas de um sensor requer algum tipo de calibração, este trabalho compara e discute quatro técnicas digitais de calibração adaptadas para aplicação em sistemas embarcados. Para fins de comparação, estes métodos de calibração foram implementados em Matlab5.3, e em um DSP (Digital Signal Processor) . Através das medidas realizadas durante a operação em regime do DSP, pode-se determinar parâmetros importantes de projeto, como potência dissipada e tempo de processamento. Outros critérios de comparação, como área consumida, tempo de processamento, facilidade de automação e taxa de crescimento do custo área e do custo velocidade com o aumento de resolução também foram analisados. Os resultados das implementações são apresentados e discutidos com o objetivo de descobrir qual o melhor método de calibração para aplicações em sistemas embarcados.

Implementação de um Módulo de Supervisão para um Sistema de Detecção de Vazamentos em Dutos de Petróleo

The transport of fluids through pipes is used in the oil industry, being the pipelines an important link in the logistics flow of fluids. However, the pipelines suffer deterioration in their walls caused by several factors which may cause loss of fluids to the environment, justifying the investment in techniques and methods of leak detection to minimize fluid loss and environmental damage. This work presents the development of a supervisory module in order to inform to the operator the leakage in the pipeline monitored in the shortest time possible, in order that the operator log procedure that entails the end of the leak. This module is a component of a system designed to detect leaks in oil pipelines using sonic technology, wavelets and neural networks. The plant used in the development and testing of the module presented here was the system of tanks of LAMP, and its LAN, as monitoring network. The proposal consists of, basically, two stages. Initially, assess the performance of the communication infrastructure of the supervisory module. Later, simulate leaks so that the DSP sends information to the supervisory performs the calculation of the location of leaks and indicate to which sensor the leak is closer, and using the system of tanks of LAMP, capture the pressure in the pipeline monitored by piezoresistive sensors, this information being processed by the DSP and sent to the supervisory to be presented to the user in real time

Sensores e interfaces com aplicações em motor mancal

Relevant researches have been growing on electric machine without mancal or bearing and that is generally named bearingless motor or specifically, mancal motor. In this paper it is made an introductory presentation about bearingless motor and its peripherical devices with focus on the design and implementation of sensors and interfaces needed to control rotor radial positioning and rotation of the machine. The signals from the machine are conditioned in analogic inputs of DSP TMS320F2812 and used in the control program. This work has a purpose to elaborate and build a system with sensors and interfaces suitable to the input and output of DSP TMS320F2812 to control a mancal motor, bearing in mind the modularity, simplicity of circuits, low number of power used, good noise imunity and good response frequency over 10 kHz. The system is tested at a modified ordinary induction motor of 3,7 kVA to be used with a bearingless motor with divided coil

Projeto e Implementação em Ambiente Foundation Fieldbus de Filtragem Estocástica Baseada em Análise de Componentes Independentes (M175)

This work considers the development of a filtering system composed of an intelligent algorithm, that separates information and noise coming from sensors interconnected by Foundation Fieldbus (FF) network. The algorithm implementation will be made through FF standard function blocks, with on-line training through OPC (OLE for Process Control), and embedded technology in a DSP (Digital Signal Processor) that interacts with the fieldbus devices. The technique ICA (Independent Component Analysis), that explores the possibility of separating mixed signals based on the fact that they are statistically independent, was chosen to this Blind Source Separation (BSS) process. The algorithm and its implementations will be Presented, as well as the results

Um novo sistema de refrigeração com controle de temperatura, compressor aberto, máquina de indução trifásica com velocidade variável e correção ativa do fator de potência do estágio de entrada

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sistema eletrônico para geração e avaliação de movimentos em paraplégicos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ottimizzazione di protocolli di trasmissione dati tramite interfaccia usb implementati su fpga

La maggior parte dei moderni dispositivi e macchinari, sia ad uso civile che industriale, utilizzano sistemi elettronici che ne supervisionano e ne controllano il funzionamento. All’ interno di questi apparati è quasi certamente impiegato un sistema di controllo digitale che svolge, anche grazie alle potenzialità oggi raggiunte, compiti che fino a non troppi anni or sono erano dominio dell’ elettronica analogica, si pensi ad esempio ai DSP (Digital Signal Processor) oggi impiegati nei sistemi di telecomunicazione. Nonostante l'elevata potenza di calcolo raggiunta dagli odierni microprocessori/microcontrollori/DSP dedicati alle applicazioni embedded, quando è necessario eseguire elaborazioni complesse, time-critical, dovendo razionalizzare e ottimizzare le risorse a disposizione, come ad esempio spazio consumo e costi, la scelta ricade inevitabilmente sui dispositivi FPGA. I dispositivi FPGA, acronimo di Field Programmable Gate Array, sono circuiti integrati a larga scala d’integrazione (VLSI, Very Large Scale of Integration) che possono essere configurati via software dopo la produzione. Si differenziano dai microprocessori poiché essi non eseguono un software, scritto ad esempio in linguaggio assembly oppure in linguaggio C. Sono invece dotati di risorse hardware generiche e configurabili (denominate Configurable Logic Block oppure Logic Array Block, a seconda del produttore del dispositivo) che per mezzo di un opportuno linguaggio, detto di descrizione hardware (HDL, Hardware Description Language) vengono interconnesse in modo da costituire circuiti logici digitali. In questo modo, è possibile far assumere a questi dispositivi funzionalità logiche qualsiasi, non previste in origine dal progettista del circuito integrato ma realizzabili grazie alle strutture programmabili in esso presenti.

Implementação de um Módulo de Supervisão para um Sistema de Detecção de Vazamentos em Dutos de Petróleo

The transport of fluids through pipes is used in the oil industry, being the pipelines an important link in the logistics flow of fluids. However, the pipelines suffer deterioration in their walls caused by several factors which may cause loss of fluids to the environment, justifying the investment in techniques and methods of leak detection to minimize fluid loss and environmental damage. This work presents the development of a supervisory module in order to inform to the operator the leakage in the pipeline monitored in the shortest time possible, in order that the operator log procedure that entails the end of the leak. This module is a component of a system designed to detect leaks in oil pipelines using sonic technology, wavelets and neural networks. The plant used in the development and testing of the module presented here was the system of tanks of LAMP, and its LAN, as monitoring network. The proposal consists of, basically, two stages. Initially, assess the performance of the communication infrastructure of the supervisory module. Later, simulate leaks so that the DSP sends information to the supervisory performs the calculation of the location of leaks and indicate to which sensor the leak is closer, and using the system of tanks of LAMP, capture the pressure in the pipeline monitored by piezoresistive sensors, this information being processed by the DSP and sent to the supervisory to be presented to the user in real time

Policy through procurement:introduction of digital signal process (DSP) hearing aids into the English NHS

Despite being a major user of many technologies and innovations, the healthcare sector's role and influence as a procurer of technologies has been poorly represented by the literature and consequently is not fully understood. Providing a practical example of the introduction of digital signal process (DSP) hearing aids in to the English NHS, this paper discusses the role of public sector procurement agencies in the uptake of technologies from the private sector and their adoption by the public sector. Employing a system of innovation (SI) approach, the paper highlights the need for policy-makers to adopt a dynamic as well as systemic perspective that recognises the shifting roles, responsibilities and interactions of key stakeholders throughout the innovation process.

Embedded DSP-Based Compact Fuzzy System and Its Application for Induction-Motor V/f Speed Control

This paper presents a compact embedded fuzzy system for three-phase induction-motor scalar speed control. The control strategy consists in keeping constant the voltage-frequency ratio of the induction-motor supply source. A fuzzy-control system is built on a digital signal processor, which uses speed error and speed-error variation to change both the fundamental voltage amplitude and frequency of a sinusoidal pulsewidth modulation inverter. An alternative optimized method for embedded fuzzy-system design is also proposed. The controller performance, in relation to reference and load-torque variations, is evaluated by experimental results. A comparative analysis with conventional proportional-integral controller is also achieved.