Este projeto de pesquisa apresenta o desenvolvimento de protótipos de transmissores industriais de pressão do tipo diferencial piezoresistivo com saída analógica a dois fios 4-20 mA. Os dispositivos usam um DSSP (processador digital de sinal do sensor) para realizar compensação térmica nas temperaturas de 0°C até 80°C e a calibração de pressão diferencial na faixa de 0-25 bard e de pressão de linha de 0-7 barg. Os transmissores permitem a leitura de diversas variáveis industriais: pressão diferencial, pressão relativa e pressão absoluta em fluidos. Os transmissores têm um TEB (total error band) menor que 0,15 de porcentagem de escala plena. A saída analógica dos transmissores diferenciais de pressão é caracterizada utilizando como base normas internacionais BS (British Standards). Os parâmetros avaliados nos transmissores de pressão são: a exatidão, o coeficiente térmico do offset, o coeficiente térmico do span, o total error band, e os desvios no tempo a curto e longo prazo. Esse trabalho é resultado da parceria dada entre o Laboratório de Sistemas Integráveis da Escola Politécnica da Universidade de São Paulo (LSI/EPUSP) e a empresa MEMS Microssistemas Integrados Híbridos de Pressão. / This research project presents the prototypes development of piezoresistive differential pressure transmitters with analog two-wire output of 4-20 mA. The devices use a DSSP (Digital Signal Processor Sensor) to achieve temperature compensation at temperatures from 0°C to 80°C and differential pressure calibration range from 0 bard to 25 bard and line pressure range from 0 barg to 7 barg. The transmitters measure several industrial variables: differential pressure, relative pressure and absolute pressure at fluids. The transmitters have a TEB (total error band) less than 0.15 percent of full scale. The analog output of the differential pressure transmitters is characterized using British Standards-BS. The parameters evaluated in the pressure transmitters are: the accuracy, the thermal coefficient of the offset, the thermal coefficient of the span, the total error band, the start-up drift and long-term drift. This work is the result of the academic and technological partnership between the Laboratory of Integrated Systems of the Polytechnic School of the University of São Paulo (LSI / EPUSP) and the MEMS company - Microssistemas Integrados Híbridos de Pressão Ltda.

Os objetivos do trabalho consistem em síntese e caracterização de três polímeros: poli(2,1,3-benzotiadiazol-4,7-ilenovinileno) (PBTDV), poli(2,1,3-benzotiadiazol-4,7-ilenovinileno-co-2-bromo-5-hexilóxi-p-fenilenovinileno (PBTDV-co-BHPPV) e poli(2-bromo-5-hexilóxi-p-fenilenovinileno) (BHPPV), sendo os dois primeiros inéditos; aplicação de polímeros condutores no desenvolvimento de um nariz eletrônico capaz de identificar madeiras; e aplicação de polímeros condutores em um sensor de pressão. Os polímeros foram preparados de maneira satisfatória via redução catódica de seus precursores tetra-halogenados, que forneceu produtos com rendimentos apreciáveis. Para o projeto do nariz eletrônico que pretende identificar madeiras, dois conjuntos de espécies de madeira foram estudadas: (a) mogno e cedro e (b) imbuia e canela-preta. O nariz eletrônico desenvolvido apresenta um conjunto de quatro sensores de gás, que foram construídos por meio da deposição de finos filmes de polímeros dopados sobre a superfície de eletrodos interdigitados. Esse conjunto de sensores foi desenvolvido com sucesso, sendo capaz de diferenciar as espécies de madeira com taxa de acerto de 100%. Por fim, foi desenvolvido também com sucesso um sensor de gás capaz de atuar como sensor de pressão. Esse dispositivo mostrou-se sensível à variação de pressão, do vácuo a ambiente, e os ensaios apresentaram boa reprodutibilidade. A resposta do sensor, frente à variação de pressão, é produto de interação(ões) entre a camada ativa do polímero utilizado (PHBPE, poli(4\'-hexilóxi-2,5-bifenilenoetileno)) e algum(ns) componente(s) do ar atmosférico ou da atmosfera particular do laboratório. Esse sensor é de fácil fabricação e barato (~ R$ 1,00), sendo possível sua aplicação como sensor para pressões menores do que a ambiente / The syntheses of three polymers via electrochemical reduction of their precursors are described. Two out of the three generated polymers have never been described before. An electronic nose was developed capable of identifying two pairs of wood species: (a) mahogany and cedar and (b) Brazilian walnut and black-cinnamon. The electronic nose consisted of four gas sensors, fabricated by the deposition of thin doped polymer films onto the surface of interdigitated electrodes. The device presented a rate of hits of 100% in 80 assays of identification of the above cited species. Finally, a gas sensor based on a conductive polymer and capable of acting as a pressure sensor was fabricated. The sensor was suitable for measuring air pressures in the range of 100 mmHg to 700 mmHg due to its sensibility to one or more specific compounds present in the air. The device is cheap, easy to fabricate and lasts for several months

abstract: Precursors of carbon fibers include rayon, pitch, and polyacrylonitrile fibers that can be heat-treated for high-strength or high-modulus carbon fibers. Among them, polyacrylonitrile has been used most frequently due to its low viscosity for easy processing and excellent performance for high-end applications. To further explore polyacrylonitrile-based fibers for better precursors, in this study, carbon nanofillers were introduced in the polymer matrix to examine their reinforcement effects and influences on carbon fiber performance. Two-dimensional graphene nanoplatelets were mainly used for the polymer reinforcement and one-dimensional carbon nanotubes were also incorporated in polyacrylonitrile as a comparison. Dry-jet wet spinning was used to fabricate the composite fibers. Hot-stage drawing and heat-treatment were used to evolve the physical microstructures and molecular morphologies of precursor and carbon fibers. As compared to traditionally used random dispersions, selective placement of nanofillers was effective in improving composite fiber properties and enhancing mechanical and functional behaviors of carbon fibers. The particular position of reinforcement fillers with polymer layers was enabled by the in-house developed spinneret used for fiber spinning. The preferential alignment of graphitic planes contributed to the enhanced mechanical and functional behaviors than those of dispersed nanoparticles in polyacrylonitrile composites. The high in-plane modulus of graphene and the induction to polyacrylonitrile molecular carbonization/graphitization were the motivation for selectively placing graphene nanoplatelets between polyacrylonitrile layers. Mechanical tests, scanning electron microscopy, thermal, and electrical properties were characterized. Applications such as volatile organic compound sensing and pressure sensing were demonstrated. / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2020

First part of this work is focused on the description exist methods for measuring refraction index of air. Second part deal with concrete problem realization measurement unit for monitoring of refraction index of air. Refraction index of air is measured indirect method which is based on a modified Edlen formula.

The dissertation thesis is focused on research and development of modern emission MEMS sensors. The emission sensor based on the field emission from nanostructured materials represents innovative approach to pressure sensing. The nanostructures serve as electron emitter in an electric field between the cathode and anode in the pressure sensor. This electric field is constant and the change in ambient pressure causes the change of distance between electrodes, thereby the electric field is increasing. This intensity is proportional to the emission from the cathode made of nanostructured material. Changing the distance between the electrodes is caused by the deflection of the deformation element - the membrane, which operates the measured pressure. In the current state of the art an extensive research is carried out to find new nanostructured materials with good emission properties. Four nanostructured materials have been chosen and then experimentally prepared and characterized inside the vacuum chamber. For the simulation of diaphragm bending, the chamber is equipped with linear nano-motion drive SmarAct that enables precise changes of the distance between two electrodes inside the vacuum chamber. The computer model to predict the deformation of diaphragm was prepared in the simulation program CoventorWare. The behavior of diaphragm in a wide range of dimensions of the membrane, its thickness and the applied pressure are possible to predict. The dependencies of the current density on the electric field are plotted from the measured emission characteristics of nanostructured materials and thus characterized nanostructured materials can be compared. The dependencies are further converted by Fowler-Nordheimovy theory on the curve (ln(J/E2) vs. 1/E), whose advantage is linear shape. Basic parameters describing the emission properties of characterized nanostructured materials are deducted. Two methods for vacuum packaging of the sensor electrodes are designed. Anodic bonding technology and encapsulating using glass frit bonding are tested. To evaluate the bonding strength, the bonded substrates are tested for tensile strength.

A ce jour, le développement de textiles intelligents, de peaux artificielles, de capteurs de paramètres environnementaux et de composés optoélectroniques souples ; qui nécessite des innovations à la fois dans la synthèse des matériaux, leur conception mécanique mais aussi, à l’échelle industrielle, en stratégie de production ; présente un intérêt majeur dans le domaine du prêt-à-porter connecté. D’un point de vue mécanique, l’obtention des propriétés de flexibilité et d’étirabilité à faible coût, via un procédé simple, au sein d’un matériau léger et capable de s’expandre sur de grandes surfaces est un prérequis essentiel pour incorporer des dispositifs optoélectroniques au sein des objets connectés portables. Parmi les différents procédés couramment utilisés, l’electrospinning est une technique simple, facilement adaptable et peu onéreuse qui permet un ajustement fin et flexible des morphologies de fibres, l’assemblage de plusieurs nanofibres fonctionnelles et une production en continue à haut débit. Ces multiples avantages sont à l’origine des nombreux travaux concernant l’utilisation de l’electrospinning dans le domaine du prêt-à-porter électronique et/ou connecté. Cependant, il est nécessaire de développer des projets innovants pour ce secteur qui incluent des capteurs détectant des paramètres environnementaux (pH, température), des chemo-capteurs colorimétriques à large spectre (full-color), des composantes électroniques étirables et capteurs tactiles. / To date, the development of smart textiles, artificial skins, environmental sensory devices, and flexible/stretchable optoelectronics involve the innovation of material synthesis, mechanical design, and fabrication strategies have attracted considerable attention in wearable displays. The mechanically flexible and stretchable functions with cost-effective, facile, lightweight, and large-area expandability are essential modules to fabricate the optoelectronic devices in various wearable display applications. Among them, electrospinning is an easy, versatile, and inexpensive technique enables flexible morphology tuning, assembling various functional nanofibers, and high-throughput continuous production has motivated extensive studies on wearable electronics applications. Therefore, it is necessary to develop innovative projects including the environment-sensing elements with pH-sensing dependency, temperature-sensitive, full-color switchable chemosensors, stretchable electronics, and tactile sensors for various wearable electronics applications.

<p>    An all-additive manufacturing technique was developed to print piezoelectrically active polymeric materials, primarily poly(vinylidene fluoride) (PVdF), for use in pressure sensors in soft robotics. The research proceeded in three stages. The initial stage used Fused Deposition Modeling (FDM) and electric poling independently to create piezoelectric PVdF pressure sensors. The second stage merged FDM and electric poling processes. The third stage introduced electrospinning to create flexible, high-output piezoelectric PVdF materials, which were combined with three-dimensional (3D) printed soft structures for stretchable pressure sensors.</p> <p>    The main achievement of the research was the development of the Electric Poling-assisted Additive Manufacturing (EPAM) technique, combining electric poling and FDM 3D printing to print piezoelectric materials with custom structures at lower costs. β-phase in semicrystalline PVdF materials is mainly responsible for piezoelectricity. A higher β-phase content results in superior sensor performance. This technique was evaluated by measuring the piezoelectric output voltage of the printed PVdF films, and β-phase content was quantified using Fourier-transform Infrared spectroscopy (FTIR). The developed EPAM technique was combined with Direct Ink Writing (DIW), becoming a hybrid 3D printing technique. This is the first demonstration of applying a hybrid printing technique to print piezoelectric PVdF-based sensors directly. The sensor was constructed using FDM printed PVdF film as the dielectric sandwiched between two parallel DIW printed silver electrodes. The PVdF sensors have both piezoelectric pressure sensing and capacitive temperature sensing functionalities. The application of the capacitive temperature sensor was demonstrated by applying heating-and-cooling cycles while measuring the capacitance as a function of temperature at a constant frequency, showing improved sensitivities at higher frequencies (i.e., 105 Hz) after dielectric polarization.</p> <p>    The third stage of research was motivated by the need for soft piezoelectric pressure sensors for soft robotics. Challenges were twofold: requiring soft piezoelectric materials with high coefficients for excellent sensors and fabrication techniques to incorporate soft materials into designed structures. Inspired by the EPAM technique, a method combining electrospinning and DIW was used to create soft piezoelectric PVdF/thermal plastic polyurethane (TPU) blend microfiber-based pressure sensors. The soft sensor was integrated with an FDM printed soft structure for a stretchable pressure sensor with both piezoelectric sensing and capacitive sensing mechanisms.</p>

Wallenius Marine, KTH and SSPA are working together on a wind powered car carrier, that will ship cars over the atlatic. KTH has a small scale prototype of this vessel, and uses this prototype to test performance and new sensor systems, that can be used on the full scale vessel. The KTH research group wanted to add a sensor system that measured the pressure on the sails of the prototype ship. This thesis is about the design, construction and implementation of this sensor system. The system was first designed. The pressure measuring system would be divided into blocks where one block would measure one part of the sail. Each block would be connected to a common communication bus. This bus was then connected to the current control system of the ship. The pressure was going to be measured through pressure taps in the sail. After the design was done, the construction began. Here the choice of components was made. The sensors were from Honeywell, the microcontroller was a Teensy 4.1, communication was done using a RS-422 transceiver from Digilent and the power components were a 24 to 3.3V regulator and a 24 to 5V regulator. A circuit board was designed and created to fit all the components. The system was tested in a wind tunnel to verify that it worked as it should. The next step was the implementation. Three segments of the sail surface was removed. A support structure and fittings was added to the removed parts, so that they can be removed and attached. The taps was added and the system blocks were fitted. The measuring system was tested on the ship out on the sea. The results were that the system was able to measure the pressure distribution over the sail surface. The resulting measurements matched what was expected from viewing the tell tales on the sail. The system worked as specified, but more testing is required to see how the measurements are affected by factors such as the other sails and the hull. This system will continue to be used by the KTH research team in their future research projects. / Wallenius Marine, KTH och SSPA jobbar tillsammans för att konstruera et vinddrivet fraktfartyg för bilar, som ska skeppa bilar över Atlanten. KTH har en nedskalad version av det färdiga fartyget, som används för testning av prestanda och test av potentiella system som kan implementeras på det färdiga skeppet. Forsknings gruppen på KTH ville ha ett tryckmätningssystem som mäter trycket på seglena. Detta masterarbetet går ut på att designa, konstruera och implementera detta tryckmätningssystem. Första steget var design, detta gick ut på att i stora drag definiera systemets utseende. Systemet skulle byggas i block, där ett block innehöll ett antal trycksensorer, mikrokontroller och kommunikations hårdvara. Ett block mätte en horisontallinje över seglet och det var multipla block på ett segel. Varje block var ihopkopplat genom en kommunikationsbus, som sen kopplades till det nuvarande kontrollsystemet på båten. Andra steget var construktion, detta steget var att välja komponenter, bygga och testa systemet. Trycksensorerna som valdes var från Honeywell, mikrokontrollern var en Teensy 4.1 och kommunikations hårdvaran var en RS- 422 transceiver från Digilent. När komponenterna var valda, designades och gjordes ett kretskort för att koppla samman komponenterna. Efter komponenterna var fästa i kretskortet, testades systemet i en vindtunnel. Detta gjordes för att verifiera funktionaliteten av systemet och se om värdena som sensorerna gav var rimliga. Efter systemet var verifierat, så börjades implementationen av systemet. Tre segment av seglet yta togs bort, på tre olika höjder. En stöd struktur adderades till de borttagna segmenten, så de skulle fortsätta hålla sin form, och ett sätt att ta bort och fästa segmenten till seglet gjordes. Pressure taps fästes på ytan och plasttuber drogs från dessa till trycksensorerna. Kretskorten fästes på insidan av seglet och segmenten stängdes. Nästa steg var att testa systemet till havs, och resultaten var lovande. Systemet fungerade som det skulle. Det kunde mäta trycket både i vindtunnel och på havs. I vindtunneln matcha trycken det som förväntades, och ute till havs visade trycket det som förväntades när man kollade på tell talesen på ytan. Mer testning behövs för att se hur olika faktorer påverkar tryckmätningarna, och tryckmätning till alla segeln ska läggas till. Forskningsgruppen på KTH kommer fortsätta använda systemet i forskningen de driver.

In this study, we propose a multi-walled carbon nanotube epoxy composite sensor for force and pressure sensing in the range of 50 N–2 kN. A manufacturing procedure, including material preparation and deposition techniques, is proposed. The electrode dimensions and the layer thickness were optimized by the finite element method. Temperature compensation is realized by four nanocomposites elements, where only two elements are exposed to the measurand. In order to investigate the influence of the filler contents, samples with different compositions were prepared and investigated. Additionally, the specimens are characterized by cyclical and stepped force/pressure loads or at defined temperatures. The results show that the choice of the filler content should meet a compromise between sensitivity, temperature influence and noise behavior. At constant temperature, a force of at least 50N can be resolved. The measurement error due to the temperature influence is 150N in a temperature range of –20°C–50°C.

Ce travail de thèse suit une logique exposée dans trois chapitres, pour terminer par un exposé sur des applications futures. La première partie fait l’inventaire des difficultés de l’apprentissage des habiletés de base de la chirurgie robotique, notamment dans ses aspects de l’exploitation des avantages ergonomiques. Elle se fonde notamment les travaux de master 2 des Docteurs N. Hubert et C. Perrenot auxquels l’auteur a participé. On conclut ainsi à la nécessité de développer un outil de monitoring de l’ergonomie plus efficace que celui existant sur les logiciels du simulateur dV-Trainer®. La deuxième partie décrit la conception et la validation d’un système de capteurs de pression des avant-bras sur les appuis-bras de la console du robot et/ou des simulateurs (Système de Surveillance de Pression - SSP-). Il est créé le concept d’Armrest Load, formule plus efficace d’évaluation des performances des stagiaires en matière d’ergonomie que l’évaluation automatique par le simulateur. La troisième partie décrit l’amélioration du système SSP via l’ajout de fonctions supplémentaires et leurs évaluations : - une alarme informant l’étudiant des mauvaises positions. Ce système crée un réflexe conditionné, accélère l’utilisation ergonomique des appuis-bras du simulateur, mais également améliore les performances globales. - des caméras et une interface, « Contrôleur d’Évènement en Simulation Robotique » (CESIR), permettant au stagiaire de visionner à volonté et pour chaque exercice les vidéos de référence, celles avec les erreurs à éviter et ses propres performances. Ces techniques vidéo, largement répandues dans le milieu sportif sont utilisées pour la première fois en chirurgie et prouvent ici leur efficacité. La partie « conclusion » synthétise les résultats de tout le travail de thèse et expose des perspectives d’amélioration du système CESIR et de son utilisation dans la poursuite de la collaboration franco-chinoise en formation robotique. / This thesis is logically split into three chapters, concluding with a discussion on future applications. The first part makes an inventory of the difficulties in learning the basic skills in robotic surgery, especially in the aspects of exploiting the ergonomic benefits. It relies in particular on the master degrees of Drs N. Hubert and C.Perrenot to which the author participated. It is concluded that there is a need to develop a more efficient monitoring tool for ergonomics than the existing software on the dV-Trainer® simulator. The second part describes the design and validation of a system of forearms pressure sensors attached on the robot’s console and/or simulator’s armrests (SSP- Pressure Surveillance System). The concept of Armrest Load is created, a more effective formula for evaluating the trainees’ performance in ergonomics than the automatic evaluation provided by the simulator. The third part describes the improvement of the SSP system by adding additional functions and their evaluation: - An alarm informing the student of bad positions. This system creates a conditioned reflex, speeds up the ergonomic use of armrests on the simulator, and also improves the overall performance. - Cameras and a "Controller of Event in Robotic Simulation " (CESIR) interface, allowing the participant to view at will the reference video, the one with mistakes to avoid and the video of their own performances. This video technique is widely used in sports but is applied for the first time in surgery and proves its effectiveness. The conclusion part summarizes the results of the whole thesis and outlines the possibilities for CESIR’s improvement and its development in the French-Chinese collaboration in robotic training.