Dissertations / Theses on the topic 'Sensor Manufacturing'
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1
Bergman, Stacy (Stacy Adele) 1972. "Building competencies in sensor harness manufacturing through prototyping." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/34717.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; and, (S.M.)--Massachusetts Institute of Technology, Sloan School of Management; in conjunction with the Leaders for Manufacturing Program at MIT, 2001.Vita.
Includes bibliographical references (p. 105-115).
Organizational knowledge is information about products, processes and customers that is held by the personnel in the organization. Institutionalization of the best practices contained within this knowledge is essential in creating competencies. Unfortunately, organizations do not utilize this knowledge effectively. This thesis introduces a framework that shows how establishing a prototype system to enhance product and process understanding can start to build organizational knowledge in the short-term. Along with external benchmarking, this internal knowledge can be used to form best practices based competencies. This framework will be illustrated through the use of a case study. The case study was conducted at the Delphi Automotive Systems Mexico Technical Center. The case study project was undertaken to improve the Energy and Chassis Systems division's competencies in sensor wire harness products. In order to support this competency development, the author worked with Delphi Automotive Systems personnel to develop best practices based competencies employing the competency development framework introduced in this thesis. Installation of a working prototyping system was achieved in the six-month project period. Through the production and delivery of these harnesses, internal best practices were developed. These were used along with benchmarking of other harness manufacturers to develop a baseline best practices based competencies repository for the division. Effective use of the best practices based competencies developed during the case study project should foster improvement in competitive metrics, particularly speed-to-market and product development costs. Extension of best practices based competencies development to other products will allow human and monetary capital to be released from re-engineering tasks. These resources can then be refocused on product advancement to exceed customer expectations in the automotive market. It will also allow the organization to focus resources on development of strategic nonautomotive markets in order to diversify the business to protect against future downturn in the automotive market.
by Stacy Bergman.
S.M.
2
Kumile, CM, and G. Bright. "Sensor fusion control system for computer integrated manufacturing." South African Journal of Industrial Engineering, 2008. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000669.
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Manufacturing companies of today face unpredictable, high frequency market
changes driven by global competition. To stay competitive, these companies must
have the characteristics of cost-effective rapid response to the market needs. As an engineering discipline, mechatronics strives to integrate mechanical, electronic, and computer systems optimally in order to create high precision products and manufacturing processes. This paper presents a methodology of increasing flexibility and reusability of a generic computer integrated manufacturing (CIM) cell-control
system using simulation and modelling of mechatronic sensory system (MSS)
concepts. The utilisation of sensors within the CIM cell is highlighted specifically for data acquisition, analysis, and multi-sensor data fusion. Thus the designed reference architecture provides comprehensive insight for the functions and methodologies of a generic shop-floor control system (SFCS), which consequently enables the rapid
deployment of a flexible system.
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Roberson, David Mathew III. "Sensor-based Online Process Monitoring in Advanced Manufacturing." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72911.
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Effective quality improvement in the manufacturing industry is continually pursued.
There is an increasing demand for real-time fault detection, and avoidance of destructive
post-process testing. Therefore, it is desirable to employ sensors for in-process monitoring,
allowing for real-time quality assurance. Chapter 3 describes the application of sensor
based monitoring to additive manufacturing, in which sensors are attached to a desktop
model fused deposition modeling machine, to collect data during the manufacturing
process. A design of experiments plan is conducted to provide insight into the process,
particularly the occurrence of process failure. Subsequently, machine learning
classification techniques are applied to detect such failure, and successfully demonstrate
the future potential of this platform and methodology. Chapter 4 relates the application of
online, image-based quantification of the surface quality of workpieces produced by
cylindrical turning. Representative samples of cylindrical shafts, machined by turning
under various conditions, are utilized, and an apparatus is constructed for acquiring images
while the part remains mounted on a lathe. The surface quality of these specimens is
analyzed, employing an algebraic graph theoretic approach, and preliminary regression
modeling displays an average surface roughness (Ra) prediction error of less than 8%.
Prediction occurs in less than 2 seconds, showing the capability for future application in a
real-time, quality control setting. Both of these cases, in additive manufacturing and in
turning, are validated using real experimental data and analysis, showing application of
sensor-based online process monitoring in multiple manufacturing areas.Master of Science
4
Locks, Stephanie Isabel. "General Bayesian approach for manufacturing equipment diagnostics using sensor fusion." Thesis, Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/55036.
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Statistical analysis is used quite heavily in production operations. To use certain advanced statistical approaches such as Bayesian analysis, statistical models must be built. This thesis demonstrates the process of building the Bayesian models and addresses some of the classical limitations by presenting mathematical examples and proofs, by demonstrating the process with experimental and simulated implementations, and by completing basic analysis of the performance of the implemented models. From the analysis, it is shown that the performance of the Bayesian models is directly related to the amount of separation between the likelihood distributions that describe the behavior of the data features used to generate the multivariate Bayesian models. More specifically, the more features that had clear separation between the likelihood distributions for each possible condition, the more accurate the results were. This is shown to be true regardless of the quantity of data used to generate the model distributions during model building. In cases where distribution overlap is present, it is found that models performance become more consistent as the amount of data used to generate the models increases. In cases where distribution overlap is minimal, it is found that models performance become consistent within 4-6 data sets.
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Mason, Julian. "Guided-wave optical and hybrid sensor systems." Thesis, Kingston University, 1995. http://eprints.kingston.ac.uk/20587/.
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This thesis is concerned with the development of new fibre optic based sensors for liquid level and temperature measurement. For the measurement of fluid level an intrinsic sensor has been developed whereby the fibre itself forms the sensing medium. This fibre is made from a plastic, doped with a dye that fluoresces when illuminated by ultra-violet light. The sensing fibre is continuously illuminated but the fluid around it absorbs the light and hence the fluid level controls the intensity of light generated within the fluorescing fibre. The measurement of temperature forms the bulk of this thesis with liquid crystals being used as the transducing medium. Many different schemes have been investigated and characterised using their thermochromic, light scattering, and electro-optic properties. The latter necessitated the production of miniature photovoltaic devices which, apart from being a novel way of generating quasi-regulated electrical power, provide an alternative approach to energising many other types of hybrid sensor systems that at present are forced to use more complex techniques. Finally a simple theory has been developed to describe the behaviour of the liquid crystal based systems. The theory has been solved numerically and is in good agreement with the experimental results.
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Nieves, Bogonez Francisco Daniel. "Manufacturing and characterisation of a fibre optic acoustic emission sensor." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7762/.
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The value of Remote Condition Monitoring for the real-time evaluation of the structural integrity of critical components is undeniable. Fibre-reinforced polymer composites are a class of materials which offer significant advantages over conventional metal alloys used for manufacturing load bearing structures in cases where weight and/or energy consumption need to be kept to a minimum, for example automotive and aerospace applications. This is due to the excellent strength to weight ratio that FRPCs exhibit. However, their strongly anisotropic microstructure of poses significant challenges for Non-Destructive Evaluation of the actual structural health of components made from such materials. Acoustic Emission is a passive condition monitoring technique based on the detection of elastic stress waves emitted when damage evolves in a structure. Conventional piezoelectric AE sensors need to be surface-mounted as their embedding in FRPCs is impractical. Fibre Optic Acoustic Emission Sensors (FOAES) offer a distinct advantage since they are light weight, have small size and can be effectively embedded in composite laminates. Moreover, they can be multiplexed with the entire structure being monitored more effectively. This study has focused in the evaluation of the manufacturing process and characterisation of FOAES. Comparison of their performance with conventional commercial sensors was carried out.
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Brownlow, Michael James. "A time-of-flight optical range sensor for mobile robot navigation." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359420.
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Chen, Nongji. "Aspects of an open architecture robot controller and its integration with a stereo vision sensor." Thesis, University of Surrey, 1994. http://epubs.surrey.ac.uk/842989/.
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The work presented in this thesis attempts to improve the performance of industrial robot systems in a flexible manufacturing environment by addressing a number of issues related to external sensory feedback and sensor integration, robot kinematic positioning accuracy, and robot dynamic control performance. To provide a powerful control algorithm environment and the support for external sensor integration, a transputer based open architecture robot controller is developed. It features high computational power, user accessibility at various robot control levels and external sensor integration capability. Additionally, an on-line trajectory adaptation scheme is devised and implemented in the open architecture robot controller, enabling a real-time trajectory alteration of robot motion to be achieved in response to external sensory feedback. An in depth discussion is presented on integrating a stereo vision sensor with the robot controller to perform external sensor guided robot operations. Key issues for such a vision based robot system are precise synchronisation between the vision system and the robot controller, and correct target position prediction to counteract the inherent time delay in image processing. These were successfully addressed in a demonstrator system based on a Puma robot. Efforts have also been made to improve the Puma robot kinematic and dynamic performance. A simple, effective, on-line algorithm is developed for solving the inverse kinematics problem of a calibrated industrial robot to improve robot positioning accuracy. On the dynamic control aspect, a robust adaptive robot tracking control algorithm is derived that has an improved performance compared to a conventional PID controller as well as exhibiting relatively modest computational complexity. Experiments have been carried out to validate the open architecture robot controller and demonstrate the performance of the inverse kinematics algorithm, the adaptive servo control algorithm, and the on-line trajectory generation. By integrating the open architecture robot controller with a stereo vision sensor system, robot visual guidance has been achieved with experimental results showing that the integrated system is capable of detecting, tracking and intercepting random objects moving in 3D trajectory at a velocity up to 40mm/s.
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Li, Shan. "Monitoring and diagnosis of process faults and sensor faults in manufacturing processes." Diss., University of Iowa, 2008. https://ir.uiowa.edu/etd/206.
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The substantial growth in the use of automated in-process sensing technologies creates great opportunities for manufacturers to detect abnormal manufacturing processes and identify the root causes quickly. It is critical to locate and distinguish two types of faults - process faults and sensor faults. The procedures to monitor and diagnose process and sensor mean shift faults are presented with the assumption that the manufacturing processes can be modeled by a linear fault-quality model.
A W control chart is developed to monitor the manufacturing process and quickly detect the occurrence of the sensor faults. Since the W chart is insensitive to process faults, when it is combined with U chart, both process faults and sensor faults can be detected and distinguished. A unit-free index referred to as the sensitivity ratio (SR) is defined to measure the sensitivity of the W chart. It shows that the sensitivity of the W chart is affected by the potential influence of the sensor measurement.
A Bayesian variable selection based fault diagnosis approach is presented to locate the root causes of the abnormal processes. A Minimal Coupled Pattern (MCP) and its degree are defined to denote the coupled structure of a system. When less than half of the faults within an MCP occur, which is defined as sparse faults, the proposed fault diagnosis procedure can identify the correct root causes with high probability. Guidelines are provided for the hyperparameters selection in the Bayesian hierarchical model. An alternative CML method for hyperparameters selection is also discussed. With the large number of potential process faults and sensor faults, an MCMC method, e.g. Metropolis-Hastings algorithm can be applied to approximate the posterior probabilities of candidate models.
The monitor and diagnosis procedures are demonstrated and evaluate through an autobody assembly example.
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Ma, Yong Qing. "Investigation into the materials and manufacturing of a new thin film magnetoresistive sensor." Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/2834.
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There is increasing interest in utilising very thin anisotropic magnetoresistive films (typically in the range of a few nano-metres) to make magnetic sensors which can be made very small and with a high signal-to-noise ratio. In this thesis, a new type of sensor is investigated which has a pair of thin film MR stripes whose magnetisation is switched alternately in opposite directions using bias fields from currents in overlay conductor films. The investigation considers in particular the Barkhausen noise in these sensors and its relationship with factors such as sensor film thickness. The effect of thickness and grain size on the coercivity of Ni81Fe19 permalloy thin films deposited by r.f. sputtering with negative substrata bias is systematically investigated as a function of under-layer materials, thickness, and substrata temperature. The results show that there is a minimum in coercivity at a thickness of about 7.5 nm with a grain size of 4 nm. This may be attributed to the grain size via its relationship with magnetic domain wall thickness. A tantalum under-layer favours a (111) (low anisotropy) surface plane in permalloy sensor films. Elevated deposition temperature may reduce defects in the films. A comparison of the magnetic domain wall structure and the state of magnetisation in the very thin (5 - 30 nm) permalloy films with and without Ta underlayer is made by using Lorentz TEM observation. The result shows that it is different in both cases. With Ta underlayer, the wider, straighter and more regular domain walls together with less rippling in magnetisation in adjacent domains may lead to a reduction in the Barkhausen noise. Barkhausen noise studies of films are carried out by sweeping an ac field of 77 Hz onto the permalloy films and recording the induced output voltage due to the flux change as a function of time on a digital storage oscilloscope. Barkhausen noise and corresponding hysteresis of the sensor is studied by analysis of the MR response of various sensors together with their magnetoresistive hysteresis, which may be reduced or improved by using a suitable external high frequency field (5 kHz to 20 kHz). Variation in the sensitivity of the sensor to the magnitude of a switched-biasing field was measured by applying a very small alternating field (from about tens to a few hundreds of nano-Tesla) at frequency above about 250 Hz and varying a transverse de field component (δH.), The effect of biasing field frequency and external linearising field on the sensitivities of these MR sensors is studied using an in-house built measurement system. Highly sensitive magnetoresistive sensors (120 different types have been available within 30 substrates) have been designed and then fabricated by photolithography in a temperature and humidity controlled clean room. Sensor thicknesses are typically in the range from 5 nm to 40 nm and other dimensions typically (10 µm - 80 µm wide) and 6.4 mm long. The sensor is linear in the range from zero to 14 400 nT. It produces an almost noise-free output of 20 to 30 millivolts for a field change of about 160 nano-Tesla.
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Francey, Samuel Dunn. "An investigation of sensor assisted robotic drilling techniques for applications in aerospace manufacturing." Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328102.
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Liu, Jia. "Heterogeneous Sensor Data based Online Quality Assurance for Advanced Manufacturing using Spatiotemporal Modeling." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78722.
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Online quality assurance is crucial for elevating product quality and boosting process productivity in advanced manufacturing. However, the inherent complexity of advanced manufacturing, including nonlinear process dynamics, multiple process attributes, and low signal/noise ratio, poses severe challenges for both maintaining stable process operations and establishing efficacious online quality assurance schemes.
To address these challenges, four different advanced manufacturing processes, namely, fused filament fabrication (FFF), binder jetting, chemical mechanical planarization (CMP), and the slicing process in wafer production, are investigated in this dissertation for applications of online quality assurance, with utilization of various sensors, such as thermocouples, infrared temperature sensors, accelerometers, etc. The overarching goal of this dissertation is to develop innovative integrated methodologies tailored for these individual manufacturing processes but addressing their common challenges to achieve satisfying performance in online quality assurance based on heterogeneous sensor data. Specifically, three new methodologies are created and validated using actual sensor data, namely,
(1) Real-time process monitoring methods using Dirichlet process (DP) mixture model for timely detection of process changes and identification of different process states for FFF and CMP. The proposed methodology is capable of tackling non-Gaussian data from heterogeneous sensors in these advanced manufacturing processes for successful online quality assurance.
(2) Spatial Dirichlet process (SDP) for modeling complex multimodal wafer thickness profiles and exploring their clustering effects. The SDP-based statistical control scheme can effectively detect out-of-control wafers and achieve wafer thickness quality assurance for the slicing process with high accuracy.
(3) Augmented spatiotemporal log Gaussian Cox process (AST-LGCP) quantifying the spatiotemporal evolution of porosity in binder jetting parts, capable of predicting high-risk areas on consecutive layers. This work fills the long-standing research gap of lacking rigorous layer-wise porosity quantification for parts made by additive manufacturing (AM), and provides the basis for facilitating corrective actions for product quality improvements in a prognostic way.
These developed methodologies surmount some common challenges of advanced manufacturing which paralyze traditional methods in online quality assurance, and embody key components for implementing effective online quality assurance with various sensor data. There is a promising potential to extend them to other manufacturing processes in the future.Ph. D.
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Bastani, Kaveh. "Compressive Sensing Approaches for Sensor based Predictive Analytics in Manufacturing and Service Systems." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/64917.
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Recent advancements in sensing technologies offer new opportunities for quality improvement and assurance in manufacturing and service systems. The sensor advances provide a vast amount of data, accommodating quality improvement decisions such as fault diagnosis (root cause analysis), and real-time process monitoring. These quality improvement decisions are typically made based on the predictive analysis of the sensor data, so called sensor-based predictive analytics. Sensor-based predictive analytics encompasses a variety of statistical, machine learning, and data mining techniques to identify patterns between the sensor data and historical facts. Given these patterns, predictions are made about the quality state of the process, and corrective actions are taken accordingly.
Although the recent advances in sensing technologies have facilitated the quality improvement decisions, they typically result in high dimensional sensor data, making the use of sensor-based predictive analytics challenging due to their inherently intensive computation. This research begins in Chapter 1 by raising an interesting question, whether all these sensor data are required for making effective quality improvement decisions, and if not, is there any way to systematically reduce the number of sensors without affecting the performance of the predictive analytics? Chapter 2 attempts to address this question by reviewing the related research in the area of signal processing, namely, compressive sensing (CS), which is a novel sampling paradigm as opposed to the traditional sampling strategy following the Shannon Nyquist rate. By CS theory, a signal can be reconstructed from a reduced number of samples, hence, this motivates developing CS based approaches to facilitate predictive analytics using a reduced number of sensors. The proposed research methodology in this dissertation encompasses CS approaches developed to deliver the following two major contributions, (1) CS sensing to reduce the number of sensors while capturing the most relevant information, and (2) CS predictive analytics to conduct predictive analysis on the reduced number of sensor data.
The proposed methodology has a generic framework which can be utilized for numerous real-world applications. However, for the sake of brevity, the validity of the proposed methodology has been verified with real sensor data associated with multi-station assembly processes (Chapters 3 and 4), additive manufacturing (Chapter 5), and wearable sensing systems (Chapter 6). Chapter 7 summarizes the contribution of the research and expresses the potential future research directions with applications to big data analytics.Ph. D.
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Sim, Lay M. "Design, manufacturing and testing of smart beams with EFPI strain sensor for damage detection." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/13207.
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This thesis aimed at the development of a fibre optic strain sensor-based damage detection and evaluation system (FODDAS) based on the composite beams. EFPI strain sensors were used with their integrity being assessed. Their performance, either bonded on the surfaces or embedded was examined extensively. They were shown to be adequate and reliable for strain measurements. Through-the-width damages were simulated by artificially-embedded delaminations, which were located at several through-the-thickness locations, each with two different sizes. The overall design considerations were guided by ply stresses and strains which were estimated by using the modified classical lamination theory (CLT). Considerable efforts were devoted to assessing the through-the-thickness mechanical behaviours of the beams containing optical fibres in three-point bending and short beam shear (SBS). They involved various optical fibre orientations with respect to 00 plies / longitudinal axis and at various through-the-thickness locations, each with different number of optical fibres. The understanding of these behaviours paved the way for the evaluation of the beam-based FODDAS. Smart preconditioned beams were subjected to the quasi -static loads whose magnitudes and locations were required to be well controlled. The viability and effectiveness of the beam-based FODDAS was evaluated in terms of strength and strain obtained by the embedded sensor as well as the surface-bonded strain gauges via the cross comparison of ten cases. For the strength, each beam was incrementally loaded up to the ultimate failure either in three-point bending or SBS. After each increment, the beam was unloaded and inspected for damage. For the given locations of EFPI-SS and artificial delamination as well as the sizes of the latter, it was found that the embedded EFPI-SSs were capable of picking up the stiffness degradation when the 10- mm as well as the 20-mm delamination was located at the 29-30 ply interface in the tensile region of a 32-ply quasi-isotropic carbon/epoxy smart composite beam. It was speculated from single tests results that the propagation of the embedded delamination of the sufficient size was able not only to be detected but also to be monitored by the sensors.
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Walker, Joseph R. "Multi-Sensor Approach to Determine the Effect of Geometry on Microstructure in Additive Manufacturing." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1558900598369986.
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Helms, Daniel Lynn. "Feasibility of Ellipsometric Sensor Development for Use During PECVD SiOx Coated Polymer Product Manufacturing." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/162.
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Polymeric materials have provided pathways to products that could not be manufactured otherwise. A new technology which merges the benefits of ceramics into these polymer products has created materials ideally suited to many different industries, like food packaging. Nano Scale Surface Systems, Inc. (NS3), a company which coats polymers with ceramic oxides like SiO2 through a process known as plasma enhanced chemical vapor deposition (PECVD), was interested in the feasibility of an in line measurement system for monitoring the deposited films on various polymer products. This project examined two different coated polymer products, polyethylene terephthalate (PET) beverage containers and biaxially oriented PET food packaging, commonly known as plastic wrap in an effort to determine the feasibility of an ellipsometry based measurement system for NS3’s purpose.
Due to its extensive use in the semiconductor industry for monitoring films deposited on silicon, a measurement systems known as ellipsometry, adept at monitoring the thickness and refractive index of thin films deposited on various substrates, appeared to be an ideal system for the measurement of ceramic oxides deposited on various polymer substrates. This project set out to determine the feasibility of using an ellipsometry based measurement system to monitor ceramic films, specifically silicon oxides (SiOX), deposited on polymer products.
A preliminary experiment determined linearly polarized light could induce a discernible change in polarized light traversing a coated beverage container relative to an uncoated container. However, the experiment lacked repeatability due to the measurement apparatus’ cheap setup, prompting the construction of a null (conventional) ellipsometer for further research. The curved surface of the beverage containers under study unnecessarily complicated the feasibility study so further research examined PECVD SiOX on biaxially oriented PET instead.
Characterization of the PECVD SiOX-PET material was divided into three experiments, with the first two analyzing the SiOX film and PET substrate separately while the third analyzed them together. To assist with the characterization experiments, NS3 provided samples, both SiOX coated and uncoated, of various deposition thicknesses on silicon and biaxially oriented PET substrates.
Null ellipsometry was used in conjunction with spectroscopic reflectometry to characterize the refractive index and thickness of the deposited films. The combined measurement systems found the refractive index of the deposited SiOX films to be between 1.461 and 1.465. The measured thicknesses resulting from the two measurement systems coincided well and were usually 10-20 nm thicker than the predicted thicknesses by the deposition processing parameters. Abeles’ method and monochromatic goniometry were attempted; however, the results had to be discarded due to irrecoverable errors discovered in the reflectance measurement. X-ray photoelectron spectroscopy (XPS) data provided by NS3 showed the deposited SiOX films to be homogeneous with stoichiometries between 2.15 and 2.23.
Characterization of the uncoated biaxially oriented PET required numerous measurement systems. From spectroscopic transmission, trirefringent anisotropy was discovered, intertwined with thickness variations in the PET foil. Goniometry measurements displayed distinct interference curves resulting from rear interface reflections interfering with front interface reflections from the PET sample. Subsequent goniometric models produced multiple solutions due to an unknown optical phenomenon, probably scattering, which degraded the reflection measurements. However, a combined measurement technique utilizing goniometry and differential scanning calorimetry (DSC) determined the refractive indices of the polymer to be NX = 1.677, NY = 1.632 and NZ = 1.495 with a thickness of 11.343 μm and a volume fraction crystallinity of 35-41%. Utilizing the measured refractive indices, ellipsometric models produced only an adequate fit of the measured data due to the presence of depolarization caused by non-uniform PET thickness and scattering resulting from embedded microscopic crystallites. The majority of the error in the ellipsometric data was observed in the Δ measurement.
XPS measurements of SiOX deposited on polypropylene (PP) provided by NS3 showed a heterogeneous interphase layer between the deposited oxide and the polymer substrate where the composition of the layer was continually changing. A similar region, which violates the homogenous assumption the ellipsometric model relied on, was anticipated for the SiOX-PET samples under investigation. The use of an effective medium approximation (EMA) to represent the interphase region was attempted, but failed to provide a decent model fit of the measured data. Depolarization and high optical anisotropy caused by the polymer substrate in combination with a heterogeneous interphase region and the effects of the deposited SiOX layer all interacted to prevent ellipsometric modelling of the null ellipsometry measurements conducted. Goniometry measurements were conducted on the thickest deposited SiOX film (approximately 100 nm) which allowed for the refractive index of the film to be approximated through Abeles’ method (n = 1.46); however the validity of this approximation was questionable given the presence of interference fringes resulting from interference between reflections at both the front and rear interfaces of the material.
From the experiments conducted, it was concluded that null ellipsometry with conventional ellipsometric models could not adequately measure a SiOX film’s refractive index or thickness when deposited on biaxially oriented PET. The reasons for the failure were interactions between multiple sources of error which led to both measurement errors and inaccurate model assumptions. Use of generalized ellipsometry, possibly with spectroscopic ellipsometry, may overcome the failures of conventional ellipsometry when studying this complex optical material.
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Hadley, Glyn James Matthew. "Development and in-vitro evaluation of a potentially implantable fibre-optic glucose sensor probe." Thesis, Bournemouth University, 2002. http://eprints.bournemouth.ac.uk/404/.
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Type I diabetics need regular injections of insulin to survive. Insulin allows the cells of the body to extract glucose from the blood supply to use as fuel. Without insulin the cells turn to other backup fuel sources,this can cause side effects that are quickly fatal or gradual wasting of the bodies tissues. The use of insulin, however, is not danger free, as an incorrect dosage can quickly lead to the reduction of glucose circulating in the blood to drop to a dangerously low level. Without glucose circulating in the blood supply the brain quickly runs out of fuel causing coma and death. Because of this, a means to constantly monitor blood glucose levels has been sought for the last two decades. With such a device, diabetics could judge the correct amount of insulin to inject and be warned of low blood glucose levels. However, to date no reliable portable system has been produced. Recent developments in fibre optic biosensor technology, suggested a possible route to achieves this goal. The work in this thesis presents the development and testing of such a sensor. The sensor presented in this thesis is based around a commercial fibre optic blood gas sensor, the Paratrend 7. The oxygen-sensing element of this device was modified into a glucose sensor using polymer membranes incorporating the enzymes glucose oxidase and catalase. The research was aimed at building a glucose sensor that could be developed into a working blood glucose sensor in the minimum amount of time if the research proved successful. For this reason the Paratrend 7 sensor system was chosen to provide a clinically tested sensor core around which the glucose sensor could be built. The initial experiment, which used a Paratrend7 sensor coated in polyHEMA and glucose oxidase, produced a sensor of diameter of 700µm with a range of 0 to 4mM/1 of glucose and a 90% response time of <100 seconds in a solution with a 15% oxygen tension. The sensor design was then developed to incorporate the enzyme catalase to protect the glucose oxidase and an outer diffusion limiting polyHEMA membrane. This produced a sensor with a range of 0 to 6 mM/l and a response time of <100 seconds. The method of coating the sensors was'then improved, through a series of stages, until an optomised dip coating technique was developed. This technique produced sensors with ranges (in 7.5KPa oxygen tension solutions) between 0 to 3mM/l and 0 to lOmM/1, responsetimes of <100 seconds in some cases and with diameters of 300µm. By using a partial polyurethane outer coat the range of the sensors was increased form 0 to 4mM/l up to 0 to 24mM/1, in one case, with 90% response times in the 100to 500 second range. The sensors were then sterilised using gamma radiation and their performance before and after sterilisation examined. The gamma sterilisation was found to cause a reduction in the range of the sensors,for example 0 to 24 m /I down to 0 to 14mM/l in one case. The affect of 24 hour operation in a 5mM/1 solution of glucose and storage, for up to three months, was then investigated. Both processes were found to reduce the operational range of the sensors,0 to 20 reduced to 0 to 15 mM/i, in one case,for 24 hour operation and form 0 to 15mM/1 reduced to 0 to 11mM/1in one case for a storage time of three months. The use of the enzymes glucose oxidase and catalase together in a fibre optic as can sensor has not been previously reported in the literature as far be ascertained. The comparison of sensor performance before and after gamma sterilisation also appears to be unique as does the gamma sterilisation of a fibre optic glucose sensor.
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SARINK, NIEKE. "Characterization and Manufacturing of Textile Pressure Sensors based on Piezoelectric Fibres." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-18054.
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The main purpose of this thesis was to investigate and characterize the use of piezoelectric yarn for use in textile (fingertip) pressure sensors in glove applications. Such applications could include healthcare, security and safety, game applications or intelligent control. Piezoelectric materials generate a voltage when pressed or squeezed. Poly(vinylidene fluoride) (PVDF) is a polymorphic material with piezoelectric properties. PVDF yarns were integrated into block sensors. These blocks consist of thermoplastic material glued to a knitted supporting fabric. The electrical signal given off by the PVDF yarn was measured with the help of an oscilloscope. The block sensor generated a distinguishable signal under a dynamic compression of 0.003 N, indicating that the structure is sensitive enough compared to the average male fingertip sensitivity threshold (0.0054N).Program: Master programme in Textile Engineering
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Vatani, Morteza. "Additive Manufacturing of Stretchable Tactile Sensors: Processes, Materials, and Applications." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1436202948.
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Söderberg, Breivik Johan. "Microscale Ceramic Pressure Sensor Element for a Carbon Isotope Analysis System for Planetary Exploration : – Design, Manufacturing and Characterization." Thesis, Uppsala universitet, Ångström Space Technology Centre (ÅSTC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257533.
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This master thesis examines the design, manufacturing and characterization of a miniaturized ceramic pressure gauge to be integrated into a system for carbon isotope analysis. Carbon isotope analysis can be used to find traces of extraterrestrial life. Screen printing, platinum bond wire threading, milling, lamination and sintering processes have been developed in order to manufacture a robust, temperature stable and chemically inert component potentially integratable to the carbon isotope analysis system. With use of the Pirani principle, which measures the pressure dependent thermal conductivity of air, promising results have been observed. A relative resistance change of 6 % within the pressure range of 1-10 Torr has been observed. This is comparable to, and even greater than, previous studies. The device has a good response for the desired pressure range. The device sensitivity was studied with different currents and geometric parameters. The results showed that the sensitivity is highly dependent on current and air volume. The work has been done at the Ångström Space Technology Centre – a research group within the Ångström Laboratory, Uppsala University – which currently researches on microscale systems for, e.g., space exploration.
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Wu, Chi-Hao. "Enhancing the production performance of automotive sensor assembly lines through the statistical design of experiments." Diss., Online access via UMI:, 2008.
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Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008.Includes bibliographical references.
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Wei, Li-Ju. "The fabrication of integrated strain sensors for 'smart' implants using a direct write additive manufacturing approach." Thesis, De Montfort University, 2015. http://hdl.handle.net/2086/11430.
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Over the 1980’s, the introduction of Additive Manufacturing (AM) technologies has provided alternative methods for the fabrication of complex three-dimensional (3D) synthetic bone tissue implant scaffolds. However, implants are still unable to provide post surgery feedback. Implants often loosen due to mismatched mechanical properties of implant material and host bone. The aim of this PhD research is to fabricate an integrated strain gauge that is able to monitor implant strain for diagnosis of the bone healing process. The research work presents a method of fabricating electrical resistance strain gauge sensors using rapid and mask-less process by experimental development (design of experiment) using the nScrypt 3Dn-300 micro dispensing direct write (MDDW) system. Silver and carbon electrical resistance strain gauges were fabricated and characterised. Carbon resistive strain gauges with gauge factor values greater than 16 were measured using a proven cantilever bending arrangement. This represented a seven to eight fold increase in sensitivity over commercial gauges that would be glued to the implant materials. The strain sensor fabrication process was specifically developed for directly fabricating resistive strain sensor structures on synthetic bone implant surface (ceramic and titanium) without the use of glue and to provide feedback for medical diagnosis. The reported novel approach employed a biocompatible parylene C as a dielectric layer between the electric conductive titanium and the strain gauge. Work also showed that parylene C could be used as an encapsulation material over strain gauges fabricated on ceramic without modifying the performance of the strain gauge. It was found that the strain gauges fabricated on titanium had a gauge factor of 10.0±0.7 with a near linear response to a maximum of 200 micro strain applied. In addition, the encapsulated ceramic strain gauge produced a gauge factor of 9.8±0.6. Both reported strain gauges had a much greater sensitivity than that of standard commercially available resistive strain gauges.
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Williams, Frances R. "Monitoring and Control of Semiconductor Manufacturing Using Acoustic Techniques." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5278.
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Since semiconductor fabrication processes require numerous steps, cost and yield are critical concerns. In-situ monitoring is therefore vital for process control. However, this goal is currently restricted by the shortage of available sensors capable of performing in this manner. The goal of this research therefore, was to investigate the use of acoustic signals for monitoring and control of semiconductor fabrication equipment and processes. Currently, most methods for process monitoring (such as optical emission or interferometric techniques) rely on "looking" at a process to monitor its status. What was investigated here involved "listening" to the process. Using acoustic methods for process monitoring enhances the amount and sensitivity of data collection to facilitate process diagnostics and control.
A silicon acoustic sensor was designed, fabricated, and implemented as a process monitor. Silicon acoustic sensors are favorable because of their utilization of integrated circuit and micromachining processing techniques; thus, enabling miniature devices with precise dimensions, batch fabrication of sensors, good reproducibility, and low costs. The fabricated sensor was used for in-situ monitoring of nickel-iron electrochemical deposition processes. During this process, changes occur in its plating bath as the alloy is being deposited. It is known that changes in the process medium affect the acoustic response. Thus, the sensor was implemented in an electroplating set-up and its response was observed during depositions. By mapping the sensor response received to the film thickness measured at certain times, a predictive model of the plated alloy thickness was derived as a function of sensor output and plating time. Such a model can lead to real-time monitoring of nickel-iron thickness.
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Zhu, Feng. "A Novel Fault Detection and Classification Approach in Semiconductor Manufacturing Using Time Series Alignment Kernel." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592135306729513.
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Swafford, Robert D. "Development of a new generation of electric current sensors through advances in manufacturing techniques and material design." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50306.
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Electrical systems have become ubiquitous, and with them come the need to
accurately monitor electric current. The aerospace industry is no exception. Modern
aircraft may contain more than one hundred current sensors, each one critical to a
properly functioning vehicle. While these sensors function acceptably, several areas
have been identified for improvement: size, weight, and cost. Each sensor is bulky,
taking up valuable space. They are also costly to manufacture. The existing design
is based on the Hall effect, and has remained fundamentally unchanged for decades.
With the recent progress in manufacturing techniques and materials, it would be beneficial
to reexamine these sensors and determine if improvements can be made using
the accomplishments of recent years. Of particular interest are microelectromechanical
systems, also known as MEMS. Using a sensor based on MEMS technologies in
which design, function, and fabrication are closely intertwined would automatically
meet two of the three goals: reducing size and weight. MEMS additionally have the
potential to allow existing systems to be miniaturized. Also of interest are advanced
materials, some of which can behave as transducers, linking different physical phenomenon.
The goal of this dissertation is to use advances in manufacturing techniques
and materials, specifically those discussed above, to design a better current sensor.
As part of this goal, several potential solutions were studied and optimized. Finally,
proof-of-concept prototypes were fabricated and tested to validate the feasibility of
the designs and offer insight into continued sensor development.
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Krantz, Marthin, and Rikard Andersson. "Robotized Polishing and Deburring with Force Feedback Control." Thesis, University West, Division for Mechanical Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-2604.
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Force control is introduced to robots to solve the problem in machining applications due to the fact that the robot compliance might cause deviation between actual and desired robot path. Also large tolerances in the casting process as well as positioning errors from the clamping create deviations for which the force control technology can adept. Force control has also shown successful in automatic learning of paths along non linear surfaces.
This study investigates the possibility of introducing robots equipped with force control at Volvo Aero Corporation in order to robotize polishing and deburring processes. These are today performed by manual labor. This study investigates more specifically the ABB Force Control machining application package. The polishing process has shown to be very complex and today’s version of the ABB force control package cannot give sufficiently robust results to be recommended for implementation. The major issue is the non-existing compliance of tool orientation needed to adapt to casting and positioning deviations due to varying work piece dimensions. The deburring process has however shown to be easier to handle, and a robot cell and methodology is proposed in this report.
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Passarella, Alice. "Hardware Design and Firmware Architecture of a Multi-Sensor Platform for Monitoring of Workpieces and Machines." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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This Thesis work focuses on the description of the curricular internship activity carried out in the R&D Division of Measuring Systems at MARPOSS S.p.A. company in Bentivoglio, BO, Italy.
Part of this work has been performed in the context of the 5G-SMART European project, whose goal is to demonstrate, evaluate and validate the potential of the usage of 5G networks in real manufacturing environments. The Thesis provides a description of the project, focusing on the objectives, the organizational structure and work-packages, as well as future developments.
An overview of the design steps for the realization of a Multi-Sensor Platform for Monitoring of Workpieces and Machines is given. The goal is to design a device equipped with different sensors, both internal and external, able to acquire multiple data from workpieces and machines of a shop floor. Sensors must be able to communicate wirelessly via the 5G network.
The analysis of the architecture options proposed as a model for the device is then provided, with the description of the final modular layout. The design schematics are examined from a circuit viewpoint, focusing on the hardware design of the various electronic components, and on their interaction with the microprocessor. In order to verify the correct functioning of the board, a basic library of the individual peripherals is developed, which is going to be used as a basis for the final Firmware.
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Clavijo, William Paul. "Low-temperature Fabrication Process for Integrated High-Aspect Ratio Metal Oxide Nanostructure Semiconductor Gas Sensors." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4781.
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This work presents a new low-temperature fabrication process of metal oxide nanostructures that allows high-aspect ratio zinc oxide (ZnO) and titanium dioxide (TiO2) nanowires and nanotubes to be readily integrated with microelectronic devices for sensor applications. This process relies on a new method of forming a close-packed array of self-assembled high-aspect-ratio nanopores in an anodized aluminum oxide (AAO) template in a thin (2.5 µm) aluminum film deposited on a silicon and lithium niobate substrate (LiNbO3). This technique is in sharp contrast to traditional free-standing thick film methods and the use of an integrated thin aluminum film greatly enhances the utility of such methods. We have demonstrated the method by integrating ZnO nanowires, TiO2 nanowires, and multiwall TiO2 nanotubes onto the metal gate of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and the delay line of a surface acoustic wave (SAW) device to form an integrated ChemFET (Chemical Field-Effect Transistor) and a orthogonal frequency coded (OFC) SAW gas sensor. The resulting metal oxide nanostructures of 1-1.7 µm in height and 40-100 nm in diameter offer an increase of up to 220X the surface area over a standard flat metal oxide film for sensing applications.
The metal oxide nanostructures were characterized by SEM, EDX, TEM and Hall measurements to verify stoichiometry, crystal structure and electrical properties. Additionally, the electrical response of ChemFETs and OFC SAW gas sensors with ZnO nanowires, TiO2 nanowires, and multiwall TiO2 nanotubes were measured using 5-200 ppm ammonia as a target gas at room temperature (24ºC) showing high sensitivity and reproducible testing results.
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Emon, Md Omar Faruk. "Ionic Liquid–Based 3D Printed Soft Pressure Sensors and Their Applications." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1593542345792441.
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Calvo, Michele. "Study and manufacturing of biosensors based on plasmonic effects and built on silicon." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI055.
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Le contexte de ce projet de doctorat celui des biocapteurs. Le but final est d’avoir un dispositif portable, composé par une partie jetable, capable de détecter des concentrations très faibles d’un analyte spécifique, à bon marché et compacte, que les médecins peuvent utiliser dans l’hôpital où chez les patients, sans avoir besoin d’un laboratoire entier. Les analytes peuvent être plusieurs (à partir de l’ADN pour la détection de maladies génétiques où des cellules cancéreuses pour la détection précoce du cancer). Cet objectif est possible seulement avec un transducteur qui arrive à convertir efficacement la présence biologique de l’analyte en information électrique. Le transducteur est dans le domaine de la photonique. On combine deux types de guides d’onde, un de type "ridge" diélectrique et un autre métallique, pour en créer un hybride qu’associe les faibles pertes d’une à la sensibilité de l’autre. L’élément innovant est la géométrie de ce guide hybride (Hybrid Plasmonic WaveGuide). Ce memoire explore l'étude theorique, les simulaiton, la fabbrication en salle blanche et la characterization des dispositifs hybride plasmoniquesLab-on-a-chip (or LOC) devices scale down the laboratory processes for detecting illnesses and monitoring sick patients without the need of medical laboratories. These criteria are made possible with a transducer that can convert the biological presence of the target molecule into electrical information. Since the early 2000s, integrated photonics have offered a possible solution for a transducer compatible with LOC needs. In particular, silicon micro-ring resonators represent a compact and sensitive choice to use as a transducer in LOC devices. In agreement with the requirements of LOC devices, the objective of this project is to design and assess the performance of a compact photonic biosensor. The system will be based on integrated photonic transduction. The requirements are that it is compatible with an industrial fabrication platform and fluidic systems, with a sensitivity equal to or higher than the state-of-the-art and simple to functionalize in order to localize the target molecules in the sensitive regions of the sensor. This project details the design, fabrication, and characterization of such a biosensor. In particular, the photonic biosensor is a ring resonators with a Hybrid Plasmonic Waveguide (HPWG) cross-section that fulfills the LOC requirements
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Zhang, Lin. "Investigation of Optical Effects of Chalcogenide Glass in Precision Glass Molding and Applications on Infrared Micro Optical Manufacturing." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574784278471913.
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Guo, Jing. "MULTI-MODE SELF-REFERENCING SURFACE PLASMON RESONANCE SENSORS." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/13.
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Surface-plasmon-resonance (SPR) sensors are widely used in biological, chemical, medical, and environmental sensing. This dissertation describes the design and development of dual-mode, self-referencing SPR sensors supporting two surface-plasmon modes (long- and short-range) which can differentiate surface binding interactions from bulk index changes at a single sensing location. Dual-mode SPR sensors have been optimized for surface limit of detection (LOD). In a wavelength interrogated optical setup, both surface plasmons are simultaneously excited at the same location and incident angle but at different wavelengths. To improve the sensor performance, a new approach to dual-mode SPR sensing is presented that offers improved differentiation between surface and bulk effects. By using an angular interrogation, both surface plasmons are simultaneously excited at the same location and wavelength but at different angles. Angular interrogation offers at least a factor of 3.6 improvement in surface and bulk cross-sensitivity compared to wavelength-interrogated dual-mode SPR sensors.
Multi-mode SPR sensors supporting at least three surface-plasmon modes can differentiate a target surface effect from interfering surface effects and bulk index changes. This dissertation describes a tri-mode SPR sensor which supports three surface plasmon resonance modes at one single sensing position, where each mode is excited at a different wavelength. The tri-mode SPR sensor can successfully differentiate specific binding from the non-specific binding and bulk index changes.
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Iervolino, Onorio. "Enhanced impact resistance and pseudo plastic behaviour in composite structures through 3D twisted helical arrangement of fibres and design of a novel chipless sensor for damage detection." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723326.
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The future of the aerospace industry in large part relies on two factors: (i) development of advanced damage tolerant materials and (ii) development of advanced smart sensors with the ability to detect and evaluate defects at very early stages of component service life. Laminated composite materials, such as carbon fibre reinforced plastics (CFRP), have emerged as the materials of choice for increasing the performance and reducing the cost and weight of aircrafts, which leads to less fuel consumption and therefore lower CO2 emissions. However, it is well known that these materials exhibit fragile behaviour, poor resistance to impact damage caused by foreign objects and require a relatively slow and labour intensive manufacturing process. These factors prevent the rapid expansion of composite materials in several industrial sectors at the current time. Inspired by the use of rope throughout history and driven by the necessity of creating a lean manufacturing process for composites and enhancing their impact properties, the first part of this work has shown that enhanced damage tolerance and pseudo-ductile behaviour can be achieved with standard CFRP by creatively arranging the fibres into a 3D twisted helical configuration. Through an extensive experimental campaign a new method to arrange fibre reinforcement was presented and its effect investigated. The second part of this PhD work focused on developing a new smart sensor. A spiral passive electromagnetic sensor (SPES) for damage detection on CFRP and glass fibre reinforced plastics (GFRP) is presented in this work. A range of defect types in glass and carbon composite has been considered, such as delamination, perforated holes and cracks. Furthermore, throughout this work, the SPES has been exploited as a multi-sensing device allowing the ability to detect temperature and humidity variation, presence of ice and act as an anti/de-icing device.
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Tong, Jingbo. "MEASUREMENT AND MODELING OF HUMIDITY SENSORS." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/59.
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Humidity measurement has been increasingly important in many industries and process control applications. This thesis research focus mainly on humidity sensor calibration and characterization. The humidity sensor instrumentation is briefly described. The testing infrastructure was designed for sensor data acquisition, in order to compensate the humidity sensor’s temperature coefficient, temperature chambers using Peltier elements are used to achieve easy-controllable stable temperatures. The sensor characterization falls into a multivariate interpolation problem. Neuron networks is tried for non-linear data fitting, but in the circumstance of limited training data, an innovative algorithm was developed to utilize shape preserving polynomials in multiple planes in this kind of multivariate interpolation problems.
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Alhusin, Alkhdur Abdullah. "Toward a Sustainable Human-Robot Collaborative Production Environment." Doctoral thesis, KTH, Industriell produktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202388.
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This PhD study aimed to address the sustainability issues of the robotic systems from the environmental and social aspects. During the research, three approaches were developed: the first one an online programming-free model-driven system that utilises web-based distributed human-robot collaboration architecture to perform distant assembly operations. It uses a robot-mounted camera to capture the silhouettes of the components from different angles. Then the system analyses those silhouettes and constructs the corresponding 3D models.Using the 3D models together with the model of a robotic assembly cell, the system guides a distant human operator to assemble the real components in the actual robotic cell. To satisfy the safety aspect of the human-robot collaboration, a second approach has been developed for effective online collision avoidance in an augmented environment, where virtual three-dimensional (3D) models of robots and real images of human operators from depth cameras are used for monitoring and collision detection. A prototype system is developed and linked to industrial robot controllers for adaptive robot control, without the need of programming by the operators. The result of collision detection reveals four safety strategies: the system can alert an operator, stop a robot, move away the robot, or modify the robot’s trajectory away from an approaching operator. These strategies can be activated based on the operator’s location with respect to the robot. The case study of the research further discusses the possibility of implementing the developed method in realistic applications, for example, collaboration between robots and humans in an assembly line.To tackle the energy aspect of the sustainability for the human-robot production environment, a third approach has been developed which aims to minimise the robot energy consumption during assembly. Given a trajectory and based on the inverse kinematics and dynamics of a robot, a set of attainable configurations for the robot can be determined, perused by calculating the suitable forces and torques on the joints and links of the robot. The energy consumption is then calculated for each configuration and based on the assigned trajectory. The ones with the lowest energy consumption are selected.QC 20170223
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Kadlec, Petr. "On robust and adaptive soft sensors." Thesis, Bournemouth University, 2009. http://eprints.bournemouth.ac.uk/15907/.
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In process industries, there is a great demand for additional process information such as the product quality level or the exact process state estimation. At the same time, there is a large amount of process data like temperatures, pressures, etc. measured and stored every moment. This data is mainly measured for process control and monitoring purposes but its potential reaches far beyond these applications. The task of soft sensors is the maximal exploitation of this potential by extracting and transforming the latent information from the data into more useful process knowledge. Theoretically, achieving this goal should be straightforward since the process data as well as the tools for soft sensor development in the form of computational learning methods, are both readily available. However, contrary to this evidence, there are still several obstacles which prevent soft sensors from broader application in the process industry. The identification of the sources of these obstacles and proposing a concept for dealing with them is the general purpose of this work. The proposed solution addressing the issues of current soft sensors is a conceptual architecture for the development of robust and adaptive soft sensing algorithms. The architecture reflects the results of two review studies that were conducted during this project. The first one focuses on the process industry aspects of soft sensor development and application. The main conclusions of this study are that soft sensor development is currently being done in a non-systematic, ad-hoc way which results in a large amount of manual work needed for their development and maintenance. It is also found that a large part of the issues can be related to the process data upon which the soft sensors are built. The second review study dealt with the same topic but this time it was biased towards the machine learning viewpoint. The review focused on the identification of machine learning tools, which support the goals of this work. The machine learning concepts which are considered are: (i) general regression techniques for building of soft sensors; (ii) ensemble methods; (iii) local learning; (iv) meta-learning; and (v) concept drift detection and handling. The proposed architecture arranges the above techniques into a three-level hierarchy, where the actual prediction-making models operate at the bottom level. Their predictions are flexibly merged by applying ensemble methods at the next higher level. Finally from the top level, the underlying algorithm is managed by means of metalearning methods. The architecture has a modular structure that allows new pre-processing, predictive or adaptation methods to be plugged in. Another important property of the architecture is that each of the levels can be equipped with adaptation mechanisms, which aim at prolonging the lifetime of the resulting soft sensors. The relevance of the architecture is demonstrated by means of a complex soft sensing algorithm, which can be seen as its instance. This algorithm provides mechanisms for autonomous selection of data preprocessing and predictive methods and their parameters. It also includes five different adaptation mechanisms, some of which can be applied on a sample-by-sample basis without any requirement to store the on-line data. Other, more complex ones are started only on-demand if the performance of the soft sensor drops below a defined level. The actual soft sensors are built by applying the soft sensing algorithm to three industrial data sets. The different application scenarios aim at the analysis of the fulfilment of the defined goals. It is shown that the soft sensors are able to follow changes in dynamic environment and keep a stable performance level by exploiting the implemented adaptation mechanisms. It is also demonstrated that, although the algorithm is rather complex, it can be applied to develop simple and transparent soft sensors. In another experiment, the soft sensors are built without any manual model selection or parameter tuning, which demonstrates the ability of the algorithm to reduce the effort required for soft sensor development. However, if desirable, the algorithm is at the same time very flexible and provides a number of parameters that can be manually optimised. Evidence of the ability of the algorithm to deploy soft sensors with minimal training data and as such to provide the possibility to save the time consuming and costly training data collection is also given in this work.
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Schühli, Luciano Alcindo. "Monitoramento de operações de retificação usando fusão de sensores." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18140/tde-07042008-130554/.
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O presente trabalho trata da análise experimental de um sistema de monitoramento baseado na técnica de fusão de sensores, aplicado em uma retificadora cilíndrica externa. A fusão é realizada entre os sinais de potência e emissão acústica para obtenção do parâmetro FAP (Fast Abrasive Power) através do método desenvolvido por Valente (2003). Através da simulação de problemas encontrados nos processos de retificação (falha de sobremetal, colisão, desbalanceamento e vibração), foram captados os sinais de potência e emissão acústica e a partir destes gerado o parâmetro FAP, comparando seu desempenho, na detecção dos problemas, com os outros dois sinais. Para a análise foram construídos os gráficos das variações dos sinais em relação ao tempo de execução do processo e os mapas do FAP e acústico. O sistema de monitoramento avaliado tem como característica baixa complexidade de instalação e execução. Os dados experimentais revelam que o FAP apresenta uma velocidade de resposta maior que a potência e levemente amortecida em relação à emissão acústica. O nível do seu sinal é igual ao da potência mantendo-se homogêneo durante o processo, ao contrário da emissão acústica que pode ser influenciada por diversos outros parâmetros, tais como geometria da peça, distância do sensor, montagem do sensor, entre outros, que independem da interação ferramenta-peça. O resultado é uma resposta dinâmica e confiável, associada à energia do sistema. Estas características são interessantes para o monitoramento de processos de retificação (excluindo a dressagem) sendo superiores àquelas apresentadas isoladamente pelos sinais de potência e emissão acústica.The present study deals with an experimental analysis of a monitoring system based on a sensor fusion strategy applied to a cylindrical grinding machine. It comprises a fusion of the power and acoustic emission signals and has as main goal to obtain the FAP (Fast Abrasive Power) using the method developed by Valente (2003). Initially, the power and acoustic emission signals were captured under operational dysfunction conditions during the grinding process (stock imperfection, collision, unbalancing e vibration). Then, based on these signals, the FAP parameter was generated and its capability in characterizing operational dysfunctions evaluated against the performance of an individual analysis of the power and acoustic emission signals. For this analysis, FAP and acoustic maps plus plots showing the FAP signals vs. working time were implemented. The experimental data revealed that the FAP presents a faster response than the power signal and a slightly dumped response when compared against the acoustic signal. The signal level of the FAP is similar to the power signal and is homogenous during the machining process. On contrary to the FAP, the acoustic emission signal may be affected by parameters that are not related to the tool-workpiece interactions, workpiece geometry and sensor positioning. The dynamic response of FAP is reliable and linked to the energy of the system. Finally, it should be highlightened that the monitoring system based on the FAP parameter presents low complexity in both implementation and execution. Such characteristics are superior to those observed when using either the power or acoustic emission signals and highly valuable in a system designed to monitor grinding processes.
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Schomer, John J. "Embedding fiber Bragg grating sensors through ultrasonic additive manufacturing." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483670362650083.
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Langlois, Patrick. "Contribution à l'élaboration de capteurs de pression à jauges de contrainte en couches minces de Constantan." Rouen, 1987. http://www.theses.fr/1987ROUES039.
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Elaboration de capteurs utilisables sur une large plage de température. Description des procédures et conditions de travail qui ont permis de réaliser un tel dispositif. Principales caractéristiques des capteurs, moyens de mesure et résultats obtenus. La conclusion met en évidence l'intérêt industriel d'un tel dispositif
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Ma, Anson Wing Kui. "Carbon nanotube : manufacturing process design and its use in gas sensors /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CENG%202005%20MA.
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Waris, Marc. "Mise en œuvre, instrumentation, validation et modélisation d’un système d’injection RTM pour la fabrication de structures composites de hautes performances." Thesis, Saint-Etienne, EMSE, 2012. http://www.theses.fr/2012EMSE0661/document.
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Les matériaux composites ont connu ces dernières années une forte croissance, croissance aujourd'hui renforcée par les nouvelles normes européenne visant à diminuer les émissions CO2 d'ici 2020. La réalisation de pièces complexes peut poser de nombreuses problématiques de fabrication comme la formation de zones sèches, ou la création de distorsions géométriques. Les origines de ces problématiques sont souvent liées à un manque de connaissance et de maîtrise des phases d'imprégnation des renforts et de cuisson du matériau. L'amélioration de la robustesse des procédés nécessite d'avoir une connaissance fine des phénomènes physiques qui ont lieu lors de l'élaboration. Dans cette perspective, les procédés d'élaboration de matériaux composites ont été étudiés à travers la mise en place d'un démonstrateur de laboratoire dans le cadre du projet LCM Smart. Ce pilote d'injection a permis de valider des solutions d'instrumentation, à partir de capteurs innovants (OFS) développés en partenariat avec le laboratoire d'optique Hubert Curien.L'application de cette instrumentation dans le cadre du suivi du procédé RTM a démontré les capacités des OFS pour le suivi des caractéristiques physiques de la pièce (le front d'écoulement, la température, les déformations résiduelles et le degré de cuisson). La comparaison des caractéristiques mesurées avec des simulations numériques effectuées en collaboration avec ESI, a montré une bonne corrélation.Enfin, l'instrumentation a permis de mettre en évidence l’intérêt d’un outillage composite en HexTool pour la réduction des contraintes résiduelles liées à l'interaction outil/pièceA significant growth in production and consumption of composite materials can be seen recently; growth reinforced by the new European standards, aimed at reducing CO2 emissions by the year 2020.The producing of complex parts can cause many difficulties for manufacturing because of their geometries and / or their constituents (using of various materials). For example, dry zones or geometric distortion formation. The origins of these difficulties are often related to a lack of knowledge and control of the reinforcement's impregnation phases and material curing.Improving the robustness of the processes demands a detailed knowledge of physical phenomena that occur during the producing. For this, we studied the composite materials production through the implementation of a laboratory demonstrator in the project LCM Smart. This pilot injection was used to validate instrumentation solutions, from innovative sensors (OFS) developed in partnership with the optical laboratory Hubert Curien. The application of this instrumentation in the context of RTM process monitoring in the development of simple parts has demonstrated the capabilities of OFS to control physical characteristics of the part (the flow front, temperature, residual strain and curing degree). The comparison of the measured characteristics with numerical simulations carried out in collaboration with ESI showed a good correlation.Finally, instrumentation has demonstrated the capacity of composite tool made by HexTool to minimize the residual stresses due to the tool/part interaction
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Zellers, Brian Andrew. "3D Printed Wearable Electronic Sensors with Microfluidics." Youngstown State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1575874880525156.
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Mehdi, Aghaei Sadegh. "Electronic and Magnetic Properties of Two-dimensional Nanomaterials beyond Graphene and Their Gas Sensing Applications: Silicene, Germanene, and Boron Carbide." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3389.
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The popularity of graphene owing to its unique properties has triggered huge interest in other two-dimensional (2D) nanomaterials. Among them, silicene shows considerable promise for electronic devices due to the expected compatibility with silicon electronics. However, the high-end potential application of silicene in electronic devices is limited owing to the lack of an energy band gap. Hence, the principal objective of this research is to tune the electronic and magnetic properties of silicene related nanomaterials through first-principles models.
I first explored the impact of edge functionalization and doping on the stabilities, electronic, and magnetic properties of silicene nanoribbons (SiNRs) and revealed that the modified structures indicate remarkable spin gapless semiconductor and half-metal behaviors. In order to open and tune a band gap in silicene, SiNRs were perforated with periodic nanoholes. It was found that the band gap varies based on the nanoribbon’s width, nanohole’s repeat periodicity, and nanohole’s position due to the quantum confinement effect. To continue to take advantage of quantum confinement, I also studied the electronic and magnetic properties of hydrogenated silicene nanoflakes (SiNFs). It was discovered that half-hydrogenated SiNFs produce a large spin moment that is directly proportional to the square of the flake’s size.
Next, I studied the adsorption behavior of various gas molecules on SiNRs. Based on my results, the SiNR could serve as a highly sensitive gas sensor for CO and NH3 detection and a disposable gas sensor for NO, NO2, and SO2. I also considered adsorption behavior of toxic gas molecules on boron carbide (BC3) and found that unlike graphene, BC3 has good sensitivity to the gas molecules due to the presence of active B atoms. My findings divulged the promising potential of BC3 as a highly sensitive molecular sensor for NO and NH3 detection and a catalyst for NO2 dissociation. Finally, I scrutinized the interactions of CO2 with lithium-functionalized germanene. It was discovered that although a single CO2 molecule was weakly physisorbed on pristine germanene, a significant improvement on its adsorption energy was found by utilizing Li-functionalized germanene as the adsorbent. My results suggest that Li-functionalized germanene shows promise for CO2 capture.
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Wilcox, Steven John. "Cutting tool condition monitoring using multiple sensors and artificialintelligence techniques on a computer numerical controlled milling machine." Thesis, Heriot-Watt University, 1992. http://hdl.handle.net/10399/1446.
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This work documents an investigation of the degradation of a variety of different tools whilst conducting milling operations on a computer numerical controlled (CNC) milling machine. The potential of a range of sensors to detect tool degradation has been investigated and the outputs have been incorporated into a monitoring system. Progressive degradation under nominal rough and finish face milling and rough groove milling has been investigated using a two point grooving tool and four and eight point face milling tools on En8, En24 and En24T workpiece materials. Rapid degradation of the cutting tool has also been observed under rough milling conditions using four and eight point face milling tools, whilst machining n8 and En24T materials in a variety of simulated and actual tool breakage situations. A limited investigation of the effect of the individual wear geometries associated with both progressive and instantaneous tool degradation has been conducted by simulating these geometries and carrying out rough miffing tests using a four point face milling tool on a workpiece of En8 material. Similarly, a limited investigation of the effect of machining on different machines has also been undertaken. A number of different sensing technologies have been used, including conventional sensors such as spindle current and cutting force but also novel sensing techniques such as Acoustic Emission. These have been combined using artificial intelligence techniques to provide automatic recognition of the tool wear state. Similarly, the feasibility of breakage detection/prediction has also been demonstrated.
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Rabenimanana, Toky Harrison. "Modélisation, fabrication et caractérisation expérimentale de réseaux MEMS faiblement couplés pour la détection de masse." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD062.
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Une étude sur les détecteurs de masse utilisant la localisation d’Anderson est menée dans le cadre de cette thèse. Différents moyens permettant d’améliorer leurs performances sont proposés et démontrés à travers deux dispositifs MEMS. Les deux dispositifs utilisent le même système composé de deux cantilevers couplés mécaniquement, mais les vibrations sont générées de deux manières différentes: le premier dispositif est actionné par une force électrostatique attractive tandis que le second est actionné par une force électrostatique répulsive. Afin de se débarrasser du déséquilibre créé par les défauts de fabrication, on utilise l’assouplissement électrostatique en réglant la tension continue de l’actionnement. Pour le premier dispositif, une approche utilisant un système asymétrique avec deux cantilevers de longueurs différentes est proposée. On réduit alors la rigidité effective de la poutre courte pour équilibrer le système. Avec le second type d’actionnement, le faible assouplissement électrostatique nous oblige à utiliser deux micropoutres de même longueur. Mais le système est toujours équilibré de la même manière. Grâce à la fonctionnalisation des non-linéarités électrostatiques, le premier dispositif montre une meilleure sensibilité, qui est de 67% supérieure à la sensibilité maximale atteignable en régime linéaire. Quant au second dispositif, il montre l’absence de non-linéarités électrostatiques, ce qui permet d’augmenter sa gamme dynamique linéaire jusqu’à 70% de la distance qui sépare les poutres des électrodes inférieures. Cela devrait améliorer non seulement la résolution en masse du détecteur, mais aussi la précision des mesures. Tous ces concepts sont d’abord étudiés théoriquement avec le modèle analytique basé sur la théorie d’Euler-Bernoulli. Ils sont ensuite démontrés expérimentalement après que les détecteurs aient été fabriqués suivant le processus MUMPSA study on mass microsensors using Anderson localization is conducted in this thesis. Different ways allowing to enhance their performances are proposed and demonstrated through two MEMS devices. Both devices use the same system composed of two mechanically coupled cantilevers, but the vibrations are generated in two different ways: the first device is actuated with an attractive electrostatic force while the second device is actuated with a repulsive electrostatic force. In order to get rid of initial imbalance due to manufacturing defects, the electrostatic softening effect is used by tuning the DC voltage of the actuation. For the first device, a concept with an asymmetric system including two cantilevers of different lengths is proposed. We thus reduce the effective stiffness of the short cantilever to balance the system. With the second type of actuation, the weak electrostatic softening effect forces us to use two microbeams of the same length. But the system is still balanced with the same approach. Thanks to the functionalization of electrostatic nonlinearities, the first device shows an enhanced sensitivity, which is 67% higher than the maximum sensitivity reachable in the linear regime. Concerning the second device, it shows the absence of electrostatic nonlinearities, which allows to increase the linear dynamic range by up to 70% of the gap. It should improve not only the mass resolution of the sensor, but also the accuracy of the mass sensing. All of these concepts are first theoretically investigated with the developed analytical model based on the Euler-Bernoulli beam theory. They are then experimentally demonstrated after the sensors are manufactured with the MUMPS
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NILSSON-HEDMAN, TOMMY, and MATTIAS DAHLQVIST. "Wireless RFID Sensors in a Mesh Network for Discrete Manufacturing : An Industry 4.0 Application." Thesis, KTH, Mekatronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217528.
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This thesis presents the work of a master degree project in mechatronics by two students from The Royal Institute of Technology. The project was carried out during spring 2017 in collaboration with Bosch Rexroth Mellansel as part of their desire to improve their operations. It is also in line with the Bosch Groups ambition to lead the development within Industry 4.0. The aim was to investigate the information need on a discrete manufacturing process and how radio-frequency identification (RFID) can be used to cover that need. The background research was made with qualitative methods using a literature review on relevant areas and a case study of Bosch Rexroth Mellansel. A discrete event simulation was created to confirm the possibilities of an RFID tracking system. It acted as a target for what the developed demonstrator should fulfil and was realised through a system of four wireless nodes connected in a mesh network. The plant in Mellansel partially implemented a Bosch standardised RFID system in parallel with the development of the demonstrator, which enabled a comparison of the two systems. The results show that from a tag event, which gives information on what, where and when, it is possible to, in real time, analyse and visualise valuable key performance indicators for a production process. It is also possible to use the data to automate transactions in an enterprise resource system which removes non-value adding activities from an operator while also ensuring consistency in the reporting procedure. The results indicate that benefits can be achieved. However, this requires further quantitative analysis before it can be fully confirmed and be used to push the development of Industry 4.0 forward.Denna rapport presenterar ett examensarbete inom mekatronik av två studenter från Kungliga Tekniska Högskolan. Projektet genomfördes under våren 2017 i samarbete med Bosch Rexroth Mellansel som en del av deras strävan att förbättra sin verksamhet. Det ligger också i linje med Bosch koncernens ambition att leda utvecklingen inom Industri 4.0. Syftet var att undersöka informationsbehovet hos en diskret tillverkningsprocess och hur radio-frequency identification (RFID) kan användas för att täcka detta behov. Bakgrundsstudien gjordes med kvalitativa metoder som litteraturstudie inom relevanta områden och en fallstudie av en produktionsprocess inom Bosch Rexroth Mellansel. En simulering av produktionsprocessen skapades för att bekräfta möjligheterna av att använda ett RFID system för spårning av objekt. Den fungerade som ett mål för vad den utvecklade demonstratorn skulle uppfylla och realiserades genom en prototyp bestående av fyra trådlösa noder samlade i ett mesh nätverk. Parallellt med utvecklingen av demonstratorn gemomförde fabriken i Mellansel en del-implementering av en Bosch-standardiserad RFID lösning, vilket möjliggjorde en jämförelse av de två systemen. Resultaten visar att det från en avläsning av en tag, som ger information om vad, var och när, så är möjligt att i realtid analysera och visualisera värdefulla nyckeltal för en produktionsprocess. Det är också möjligt att använda data för att automatisera transaktioner i ett affärssystem som tar bort icke värdeskapande aktiviteter för operatören och samtidigt säkerställer en standardiserad rapporteringsprocess. Resultaten visar att fördelar kan uppnås men kräver ytterligare kvantitativ analys innan de kan bekräftas till fullo och användas för att driva utvecklingen av Industri 4.0 framåt.
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Chilelli, Sean Kelty. "Structural health monitoring with fiber Bragg grating sensors embedded into metal through ultrasonic additive manufacturing." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563529169604482.
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Robert, Pascal. "Conception et fabrication de pièces métalliques intelligentes par procédé WAAM." Thesis, Université Grenoble Alpes, 2022. http://www.theses.fr/2022GRALI055.
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L’industrie 4.0 a mis en évidence la nécessité de collecter massivement des données et s’appuie donc en partie sur l’usage de pièces intelligentes qui sont capables de fournir des données lors de leur utilisation. De plus, les technologies de fabrication additive métallique semblent être un moyen de réaliser aisément des pièces intelligentes et particulièrement le procédé Wire & Arc Additive Manufacturing (WAAM) qui utilise une technologie de soudure à l’arc. Cela lève la problématique suivante : Comment fabriquer et concevoir une pièce métallique intelligente par fabrication additive WAAM ? Le périmètre de recherche est limité à la mesure de contraintes dans des pièces en aluminium. Afin de répondre à cette problématique quatre verrous scientifiques sont identifiées et résolus dans ce manuscrit :• L’intégration d’une technologie de mesure au sein d’une pièce nécessite que celle-ci soit massive (composée de cordons juxtaposés). Ainsi, réaliser des pièces massives en aluminium est donc le premier verrou à lever. Les paramètres de fabrication du procédé WAAM sont listés et expliqués dans l’état de l’art. Le mouillage, la régularité et l’énergie massique d’un cordon sont identifiés comme des indicateurs de l’aptitude des paramètres sélectionnés à être utilisés pour produire des pièces massives saines. Des campagnes expérimentales sont menées pour sélectionner les paramètres non identifiés par l’état de l’art pour produire un cordon mouillé et ayant une faible énergie massique. Des blocs sont réalisés et des éprouvettes en sont extraites puis leurs caractéristiques mécaniques sont déterminées par essai de traction afin de valider les paramètres retenus.• Le deuxième verrou scientifique identifié est de choisir correctement la technologie de mesure de contrainte à insérer. De nombreux dispositifs pouvant être insérés au cours du procédé WAAM mais également des méthodes de sélection sont passés en revue dans le chapitre bibliographique. Une synthèse en quatre familles des technologies de mesure de contrainte pertinentes pour l’insertion au cours du procédé WAAM est donc proposée. Un guide de sélection s’appuyant sur des critères d’évaluation, sur la connaissance de ces technologies et sur les spécifications de pièces à rendre intelligente est proposé. Le suivi d’un témoin de contrainte magnétostrictif enfoui par induction est la technologie la plus prometteuse d’après le guide proposé. Cette technologie est utilisée dans la suite de l’étude.• Le troisième verrou est de rendre fabricable la pièce intelligente avec la technologie de mesure sélectionnée. Cette technologie nécessite l’insertion d’un témoin fin en acier au sein de la pièce hôte en aluminium. Afin d’en démontrer la faisabilité, divers paramètres (revêtement du témoin, trajectoire de la torche de soudure) sont explorés lors de campagnes expérimentales. Les échantillons produits sont analysés par tomographie. Des cartes d’épaisseur des témoins sont ainsi produites et permettent de juger de leur détérioration. L’analyse par microscopie électronique à balayage de la couche intermétallique montre la fusion entre le témoin et la pièce hôte et donc la faisabilité de réaliser une pièce intelligente ainsi.• Enfin, pour réaliser une pièce intelligente avec cette technologie, le dernier verrou est le choix de l’emplacement du témoin dans la pièce pour que celui-ci rende compte de l’évolution de l’état de contrainte de celle-ci. Ainsi, des préconisations pour la sélection des caractéristiques mécaniques du témoin ont été formulées à l’aide de l’analyse de son comportement magnétostrictif et de son couplage mécanique à son environnement. Puis, une méthode de placement du témoin pour la mesure de la contrainte maximale dans la pièce et basée sur des simulations éléments finis est proposée pour quatre scénarios de mesures distincts.L’ensemble des études menées permet de conclure sur l’intérêt de l’usage du procédé WAAM pour la production de pièces intelligentesIndustry 4.0 highlights the need for massive data collection and therefore relies partly on the use of smart parts that are capable of providing data when they are used. In addition, metal additive manufacturing technologies seem to be a way to easily make smart parts and particularly the Wire & Arc Additive Manufacturing (WAAM) process that uses arc-welding technology. This raises the following issue, how to manufacture and design a smart metal part by WAAM? The research scope is limited to stress measurement in aluminum parts. In order to answer this problem, four scientific issues are identified and resolved in this manuscript:• The integration of a sensing technology within a part requires the part to be massive (composed of juxtaposed beads). Thus, making massive parts in aluminum is the first scientific challenge to resolve. Manufacturing parameters of the WAAM process are listed and explained in the state of the art. Wetting, regularity and mass energy of a bead are identified as indicators of the suitability of the selected parameters to be used to produce sound massive parts. Experimental campaigns are conducted to select parameters not identified by the state of the art to produce a wetted bead with low mass energy. Blocks are made and specimens are extracted then their mechanical characteristics are determined by tensile test in order to validate the selected parameters.• The second scientific challenge identified is to correctly choose the stress measurement technology to be inserted. Many devices that can be inserted during the WAAM process but also selection methods are reviewed in the bibliographic chapter. A synthesis in four families of strain measurement technologies relevant for the insertion during the WAAM process is therefore proposed. A selection guide based on evaluation criteria, on the knowledge of these technologies and on the specifications of parts to design as smart parts is proposed. Control by induction of an embedded magnetostrictive stress indicator is the most promising technology according to the proposed guide. This technology is used in the rest of the study.• The third challenge is to make the smart part manufacturable with the selected sensing technology. This technology requires the insertion of a thin steel indicator within the aluminum host part. In order to demonstrate its feasibility, various parameters (indicator’s coating, trajectory of the welding torch) are explored during experimental campaigns. Samples produced are analyzed by tomography. Thickness maps of the indicator are thus produced and allow to evaluate their deterioration. Scanning electron microscopy analysis of the intermetallic layer shows the fusion between the indicator and the host part and thus the feasibility of producing a smart part.• Finally, to realize a smart part with this technology, the last challenge is the choice of the indicator location in the part so that it reports the evolution of the stress in this one. Thus, recommendations for the selection of the mechanical characteristics of the indicator were formulated using the analysis of its magnetostrictive behavior and its mechanical coupling to its environment. Then, a method of placing the indicator for the measurement of the part maximum stress based on finite element simulations is presented for four distinct measurement scenarios.All the studies carried out allow to conclude on the interest of the use of the WAAM process for the production of smart parts
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Mulvihill, Paul. "Manufacturing optical fibre Bragg grating strain sensors with an excimer laser for high-strain, multiplexed embedded applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29369.pdf.
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Kauffmann, Philippe. "Mesure de densité de courant électrique en vue d'améliorer l'automatisation du processus de galvanoplastie industrielle." Angers, 1995. http://www.theses.fr/1995ANGE0017.
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Le travail présenté dans ce mémoire concerne l'amélioration du processus industriel de traitement de surface électrolytique par la mesure de densité de courant électrique ponctuelle dans les bains de galvanisation. La méthode générale adoptée consiste en la mise au point d'un capteur de densité relative, puis l'étude d'un capteur de densité absolue plus performant. On présente enfin l'association des capteurs avec des automates, eux-mêmes intégrés à un système informatique communiquant, généralisé à l'entreprise.