1,543 research outputs found
On flexibly integrating machine vision inspection systems in PCB manufacture
The objective of this research is to advance computer vision techniques
and their applications in the electronics manufacturing industry. The research has
been carried out with specific reference to the design of automatic optical inspection
(AOI) systems and their role in the manufacture of printed circuit boards (PCBs).
To achieve this objective, application areas of AOI systems in PCB manufacture
have been examined. As a result, a requirement for enhanced performance
characteristics has been identified and novel approaches and image processing algorithms
have been evolved which can be used within next generation of AOI systems.
The approaches are based on gaining an understanding of ways in which
manufacturing information can be used to support AOI operations. Through providing
information support, an AOI system has access to product models and associated
information which can be used to enhance the execution of visual inspection
tasks. Manufacturing systems integration, or more accurately controlled access to
electronic information, is the key to the approaches. Also in the thesis methods are
proposed to achieve the flexible integration of AOI systems (and computer vision
systems in general) within their host PCB manufacturing environment. Furthermore,
potential applications of information supported AOI systems at various stages of
PCB manufacturing have been studied.
It is envisaged that more efficient and cost-effective applications of AOI
can be attained through adopting the flexible integration methods proposed, since
AOI-generated information can now be accessed and utilized by other processes
Automatic breach detection during spine pedicle drilling based on vibroacoustic sensing
Pedicle drilling is a complex and critical spinal surgery task. Detecting
breach or penetration of the surgical tool to the cortical wall during
pilot-hole drilling is essential to avoid damage to vital anatomical structures
adjacent to the pedicle, such as the spinal cord, blood vessels, and nerves.
Currently, the guidance of pedicle drilling is done using image-guided methods
that are radiation intensive and limited to the preoperative information. This
work proposes a new radiation-free breach detection algorithm leveraging a
non-visual sensor setup in combination with deep learning approach. Multiple
vibroacoustic sensors, such as a contact microphone, a free-field microphone, a
tri-axial accelerometer, a uni-axial accelerometer, and an optical tracking
system were integrated into the setup. Data were collected on four cadaveric
human spines, ranging from L5 to T10. An experienced spine surgeon drilled the
pedicles relying on optical navigation. A new automatic labeling method based
on the tracking data was introduced. Labeled data was subsequently fed to the
network in mel-spectrograms, classifying the data into breach and non-breach.
Different sensor types, sensor positioning, and their combinations were
evaluated. The best results in breach recall for individual sensors could be
achieved using contact microphones attached to the dorsal skin (85.8\%) and
uni-axial accelerometers clamped to the spinous process of the drilled vertebra
(81.0\%). The best-performing data fusion model combined the latter two sensors
with a breach recall of 98\%. The proposed method shows the great potential of
non-visual sensor fusion for avoiding screw misplacement and accidental bone
breaches during pedicle drilling and could be extended to further surgical
applications
Perancangan Sistem Kontrol CNC Pengebor PCB Otomatis Berbasis Raspberry PI
Circuit Board (PCB) is a micro-board containing various components electronics used in an automatic circuit. In PCB drilling is usually done human which takes a lot}when the hole in the PCB is getting more and more. And it takes precision when the eye touches the PCB board which gives rise to friction force and can cause drilling. The purpose of this research was the development of tools in the form of automated drills using computers with BCNC software as face-to-face CNC movements. The engine is driven with stepper motor and dc motor as spindle. In this BCNC software the drilling process is done by entering the codes in the form of gcode which can later be read by CNC. The coordinates of the holes in the layout that have been created are obtained by converting the layout into codes called gcode. The process is carried out using PCB designer software. Thoroughness testing on all six axes found an error 1,2% with ten attempts each. PID implementation on DC motor obtained constant value Kp = 54, Ki = 38 and Kd = 0.9. As well as before drilling, the installation of drill bits must be precise so that at the time of spinning, the drill bits do not shake
Advancement in robot programming with specific reference to graphical methods
This research study is concerned with the derivation of advanced robot
programming methods. The methods include the use of proprietary
simulation modelling and design software tools for the off-line
programming of industrial robots. The study has involved the generation
of integration software to facilitate the co-operative operation of these
software tools.
The three major researcli'themes7of "ease of usage", calibration and the
integration of product design data have been followed to advance robot
programming. The "ease of usage" is concerned with enhancements in the
man-machine interface for robo t simulation systems in terms of computer
assisted solid modelling and computer assisted task generation.
Robot simulation models represent an idealised situation, and any off-line
robot programs generated from'them may contain'discrepancies which could
seriously effect thq programs' performance; Calibration techniques have
therefore been investigated as 'a method of overcoming discrepancies
between the simulation model and the real world.
At the present time, most computer aided design systems operate as
isolated islands of computer technology, whereas their product databases
should be used to support decision making processes and ultimately
facilitate the generation of machine programs. Thus the integration of
product design data has been studied as an important step towards truly
computer integrated manufacturing.
The functionality of the three areas of study have been generalised and
form the basis for recommended enhancements to future robot programming
systems
Versatile bipolar temperature controller for custom in vitro applications
Effective temperature control is crucial in many studies of isolated biological tissues, with preparations often requiring specialized holding chambers. In these situations, the design flexibility and optimizations offered by a custom made temperature controller may be preferable over a commercial model. We present a versatile controller for heating and cooling applications, providing simple step-by-step instructions to mathematically model your specific system and optimize controller parameters. The apparatus uses analog components and linear stages to simplify circuit comprehension and customization, achieving fast transitions with small static errors and overshoots over a wide range of temperatures without readjustment. A fully featured rackable enclosure is complemented by two temperature probes based on the LMT70A linear microchip sensor (for the control loop and for bath monitoring). BNC outputs provide scaled probe signals for continuous temperature data acquisition. The maximum achievable power output of the controller is -23.5 W/+22.0 W (-4.7 V/+4.4 V, \ub15.0 A), sufficient to bring a well designed holder for standard 35 mm chambers from 23 \ub0C up to 37 \ub0C in ~1 min and down to 3 \ub0C in ~4 min. Any biologist with some technical prowess should be able to follow our instructions from modeling to assembly and calibration
Complex low volume electronics simulation tool to improve yield and reliability
Assembly of Printed Circuit Boards (PCB) in low volumes
and a high-mix requires a level of manual intervention during
product manufacture, which leads to poor first time yield and
increased production costs. Failures at the component-level
and failures that stem from non-component causes (i.e.
system-level), such as defects in design and manufacturing,
can account for this poor yield. These factors have not been
incorporated in prediction models due to the fact that systemfailure
causes are not driven by well-characterised
deterministic processes. A simulation and analysis support
tool being developed that is based on a suite of interacting
modular components with well defined functionalities and
interfaces is presented in this paper. The CLOVES (Complex
Low Volume Electronics Simulation) tool enables the
characterisation and dynamic simulation of complete design;
manufacturing and business processes (throughout the entire
product life cycle) in terms of their propensity to create
defects that could cause product failure. Details of this system
and how it is being developed to fulfill changing business
needs is presented in this paper. Using historical data and
knowledge of previous printed circuit assemblies (PCA)
design specifications and manufacturing experiences, defect
and yield results can be effectively stored and re-applied for
future problem solving. For example, past PCA design
specifications can be used at design stage to amend designs or
define process options to optimise the product yield and
service reliability
Intelligent upper-limb exoskeleton using deep learning to predict human intention for sensory-feedback augmentation
The age and stroke-associated decline in musculoskeletal strength degrades
the ability to perform daily human tasks using the upper extremities. Although
there are a few examples of exoskeletons, they need manual operations due to
the absence of sensor feedback and no intention prediction of movements. Here,
we introduce an intelligent upper-limb exoskeleton system that uses cloud-based
deep learning to predict human intention for strength augmentation. The
embedded soft wearable sensors provide sensory feedback by collecting real-time
muscle signals, which are simultaneously computed to determine the user's
intended movement. The cloud-based deep-learning predicts four upper-limb joint
motions with an average accuracy of 96.2% at a 200-250 millisecond response
rate, suggesting that the exoskeleton operates just by human intention. In
addition, an array of soft pneumatics assists the intended movements by
providing 897 newton of force and 78.7 millimeter of displacement at maximum.
Collectively, the intent-driven exoskeleton can augment human strength by 5.15
times on average compared to the unassisted exoskeleton. This report
demonstrates an exoskeleton robot that augments the upper-limb joint movements
by human intention based on a machine-learning cloud computing and sensory
feedback.Comment: 15 pages, 6 figures, 1 table, Submitted for possible publicatio
Design of a Personal Health Monitor Interface for Wireless, IP-based, Data Logging
Collaborating with the Enterprise Research Centre at the University of Limerick (UL) in Ireland, we designed, developed, and implemented a proof-of-concept glucose meter adapter that allows blood glucose level readings to be securely transmitted to a remote database via existing WiFi technology. By using open source software and embedded components, we have created a highly flexible platform that allows healthcare professionals to monitor patients in near real-time. Our device aims to simplify the lifestyle of diabetics while providing new opportunities for statistical research and analysis of diabetes
A reference architecture for flexibly integrating machine vision within manufacturing
A reference architecture provides an overall framework that may embrace models, methodologies and
mechanisms which can support the lifecycle of their target domain. The work described in this thesis
makes a contribution to establishing such a generally applicable reference architecture for supporting
the lifecycIe of a new generation of integrated machine vision systems.
Contemporary machine vision systems consist of a complex combination of mechanical engineering,
the hardware and software of an electronic processor, plus optical, sensory and lighting components.
"This thesis is concerned with the structure of the software which characterises the system application.
The machine vision systems which are currently used within manufacturing industry are difficult to
integrate within the information systems required within modem manufacturing enterprises. They are
inflexible in all but the execution of a range of similar operations, and their design and implementation
is often such that they are difficult to update in the face of the required change inherent within modem
manufacturing.
The proposed reference architecture provides an overall framework within which a number of supporting
models, design methodologies, and implementation mechanisms can combine to provide support
for the rapid creation and maintenance of highly structured machine vision applications. These applications
comprise modules which can be considered as building blocks of CIM systems. Their integrated
interoperation can be enabled by the emerging infrastructural tools which will be required to underpin
the next generation of flexibly integrated manufacturing systems.
The work described in this thesis concludes that the issues of machine vision applications and the
issues of integration of these applications within manufacturing systems are entirely separate. This separation
is reflected in the structure of the thesis. PART B details vision application issues while PAIIT C
deals with integration. The criteria for next generation integrated machine vision systems, derived in
PART A of the thesis, are extensive. In order to address these criteria and propose a complete architecture,
a "thin slice" is taken through the areas of vision application, and integration at the lifecycle
stages of design, implementation, runtime and maintenance.
The thesis describes the reference architecture, demonstrates its use though a proof of concept implementation
and evaluates the support offered by the architecture for easing the problems of software change
IDENTIFICATION OF CHATTER VIBRATIONS AND ACTIVE VIBRATION CONTROL BY USING THE SLIDING MODE CONTROLLER ON DRY TURNING OF TITANIUM ALLOY (TI6AL4V)
In recent years, with the development of sensor technologies, communication platforms, cyber-physical systems, storage technologies, internet applications and controller infrastructures, the way has been opened to produce competitive products with high quality and low cost. In turning, which is one of the important processes of machining, chatter vibrations are among the biggest problems affecting product quality, productivity and cost. There are many techniques proposed to reduce chatter vibrations for which the exact cause cannot be determined. In this study, an active vibration control based on the Sliding Mode Control (SMC) has been implemented in order to reduce and eliminate chatter vibration, which is undesirable for the turning process. In this context, three-axis acceleration data were collected from the cutting tool during the turning of Ti6Al4V. Finite Impulse Response (FIR) filtering, Fast Fourier Transform (FFT) analysis and integral process were carried out in order to use the raw acceleration data collected over the system in control. The system is modeled mathematically and an active control block diagram is created. It is observed that chattering decreased significantly after the application of active vibration control. The surface quality formed by the amplitude of the graph obtained after active control has been compared and verified with the data obtained from the actual manufacturing result
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