Showing papers in "Insight in 2020"

Enabling robotic adaptive behaviour capabilities for new industry 4.0 automated quality inspection paradigms

Abstract: The seamless integration of industrial robotic arms with server computers, sensors and actuators can revolutionize the way automated Non-Destructive Testing (NDT) is performed and conceived Achieving effective integration and the full potential of robotic systems presents significant challenges, since robots, sensors and end-effector tools are often not necessarily designed to be put together and form a holistic system This paper presents recent breakthroughs, opening up new scenarios for the inspection of product quality in advanced manufacturing Many years of research have brought to software platforms the ability to integrate external data acquisition instrumentation with industrial robots for improving the inspection speed, accuracy and repeatability of NDT Robotic manipulators have typically been operated by predefined tool-paths generated through off-line path-planning software applications Recent developments pave the way to data-driven autonomous robotic inspections, enabling real-time path planning and adaptive control This paper presents a toolbox with highly efficient algorithms and software functions, developed to be used through high-level programming languages (eg MATLAB, LabVIEW, Python) and/or integrated with low-level languages (eg C#, C++) applications The use of the toolbox can speed-up the development and the robust integration of new robotic NDT systems with real-time adaptive capabilities and is compatible with all 6-DOF KUKA robots, which are equipped with Robot Sensor Interface (RSI) software add-on The paper describes the architecture of the toolbox and shows two application examples, where performance results are provided The concepts described in the paper are aligned with the emerging Industry 40 paradigms and have wider applicability beyond NDT

Pattern of infantile skin problems in a tertiary care hospital

Abstract: Introduction: Skin diseases are a major health problem in children, which is associated with significant morbidity. Its prevalence ranges from 21% to 37% in various parts of Bangladesh in school-based study. The present study was conducted to know the prevalence and pattern of infantile skin problems. Materials and Methods: A cross-sectional descriptive study was conducted OPD in a tertiary care hospital in Dhaka between July 2014 to June 2015. A total of 212 children between 0 to 12 months were examined for diseases of the skin and socio-demography. Data were coded and analyzed through SPSS 26 version. Results: There were 75 female infants (35%) and 137 male infants (65%). Seborrheic dermatitis was more common problem and nearly half (47.5%) of all infants and remaining half was other six skin conditions. In case of gender variation both sexes suffered mostly from seborrheic dermatitis. However, more females (n-8) suffered from dermatophyte infection and impetigo than male (n-4). Total 11 types of occupations were identified. Among them most common (29%) was private service and business was the 2nd common father’s occupation. Fathers living in abroad were 12%. Prevalence of seborrheic dermatitis was less (9%), whose parents were educated more than 12 years and prevalence was more (40.5%) who were educated less than 12 years (X2 -8.74, df-2, P-0.05). Conclusion: Findings of present study indicates a shift in prevalence of skin diseases from infectious to noninfectious one. A multicenter study with large sample is required to investigate whether this trend is common in Bangladesh.

Remaining useful life prediction of rolling bearings based on the three-parameter Weibull distribution proportional hazards model

Abstract: In order to accurately predict the remaining useful life (RUL) of rolling bearings, a novel method based on the threeparameter Weibull distribution proportional hazards model (WPHM) is proposed in this paper. In this new method, degradation features of the bearing vibration signals were calculated in the time, frequency and time-frequency domains and treated as the input covariates of the predictive WPHM. Essential knowledge of the bearing degradation dynamics was learnt from the input features to build an effective three-parameter WPHM for bearing RUL prediction. Experimental data acquired from the run-to-failure bearing tests of the intelligent maintenance system (IMS) was used to evaluate the proposed method. The analysis results demonstrate that the proposed model is able to produce accurate RUL prediction for the tested bearings and outperforms the popular two-parameter WPHM.

Review of non-contact methods for automated aircraft inspections

Abstract: Damage on the aircraft structure can be caused by lightning strikes, hail, accidental impacts or ageing. Scratches or dents on the aircraft surface are typical indications of impact damage. General visual inspection (GVI) is the primary way in which to detect such forms of damage. The inspection process is time consuming, raises safety concerns for the inspector and is subject to variations due to human factors. Significant inspection automation remains challenging, mainly because GVI requires the critical human ability to assess anomalies. Also, damage specifications in maintenance manuals are influenced by human interpretation. Some automated tools are beginning to be available for aircraft inspection checks. However, none of them are capable of replacing the inspector judgement yet. Humans still need to manually assess the location or the data generated by the tools. Their performance is also affected by different environmental conditions, materials and the overall characteristics of the damage. This review presents the main methods for non-contact visual aircraft inspection, explaining their basic working principles and limitations. Their suitability for automation in aircraft inspection is also discussed.

A fast numerical method for the analytical model of pulsed eddy current for pipelines

Abstract: The analytical model of pulsed eddy current (PEC) serves as a tool to explore the detection mechanism of PEC testing, which is widely used to optimise the design of probes and analyse the influence on PEC signals. However, based on the analytical model of impedance change, the computational efficiency of the PEC model for pipelines is low at present, which means that a lot of time is consumed and the application of the analytical model of PEC is suppressed. In order to improve the efficiency of numerical calculation, this paper proposes a fast numerical calculation method for the analytical model of PEC for pipelines, based on the integral model of impedance change. Firstly, in order to improve the calculation efficiency of the Dodd and Cheng model, this paper reveals that the generalised integral can be changed into a definite integral by studying the properties of the integral function. Secondly, according to the partial derivative characteristic of impedance change with frequency, the method of piecewise cubic spline interpolation is used to calculate the impedance change of harmonics. Finally, an analytical model of PEC for single-layer pipeline is calculated and the results are compared with the finite element method (FEM) to verify the accuracy and efficiency of the proposed method. The results indicate that the method could be used to improve the computational efficiency of the PEC model for pipelines when only conductivity is changed.

Perancangan Enterprise Architecture Menggunakan Zachman Framework (Study Case: Perusahaan Farmasi)

Abstract: Teknologi informasi merupakan suatu teknologi yang digunakan untuk mengolah data, termasuk memproses, mendapatkan, menyusun, menyimpan, memanipulasi data dalam berbagai cara untuk menghasilkan informasi yang berkualitas. Dengan meningkatkan peran teknologi informasi maka investasi di bidang teknologi informasi semakin besar dan semakin kompleks dalam pengelolaanya. Oleh karena itu untuk perkembangan arsitektur Enterprise Architecture perlu diadopsi atau dikembangkan sendiri suatu EA framework. framework yang dapat dimanfaatkan untuk pengembangan arsitektur enterprise, yaitu dengan menggunakan Zachman Framework. Zachman Framework adalah framework Architecture Enterprise yang menyediakan cara untuk memandang dan mendefinisikan sebuah enterprise secara formal dan terstruktur dengan baik. Dengan menggunakan framework Zachman target perusahaan farmasi dapat terealisasikan dengan baik dan benar

A flexible robotic cell for in-process inspection of multi-pass welds

Abstract: Welds are currently only inspected after all the passes are complete and after allowing sufficient time for any hydrogen cracking to develop, typically over several days. Any defects introduced between passes are therefore unreported until fully buried, greatly complicating rework and also delaying early corrections to the weld process parameters. In-process inspection can provide early intervention but involves many challenges, including operation at high temperatures with significant gradients affecting acoustic velocities and, hence, beam directions. Reflections from the incomplete parts of the weld would also be flagged as lack-of-fusion defects, requiring the region of interest (ROI) to adapt as the weld is built up. The collaborative SIMPLE (SIngle Manufacturing PLatform Environment) project addresses these challenges by incorporating robotic inspection within a robotic tungsten inert gas (TIG) welding cell. This has been accomplished initially with commercial off-the-shelf ultrasonic phased arrays, but is flexible enough to adapt to future developments with solutions suitable for higher temperatures. The welding and inspection robots operate autonomously. The former can introduce deliberate defects to validate the latter, which uses 5 MHz 64-element phased arrays on high-temperature wedges to generate sector scans after each weld pass. The results are presented, confirming that the challenges have been addressed and demonstrating the feasibility of this approach.

Evolusi Penggunaan Teknologi Web 3.0 : Semantic Web

Abstract: Generasi baru dari konsep teknologi yang digunakan pada halaman website mengalami perubahan yang juga selaras dengan kebutuhan bisnis yang ada dalam dunia digital. Halaman website mengalami transformasi dari pada mulanya adalah hanya berupa halaman website statis, kemudian pada versi atau generasi berikutnya menjadi halaman website 2.0 sampai dengan generasi ketiga atau halaman website 3.0 (web 3.0) atau yang juga dikenal dengan istilah website semantik (Semantic Web). Generasi ketiga dari teknologi halaman website inilah yang akan menjadi topik utama dari penulisan paper ini, dimana pembahasan yang akan dituliskan dan dijelaskan pada paper ini adalah mengenai karakteristik dari web 3.0, teknologi yang ada pada web 3.0 seperti RDF (Resource Description Framework), SPARQL dan Web Ontology. Kemudian dalam penulisan jurnal ini juga akan diberikan contoh atau implementasi dari penggunaan teknologi web 3.0 dan kemudian penjelasan teknis mengenai cara kerja web 3.0. Hasil dari penulisan paper ini adalah untuk mengetahui perbedaan apakah yang ditawarkan oleh halaman website yang mengadopsi atau menggunakan teknologi web 3.0 dan juga untuk mengetahui keunggulan yang dimiliki oleh teknologi web 3.0.

A non-contact method for estimating the pre-tension of a rectangular membrane structure

Abstract: The stiffness of membrane structures widely used in modern buildings is provided by pre-tension, which means that any loss of pre-tension during service life may endanger structural safety and lead to engineering accidents. Therefore, the pre-tension of membrane structures needs to be estimated effectively and a corresponding estimation method is proposed in this study. Firstly, a theoretical model of a rectangular membrane structure is established using the constant deflection contour method (CDCM) to analytically derive a relationship between the pre-tension and the frequency. Then, the pre-tension is calculated using the frequency obtained experimentally by non-contact modal testing using a three-dimensional digital image correlation (3D-DIC) technique. Furthermore, the estimation method is validated by experimental study. The results show that the proposed method can provide a satisfactory assessment of the pre-tension in rectangular membrane structures and has significant potential to be utilised by industry.

Evaluation of circumferential cracks in metal tubes based on a magnetic field response model of eddy current testing

Abstract: According to the characteristics of circumferential cracks on the inner surface of metal tubes, a magnetic field response method has been proposed and a mathematical analytical model for detecting the circumferential crack has also been established. The theoretical model, based on the magnetic field response, could be expressed as a series sum of trigonometric and Bessel functions. The relationship between the distribution of the magnetic field in the inner region of the metal tube and the geometrical size of the cracks is also analysed. The results show that the analytical model can effectively explain and analyse the variation of the surrounding magnetic field caused by the crack. The characteristic parameters of the crack, Br and Bz , which are extracted from the magnetic field, have certain quantitative recognition abilities. In addition, an increase in the thickness of the metal tube causes a larger range of magnetic field variations and is considered to be disadvantageous for detecting a change in the magnetic induction intensity that is a result of the crack. A theoretical model and research results contribute to the development of eddy current testing and improve the accuracy of the non-destructive testing and evaluation of metal tubes.Publisher Note: Following the original publication of this paper, a change was made to the author affiliations on page 91. Full details can be found in the correction notice given after page 97 of the PDF for this article.

Influence of electrical and thermal ageing on the mineral insulating oil performance for power transformer applications

Abstract: In the present work, a new electrothermal combined stress test cell has been designed and fabricated to conduct accelerated electrothermal ageing. The fabricated test cell includes all possible real working conditions of the transformers. The effects of accelerated electrothermal ageing on the performance of power transformers with thermally upgraded Kraft (TUK), Nomex-910 and Nomex-410 solid dielectrics in conjunction with mineral oil have been investigated. The accelerated electrothermal ageing has been performed for a temperature range of 100°C to 220°C, along with 10 kV electrical stress. Subsequently, several electrical, thermal, mechanical and chemical properties of transformer oil and different paper dielectrics have been determined. It has been observed from the diagnostic test results that Nomex impregnated mineral oil samples have better electrothermal performance as well as oxidation stability when compared to the thermally upgraded Kraft oil samples. Therefore, Nomex insulating materials in conjunction with mineral oil are suggested as alternative solid dielectrics for power transformers in order to achieve better oxidation stability, improved thermal performance for long service runs and reduced operating and maintenance costs. It is envisioned that the present experimental study will be very beneficial to utility managers and end-users of power transformers.

Enhanced ACFM detection performance by multi-parameter synergy analysis

Abstract: A procedure for the enhancement of alternating current field measurement (ACFM) detection performance is proposed based on a multi-parameter synergy analysis (MPSA) algorithm. Firstly, to gain the maximised ACFM signal characteristics, wavelet base property matching is adopted to choose the favourable wavelet bases. To this aim, the following six base properties should be considered: orthogonality, compact support, symmetry, discrete wavelet transform (DWT), vanishing moment and regularity. It is found that the applicable wavelet bases are Haar, Daubechies (DbN), Symlets (SymN) and Coiflets (CoifN). Secondly, the MPSA method is applied to select the optimal mother wavelet candidates. The candidate with the largest MPSA index value is regarded as the optimum wavelet base. Finally, the proposed MPSA denoising strategy is demonstrated using an ACFM experiment. The results indicate that wavelets Db4 with decomposition level (DL)9 and Sym7 with DL8 are most appropriate for x- and z-axis ACFM signal denoising, respectively. The enhanced ACFM detection performance is experimentally verified and it is found that the signal-to-noise ratio (SNR) is increased by 33.8 dB and 26.7 dB for the x- and z-axis signal, respectively.

Edge-preserving compression of CT scans using wavelets

Abstract: This work addresses the subject of efficient storage of computed tomography (CT) data with an emphasis on the quality of surfaces. Industrial dimensional metrology often requires high measurement accuracy and we show that this is retained using wavelet-based compression methods. The applied techniques include a tensor product wavelet transform and soft wavelet shrinkage. In our tests on real objects, we compared dimensional CT measurements of compressed and uncompressed volumes. We were able to reduce the necessary storage space significantly with a minimal loss of accuracy. For a multi sphere phantom, we decreased the storage space to 4.7% (from 638 MB to 30 MB) with an average deviation below 1 μm from the original volume.

A robust self-driven surface crack detection algorithm using local features

Abstract: This paper presents an effective image analysis method for visual surface crack detection, called a robust self-driven crack detection algorithm (RSCDA). Firstly, a local texture anisotropy (LTA) is estimated based on self-driven local feature statistics from the original photograph. Secondly, the LTA is used to detect candidate crack pixels. Finally, the actual crack pixels are accurately identified using two effective measurements for connected domains based on discriminative direction and relative sparse features. The results demonstrate that the RSCDA is an effective and robust surface crack detection method for building materials or textiles.

A method for quantitative identification of magnetic flux leakage of fatigue cracks in ferromagnetic components

Abstract: A modelling method integrating principal component analysis (PCA) and the least-squares support vector machine with particle swarm optimisation (PSO-LSSVM) is proposed to address the difficulties in quantitative identification of fatigue cracks. The widths and depths of fatigue cracks are quantitatively identified by establishing a non-linear mapping relationship between these dimensions and magnetic flux leakage (MFL) signals. A series of fatigue crack samples are prepared through the fatigue tensile test for the MFL detection system. A sample library is established through MFL experimentation to verify the feasibility of the method for quantitative identification of fatigue cracks based on PSO-LSSVM. The results indicate that the method is in a position to effectively and quantitatively identify the widths and depths of fatigue cracks less than 1 mm in size with a maximum error of approximately 0.3 mm.

Practical evaluation of velocity effects on the magnetic flux leakage technique for storage tank inspection

Abstract: Magnetic flux leakage (MFL) is a technique commonly used to inspect storage tank floors. This paper describes a practical evaluation of the effect of scanning velocity on defect detection in mild steel plates with thicknesses of 6 mm, 12 mm and 16 mm using a fixed permanent magnetic yoke. Each plate includes four semi-spherical defects ranging from 20% to 80% through-wall thickness. It was found that scanning velocity has a direct effect on defect characterisation due to the distorted magnetic field resulting from induced eddy currents that affect the MFL signal amplitude. This occurs when the inspection velocity is increased and a reduction in the MFL signal amplitudes is observed for far-surface defects. The opposite applies for the top surface, where an increase is seen for near-surface MFL amplitudes when there is insufficient flux saturating the inspection material due to the concentration of induced flux near the top surface. These findings suggest that procedures should be altered to minimise these effects based on inspection requirements. For thicker plates and when far-surface defects are of interest, inspection speeds should be reduced. If only near-surface defects are being considered then increased speeds can be used, provided that the sensor range is sufficient to cope with the increased signal amplitudes so that signal clipping does not become an issue.

A rolling bearing fault diagnosis method based on fastDTW and an AGBDBN

Abstract: In order to improve fault feature extraction and diagnosis for rolling bearings, a fault diagnosis method based on fast dynamic time warping (fastDTW) and an adaptive Gaussian-Bernoulli deep belief network (AGBDBN) is proposed in this paper. Firstly, for the non-stationary vibration signal characteristics of the bearing, the fastDTW algorithm is used to calculate the residual vector of the fault signal, thereby enhancing the fault characteristic information. Then, according to the continuous vibration value of the bearing vibration signal, a standard deep belief network (DBN) is improved to deal with the problem that the optimal setting for the learning rate is difficult to achieve in the deep neural network training process and the AGBDBN model is used for fault diagnosis. Finally, the proposed method is compared with a variety of model diagnosis methods. The experimental results show that the proposed method achieved good diagnostic results.

Correction of B-scan distortion for optimum ultrasonic imaging of backwalls with complex geometries

Abstract: Ultrasound undergoes refraction and reflection at interfaces between media of different acoustic refractive indices. The most common ultrasonic method (pulse-echo) monitors the reflected energy to infer the presence of flaws, whereas the lower amplitude of refracted signals is ignored. When the reflector is oriented normally, with respect to the ultrasonic beam, the received echo signal shows the maximum amplitude. The pulse-echo method also relies on monitoring the amplitude of the back wall echo, to identify or confirm the presence of defects. This works well for parts with constant thickness and with planar back walls. Unfortunately, parts with complex back walls are common to many industrial sectors. For example, in applications such as aerospace structures often require parts with complex shapes. Assessing such parts reliably is not trivial and can cause severe downtimes in the aerospace manufacturing processes or in in-service inspections. This work aims to improve the ultrasonic inspectability of parts with complex back walls, through sending ultrasonic beams from the front wall side. Ultrasonic phased array probes and state-of-the-art instrumentation allow sending ultrasonic energy into a part at wide ranges of focusing depths and steering angles. This allows tracking the back wall profile, thus hitting it normally and maximizing the amplitude of the reflected echo at any point. However, our work has shown that a cross-sectional scan resulting from multiple ultrasonic beams, which are sent at variable incidence angles, can present significant geometrical distortion and can be not of much use for accurate defect visualization and sizing. This paper introduces a generalized algorithm developed to remove geometric distortions and the effect that variable refraction coefficients have on the transmitted and received amplitudes. The algorithm was validated through CIVA simulations for two example parts with complex back walls, considering isotropic materials.

Magnetic Field Frequency Optimisation for MFL Imaging using QWHE Sensors

Abstract: Magnetic particle and other magnetic flux leakage-based methods for the detection and evaluation of surface-breaking flaws in ferromagnetic materials typically use highstrength (~ 0.5 T rms), low frequency (≤ 50 Hz) magnetic fields. The rationale behind this is the ready availability of strong permanent magnets and mains power to create high strength electromagnets. This high field strength is needed to saturate the sample and compensate for the insensitivity of magnetic particles, silicon Hall sensors, coils and other magnetic transducers. As such, the frequency of applied magnetic field is typically limited to ≤ 50 Hz and does not take into account the frequency response of the material under test (some MFL applications use this low frequency to detect sub-surface or flaws on the back wall). In this study, a probe consisting of a Quantum Well Hall Effect (QWHE) sensor, illuminating electromagnet and sensor circuitry was controlled using an automated XYZ scanner with an x y measurement step size (i.e. magnetic image pixel size) of 100 microns. This probe was used to apply a magnetic field of various frequencies (DC to 1 kHz) and field strengths (5 mT to 100 mT) to ascertain a frequency and field range best suited to detecting 10 and 11 mm length longitudinal surface-breaking toe cracks in ground mild steel welds. A lift-off distance of < 1 mm was controlled using a proximity laser and z direction motor module to autonomously control the probe lift-off and conform to sample geometry. This study found that an applied magnetic field of frequency 800 Hz and strength 10 mT rms was optimal, based on the ratio of MFL responses from the two flaws and the weld. The power dissipation of the coil was taken into account in this determination, where other frequency-field combinations had comparable or higher detection but were discounted as they had substantially higher power consumption. Page 1 of 16