201 results on '"Position tolerance"'
Search Results
2. A Coupling-Insensitive X-Type IPT System for High Position Tolerance.
- Author
-
Feng, Hao, Dayerizadeh, Alireza, and Lukic, Srdjan M.
- Subjects
- *
MAGNETIC declination , *MAGNETIC flux - Abstract
The output characteristic of an inductive power transfer (IPT) system is highly susceptible to variations in magnetic coupling. In this article, a primary-side X-type compensation topology is proposed to acquire stable output characteristics against a wide range of magnetic coupling without resorting to tight control and coil design. By introducing the concept and derivation principle for the coupling-insensitive compensation topologies, the X-type network is presented to provide self-regulation ability for primary coil current against variable coupling, thereby enabling steady power transfer in a highly dynamic environment. The design considerations for the passive parameters are elaborated, followed by the comparison with regular compensation methods. Owing to its unique structure and design flexibility, the X-type compensation exhibits a stable output characteristic that is beneficial in enhancing the tolerance to position shifts. Moreover, it also features a wide soft-switching range and more flexible design for the output level range than previous topologies. Experimental results show stable power transfer over a coupling factor of 0.14–0.28, where the power fluctuation is less than 20%. The presented method is seen as a potential solution for low power IPT systems, where high mobility is demanded. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Modification and hardware implementation of cortex‐like object recognition model.
- Author
-
Mohammadi Anbaran, Alireza, Torkzadeh, Pooya, Ebrahimpour, Reza, and Bagheri, Nasour
- Abstract
Object recognition in the visual cortex of mammals and humans has inspired many computational object recognition models. Hierarchical model and X (HMAX) is a well‐known biologically motivated object recognition model with scale and position tolerance and high accuracy. Due to the computational intensive nature, hardware implementation with massive parallel processing is suggested for real‐time applications. However, it is important to explore algorithmic trade‐offs when mapping an algorithm to are configurable hardware. A direct conversion of the software implementation of an algorithm generally results inefficient hardware resource usage. In this study, the authors propose a novel modification into the HMAX model which makes it suitable for hardware implementation. More precisely, to reduce the number of memory blocks and multipliers of the S2 layer of HMAX produces, they replace the first norm by the second norm, which critically affects the silicon area in an application‐specific integrated circuit implementation or the required resources in field‐programmable gate array (FPGA). To evaluate the proposed model, they implement a pipelined version of the revised model on a mid‐range commercial Xilinx FPGA, i.e. XC6VLX240T platform from a Virtex 6 family of Xilinx using ISE. Compared to the recent hardware implementation of HMAX, the proposed model offers 83% resource degradation in DSP48 slices and 3% in memory blocks. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Tel Erozyon Tezgahlari ile Üretilen Makine ve Kalıp Elemanlarının Üretim Maliyetleri Açısıdan İncelenmesi.
- Author
-
Basmacı, Gültekin, Ay, Mustafa, Etyemez, Ayhan, and Paksoy, Coşkun
- Abstract
Production and manufacturing industry products, increasing production and production speeds ensuring production and making it one of the most important factors. The fastest possible delivery of the product or service to the end user has a significant impact on production, inventory and marketing costs. For his reason, manufacturing techniques with high precision and surface roughness values gain importance in all machinery manufacturing sectors, aerospace, automotive and all mold manufacturing sectors. For this purpose, machine parts and mold elements produced by wire erosion come to the forefront. This is due to the high position, tolerance, surface roughness values. With the appropriate parameters and wire, tolerance values that can be obtained by several different operations can be obtained more quickly and easily. In order to improve the surface roughness values of the machine elements produced by known machining methods, a series of grinding and polishing processes are carried out which increase the production costs. Machine parts and mold elements produced by wire erosion, while skipping by wire erosion, while skipping one or more of these process stages, surface roughness values with higher dimension and tolerance sensitivity are obtained products with surface roughness values obtained by almost grinding. The aim of this study is to make a scientific study to reduce the production costs in the machine and manufacturing industry by experiencing experimentally the surface tolarence and roughness values of the measurement tolerances of the machining and wire erosion terminals. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
5. A Coupling-Insensitive X-Type IPT System for High Position Tolerance
- Author
-
Alireza Dayerizadeh, Srdjan Lukic, and Hao Feng
- Subjects
Coupling ,Physics ,Control and Systems Engineering ,Electromagnetic coil ,Maximum power transfer theorem ,Topology (electrical circuits) ,Electrical and Electronic Engineering ,Topology ,Inductive coupling ,Position tolerance ,Compensation (engineering) ,Power (physics) - Abstract
The output characteristic of an inductive power transfer (IPT) system is highly susceptible to variations in magnetic coupling. In this article, a primary-side X-type compensation topology is proposed to acquire stable output characteristics against a wide range of magnetic coupling without resorting to tight control and coil design. By introducing the concept and derivation principle for the coupling-insensitive compensation topologies, the X-type network is presented to provide self-regulation ability for primary coil current against variable coupling, thereby enabling steady power transfer in a highly dynamic environment. The design considerations for the passive parameters are elaborated, followed by the comparison with regular compensation methods. Owing to its unique structure and design flexibility, the X-type compensation exhibits a stable output characteristic that is beneficial in enhancing the tolerance to position shifts. Moreover, it also features a wide soft-switching range and more flexible design for the output level range than previous topologies. Experimental results show stable power transfer over a coupling factor of 0.14–0.28, where the power fluctuation is less than 20%. The presented method is seen as a potential solution for low power IPT systems, where high mobility is demanded.
- Published
- 2021
6. Hierarchical stimulus processing in rodent primary and lateral visual cortex as assessed through neuronal selectivity and repetition suppression.
- Author
-
Kaliukhovich, Dzmitry A. and de Beeck, Hans Op
- Subjects
- *
IMMUNOSUPPRESSION , *HIERARCHICAL Bayes model , *BRAIN imaging , *VISUAL cortex , *NEUROPLASTICITY - Abstract
Similar to primates, visual cortex in rodents appears to be organized in two distinct hierarchical streams. However, there is still little known about how visual information is processed along those streams in rodents. In this study, we examined how repetition suppression and position and clutter tolerance of the neuronal representations evolve along the putative ventral visual stream in rats. To address this question, we recorded multiunit spiking activity in primary visual cortex (V1) and the more downstream visual laterointermediate (LI) area of head-restrained Long-Evans rats. We employed a paradigm reminiscent of the continuous carry-over design used in human neuroimaging. In both areas, stimulus repetition attenuated the early phase of the neuronal response to the repeated stimulus, with this response suppression being greater in area LI. Furthermore, stimulus preferences were more similar across positions (position tolerance) in area LI than in V1, even though the absolute responses in both areas were very sensitive to changes in position. In contrast, the neuronal representations in both areas were equally good at tolerating the presence of limited visual clutter, as modeled by the presentation of a single flank stimulus. When probing tolerance of the neuronal representations with stimulus-specific adaptation, we detected no position tolerance in either examined brain area, whereas, on the contrary, we revealed clutter tolerance in both areas. Overall, our data demonstrate similarities and discrepancies in processing of visual information along the ventral visual stream of rodents and primates. Moreover, our results stress caution in using neuronal adaptation to probe tolerance of the neuronal representations. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. Relaxed Steering towards Oriented Region Goals
- Author
-
Boulic, Ronan, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Egges, Arjan, editor, Kamphuis, Arno, editor, and Overmars, Mark, editor
- Published
- 2008
- Full Text
- View/download PDF
8. Tolerance-Maps Applied to the Straightness and Orientation of an Axis
- Author
-
Bhide, S., Ameta, G., Davidson, J. K., Shah, J.J., and Davidson, Joseph K., editor
- Published
- 2007
- Full Text
- View/download PDF
9. Integrated Databasing and Analysis
- Author
-
Vauterin, Luc, Vauterin, Paul, and Stackebrandt, Erko, editor
- Published
- 2006
- Full Text
- View/download PDF
10. A Solution to the Accuracy of Multi-Pin Positioning Based on Optimization
- Author
-
Huan Guo, Zhijing Zhang, Heng Liu, Muzheng Xiao, and Xin Jin
- Subjects
0209 industrial biotechnology ,business.product_category ,General Computer Science ,Computer science ,positioning error ,02 engineering and technology ,Coordinate measuring machine ,Position tolerance ,Set (abstract data type) ,020901 industrial engineering & automation ,Machining ,Position (vector) ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Electrical and Electronic Engineering ,multi-pin positioning ,Selection (genetic algorithm) ,tolerance ,General Engineering ,Pinhole ,Machine tool ,020201 artificial intelligence & image processing ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,Stage (hydrology) ,business ,optimization ,lcsh:TK1-9971 - Abstract
To ensure the precise relative position between two adjacent parts, multiple pins (10, or even more) are usually set on the parts for positioning. In this case, whether the two adjacent parts can be assembled, and the consequent positioning error is unknown, which might cause a failure in the reasonable selection of parts in the assembly stage, and the reasonable design of relevant parameters (such as the diameters of pins and pinholes, and positional tolerances) in the design stage. In this study, considering the positional tolerance of the pinhole as well as the diameter tolerance of the pin and pinhole, the mathematical model of the accuracy of multi-pin positioning was established, and determined by optimization, obtaining the positioning error. The related assembly experiments were conducted. The measurement results were all in the range of mathematical calculation with the measured data, indicating that the proposed method is effective, and it can provide a direct basis for the part selection in the assembly stage, and the tolerance design in the design stage.
- Published
- 2021
11. Modification and hardware implementation of cortex‐like object recognition model
- Author
-
Alireza Mohammadi Anbaran, Nasour Bagheri, Reza Ebrahimpour, and Pooya Torkzadeh
- Subjects
Virtex ,business.industry ,Computer science ,Cognitive neuroscience of visual object recognition ,020206 networking & telecommunications ,02 engineering and technology ,Integrated circuit ,Position tolerance ,Hierarchical database model ,law.invention ,law ,Gate array ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer Vision and Pattern Recognition ,Electrical and Electronic Engineering ,business ,Field-programmable gate array ,Massively parallel ,Software ,Computer hardware - Abstract
Object recognition in the visual cortex of mammals and humans has inspired many computational object recognition models. Hierarchical model and X (HMAX) is a well-known biologically motivated object recognition model with scale and position tolerance and high accuracy. Due to the computational intensive nature, hardware implementation with massive parallel processing is suggested for real-time applications. However, it is important to explore algorithmic trade-offs when mapping an algorithm to are configurable hardware. A direct conversion of the software implementation of an algorithm generally results inefficient hardware resource usage. In this study, the authors propose a novel modification into the HMAX model which makes it suitable for hardware implementation. More precisely, to reduce the number of memory blocks and multipliers of the S2 layer of HMAX produces, they replace the first norm by the second norm, which critically affects the silicon area in an application-specific integrated circuit implementation or the required resources in field-programmable gate array (FPGA). To evaluate the proposed model, they implement a pipelined version of the revised model on a mid-range commercial Xilinx FPGA, i.e. XC6VLX240T platform from a Virtex 6 family of Xilinx using ISE. Compared to the recent hardware implementation of HMAX, the proposed model offers 83% resource degradation in DSP48 slices and 3% in memory blocks.
- Published
- 2020
12. Practical Procedure for Position Tolerance Uncertainty Determination via Monte-Carlo Error Propagation
- Author
-
Kosarevsky S. and Latypov V.
- Subjects
uncertainty evaluation ,propagation of distributions ,monte-carlo simulation ,position tolerance ,Mathematics ,QA1-939 - Published
- 2012
- Full Text
- View/download PDF
13. Practical Applications for Intersection of Primitives for Geometrical Modelling and Tolerancing
- Author
-
Valluri, S. R., ElMaraghy, W. H., Gadalla, Mohamed A. E., and ElMaraghy, Hoda A., editor
- Published
- 1998
- Full Text
- View/download PDF
14. Typical specifications
- Author
-
Loweth, R. P. and Loweth, R. P.
- Published
- 1997
- Full Text
- View/download PDF
15. Effect of Manufacturing Tolerances on the Multipoles of the SSC Dipole Magnet
- Author
-
Nguyen, L., Gurol, H., and Nonte, John, editor
- Published
- 1991
- Full Text
- View/download PDF
16. Calculation of delivered composite dose from Calypso tracking data for prostate cancer: And subsequent evaluation of reasonable treatment interruption tolerance limits
- Author
-
Y. Jessica Huang, Martin Szegedi, Bill J. Salter, Jonathan D. Tward, Vikren Sarkar, Prema Rassiah-Szegedi, Hui Zhao, Brian Wang, and L. Huang
- Subjects
Male ,Patient Positioning ,Position tolerance ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Prostate cancer ,0302 clinical medicine ,Planned Dose ,Prostate ,Image Processing, Computer-Assisted ,medicine ,Humans ,Radiation Oncology Physics ,PTV margin ,Radiology, Nuclear Medicine and imaging ,Tracking data ,Patient treatment ,Instrumentation ,Retrospective Studies ,87.55.-X ,Radiation ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Prostatic Neoplasms ,Radiotherapy Dosage ,Ptv margin ,Prognosis ,medicine.disease ,medicine.anatomical_structure ,Treatment interruption ,030220 oncology & carcinogenesis ,composite dose ,Radiotherapy, Intensity-Modulated ,Tomography, X-Ray Computed ,Calypso ,Calypso tolerance level ,Nuclear medicine ,business - Abstract
Purpose In this study we calculate composite dose delivered to the prostate by using the Calypso tracking ‐data‐ stream acquired during patient treatment in our clinic. We evaluate the composite distributions under multiple simulated Calypso tolerance level schemes and then recommend a tolerance level. Materials and methods Seven Calypso‐localized prostate cancer patients treated in our clinic were selected for retrospective analysis. Two different IMRT treatment plans, with prostate PTV margins of 5 and 3 mm respectively, were computed for each patient. A delivered composite dose distribution was computed from Calypso tracking data for each plan. Additionally, we explored the dosimetric implications for “worst case” scenarios by assuming that the prostate position was located at one of the eight extreme corners of a 3 or 5 mm “box.” To characterize plan quality under each of the studied scenarios, we recorded the maximum, mean, and minimum doses and volumetric coverage for prostate, PTV, bladder, and rectum. Results and discussions Calculated composite dose distributions were very similar to the original plan for all patients. The difference in maximum, mean, and minimum doses as well as volumetric coverage for the prostate, PTV, bladder, and rectum were all
- Published
- 2019
17. A new contouring error estimation for the high form accuracy of a multi-axis CNC machine tool
- Author
-
Jiexiong Ding, Qicheng Ding, Zhong Jiang, Li Du, Qingzhao Li, Wei Wang, and Jing Zhang
- Subjects
0209 industrial biotechnology ,Contouring ,Computer science ,Orientation (computer vision) ,Mechanical Engineering ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,02 engineering and technology ,Industrial and Manufacturing Engineering ,Position tolerance ,Computer Science Applications ,020901 industrial engineering & automation ,Machining ,Control and Systems Engineering ,Position (vector) ,Numerical control ,Point (geometry) ,Algorithm ,Software - Abstract
The evaluation of contouring error is important for multi-axis CNC machines because the tolerance specifications of manufactured parts are directly affected by contouring error. One of the fundamental quality inspections to verify that a manufactured part meets the expected tolerance is via form error evaluations. However, the existing estimation methods of contouring error are based on the position tolerance requirements. To meet the form tolerance requirements for the parts, this paper focuses on developing a high-accuracy estimation method of contouring error that is not related to a datum (ND-contouring error). In the proposed estimation method, at first, the minimum zone tolerance (MZT) method is used to transform the ideal tool tip path to match the actual one. Subsequently, by comparing the position and orientation between the actual point and the nearest point on the transformed ideal tool path, the ND-contouring error and orientation contouring error of the tool can be estimated, respectively. In addition, the difference between the proposed estimation method and previous evaluation methods is comparatively analyzed. Finally, simulations and experiments are conducted by applying the S-shaped and B-shaped machining trajectories, respectively, and the results all verify the estimation accuracy of the ND-contouring error estimation method. By adoption of compensation based on the ND-contouring error estimation, the contouring error could be significantly reduced, which will improve the quality of parts.
- Published
- 2018
18. Functional specialization in rat occipital and temporal visual cortex.
- Author
-
Vermaercke, Ben, Gerich, Florian J., Ytebrouck, Ellen, Arckens, Lutgarde, Op de Beeck, Hans P., and Vanden Bergh, Gert
- Subjects
- *
OCCIPITAL lobe , *TEMPORAL lobe , *VISUAL cortex physiology , *LABORATORY rats , *VISUAL pathways , *STIMULUS & response (Psychology) , *PHYSIOLOGY - Abstract
Recent studies have revealed a surprising degree of functional specialization in rodent visual cortex. Anatomically, suggestions have been made about the existence of hierarchical pathways with similarities to the ventral and dorsal pathways in primates. Here we aimed to characterize some important functional properties in part of the supposed "ventral" pathway in rats. We investigated the functional properties along a progression of five visual areas in awake rats, from primary visual cortex (V1) over lateromedial (LM), latero-intermediate (LI), and laterolateral (LL) areas up to the newly found lateral occipito-temporal cortex (TO). Response latency increased >20 ms from areas V1/LM/LI to areas LL and TO. Orientation and direction selectivity for the used grating patterns increased gradually from V1 to TO. Overall responsiveness and selectivity to shape stimuli decreased from V1 to TO and was increasingly dependent upon shape motion. Neural similarity for shapes could be accounted for by a simple computational model in V1, but not in the other areas. Across areas, we find a gradual change in which stimulus pairs are most discriminable. Finally, tolerance to position changes increased toward TO. These findings provide unique information about possible commonalities and differences between rodents and primates in hierarchical cortical processing. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
19. Source data for Matteucci et al paper: Unsupervised experience with temporal continuity of the visual environment is causally involved in the development of V1 complex cells
- Author
-
Giulio Matteucci and Davide Zoccolan
- Subjects
unsupervised temporal learning ,rat ,complex cells ,position tolerance ,primary visual cortex - Abstract
Source data file for the article authored by Matteucci and Zoccolan on the role of temporal continuity in the development of complex cells in rat V1.
- Published
- 2020
20. A Hybrid Tolerance Design Method for the Active Phased-Array Antenna
- Author
-
Chan Qiu, Jianrong Tan, Guodong Sa, and Liu Zhenyu
- Subjects
Relation (database) ,Computer science ,Phased array ,Flatness (systems theory) ,02 engineering and technology ,lcsh:Technology ,Position tolerance ,lcsh:Chemistry ,symbols.namesake ,statistical analysis ,Position (vector) ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Taylor series ,General Materials Science ,lcsh:QH301-705.5 ,Instrumentation ,tolerance design ,Fluid Flow and Transfer Processes ,lcsh:T ,Process Chemistry and Technology ,Taylor expansion ,General Engineering ,020206 networking & telecommunications ,021001 nanoscience & nanotechnology ,lcsh:QC1-999 ,Computer Science Applications ,lcsh:Biology (General) ,lcsh:QD1-999 ,lcsh:TA1-2040 ,symbols ,Reflection (physics) ,Antenna (radio) ,hybrid geometric errors ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,lcsh:Physics ,array antenna - Abstract
With the increase of the working frequency of the array antenna, tolerance design has become increasingly important. The state-of-art tolerance design methods mainly deal with the position tolerance of the discrete elements. However, the geometric errors of the whole array have resulted from two aspects: (1) the position errors of the discrete elements and (2) the form errors of the continuous reflection plate. To optimize the position tolerance and flatness simultaneously, a hybrid tolerance design method is proposed. First, the relation between the performance of the array antenna and hybrid tolerances was determined based on the second order Taylor expansion. Then the expectation and variance of the performance were derived. Finally, the hybrid tolerances were optimized and the performance of the antenna was improved. Simulation results proved the effectiveness and efficiency of the proposed hybrid tolerance design method.
- Published
- 2020
- Full Text
- View/download PDF
21. A Variation Analysis Method for Linkage Mechanism with Consideration of Joint Clearance and Deformation
- Author
-
Sun Jin, Tao Liu, Wei Chen, and Zhi-Min Li
- Subjects
Timoshenko beam theory ,0209 industrial biotechnology ,Deformation (mechanics) ,business.industry ,Computer science ,Mechanical Engineering ,02 engineering and technology ,Structural engineering ,Linkage (mechanical) ,Industrial and Manufacturing Engineering ,Position tolerance ,law.invention ,Mechanism (engineering) ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,0203 mechanical engineering ,Transmission (telecommunications) ,law ,Component (UML) ,Electrical and Electronic Engineering ,business ,Joint (geology) - Abstract
As typical transmission mechanisms, linkage mechanisms are widely applied in mechanical engineering field, and accuracy prediction of them has received much more attentions especially from some high-precision application fields. For a certain linkage mechanism system, external forces will also cause linkage deformations and deterministic oriented-drift of joint clearances, which become additional variation sources besides component tolerances. In order to perform a more accurate prediction of linkage mechanism, a variation analysis method is proposed in this study, in which component tolerances, joint clearances and deformations are considered. With an equivalent method, positional tolerance and joint clearances are taken into the present variation analysis model, and serve as circular tolerances. Based on classical Euler-Bernoulli beam theory, linkage deformations are disposed as equivalent deviations and contribute to assembly deviations. A decomposing method of percentage contribution, which contains different variation sources, is presented as well. A case study of four-bar linkage mechanism is illustrated to validate the accuracy of the present method by corresponding FEA simulation and experimental test. Moreover, a case study of a three-loop mechanism is also analyzed for the accuracy and percentage contribution of different variation sources with the present method.
- Published
- 2018
22. Complementing and enhancing definitions of position tolerance for a real point based on ISO Geometrical Product Specifications (GPS)
- Author
-
Uwe Heisel, Martin Bohn, Yiqing Yan, and Steven Peters
- Subjects
Surface (mathematics) ,Product design specification ,0209 industrial biotechnology ,Real point ,Computer science ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Industrial and Manufacturing Engineering ,Position tolerance ,Symbol (chemistry) ,020901 industrial engineering & automation ,Position (vector) ,Feature (machine learning) ,Point (geometry) ,Algorithm ,0105 earth and related environmental sciences - Abstract
According to ISO standards, the position tolerance symbol has only explicit definitions and examples of the specification for a derived point from a sphere under classification of a punctiform toleranced feature. For a real point on an integral surface, there are no explicit definitions and examples. Thus there are gaps in definition here causing undefined and irreproducible applications of position specifications into a real point. This paper suggests a new approach for explicitly defining the function-oriented position tolerance for real points, based on the analysis of its physical behaviour. As a result, an enhanced systematic approach for position tolerance is developed, which fills definition gaps.
- Published
- 2018
23. Unsupervised experience with temporal continuity of the visual environment is causally involved in the development of V1 complex cells
- Author
-
Giulio Matteucci and Davide Zoccolan
- Subjects
Temporal continuity ,genetic structures ,Computer science ,Position tolerance ,03 medical and health sciences ,0302 clinical medicine ,Development (topology) ,Developmental Neuroscience ,mental disorders ,medicine ,Visual experience ,Adaptation (computer science) ,Research Articles ,030304 developmental biology ,0303 health sciences ,Computational model ,Multidisciplinary ,SciAdv r-articles ,eye diseases ,Visual cortex ,medicine.anatomical_structure ,Settore M-PSI/02 - Psicobiologia e Psicologia Fisiologica ,Cellular Neuroscience ,Neuroscience ,030217 neurology & neurosurgery ,Research Article - Abstract
Unsupervised learning of visual temporal statistics drives postnatal development of position invariance in visual cortex., Unsupervised adaptation to the spatiotemporal statistics of visual experience is a key computational principle that has long been assumed to govern postnatal development of visual cortical tuning, including orientation selectivity of simple cells and position tolerance of complex cells in primary visual cortex (V1). Yet, causal empirical evidence supporting this hypothesis is scant. Here, we show that degrading the temporal continuity of visual experience during early postnatal life leads to a sizable reduction of the number of complex cells and to an impairment of their functional properties while fully sparing the development of simple cells. This causally implicates adaptation to the temporal structure of the visual input in the development of transformation tolerance but not of shape tuning, thus tightly constraining computational models of unsupervised cortical learning.
- Published
- 2019
24. Deformation control during the welding of AP1000 main pump casing and steam generator
- Author
-
Disi Wang, Bo Liu, Guang-qing He, You-peng Zhang, Song Li, Zhen-guo Yang, and Bin Xi
- Subjects
Nuclear and High Energy Physics ,Materials science ,Materials Science (miscellaneous) ,TK9001-9401 ,Nozzle ,Mechanical engineering ,Welding ,Position tolerance ,Steam generator (boiler) ,law.invention ,Nuclear Energy and Engineering ,Welding process ,law ,AP1000 ,Welding deformation control ,Nuclear engineering. Atomic power ,Deformation control ,Main pump casing ,Casing ,Groove (engineering) - Abstract
The welding of the AP1000 Reactor Coolant Pump (RCP) casing and Steam Generator (SG) is an important issue to maintain the integrity of pressure boundary. The position tolerance of pump casing nozzles after welding will directly affect the internal components of the main pump, as well as the on-site assembling processes. This article investigated the method of controlling deformations during welding (such as assembly alignment, groove design, welding process control, etc), in order to prevent excessive welding deformation and therefore extra discrepancies during pump casing positioning. In this paper, we have developed a welding process, which can allow the installations of AP1000 pump casings to meet all nuclear grade requirements.
- Published
- 2021
25. Can ISO GPS and ASME Tolerancing Systems Define the Same Functional Requirements?
- Author
-
Zbigniew Humienny
- Subjects
Technology ,Standardization ,ASME Y14.5 ,QH301-705.5 ,Computer science ,QC1-999 ,engineering design ,Position tolerance ,Set (abstract data type) ,geometrical tolerancing ,Orientation (geometry) ,General Materials Science ,Biology (General) ,QD1-999 ,Instrumentation ,standardization ,Fluid Flow and Transfer Processes ,business.industry ,Physics ,Process Chemistry and Technology ,geometrical product specifications ,GD&T ,General Engineering ,Functional requirement ,Engineering (General). Civil engineering (General) ,Computer Science Applications ,Geometrical product specification ,Reliability engineering ,ISO 1101 ,Chemistry ,ISO GPS system ,Global Positioning System ,TA1-2040 ,Engineering design process ,business - Abstract
Geometrical tolerances are defined in the ISO Geometrical Product Specification system that is used worldwide, but on the other hand, the ASME Y14.5 standard is used in American companies to define how far actual parts may be away from their nominal geometry. This paper aimed to investigate whether specifications defining acceptable geometrical deviations in one system can be transformed to specifications in the other system. Twelve selected cases are discussed in the paper. Particularly, two cases of size tolerance, three cases of form tolerances, one case of orientation tolerance, four cases of position tolerance (including position tolerance with MMR for the pattern of five holes) and, finally, two cases of surface profile tolerance (unequally disposed tolerance zone and dynamic profile tolerance). The issue is not only in the several different symbols and a set of different defaults, but also in the different meanings and different application contexts of some symbols that have the same graphical form. The answer to the question raised in the paper title is yes for the majority of indications specified according to ASME Y14.5 when new tools from the 2017 edition of ISO 1101 are applied.
- Published
- 2021
26. Capability Estimation of Geometrical Tolerance With a Material Modifier by a Hasofer-Lind Index.
- Author
-
Tahan, Antoine S. and Cauvier, Jason
- Subjects
- *
MATHEMATICAL models , *DISTRIBUTION (Probability theory) , *MATHEMATICAL functions , *MATHEMATICS , *STATISTICAL process control - Abstract
This paper considers a way of measuring a process capability index in order to obtain the geometric tolerance of a pattern of position elements according to the ASME Y14.5 standard. The number of elements present in the pattern, as well as its material condition (least LMC or maximum MMC), are taken into consideration during the analysis. An explicit mathematical model will be developed to identify the distribution functions (PDF and CDF) of defects on the location and diameter. Using these distributions and the Hasofer-Lind index, we will arrive at a new definition of process capability--meaning the value of tolerances that can meet the threshold of x% compliance. Finally, our method is validated using a variety of typical case studies. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
27. Exploitation des études de capabilité dans le calcul statistique des tolérances géométriques de localisation.
- Author
-
Tahan, Antoine S. and Lévesque, Sylvain
- Subjects
- *
MANUFACTURING processes , *DISTRIBUTION (Probability theory) , *ESTIMATION theory , *ENGINEERING tolerances , *MATHEMATICAL models - Abstract
This paper proposes a new methodology to exploit the capability of manufacturing processes in the statistical calculation of the tolerance of localization of a set of features according to the standards ISO 1101 and ASME Y14.5. The number of features that form the pattern studied, the systematic and random errors in the manufacturing process will all be retained and included in the approach. An explicit mathematical model is developed to identify the statistical distribution functions for different types of localization tolerances. From these distributions, we present a methodology to estimate the values of tolerance that can meet a compliance threshold for a pre-established value, and vice versa. The article also presents a series of charts that are usable in an industrial context. Many examples are illustrated and a case study is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
28. On-machine measurement method for the geometric error of shafts with a large ratio of length to diameter
- Author
-
Li Guochao, Xie Zhancheng, Liu Yunlong, Honggen Zhou, Feng Feng, and Ge Wen
- Subjects
Accuracy and precision ,Computer science ,Applied Mathematics ,Acoustics ,System of measurement ,020208 electrical & electronic engineering ,010401 analytical chemistry ,Geodetic datum ,02 engineering and technology ,Condensed Matter Physics ,01 natural sciences ,Position tolerance ,Displacement (vector) ,0104 chemical sciences ,Machining ,Line (geometry) ,0202 electrical engineering, electronic engineering, information engineering ,Measuring instrument ,Electrical and Electronic Engineering ,Instrumentation - Abstract
For shafts with a large ratio of length to diameter, the existing measurement method mainly uses a contact coordinate machine. But machining errors have a strong influence on the offline measurement results, and the accumulation errors of the measurement system also make the measurement datum difficult to identify. For this reason, a new on-machine measuring method is proposed based on the spatial analytical geometry theory to achieve the measurement of the shape and position tolerance of shafts. Through the method, the measurement system combines the line laser measuring instrument and the laser displacement sensor together. Then, the ideal central axis of the workpieces can be obtained and serve as a datum. Finally, the on-machine non-contact measurement of large-size shafts with geometric errors is realized with high measurement accuracy (
- Published
- 2021
29. Geometrical position tolerance assignment in reverse engineering.
- Author
-
Kaisarlis, G.J., Diplaris, S.C., and Sfantsikopoulos, M.M.
- Subjects
REVERSE engineering ,TECHNICAL specifications ,TECHNOLOGY ,INDUSTRIAL design ,DEVIATION (Statistics) - Abstract
Geometric dimensioning and tolerancing constitutes the dominant approach for design and manufacture of mechanical parts that control inevitable dimensional and geometric deviations within appropriate limits. Position tolerance is a critical geometric tolerance very frequently used in industry. Its designation requires size data in conjunction with appropriate datums and location coordinates for the position. In reverse engineering, where typically relevant engineering information does not exist, conventional, human-based, trial and error approach for the allocation of positional tolerances requires much effort and time and offers no guarantee for the generation of the best results. This is mainly due to the large number of possible data combinations and the applicable relationships that have to be developed and processed. A methodology that aims towards the systematic solution of this problem in reasonable computing time and provides realistic and industry approved results is presented, demonstrated and discussed in the paper. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
30. Calculating Cp of Position Tolerance when MMC Applied at Datum and Position Tolerance
- Author
-
Sung-Ho Chang and Jun-Ho Kim
- Subjects
Control theory ,Process capability ,Geometric dimensioning and tolerancing ,Geodetic datum ,Position tolerance ,Mathematics - Published
- 2017
31. A Standard Procedure for Development Performance Map of CNC Machining Centers by Using Double Ball-Bar
- Author
-
Tawee Ngamvilaikorn, Siriluk Phankhoksoong, Chatchapol Chungchoo, and Anchasa Pramuanjaroenkij
- Subjects
0209 industrial biotechnology ,Engineering drawing ,Engineering ,business.industry ,Mechanical Engineering ,02 engineering and technology ,Position tolerance ,Standard procedure ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,0203 mechanical engineering ,Mechanics of Materials ,Ball (bearing) ,Numerical control ,General Materials Science ,business - Abstract
Currently, CNC machining centers have been designed to provide flexibility for a wide range of applications. They are widely used in the metal cutting industry with many advantages; their accuracy, reliability, repeatability, and productivity are the important factors. Generally, for CNC machining centers, the working area of the machine table is larger than the size of the workpiece. In case of machining small workpieces, the operators can produce several workpieces at the same time by setting several fixtures at different positions on the table. This can reduce setup time for cutting a new set of workpieces. However, the performance of a machine varies throughout the workspace. It is thus possible that two finished parts produced from the different positions of the table will have different values in geometric dimensioning and tolerance (GD&T). Therefore, in this study, the researchers developed a new procedure for establishing the performance map of CNC machines. As a result, the operators are able to know which area can produce workpieces with positional tolerances that do not exceed a given threshold. By using a CNC model DMC 635V DECKEL MAHO together with double ball-bar model Renishaw QC10 ball-bar as a case study, experimental results indicated that this procedure can provide a performance map of the machining centers efficiently.
- Published
- 2017
32. Maximum material condition in process planning.
- Author
-
Diplaris, S. C. and Sfantsikopoulos, M. M.
- Subjects
BUSINESS planning ,COST effectiveness ,INDUSTRIAL costs ,PRODUCT quality ,PRODUCTION planning ,PRODUCTION management (Manufacturing) - Abstract
Appropriate and cost effective assignment and interpretation of dimensional and geometrical tolerances, in conjunction with tolerancing principles such as the maximum material condition (MMC), constitute a major area of concern for manufacturing SMEs. This is particularly true for the process planning stage, where production operations and parameter values establish the final product quality and cost. A frequently used geometrical tolerance is the position tolerance. It allows at least 57% more space for feature allocation without affecting product quality and is very useful for accurate specification of multiple-hole assemblies. Feature allocation becomes further relaxed in case a position tolerance is assigned to the MMC. This assignment is mainly exploited during inspection, because it permits fewer rejections. In terms of cost, it is advantageous to systematically integrate the MMC tolerance bonus into the position tolerance at the process planning stage. A methodology that allows a new MMC-adapted position tolerance to be calculated is presented in this paper. The new, increased, position tolerance can then be taken into consideration early in the process planning stage, in order to achieve lower production cost, without affecting the quality. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
33. Quantitative circularity tolerance analysis and design for 2D precision assemblies
- Author
-
Cho, N. and Tu, J.F.
- Subjects
- *
ENGINEERING tolerances , *MACHINING - Abstract
Circular, cylindrical, or spherical features are fundamental geometric features in engineering. As precision requirement becomes more stringent, it is not sufficient to consider only size tolerance of circular and cylindrical parts. However, currently there is no quantitative and systematic way of assigning circularity and cylindricity tolerances. This paper investigates how to specify circularity tolerance quantitatively for 2D assemblies. Statistical matrices to quantify positioning error of two perfectly circular mating parts subject to size tolerance for both clearance and transition fit conditions are first developed. The analysis is then extended to nonideal profiles whose profile errors are assumed to deviate from a best-fit circle according to a normal distribution. The assumption of the normal distribution is then removed for more general results via computer simulation. For this purpose, an experimentally verified profile model is used to generate realistic profiles as those produced by various machining processes. Numerous pairs of these realistic profiles are then assembled virtually using Monte Carlo simulation to quantify their positioning errors. The simulation results and the analytical results are compared for cross-checking. Finally, systematic design procedures are proposed to assign circularity tolerance by prescribing a fit condition with a desirable process capability. By the nature of circularity tolerance, this paper addresses a 2D assembly. The result of this 2D analysis can be a foundation for more complicated 3D problems, such as assigning cylindricity tolerance. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
34. Positioning variation synthesis for an automated drilling system in wing assembly
- Author
-
Zengsheng Liang, Biao Mei, Weidong Zhu, and Yinglin Ke
- Subjects
0209 industrial biotechnology ,business.product_category ,Wing ,Drilling system ,Computer science ,General Mathematics ,020208 electrical & electronic engineering ,Process (computing) ,Drilling ,Mechanical engineering ,02 engineering and technology ,Variation (game tree) ,Fastener ,Industrial and Manufacturing Engineering ,Position tolerance ,Computer Science Applications ,Compensation (engineering) ,020901 industrial engineering & automation ,Control and Systems Engineering ,0202 electrical engineering, electronic engineering, information engineering ,business ,Software - Abstract
Tight position tolerance is required for fastener holes in wing manufacturing. Automated drilling system with high positioning accuracy is the key to achieve the requirement. The paper seeks to determine allowable values of variation sources and guarantee the hole position tolerance. The process of reference hole positioning and the compensation of drilling positions are firstly explored and formalized for an automated drilling system integrated with an industrial camera. Based on this, a positioning variation model for automated drilling considering positioning error measurement and compensation is built. After that, positioning variation synthesis being imposed engineering constraints on is mathematically modeled based on the theory of mathematical statistics. In the positioning variation synthesis, imperfect camera installation, nonideal measurement conditions, equipment positioning error, etc. are included. The positioning variation model and involving synthesis strategy have been used to develop an automated drilling system for wing assembly. Experiments conducted on the developed drilling system show that the fastener holes’ desired position tolerance 0.3 mm will not be exceeded, which is a necessary condition of the satisfactory drilling quality of the aircraft wing.
- Published
- 2021
35. Complements and Enhancements of Position Tolerance for Axis and Derived Line Imposed by ISO Standards
- Author
-
Martin Bohn and Yiqing Yan
- Subjects
Artificial Intelligence ,Control and Systems Engineering ,Computer science ,Mechanical Engineering ,Mechanical engineering ,Iso standards ,Line (text file) ,Position tolerance - Published
- 2016
36. An Improved Tolerance Analysis Method Based on Skin Model Shapes of Planar Parts
- Author
-
Nabil Anwer, Zuowei Zhu, and Lihong Qiao
- Subjects
assembly ,Model theory ,0209 industrial biotechnology ,Engineering drawing ,Engineering ,Tolerance analysis ,Orientation (computer vision) ,business.industry ,tolerance analysis ,02 engineering and technology ,Position tolerance ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,0203 mechanical engineering ,Position (vector) ,Product (mathematics) ,New product development ,Computer-aided ,General Earth and Planetary Sciences ,business ,Skin Model Shapes ,Algorithm ,GPS ,General Environmental Science - Abstract
Geometric deviations have huge influences on the functional behavior of product, which should be analyzed and properly controlled. Tolerance analysis, as a way to evaluate geometric deviations, is an essential part of product development. Current Computer Aided Tolerancing systems provide solutions for tolerance analysis but have limitations in the consideration of form deviations. The Skin Model theory, as a new research topic, represents part with non-ideal model that comprises geometric deviations, thus developing into a new computer aided tolerancing approach. In this paper, the related work with respect to the generation of Skin Model Shapes and its application in assembly simulation and tolerance analysis is briefly introduced. In order to overcome its shortcomings in the tolerance analysis employing SMSs, this paper proposes an improved method by taking advantage of the method adopted in a CAT system. The proposed method supports the analysis of position and orientation tolerances and has been proved to be valid through a case study.
- Published
- 2016
- Full Text
- View/download PDF
37. Physics-driven Shape Variation Modelling at Early Design Stage
- Author
-
Darek Ceglarek, David Williams, Abhishek Das, and Pasquale Franciosa
- Subjects
0209 industrial biotechnology ,Engineering drawing ,Engineering ,Automotive industry ,02 engineering and technology ,Fixture ,Position tolerance ,020901 industrial engineering & automation ,0203 mechanical engineering ,Component (UML) ,Sheet metal parts ,Decomposition (computer science) ,Design process ,Shape error ,General Environmental Science ,Physics ,business.industry ,Right first time ,Process (computing) ,Control engineering ,020303 mechanical engineering & transports ,Computer-aided ,General Earth and Planetary Sciences ,Variational parts ,business - Abstract
Modern markets are becoming increasingly competitive emphasizing the importance of achieving Right First Time (RFT) during the early design stage as a key enabler facilitating cost and time-to-launch (or time-to-market) reduction. One of the leading challenges to deliver RFT is the lack of effective methods to model product errors at early design stage. Usually, the assembly process is designed under the assumption of ideal (nominal) products. On the contrary, it has been demonstrated that product errors (both geometrical and dimensional) affect the performance of the final assembly. To facilitate easy decision making at early design stage, new methods and models are required to support design engineers. In this study, a framework has been proposed for early design support to generate product variation. International standard provides guidelines for product control and inspection (ISO-GPS or ASME-GDT however, the integration of tolerance standard into nominal sized CAD models is not yet achieved. Current, Computer Aided Tolerancing (CAT) tools mainly capable to model orientation and position tolerance specifications, whereas part shape errors are omitted. This paper presents an innovative physics-driven simulation framework to model shape errors of compliant sheet metal parts at early design stage. The modelling framework consists of three important stages: (i) initial shape error prediction using physic-based simulation, such as, stamping process simulation; (ii) individual orthogonal shape error modes/patterns identification based on decomposition techniques, such as, Geometric Modal Analysis (GMA); and, (iii) simulation of shape error variation classes by assigning distribution to each orthogonal shape error modes. The proposed approach enables to generate shape errors at early design stage of assembly process which can be utilized to optimize the assembly process, including fixture design and joining process parameters. An industrial automotive component illustrates the proposed methodology.
- Published
- 2016
38. Sensitive factor for position tolerance.
- Author
-
Wu, Zhang
- Abstract
A tolerance sensitivity study evaluates the influence of each component tolerance on the assembly tolerance. It is crucial to the improvement to tolerance design. This paper discusses a difficulty in evaluating the sensitive factors of some geometric tolerances (e.g. the position tolerance), due to their connections with a random orientation angle α. An average sensitive factor over α is proposed for the position tolerance. The usefulness of the average sensitive factor is demonstrated through a mechanical example. [ABSTRACT FROM AUTHOR]
- Published
- 1997
- Full Text
- View/download PDF
39. Local Corner Smoothing with Kinematic and Real-time Constraints for Five-axis Linear Tool Path
- Author
-
Jo-Ting Wang, Jih-Chieh Lee, Ming-Tsung Lin, Chien-Yi Lee, and Chien-Chun Shen
- Subjects
0209 industrial biotechnology ,Computer science ,Mathematical analysis ,Motion (geometry) ,02 engineering and technology ,Kinematics ,Position tolerance ,Vibration ,Jerk ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,0203 mechanical engineering ,Control theory ,Trajectory ,Smoothing - Abstract
In this paper, a local corner smoothing method with consideration of kinematic and real-time constraints (LCS-KRC) is proposed to generate smooth motion trajectory in the vicinity of corners of five-axis linear tool path. Instead of inserting a spline curve at adjacent linear segments, the method directly blends velocities and accelerations of five motion axes and generates C2 cornering trajectories while respecting corner position tolerance and kinematic limits of the drives. The axial and tangential jerk in cornering transition are simultaneously evaluated to avoid excitation of structure vibration. To achieve local corner smoothing, corner feedrate is moderately adjusted and rotary-axis speeds are synchronized with corner velocity profile, especially in reverse motion or at sharp corners. Finally, simulations and experiments results demonstrate effectiveness of the proposed method compared with a commercial controller.
- Published
- 2018
40. Hierarchical stimulus processing in rodent primary and lateral visual cortex as assessed through neuronal selectivity and repetition suppression
- Author
-
Dzmitry A. Kaliukhovich and Hans Op de Beeck
- Subjects
0301 basic medicine ,Male ,Visual perception ,MOTION ,Rodent ,genetic structures ,Physiology ,Photic Stimulation ,Surround suppression ,SURROUND SUPPRESSION ,NORMALIZATION ,0302 clinical medicine ,ventral stream ,OBJECT RECOGNITION ,ADAPTATION ,CORTICAL AREA ,Visual Cortex ,Neurons ,clutter tolerance ,biology ,General Neuroscience ,Functional specialization ,Cognitive neuroscience of visual object recognition ,Adaptation, Physiological ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Models, Animal ,Visual Perception ,Life Sciences & Biomedicine ,Research Article ,Stimulus (physiology) ,Statistics, Nonparametric ,RATS ,03 medical and health sciences ,FUNCTIONAL SPECIALIZATION ,biology.animal ,medicine ,Animals ,CONNECTIONS ,Rats, Long-Evans ,position tolerance ,SPATIAL INTEGRATION ,Science & Technology ,Neurosciences ,Rats ,030104 developmental biology ,Visual cortex ,Neurosciences & Neurology ,repetition suppression ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Similar to primates, visual cortex in rodents appears to be organized in two distinct hierarchical streams. However, there is still little known about how visual information is processed along those streams in rodents. In this study, we examined how repetition suppression and position and clutter tolerance of the neuronal representations evolve along the putative ventral visual stream in rats. To address this question, we recorded multiunit spiking activity in primary visual cortex (V1) and the more downstream visual laterointermediate (LI) area of head-restrained Long-Evans rats. We employed a paradigm reminiscent of the continuous carry-over design used in human neuroimaging. In both areas, stimulus repetition attenuated the early phase of the neuronal response to the repeated stimulus, with this response suppression being greater in area LI. Furthermore, stimulus preferences were more similar across positions (position tolerance) in area LI than in V1, even though the absolute responses in both areas were very sensitive to changes in position. In contrast, the neuronal representations in both areas were equally good at tolerating the presence of limited visual clutter, as modeled by the presentation of a single flank stimulus. When probing tolerance of the neuronal representations with stimulus-specific adaptation, we detected no position tolerance in either examined brain area, whereas, on the contrary, we revealed clutter tolerance in both areas. Overall, our data demonstrate similarities and discrepancies in processing of visual information along the ventral visual stream of rodents and primates. Moreover, our results stress caution in using neuronal adaptation to probe tolerance of the neuronal representations. NEW & NOTEWORTHY Rodents are emerging as a popular animal model that complement primates for studying higher level visual functions. Similar to findings in primates, we demonstrate a greater repetition suppression and position tolerance of the neuronal representations in the downstream laterointermediate area of Long-Evans rats compared with primary visual cortex. However, we report no difference in the degree of clutter tolerance between the areas. These findings provide additional evidence for hierarchical processing of visual stimuli in rodents. ispartof: JOURNAL OF NEUROPHYSIOLOGY vol:120 issue:3 pages:926-941 ispartof: location:United States status: published
- Published
- 2018
41. Composite positional tolerance inspection using virtual graphic analysis
- Author
-
Indra Djodikusumo, Rifko Rahmat Kurnianto, and Brilliant Dwinata
- Subjects
Product design specification ,Data processing ,Engineering drawing ,Computer science ,Frame (networking) ,Process (computing) ,Overlay ,Grid ,Batch production ,Position tolerance - Abstract
Verification activity in a streamline manufacturing system is one of the most important activity to make sure that the design requirements and the actual product specifications are met. It helps designer or manufacturing engineer as a feedback by detecting issue at early stage. However, we have to select the most effective verification method that will lead to low cost and relatively fast production. Many industries make machined components that are mounted to welded frame, the locations of the components may float with a larger tolerance to the welded frame than the feature to feature tolerance needed for mounting hole pattern. The composite tolerance is needed for this particular case. The most suitable method for gathering measurement data for small batch production is either automatically using CMM or manually using pin gages and size measurement devices. While, the data processing step can be done by graphic analysis or paper gage method for inspecting composite positional tolerance. The innovation of this journal is changing the way of data processing method by reducing the papers (coordinate grid and polar overlay) required for graphic analysis and converting them into mathematical model that can be processed by computer. Hence, we call this virtual graphic analysis. The benefits of using virtual graphic analysis are reducing cost and time of overall inspection process.
- Published
- 2018
42. Position Tolerance Design Method for Array Antenna in Internet of Things
- Author
-
Wei Gao, Xiaodong Yang, Zhihai Wang, Congsi Wang, Shuai Yuan, Cheng Zhu, Peng Xuelin, and Shaoxi Wang
- Subjects
Article Subject ,lcsh:T ,Computer Networks and Communications ,business.industry ,Computer science ,020208 electrical & electronic engineering ,Planar array ,020206 networking & telecommunications ,02 engineering and technology ,lcsh:Technology ,Position tolerance ,lcsh:Telecommunication ,Position (vector) ,Antenna element ,lcsh:TK5101-6720 ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Sensitivity (control systems) ,Electrical and Electronic Engineering ,Antenna (radio) ,Internet of Things ,business ,Realization (systems) ,Information Systems - Abstract
The position error of array antenna significantly deteriorates the gain and sidelobe of the array, which seriously hinders the realization of high performance of communication antenna for Internet of Things (IoT). Based on the sensitivity analysis theory, the sensitivity of the array radiation field with respect to the position of the antenna element is derived. Besides, a novel design method of position tolerance for array antenna is proposed and applied to a 20×20 planar array. Compared with the array designed by traditional method, the gain loss is basically the same (being 0.5 dB), while the peak sidelobe level is lowered by 1.937 dB (φ=0°)/1.586 dB (φ=90°). Besides, the uncertainty analysis results show that the newly designed array has a much higher chance to achieve the desired performance, which fully demonstrates the innovation and effectiveness of the new method.
- Published
- 2018
- Full Text
- View/download PDF
43. Position tolerancing in reverse engineering: the fixed fastener case.
- Author
-
Kaisarlis, G J, Diplaris, S C, and Sfantsikopoulos, M M
- Subjects
REVERSE engineering ,MANUFACTURING processes ,COMPUTER-aided design ,SYSTEMS design ,GEOMETRIC modeling - Abstract
The present paper addresses the assignment of geometrical position tolerances in reverse engineering. Specification of manufacturing position tolerances for a reconstructed component of an existing mechanical assembly constitutes a complicated task that requires a well-grounded approach. Among features of size, cylindrical features such as holes in conjunction with pegs, pins, or screws are the most frequently used for critical functions, as are the alignment of mating surfaces or the fastening of mating parts. The relationship between mating features is classified either as a fixed or as a floating fastener type. The presented method focuses on the fixed fastener case. It is based on the systematic formulation of dimensional and geometrical relationships and constrains that allow for rational computer-aided processing and evaluation of the measured data from the reference parts, for which appropriately developed algorithmic tools are used. It is shown that the method is reliable, provides for realistic results, and is also time and cost competent as compared with the conventional trial-and-error methods. A case study demonstrates the concept and method. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
44. Process capability requirement under maximum material condition.
- Author
-
Diplaris, S. C. and Sfantsikopoulos, M. M.
- Subjects
MACHINING ,MANUFACTURING processes ,INDUSTRIAL costs ,PRODUCT quality ,PRODUCTION planning ,PRODUCTION engineering - Abstract
A frequently used geometrical tolerance is the position tolerance. When it is assigned at the maximum material condition (MMC), an increase in the position tolerance is allowed, equal to the departure of the particular feature from the maximum material condition size.Neither concept - position tolerance and maximum material condition - analytically related with the exact coordinate dimensions that locate the feature. A feature position is usually allocated on the basis of its theoretically exact co-ordinate dimensions, whereas positional accuracy is pursued through an appropriate planning of the machining process in conjunction with appropriate machine tool(s) and/or jig(s). Exploitation of the MMC tolerance bonus is taken into account mainly during part inspection in order to reduce rejects. Such an approach is not systematic, considering that the MMC benefits are not taken directly into account in the process planning stage in order to control the overall process cost.In this paper, the permitted manufacturing errors of a feature size and position are considered and studied simultaneously in an analytical way. It is shown that a lower process capability (PC) requirement can then be established that leads to a significant process cost reduction. An application example demonstrates the use of the method and the obtained results are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
45. Miniature Reflection-Type Optical Displacement Sensor Incorporating a Projected Beam
- Author
-
Yong-Geon Lee, Sang-Shin Lee, and Hak-Soon Lee
- Subjects
lcsh:Applied optics. Photonics ,Materials science ,Sensors ,business.industry ,lcsh:TA1501-1820 ,Photodetector ,Laser ,Atomic and Molecular Physics, and Optics ,Collimated light ,Position tolerance ,law.invention ,Quadrature (astronomy) ,micro-optics ,gratings ,Optics ,Aspheric lens ,law ,Optical cavity ,lcsh:QC350-467 ,electro-optical systems ,Electrical and Electronic Engineering ,business ,lcsh:Optics. Light ,Phase relationship - Abstract
We embody a miniature reflection-type optical displacement sensor tapping into a projected beam that features high structural tolerance. A code scale with periodic patterns spatially encrypts the projected beam, which is established by imaging a collimated beam from a vertical-cavity surface-emitting laser via an aspheric lens, and linearly expands it, so as to be decoded by a receiver that comprises four serially cascaded identical photodetector cells. For the modulated beam, we observe a pitch increase with a rate of 18 μm/mm along the propagation direction. The two quadrature signals Sig-A and Sig-B derived from the PD signals exhibit a 900 phase relationship. The proposed sensor has been designed via ray-optic simulations and embodied through passive alignment, combined with plastic injection mold. We achieve a positional resolution of 10 μm from either of Sig-A and Sig-B. By concurrently considering the two quadrature outputs, we efficiently enhance the resolution to 2.5 μm, with the discovered direction of displacement. Finally, we thoroughly investigate the crucial dependence of the sensor performance on the positional tolerance pertaining to the constituent elements, which is discovered to be as large as +/-100 μm, under a certain resolution.
- Published
- 2015
46. AIMS – A Metal Additive-hybrid Manufacturing System: System Architecture and Attributes
- Author
-
Ola L. A. Harrysson, Guha Manogharan, Ronald Aman, and Richard A. Wysk
- Subjects
Engineering ,Subtractive color ,business.industry ,Process (engineering) ,AIMS ,CAD ,CNC-RP ,Hybrid manufacturing ,Industrial and Manufacturing Engineering ,Position tolerance ,Manufacturing engineering ,Variety (cybernetics) ,Reliability engineering ,Performance Metrics and Additive manufacturing ,Artificial Intelligence ,Hybrid system ,Systems architecture ,business ,Data transmission - Abstract
This paper presents an integrated hybrid manufacturing approach to enhance and accelerate the adoption of metal Additive Manufacturing (AM) by adding a direct digital subtractive process to the production that is capable of improving the form, location and position tolerance of critical part features as well as improving surface finish. The hybrid system, AIMS (Additive systems Integrated with subtractive MethodS) can be integrated with existing metal AM systems without any significant modifications. The intent of this paper is to: 1) detail the system architecture, 2) highlight the process requirements, and 3) illustrate the sequential functions from development of CAD models through AM processing, to subtractive post-processing and corresponding process monitoring. Attributes of individual components such as physical and computational requirements associated with each discrete step of the overall process is presented. Advantages and current limitations of AIMS are also noted. The developed models provide insight into how the overall process-flow could be affected by errors (variability) due to both physical and data transfer across multiple systems. This paper also presents a generalized use of AIMS-for a variety of part geometries, noting materials and processing efficiencies associated with this unique hybrid method.
- Published
- 2015
47. Innovative tooling concepts for cocured composite structures in aircraft applications
- Author
-
Kotresh M. Gaddikeri, M. N. N. Gowda, Ramesh Sundaram, and M Subba Rao
- Subjects
Engineering ,business.product_category ,Consolidation (soil) ,business.industry ,Composite skin ,Composite number ,Structural engineering ,business ,Fastener ,Position tolerance - Abstract
Cocuring process is a unique characteristic of composite materials wherein multiple parts like stringers, ribs and spars are simultaneously cured and bonded to a composite skin resulting in an integral structure. It has many benefits like reduction in part count, elimination of stress concentration due to fastener holes in the cocured regions and reduced assembly time and related costs. However, the application of cocuring has been limited on contoured components because of the complexities associated with the tooling. The basic requirements to be fulfilled are (a) consolidation of skins and stiffeners and (b) dimensional tolerance on position and thickness of stiffeners. Proper consolidation can be ensured through the faithful transfer of autoclave pressure by designing tools which are flexible so that they conform to desired shape whereas the positional tolerance can be achieved by using rigid tools. The resolution of such conflicting requirements requires a detailed study of the geometry of the part, design requirements and tolerances achievable on tools. This paper discusses design of tools for two types of cocured structures viz., open and closed cocured structures. The tooling technologies for realising above structures differ considerably. A few tooling concepts have been discussed based on the authors’ experience of developing cocured structures over the last two decades.
- Published
- 2014
48. Tolerance analyses for metal EBG waveguides
- Author
-
Ningfeng Bai and Wei Hong
- Subjects
Physics ,Distribution (mathematics) ,Electromagnetics ,Tolerance analysis ,law ,Electric field ,Mathematical analysis ,Radius ,Constant (mathematics) ,Waveguide ,Position tolerance ,law.invention - Abstract
We investigate the characteristics of tolerance of metal EBG waveguide, and establish a tolerance analysis model. We get the relation curve of radius tolerance factor, φ, versus the distribution of electric field and the relation curve of position tolerance factor, ψ, versus the distribution of electric field. The double-half-algorithm was firstly proposed, with the admitting criteria, we get φ max with constant ψ, ψ max with constant φ. Meanwhile, the φ max and ψ max can be optimized when φ and ψ varies in the given way. At last, we find the fact that the influence of the first, second, third row metal rods to f and η p descends rapidly. These results will be useful guides for fabrication and performance analyzing of metal EBG devices in the future.
- Published
- 2017
49. Comparison of different wavefront measurement setups to judge the position tolerance of intraocular lenses in a model eye
- Author
-
Natascha Bayer, Bernd Reutterer, Lukas Traxler, and Andreas Drauschke
- Subjects
Wavefront ,genetic structures ,business.industry ,Computer science ,food and beverages ,eye diseases ,Position tolerance ,law.invention ,Lens (optics) ,Aberrations of the eye ,medicine.anatomical_structure ,Optics ,Intraocular lenses ,law ,Quality of vision ,medicine ,Optometry ,Human eye ,sense organs ,business - Abstract
To treat cataract intraocular lenses (IOLs) are used to replace the clouded human eye lens. Due to postoperative healing processes the IOL can displace within the eye, which can lead to deteriorated quality of vision. To test and characterize these effect an IOL can be embedded into a model of the humane eye. One informative measure are wavefront aberrations. In this paper three different setups, the typical double-pass configuration (DP), a single-pass (SP1) where the measured light travels in the same direction as in DP and a single-pass (SP2) with reversed direction, are investigated. All three setups correctly measure the aberrations of the eye, where SP1 is found to be the simplest to set up and align. Because of the lowest complexity it is the proposed method for wavefront measurement in model eyes.
- Published
- 2017
50. Integrated Flexible Electronic Devices Based on Passive Alignment for Physiological Measurement
- Author
-
Won Ick Jang, Sangwon Byun, Han Yung Yu, Eun-Hye Jang, Ah-Yung Kim, In-Bok Baek, Bong Kuk Lee, and Jin Hwa Ryu
- Subjects
Engineering ,flexible electronic device ,02 engineering and technology ,Substrate (printing) ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,Article ,Position tolerance ,Analytical Chemistry ,law.invention ,Electrocardiography ,law ,0103 physical sciences ,Electronic engineering ,Hardware_INTEGRATEDCIRCUITS ,lcsh:TP1-1185 ,Electronics ,Electrical and Electronic Engineering ,Instrumentation ,interconnection ,010302 applied physics ,Interconnection ,passive alignment ,business.industry ,Solder paste ,021001 nanoscience & nanotechnology ,Chip ,Atomic and Molecular Physics, and Optics ,Electronics, Medical ,electrocardiogram (ECG) sensor ,Optoelectronics ,electrocardiogram (ECG)sensor ,Photolithography ,0210 nano-technology ,business ,Layer (electronics) - Abstract
This study proposes a simple method of fabricating flexible electronic devices using a metal template for passive alignment between chip components and an interconnect layer, which enabled efficient alignment with high accuracy. An electrocardiogram (ECG) sensor was fabricated using 20 mu m thick polyimide (PI) film as a flexible substrate to demonstrate the feasibility of the proposed method. The interconnect layer was fabricated by a two-step photolithography process and evaporation. After applying solder paste, the metal template was placed on top of the interconnect layer. The metal template had rectangular holes at the same position as the chip components on the interconnect layer. Rectangular hole sizes were designed to account for alignment tolerance of the chips. Passive alignment was performed by simply inserting the components in the holes of the template, which resulted in accurate alignment with positional tolerance of less than 10 mu m based on the structural design, suggesting that our method can efficiently perform chip mounting with precision. Furthermore, a fabricated flexible ECG sensor was easily attachable to the curved skin surface and able to measure ECG signals from a human subject. These results suggest that the proposed method can be used to fabricate epidermal sensors, which are mounted on the skin to measure various physiological signals.
- Published
- 2017
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.