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Статті в журналах з теми "Rotation accuracy"
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Foss, O. A., J. Klaksvik, P. Benum, and S. Anda. "Validation of the rotation ratios method." Acta Radiologica 48, no. 6 (July 2007): 658–64. http://dx.doi.org/10.1080/02841850701348705.
Повний текст джерелаАнотація:
Background: The rotation ratios method describes rotations between pairs of sequential pelvic radiographs. The method seems promising but has not been validated. Purpose: To validate the accuracy of the rotation ratios method. Material and Methods: Known pelvic rotations between 165 radiographs obtained from five skeletal pelvises in an experimental material were compared with the corresponding calculated rotations to describe the accuracy of the method. The results from a clinical material of 262 pelvic radiographs from 46 patients defined the ranges of rotational differences compared. Repeated analyses, both on the experimental and the clinical material, were performed using the selected reference points to describe the robustness and the repeatability of the method. Results: The reference points were easy to identify and barely influenced by pelvic rotations. The mean differences between calculated and real pelvic rotations were 0.0° (SD 0.6) for vertical rotations and 0.1° (SD 0.7) for transversal rotations in the experimental material. The intra- and interobserver repeatability of the method was good. Conclusion: The accuracy of the method was reasonably high, and the method may prove to be clinically useful.
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Green, Andrew, Samantha Kerr, Benita Olivier, Chloe Dafkin, and Warrick McKinon. "The trade-off between distance and accuracy in the rugby union place kick." Kinesiology 48, no. 2 (2016): 251–57. http://dx.doi.org/10.26582/k.48.2.4.
Повний текст джерелаАнотація:
Little attention has been given to the rotational kinematics of the rugby union place kicking performance, especially in a field setting. The place kick is a means to score points. By maximizing the distance and accuracy a kicker is able to achieve increases the number of point scoring opportunities available to a team. The hypothesis of this study was that there is a relationship between distance and accuracy and the rotational kinematics of place kicking performance of rugby players in the field setting. Twelve first-team university rugby players had their full body kinematics measured for five place kicks. Kick distance and accuracy were directly measured. The current study showed a positive correlation between torso (r=.76) and pelvis (r=.66) rotation with kick distance. Place kick distance (r=.24) or accuracy (r=.54) were not correlated to playing experience. Negative correlations between stance elbow flexion (r=-.78), torso rotation (r=-.74) and X-factor (r=-.79) with kick accuracy were noted. Place kick distance could potentially be maximized by improving torso and pelvic rotations. Place kick accuracy could be improved by full extension of the stance arm. The data suggests that larger torso rotations may promote kicking distance; however, they impede kicking accuracy.
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Liu, Yiqing, Wenzhi Zhao, Shuo Chen, and Tao Ye. "Mapping Crop Rotation by Using Deeply Synergistic Optical and SAR Time Series." Remote Sensing 13, no. 20 (October 17, 2021): 4160. http://dx.doi.org/10.3390/rs13204160.
Повний текст джерелаАнотація:
Crop rotations, the farming practice of growing crops in sequential seasons, occupy a core position in agriculture management, showing a key influence on food security and agro-ecosystem sustainability. Despite the improvement in accuracy of identifying mono-agricultural crop distribution, crop rotation patterns remain poorly mapped. In this study, a hybrid convolutional neural network (CNN) and long short-term memory (LSTM) architecture, namely crop rotation mapping (CRM), were proposed to synergize the synthetic aperture radar (SAR) and optical time series in a rotational mapping task. The proposed end-to-end architecture had reasonable accuracies (i.e., accuracy > 0.85) in mapping crop rotation, which outperformed other state-of-the-art non-deep or deep-learning solutions. For some confusing rotation types, such as fallow-single rice and crayfish-single rice, CRM showed substantial improvements from traditional methods. Furthermore, the deeply synergistic SAR-optical, time-series data, with a corresponding attention mechanism, were effective in extracting crop rotation features, with an overall gain of accuracy of four points compared with ablation models. Therefore, our proposed method added wisdom to dynamic crop rotation mapping and yields important information for the agro-ecosystem management of the study area.
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Danielsson, Per-Erik, and Magnus Hammerin. "High-accuracy rotation of images." CVGIP: Graphical Models and Image Processing 54, no. 4 (July 1992): 340–44. http://dx.doi.org/10.1016/1049-9652(92)90080-h.
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Lu, Feng, Hong Bo Shen, Xiao Fei Zhang, Li Xiu Zhang, Yu Hou Wu, and Ke Zhang. "Analysis of Spindle Rotary Precision Based on Two-Point Methods." Applied Mechanics and Materials 624 (August 2014): 327–31. http://dx.doi.org/10.4028/www.scientific.net/amm.624.327.
Повний текст джерелаАнотація:
Two-point method designed of the test system for application, the precision of the motorized spindle rotation was dynamic measurements. The system consists of standard bars, high-precision non-contact eddy current sensor. Analyzed by a mathematical model to establish error separation, measurement of two spindle rotation accuracy. The use of two isolated error method for processing the experimental data obtained spindle rotation accuracy at different speeds. Studies have shown that when the spindle speed of 10,000 rpm rotational error is small and tends to be more stable. Identify the factors that affect the accuracy of spindle rotation and summarized. Spindle rotation accuracy on-line monitoring and speed control provides an important theoretical, experimental basis.
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Sun, Yanhui, Junkang Guo, Jun Hong, and Guanghui Liu. "Modeling of rotation accuracy of multi-support rotating machinery considering geometric errors and part deformation." Assembly Automation 40, no. 5 (September 15, 2020): 665–73. http://dx.doi.org/10.1108/aa-07-2018-099.
Повний текст джерелаАнотація:
Purpose This paper aims to develop a theoretical method to analyze the rotation accuracy of rotating machinery with multi-support structures. The method effectively considers the geometric errors and assembly deformation of parts. Design/methodology/approach A method composed of matrix and FEA methods is proposed to do the analysis. The deviation propagation analysis results and external loads are set as boundary conditions of the model which is built with Timoshenko beam elements to calculate the spatial pose of the rotor. The calculation is performed repeatedly as the rotation angle increased to get the rotation trajectories of concerned nodes, and further evaluation is done to get the rotation accuracy. Additionally, to get more reliable results, the bearing motion errors and stiffness are analyzed by a static model considering manufacturing errors of parts. Findings The feasibility of the proposed method is verified through a case study of a high-precision spindle. The method reasonably predicts the rotation accuracy of the spindle. Originality/value For rotating machinery with multi-support structures, the paper proposes a modeling method to predict the rotation accuracy, simultaneously considering geometric errors and assembly deformation of parts. This would improve the accuracy of tolerance analysis.
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Jing, Zhengyao, Jie Li, Xi Zhang, Kaiqiang Feng, and Tao Zheng. "A Novel Rotation Scheme for MEMS IMU Error Mitigation Based on a Missile-Borne Rotation Semi-Strapdown Inertial Navigation System." Sensors 19, no. 7 (April 9, 2019): 1683. http://dx.doi.org/10.3390/s19071683.
Повний текст джерелаАнотація:
In previous research, a semi-strapdown inertial navigation system (SSINS), based on micro-electro-mechanical system (MEMS) sensors, was able to realize over-range measurement of the attitude information of high-rotation missiles by constructing a single axis “spin reduction” platform. However, the MEMS sensors in SSINS were corrupted by significant sensor errors. In order to further improve SSINS measurement accuracy, a rotational modulation technique has been introduced to compensate for sensor errors. The ideal modulation angular velocity is changed sharply to achieve a constant speed, while in practical applications, the angular rate of the rotating mechanism’s output needs to go through an acceleration-deceleration process. Furthermore, the stability of the modulation angular rate is difficult to achieve in a high-speed rotation environment. In this paper, a novel rotation scheme is proposed which can effectively suppress the residual error in the navigation coordinate system caused by the modulation angular rate error, including the acceleration-deceleration process and instability of angular rate. The experiment results show that the position and attitude accuracy of the new rotation scheme was increased by more than 56%. In addition, the proposed scheme is applicable to navigation accuracy improvement under various dynamic conditions.
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Zhang, H., L. Wang, TX Song, and K. Li. "Error analysis and compensation for dual-axis inertial navigation system with horizontal rotation modulation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 1 (February 13, 2018): 313–22. http://dx.doi.org/10.1177/0954406218756940.
Повний текст джерелаАнотація:
Rotational inertial navigation system can significantly improve the navigation accuracy by rotating the inertial measurement unit about gimbals periodically. The precise calibration for installation errors and scale factor errors in rotational inertial navigation system can contribute to better navigation performance further. Especially in application requiring excellent azimuth precision, the horizontal rotation modulation will be badly required to modulate the vertical sensors’ errors as periodic variation, which can make inhibiting effect on the navigation errors. However, it also enlarges the impact of specific errors, which contains gyro’s scale factor error and the installation errors of inertial components. To meet the requirement of navigation precision, this paper has made error analysis and established mathematical model for a proposed horizontal rotation modulation in dual-axis rotational inertial navigation system. The crucial error parameters can be calibrated based on the measurements of attitude and velocity output without additional equipment. The results of experiment performed in an actual system demonstrate that navigation accuracy has been improved significantly, fully illustrating the significance and necessity of the calibration for specific errors in the horizontal rotation modulation.
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Liu, Yan, Zhendong Ge, Yingtao Yuan, Xin Su, Xiang Guo, Tao Suo, and Qifeng Yu. "Study of the Error Caused by Camera Movement for the Stereo-Vision System." Applied Sciences 11, no. 20 (October 9, 2021): 9384. http://dx.doi.org/10.3390/app11209384.
Повний текст джерелаАнотація:
The stereo-vision system plays an increasingly important role in various fields of research and applications. However, inevitable slight movements of cameras under harsh working conditions can significantly influence the 3D measurement accuracy. This paper focuses on the effect of camera movements on the stereo-vision 3D measurement. The camera movements are divided into four categories, viz., identical translations and rotations, relative translation and rotation. The error models of 3D coordinate and distance measurement are established. Experiments were performed to validate the mathematical models. The results show that the 3D coordinate error caused by identical translations increases linearly with the change in the positions of both cameras, but the distance measurement is not affected. For identical rotations, the 3D coordinate error introduced only in the rotating plane is proportional to the rotation angle within 10° while the distance error is zero. For relative translation, both coordinate and distance errors keep linearly increasing with the change in the relative positions. For relative rotation, the relationship between 3D coordinate error and rotation angle can be described as the nonlinear trend similar to a sine-cosine curve. The impact of the relative rotation angle on distance measurement accuracy does not increase monotonically. The relative rotation is the main factor compared to other cases. Even for the occurrence of a rotation angle of 10°, the resultant maximum coordinate error is up to 2000 mm, and the distance error reaches 220%. The results presented are recommended as practice guidelines to reduce the measurement errors.
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Iosif, Panagiotis, and Nikolaos Stergioulas. "Differentially Rotating Relativistic Stars beyond the J-Constant Law." Physical Sciences Forum 2, no. 1 (February 22, 2021): 62. http://dx.doi.org/10.3390/ecu2021-09312.
Повний текст джерелаАнотація:
The merger of a binary neutron star (BNS) system can lead to different final states depending on the total mass of the binary system and the equation of state (EOS). One of the possible outcomes of the merger is a long-lived (lifetime > 10 ms), compact and differentially rotating remnant. The Komatsu, Eriguchi and Hachisu (1989) differential rotation law (KEH) has been used almost exclusively in the literature to describe such configurations, despite the tension with corresponding rotational profiles reported from numerical simulations. New rotation laws suggested by Uryu et al. (2017) aspire to ease this tension and provide more realistic choices to describe the rotational profiles of BNS merger remnants. We recently started constructing equilibrium models with one of the new rotation laws proposed and comparing their physical properties to the KEH rotation law counterpart models. In addition, building on earlier work, the accuracy of the IWM-CFC conformal flatness approximation with the new differential rotation law was confirmed.
Дисертації з теми "Rotation accuracy"
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Docampo-Sanchez, Julia. "Smoothness-increasing accuracy-conserving (SIAC) line filtering : effective rotation for multidimensional fields." Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/63740/.
Повний текст джерелаАнотація:
Over the past few decades there has been a strong effort towards the development of Smoothness-Increasing Accuracy-Conserving (SIAC) filters for Discontinuous Galerkin (DG) methods, designed to increase the smoothness and improve the convergence rate of the DG solution through this post-processor. The applications of these filters in multidimension have traditionally employed a tensor product kernel, allowing a natural extension of the theory developed for one-dimensional problems. In addition, the tensor product has always been done along the Cartesian axis, resulting in a filter whose support has fixed shape and orientation. This thesis has challenged these assumptions, leading to the investigation of rotated filters: tensor product filters with variable orientation. Combining this approach with previous experiments on lower-dimension filtering, a new and computationally efficient subfamily for post-processing multidimensional data has been developed: SIAC Line filters. These filters transform the integral of the convolution into a line integral. Hence, the computational advantages are immediate: the simulation times become significantly shorter and the complexity of the algorithm design reduces to a one-dimensional problem. In the thesis, a solid theoretical background for SIAC Line filters has been established. Theoretical error estimates have been developed, showing how Line filtering preserves the properties of traditional tensor product filtering, including smoothness recovery and improvement in the convergence rate. Furthermore, different numerical experiments were performed, exhibiting how these filters achieve the same accuracy at significantly lower computational costs. This affords great advantages towards the applications of these filters during flow visualization; one important limiting factor of a tensor product structure is that the filter grows in support as the field dimension increases, becoming computationally expensive. SIAC Line filters have proven efficiency in computational performance, thus overcoming the limitations presented by the tensor product filter. The experiments carried out on streamline visualization suggest that these filters are a promising tool in scientific visualisation.
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Hudson, Derek Lavell. "Improving Accuracy in Microwave Radiometry via Probability and Inverse Problem Theory." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3244.pdf.
Повний текст джерела
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Dogantimur, Erkan, and Daniel Johnsson. "Analysis of Accuracy for Engine and Gearbox Sensors." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388346.
Повний текст джерелаАнотація:
This thesis provides a standardized method to measure accuracy for engine and gearbox sensors. Accuracy is defined by ISO 5725, which states that trueness and precision need to be known to provide a metric for accuracy. However, obtaining and processing the data required for this is not straight forward. In this thesis, a method is presented that consists of two main parts: data acquisition and data analysis. The data acquisition part shows how to connect all of the equipment used and how to sample and store all the raw data from the sensors. The data analysis part shows how to process that raw data into statistical data, such as trueness, repeatability and reproducibility for the sensors. Once repeatability and reproducibility are known, the total precision can be determined. Accuracy can then be obtained by using information from trueness and precision. Besides, this thesis shows that measurement error can be separated into error caused by the sensors and error caused by the measurand. This is useful information, because it can be used to assess which type of error is the greatest, whether or not it can be compensated for, and if it is economically viable to compensate for such error. The results are then shown, where it is possible to gain information about the sensors’ performance from various graphs. Between Hall and inductive sensors, there were no superior winner, since they both have their strengths and weaknesses. The thesis ends by making recommendations on how to compensate for some of the errors, and how to improve upon the method to make it more automatic in the future.
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Mach, Taylor Joseph. "Accurate Prediction of Chiroptical Properties." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64301.
Повний текст джерелаАнотація:
Accurate theoretical predictions of optical rotation are of substantial utility to the chemical community enabling the determination of absolute configuration without the need for poten- tially lengthy total synthesis. The requirements for robust calculation of gas-phase optical rotation are well understood, but too expensive for routine use. In an effort to reduce this cost we have examined the performance of the LPol and ORP basis sets, created for use in density functional theory calculations of optical rotation, finding that at the coupled cluster level of theory they perform the same or better than comparably sized general basis sets that are often used.
We have also examined the performance of a perturbational approach to inclusion of explicit solvent molecules in an effort to extend the calculation of response properties from the gas phase to the condensed phase. This N-body approach performs admirably for interaction energies and even dipole moments but breaks down for optical rotation, exhibiting large basis set superposition errors and requiring higher-order terms in the expansion to provide reasonable accuracy.
In addition, we have begun the process of implementing a gauge invariant version of coupled cluster response properties to address the fundamentally unphysical lack of gauge invariance in coupled cluster optical rotations. Correcting this problem, which arises from the non- variational nature of the coupled cluster wavefunction, involves reformulating the response amplitude and function expressions and solving for all necessary amplitudes simultaneously.Ph. D.
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Shenoy, Rajiv. "Overset adaptive strategies for complex rotating systems." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51796.
Повний текст джерелаАнотація:
The resolution of the complex physics of rotating configurations is critical for any engineering analysis that requires multiple frames of reference. Two well-known applications are in the rotorcraft and wind energy industries. Rotor wake impingement from rotor-fuselage and wind turbine-tower interactions impact structural and acoustic characteristics. Additionally, parasite drag resulting from rotorcraft hubs may result in severe limitations on forward flight vehicle performance. Complex turbulent wakes from rotors and hubs impinging on downstream empennage can create adverse aeroelastic behavior and can affect handling qualities. Numerical simulations of these flows require state-of-the-art Navier Stokes methods using dynamic overset grids. However, many current methods typically used in industry result in wakes that dissipate essential features. In order to address these concerns, two advancements are introduced in this thesis. Feature-based grid adaptation on dynamic overset grids has been developed and demonstrated with an unstructured Navier Stokes solver. The unique feature of the adaptation technique is that it is applied globally on the overset grid system except within the boundary layer. In concert with grid adaptation, an efficient parallelized search algorithm for solution interpolation over massively distributed systems has been created. This results in cost-effective interpolation that retains the numerical order of accuracy and has been verified in both space and time. The improvements have been demonstrated for rotor-fuselage interaction and a generic rotating hub. Detailed analysis of convergence of the methodology and sensitivity of the results to relevant parameters have also been included.
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Bezuidenhout, Carel Willem. "The accuracy of clinical examination of rotational and sagittal laxity of the knee." Master's thesis, University of Cape Town, 2020. http://hdl.handle.net/11427/32462.
Повний текст джерелаАнотація:
Purpose: This study evaluates the accuracy and reliability of clinical examination for knee laxity in degrees and millimetres when compared to movement measured by computer-assisted navigation. Methods: A cadaver lower limb was connected to a computer assisted knee surgery system (CAS) and calibrated through a mini medial parapatellar arthrotomy. Examiners estimated millimetres of sagittal and degrees of rotational laxity of the knee at 30º and 90º of knee flexion. This examination was done in the ligamentous intact knee and again after sequential release of the anterior cruciate ligament (ACL) and anterolateral ligament (ALL). The clinical assessments were compared with measurements produced by CAS. Intraclass correlation coefficient (ICC), correlation coefficient (CC) and Bland Altman plots were used to compare and summarize the data. Results: At least 21 participants assessed the knee after each sequence of ligament sectioning. The reliability of clinical examination when correlated with the CAS measurements was poor for all examination groups. The ICC was poor for sagittal laxity at 30º (R=0.02; p=0.04), rotational laxity at 30º and 90º (R=0.17; p=0.04) (R=0.3; p=0.04) respectively and sagittal laxity at 90º(R=0.47; p=0.04). The correlation coefficients were very weak for sagittal laxity at 30º (R=0.09; p=0.46), weak for rotational laxity at 30º (R=0.24; p=0.06) and 90º (R=0.3; p=0.01) and moderately weak for sagittal laxity at 90º(R=0.4; p=0.001). Clinical examination was only accurate in the detection of sagittal laxity greater than 11.6mm at 30°, and greater than 9.4mm at 90°. Clinical examination for rotational laxity was only accurate for rotational instability greater than 27.7° at 30°flexion, and 28.9° rotation at 90°. Conclusions: There was poor reliability and weak correlation between clinician estimated sagittal and rotational laxity and measurements produced by CAS. This study showed that participants could not accurately estimate laxity in degrees and millimetres and supports the need for accurate objective knee laxity measurements.
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Marek, Tomáš. "Predikování vybraných vlastností rotačních kinematických dvojic obráběcích strojů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-408064.
Повний текст джерелаАнотація:
The dissertation thesis is used as a methodology for prediction of selected parameters of rotational kinematic pairs of machine tools. The motivation for its writing has been continually increasing requirements for parameters (performance, accuracy, static and dynamic stiffness) of machine tools. The methodology takes into account the availability of suitable measuring devices and description of the design of rotary kinematic pairs. It will be useable for predicting the behavior of rotational kinematic pairs, even at the design stage by applying results to the machine design. The work is processed so that first is used a system approach to suggest methodology for prediction of the behavior of rotary kinematic pair in CNC machine tools, planning measurement strategy and verifying the results, including applications for specific kinematic chain of the selected machine. Based on this system approach and the resulting methodology, the measurement of the rotary kinematic pair was performed. The results of the system approach and measurement are generalized in the form of recommendations for designers of machining centers, allowing to increase the accuracy of the rotational kinematic pair.
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Чирков, Д. А., та D. A. Chirkov. "Автоматизация контроля и сортировки бомбинированных подшипниковых роликов по биению сферического торца : магистерская диссертация". Master's thesis, б. и, 2019. http://hdl.handle.net/10995/74340.
Повний текст джерелаАнотація:
Цель работы – разработка, исследование точности и конструирование измерительной станции для контроля биения сферического торца ролика радиального двухрядного сферического подшипника качения на базе существующего автомата (А-2292-М) для контроля гранности бочкообразных роликов. В ходе работы была предложена метрологическая схема, необходимая для контроля сферического торца ролика, исследована её точность, разработана конструкция измерительной станции. Показана реализация измерительной системы в конструкции автомата для контроля гранности с двумя вариантами источников вращения ролика в процессе измерения. Проведен расчет экономической эффективности от повышения качества роликов и увеличения межремонтных периодов. В основу измерительного узла положено использование индуктивного (автогенераторного) датчика и элемента посредника совместно с метрологической схемой, представленной в работе.The aim of the work is to develop, study the accuracy and design of a measuring station for monitoring the runout of a spherical roller end of a radial two-row spherical rolling bearing based on an existing machine (A-2292-M) to control the granularity of barrel rollers. In the course of the work, a metrological scheme was proposed, which was necessary to control the spherical end of the roller, its accuracy was investigated, and the design of the measuring station was developed. The implementation of the measuring system in the design of the automatic machine for control of granularity with two options for sources of rotation of the roller in the measurement process is shown. The calculation of economic efficiency from improving the quality of rollers and increasing the period between repairs is carried out. The basis of the measuring node is the use of an inductive (auto-oscillating) sensor and an intermediary element in conjunction with the metrological scheme presented in the work.
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Дзюра, Володимир Олексійович. "Наукові основи забезпечення параметрів якості робочих поверхонь тіл обертання технологічними методами". Diss., Тернопільський національний технічний університет імені Івана Пулюя, 2021. https://ena.lpnu.ua/handle/ntb/56686.
Повний текст джерелаАнотація:
У дисертаційній роботі отримано нові науково обґрунтовані результати вирішення актуальної для технології машинобудування науково-прикладної проблеми забезпечення параметрів якості робочих поверхонь деталей машин у вигляді тіл обертання з урахуванням комплексного підходу та умов експлуатації шляхом оптимізації структури технологічних процесів за параметрами якості та забезпеченні прогресивних режимів обробки. При цьому параметри якості поверхонь, які забезпечують їх експлуатаційні властивості, запропоновано забезпечувати недорогою операцією ППД із формуванням регулярних мікрорельєфів, що дозволить усунути зі структури ТП вартісні фінішні технологічні операції. Запропоновано метод визначення впливу технологічної спадковості на точність форми поперечних перерізів циліндричних поверхонь отриманих на операціях технологічного процесу, а також метод імовірнісного оцінювання впливу подачі на мікрогеометрію поверхні, сформованої точінням. Встановлено основні закономірності впливу форм та розмірів циліндричних поверхонь на параметр шорсткості. Розроблено нову математичну модель динамічного процесу формування регулярного мікрорельєфу шляхом віброобкочування на внутрішній циліндричній поверхні з урахуванням силових характеристик процесу та кінематику руху деформуючого інструменту. Використовуючи блочний підхід, отримано множину варіантів нових математичних моделей та розроблено класифікацію частково регулярних мікрорельєфів, сформованих на торцевих поверхнях деталей класу «тіла обертання», які враховують їх геометричні характеристики. Розроблено спосіб формування частково регулярного мікрорельєфу на торцевих поверхнях деталей класу «тіла обертання», який забезпечує його однакову відносну площу на різній відстані від центра обертання та
запропоновано аналітичні залежності визначення амплітуди канавок V-подібної форми для мікрорельєфів І і ІІ виду. Запропоновано конструкції інструментів для обробки різанням внутрішніх циліндричних поверхонь та формування регулярних мікрорельєфів. Розроблено програмне забезпечення для побудови математичної моделі профілю шорсткості поверхні на основі параметрів профілограми. Матеріали досліджень, методики розрахунків передані для використання машинобудівними підприємствами. A very important mechanical engineering scientific-applied problem of complex assurance of the quality parameters of bodies-of- rotation-type machine parts working surfaces has been solved in the thesis under discussion on the basis of the obtained new scientifically substantiated results taking into account the operating conditions due to the technological processes structure optimization by the quality parameters and the machining progressive modes assurance by means of statistical methods of assessment. Therefore, the physical-mechanical parameters of quality providing the surface performance characteristics have been proposed to achieve by means of SPD (surface plastic deformation) operations with regular microreliefs formation. The analysis of technological methods and facilities providing the high-quality parameters of the surfaces of machine parts of “bodies of rotation” type has been made on the basis of literature sources review. The results of the research have been analysed aimed
at formation of high-quality parameters of the machine parts surfaces. Some methods of regular microrelief formation on the surfaces of bodies of rotation of machine parts have been taken into consideration. The procedure of conducting the study of high-quality parameters formation of bodies-of-rotation-type machine parts cylindrical surfaces has been described. For this purpose the technological heredity and the shape accuracy of cylindrical surfaces cross sections of the object of investigation has been taken into consideration. The analysis and optimization of the technological process of internal cylindrical surface formation of a hydraulic cylinder barrel have been made based on the analysis of topography and microrelief formed in different technological operations. The probabilistic-statistical method of feeding impact assessment on the surface roughness formed by turning and the probabilistic-statistical method of flexure impact assessment on the surface roughness formed by turning have been developed. Moreover, the technique of analytical description of the surface contour has been developed which made possible to describe the surface roughness in the form of a mathematical model. The investigation has been carried out and some mathematical model of dynamic process of regular microrelief formation on the machine part internal cylindric surface has been developed. The peculiarity of the study under discussion is that the formation process is taking place under concentrated (point) force conditions whose point of application varies in radial and axial directions relative to the workpiece. The action under study has been proposed to be simulated by means of linear and time variables of Dirac delta functions using both the method of the above mentioned features regularization and the conventional methods of integrating the appropriate nonlinear mathematical models of longitudinal and lateral vibrations of the part as well. The partially regular microreliefs (PRM) formed on the end surfaces of the bodies of rotation have been classified in the form of a multistage system: class – classification criteria – subcriterion – characteristics of these subcriteria structured on the basis of kinematics of the technological process of the partially regular microreliefs (PRM) formation. The following classification criteria have been proposed to be accepted: ways of PRM formation; form of CRM (continuous regular microroughness) center line; relative position of adjacent grooves; relative position of CRM center lines; forms of grooves. Some partially regular microreliefs formed on the end surfaces of bodies of rotation have been simulated by means of block principle where each characteristic feature of the microrelief groove is described by the system of separate mathematical dependencies. The analytical dependencies to find the area of grooves of triangular shape of the partially regular microrelief formed on the end surfaces of bodies of rotation have been obtained. The optimal parameters of the grooves of partially regular microrelief of I and II type formed on the end surfaces of bodies of rotation have been determined. The dependencies and the range of their existence to find the grooves overlapped area of the PRM of III type have been derived. The results of experimental studies of partially regular microrelief formation on the end surfaces of bodies of rotation have been given. In this connection the equipment used, special tools and software to calculate the target points coordinates of the microrelief have been described, the shape and size of the test sample have been substantiated. The process of the test sample surface preparation for the full factorial experiment carrying out, namely the sample division into sectors and areas, has been described. The program and the technique of the experimental research have been developed. The impact of deformation effort, feeding speed and the groove axial pitch on the average value of the groove width of the formed partially regular microrelief formed on the end surface of the body of rotation has been determined on the basis of the results of the full factorial experiment. Some regression dependencies, response surfaces and their two-dimensional cross sections have been obtained which describe the influence of these parameters on the groove width whithin the boundaries of variable factors levels of variation determined by the conducted experiment. The design and calculation procedure of main design parameters of a twin-cutter adaptive boring head have been developed. The design of the tool for regular microrelief formation on internal cylindric surfaces of some long cylindric workpieces by vibration burnishing and the calculation procedure of main design parameters of the tool have been developed.
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Goubeaux, Craig A. "The Accuracy of Measuring Lumbar Vertebral Displacements Using a Dynamic MRI Sequence." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1480436812645944.
Повний текст джерелаЧастини книг з теми "Rotation accuracy"
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Dickey, J. O., T. M. Eubanks, and J. A. Steppe. "High Accuracy Earth Rotation and Atmospheric Angular Momemtum." In Earth Rotation: Solved and Unsolved Problems, 137–62. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4750-4_11.
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Sofue, Yoshiaki. "Dark-Matter Distribution Inferred from High-Accuracy Rotation Curves." In Toward a New Millennium in Galaxy Morphology, 593–96. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4114-7_54.
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Jiao, Haisong, Shentang Li, Haiqiang Yang, Liangjian Jiang, and Lili Wang. "Antenna Circular Rotation Method for Detecting Receiver Dynamic Positioning Accuracy." In Lecture Notes in Electrical Engineering, 403–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37398-5_37.
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Montag, H., and G. Gendt. "The ZIPE Solution for the Earth’s Rotation Parameters and Some Accuracy Estimations." In International Association of Geodesy Symposia, 15–23. New York, NY: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-6399-6_3.
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Lei, Yu, Hongbing Cai, and Danning Zhao. "A Simple Differencing Technology to Improve Prediction Accuracy of Earth Rotation Parameters." In Lecture Notes in Electrical Engineering, 201–11. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0940-2_18.
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Nagashima, Sei, Koichi Ito, Takafumi Aoki, Hideaki Ishii, and Koji Kobayashi. "A High-Accuracy Rotation Estimation Algorithm Based on 1D Phase-Only Correlation." In Lecture Notes in Computer Science, 210–21. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-74260-9_19.
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Kuramoto, Kanta, Wataru Ohyama, Tetsushi Wakabayashi, and Fumitaka Kimura. "Accuracy Improvement of Viewpoint-Free Scene Character Recognition by Rotation Angle Estimation." In Camera-Based Document Analysis and Recognition, 60–70. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-05167-3_5.
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Rodtook, Sittisak, and Stanislav Makhanov. "On the Accuracy of Rotation Invariant Wavelet-Based Moments Applied to Recognize Traditional Thai Musical Instruments." In Lecture Notes in Computer Science, 408–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-45224-9_57.
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Carter, W. E., and D. S. Robertson. "Accurate Earth Orientation time Series from vlbi Observations." In Earth Rotation: Solved and Unsolved Problems, 61–67. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4750-4_5.
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Sarabandi, Soheil, and Federico Thomas. "Accurate Computation of Quaternions from Rotation Matrices." In Advances in Robot Kinematics 2018, 39–46. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-93188-3_5.
Повний текст джерелаТези доповідей конференцій з теми "Rotation accuracy"
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Ulmer, Jr., Edward A. "High Accuracy Faraday Rotation Measurements." In Optical Fiber Sensors. Washington, D.C.: OSA, 1988. http://dx.doi.org/10.1364/ofs.1988.thcc21.
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Zhang, Yanfei, Xiaohu Li, Jun Hong, Sun’an Wang, Baotong Li, Yanhui Sun, and Shuai Zheng. "Rotation Accuracy Analysis of Spindle Under Variable Preload." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71264.
Повний текст джерелаАнотація:
Variable preload technology is used to achieve appropriate preload applied on spindle bearing based on machining conditions. However, the bearing temperature rise will be directly affected by bearing preload as well as bearing rotation accuracy. So, the main objective of this paper is to propose a method to determine the rotation accuracy of the spindle affected by the thermal expensive due to heat generation under variable preloads. Five degrees of freedom (5-DOF) quasi-static model of angular contact ball bearing was established to investigate the internal load distribution of the contact areas between the race way and balls. Then local contact heat generation of the bearing is calculated based on hertz contact theory. Finally, an experimental platform equipped with hydraulic system is designed and fabricated, which is preloaded by a hydraulic chamber. Studies have shown that the rotation accuracy presents drastically with the spindle rotational speed. Moreover, the influence of the bearing preload has a secondary importance. Comparative analysis about the rotation accuracy between starting running state and stable running state after a few hours under the same preload has been investigated. Results show that the accuracy of rotation spindle present no obviously difference when the uneven thermal deformation of parts occurs in the spindle system.
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Ruth, Richard, Timothy Brown, and James Lau. "Accuracy of EDR During Rotation on Low Friction Surfaces." In SAE 2010 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2010. http://dx.doi.org/10.4271/2010-01-1001.
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Qi Nie, Xiaoying Gao, and Zhun Liu. "Research on accuracy improvement of INS with continuous rotation." In 2009 International Conference on Information and Automation (ICIA). IEEE, 2009. http://dx.doi.org/10.1109/icinfa.2009.5205041.
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Liu, Xinyu, and Gongliu Yang. "The Influence of Multi-Samples Rotation Vector Algorithms on Navigation Accuracy." In 2017 4th International Conference on Information Science and Control Engineering (ICISCE). IEEE, 2017. http://dx.doi.org/10.1109/icisce.2017.267.
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Xing, Haifeng, Meifeng Guo, Xinxi Zhang, Feng Ji, and Wenming Zhang. "Effect of Rotation Rate Change of Rotary MIMU On System Navigation Accuracy." In 2019 Chinese Control And Decision Conference (CCDC). IEEE, 2019. http://dx.doi.org/10.1109/ccdc.2019.8833146.
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Pendem, Suganda, and Rajshekar B. Shettar. "Enhancing Computational Accuracy and Performance of Interval Arithmetic Double Rotation Cordic algorithm." In 2018 International Conference on Networking, Embedded and Wireless Systems (ICNEWS). IEEE, 2018. http://dx.doi.org/10.1109/icnews.2018.8903935.
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Yoshino, Yoshimi, Kenichi Ao, Mitsuharu Kato, and Shuji Mizutani. "MRE Rotation Sensor: High-Accuracy, High-Sensitivity Magnetic Sensor for Automotive Use." In SAE International Congress and Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1987. http://dx.doi.org/10.4271/870470.
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Schneider, Rafael Zandona. "On the accuracy of scatterers LOS rotation estimation procedures in radar polarimetry." In 2009 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2009. http://dx.doi.org/10.1109/igarss.2009.5417961.
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Huang, Xuemei, Xiuting Wei, and Chengtao Wang. "Accuracy Assessment for Hip Rotation Centre in Total Knee Replacement Surgical Navigation." In 2008 2nd International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2008. http://dx.doi.org/10.1109/icbbe.2008.125.
Повний текст джерелаЗвіти організацій з теми "Rotation accuracy"
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Seginer, Ido, Louis D. Albright, and Robert W. Langhans. On-line Fault Detection and Diagnosis for Greenhouse Environmental Control. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7575271.bard.
Повний текст джерелаАнотація:
Background Early detection and identification of faulty greenhouse operation is essential, if losses are to be minimized by taking immediate corrective actions. Automatic detection and identification would also free the greenhouse manager to tend to his other business. Original objectives The general objective was to develop a method, or methods, for the detection, identification and accommodation of faults in the greenhouse. More specific objectives were as follows: 1. Develop accurate systems models, which will enable the detection of small deviations from normal behavior (of sensors, control, structure and crop). 2. Using these models, develop algorithms for an early detection of deviations from the normal. 3. Develop identifying procedures for the most important faults. 4. Develop accommodation procedures while awaiting a repair. The Technion team focused on the shoot environment and the Cornell University team focused on the root environment. Achievements Models: Accurate models were developed for both shoot and root environment in the greenhouse, utilizing neural networks, sometimes combined with robust physical models (hybrid models). Suitable adaptation methods were also successfully developed. The accuracy was sufficient to allow detection of frequently occurring sensor and equipment faults from common measurements. A large data base, covering a wide range of weather conditions, is required for best results. This data base can be created from in-situ routine measurements. Detection and isolation: A robust detection and isolation (formerly referred to as 'identification') method has been developed, which is capable of separating the effect of faults from model inaccuracies and disturbance effects. Sensor and equipment faults: Good detection capabilities have been demonstrated for sensor and equipment failures in both the shoot and root environment. Water stress detection: An excitation method of the shoot environment has been developed, which successfully detected water stress, as soon as the transpiration rate dropped from its normal level. Due to unavailability of suitable monitoring equipment for the root environment, crop faults could not be detected from measurements in the root zone. Dust: The effect of screen clogging by dust has been quantified. Implications Sensor and equipment fault detection and isolation is at a stage where it could be introduced into well equipped and maintained commercial greenhouses on a trial basis. Detection of crop problems requires further work. Dr. Peleg was primarily responsible for developing and implementing the innovative data analysis tools. The cooperation was particularly enhanced by Dr. Peleg's three summer sabbaticals at the ARS, Northem Plains Agricultural Research Laboratory, in Sidney, Montana. Switching from multi-band to hyperspectral remote sensing technology during the last 2 years of the project was advantageous by expanding the scope of detected plant growth attributes e.g. Yield, Leaf Nitrate, Biomass and Sugar Content of sugar beets. However, it disrupted the continuity of the project which was originally planned on a 2 year crop rotation cycle of sugar beets and multiple crops (com and wheat), as commonly planted in eastern Montana. Consequently, at the end of the second year we submitted a continuation BARD proposal which was turned down for funding. This severely hampered our ability to validate our findings as originally planned in a 4-year crop rotation cycle. Thankfully, BARD consented to our request for a one year extension of the project without additional funding. This enabled us to develop most of the methodology for implementing and running the hyperspectral remote sensing system and develop the new analytical tools for solving the non-repeatability problem and analyzing the huge hyperspectral image cube datasets. However, without validation of these tools over a ful14-year crop rotation cycle this project shall remain essentially unfinished. Should the findings of this report prompt the BARD management to encourage us to resubmit our continuation research proposal, we shall be happy to do so.
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Wu, Qihua, Kathryn Kremer, Stephen Gibbons, and Alan Kennedy. Determination of nanomaterial viscosity and rheology properties using a rotational rheometer. Engineer Research and Development Center (U.S.), April 2022. http://dx.doi.org/10.21079/11681/43964.
Повний текст джерелаАнотація:
Rheology studies the flow of matter and is one of the most important methods for materials characterization because flow behavior is responsive to properties such as molecular weight and molecular weight distribution. Rheological properties help practitioners understand fluid flow and how to improve manufacturing processes. Rheometers have been extensively used to determine the viscosity and rheological properties of different materials because the measurements are quick, accurate, and reliable. In this standard operating procedure, a general protocol using a rotational rheometer is developed for characterizing rheological properties of nanomaterials. Procedures and recommendations for sample preparation, instrument preparation, sample measurements, and results analysis are included. The procedure was tested on a variety of carbon-based nanomaterials.
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Anderson, Gerald L., and Kalman Peleg. Precision Cropping by Remotely Sensed Prorotype Plots and Calibration in the Complex Domain. United States Department of Agriculture, December 2002. http://dx.doi.org/10.32747/2002.7585193.bard.
Повний текст джерелаАнотація:
This research report describes a methodology whereby multi-spectral and hyperspectral imagery from remote sensing, is used for deriving predicted field maps of selected plant growth attributes which are required for precision cropping. A major task in precision cropping is to establish areas of the field that differ from the rest of the field and share a common characteristic. Yield distribution f maps can be prepared by yield monitors, which are available for some harvester types. Other field attributes of interest in precision cropping, e.g. soil properties, leaf Nitrate, biomass etc. are obtained by manual sampling of the filed in a grid pattern. Maps of various field attributes are then prepared from these samples by the "Inverse Distance" interpolation method or by Kriging. An improved interpolation method was developed which is based on minimizing the overall curvature of the resulting map. Such maps are the ground truth reference, used for training the algorithm that generates the predicted field maps from remote sensing imagery. Both the reference and the predicted maps are stratified into "Prototype Plots", e.g. 15xl5 blocks of 2m pixels whereby the block size is 30x30m. This averaging reduces the datasets to manageable size and significantly improves the typically poor repeatability of remote sensing imaging systems. In the first two years of the project we used the Normalized Difference Vegetation Index (NDVI), for generating predicted yield maps of sugar beets and com. The NDVI was computed from image cubes of three spectral bands, generated by an optically filtered three camera video imaging system. A two dimensional FFT based regression model Y=f(X), was used wherein Y was the reference map and X=NDVI was the predictor. The FFT regression method applies the "Wavelet Based", "Pixel Block" and "Image Rotation" transforms to the reference and remote images, prior to the Fast - Fourier Transform (FFT) Regression method with the "Phase Lock" option. A complex domain based map Yfft is derived by least squares minimization between the amplitude matrices of X and Y, via the 2D FFT. For one time predictions, the phase matrix of Y is combined with the amplitude matrix ofYfft, whereby an improved predicted map Yplock is formed. Usually, the residuals of Y plock versus Y are about half of the values of Yfft versus Y. For long term predictions, the phase matrix of a "field mask" is combined with the amplitude matrices of the reference image Y and the predicted image Yfft. The field mask is a binary image of a pre-selected region of interest in X and Y. The resultant maps Ypref and Ypred aremodified versions of Y and Yfft respectively. The residuals of Ypred versus Ypref are even lower than the residuals of Yplock versus Y. The maps, Ypref and Ypred represent a close consensus of two independent imaging methods which "view" the same target. In the last two years of the project our remote sensing capability was expanded by addition of a CASI II airborne hyperspectral imaging system and an ASD hyperspectral radiometer. Unfortunately, the cross-noice and poor repeatability problem we had in multi-spectral imaging was exasperated in hyperspectral imaging. We have been able to overcome this problem by over-flying each field twice in rapid succession and developing the Repeatability Index (RI). The RI quantifies the repeatability of each spectral band in the hyperspectral image cube. Thereby, it is possible to select the bands of higher repeatability for inclusion in the prediction model while bands of low repeatability are excluded. Further segregation of high and low repeatability bands takes place in the prediction model algorithm, which is based on a combination of a "Genetic Algorithm" and Partial Least Squares", (PLS-GA). In summary, modus operandi was developed, for deriving important plant growth attribute maps (yield, leaf nitrate, biomass and sugar percent in beets), from remote sensing imagery, with sufficient accuracy for precision cropping applications. This achievement is remarkable, given the inherently high cross-noice between the reference and remote imagery as well as the highly non-repeatable nature of remote sensing systems. The above methodologies may be readily adopted by commercial companies, which specialize in proving remotely sensed data to farmers.
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Tire Experimental Characterization Using Contactless Measurement Methods. SAE International, August 2021. http://dx.doi.org/10.4271/2021-01-1114.
Повний текст джерелаАнотація:
In the frame of automotive Noise Vibration and Harshness (NVH) evaluation, inner cabin noise is among the most important indicators. The main noise contributors can be identified in engine, suspensions, tires, powertrain, brake system, etc. With the advent of E-vehicles and the consequent absence of the Internal Combustion Engine (ICE), tire/road noise has gained more importance, particularly at mid-speed driving and in the spectrum up to 300 Hz. At the state of the art, the identification and characterization of Noise and Vibration sources rely on pointwise sensors (microphones, accelerometers, strain gauges). Optical methods such as Digital Image Correlation (DIC) and Laser Doppler Vibrometer (LDV) have recently received special attention in the NVH field because they can be used to obtain full-field measurements. Moreover, these same techniques could also allow to characterize the tire behavior in operating conditions, which would be practically impossible to derive with standard techniques. In this paper we will demonstrate how non-contact full-field measurement techniques can be used to reliably and robustly characterize the tire behavior up to 300 Hz, focusing on static conditions. Experimental modal analysis will extract the modal characteristic of the tire in both free-free and statically preloaded boundary conditions, using both DIC and LDV. The extracted natural frequencies, damping ratios and full-field mode shapes will be used on one side to improve the accuracy of tire models (either by deriving FRF based models or updating FE ones) but also as a reference for future investigation on the tire behavior characterization in rotating conditions.