A comparison of 2D and 3D analysis methods for the prediction of cogging torque in an electrical machine having skewed slots

In artistic gymnastics, the possibility of using 2D video analysis to measure the peak height (hpeak) and length of flight (L) during routine training in order to monitor the execution and development of difficult elements is intriguing. However, the validity and reliability of such measurements remain unclear. Therefore, in this study, the hpeak and L of 38 vaults, performed by top-level gymnasts, were assessed by 2D and 3D analysis in order to evaluate criterion validity and both intrarater and interrater reliability of the 2D method. Validity calculations showed higher accuracy for hpeak (±95% LoA: ±3.6% of average peak height) than for L (±95% LoA: ±7.6% of average length). Minor random errors, but no systematic errors, were observed in the examination of intrarater reliability (hpeak: CV% = 0.44%, p = 0.81; L: CV% = 0.87%, p = 0.14) and interrater reliability (hpeak: CV% = 0.51%, p = 0.55; L: CV% = 0.72%, p = 0.44). In conclusion, the validity and reliability of the 2D method are deemed sufficient (particularly for hpeak, but with some limitations for L) to justify its use in routine training of the vault. Due to its simplicity and low cost, this method could be an attractive monitoring tool for gymnastics coaches.

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Comparison of Three Analytical Methods for the Precise Calculation of Cogging Torque and Torque Ripple in Axial Flux PM Machines

Mathematical Problems in Engineering ◽

10.1155/2016/2171547 ◽

2016 ◽

Vol 2016 ◽

pp. 1-14 ◽

Cited By ~ 6

Author(s):

Ahmed Hemeida ◽

Bert Hannon ◽

Hendrik Vansompel ◽

Peter Sergeant

Keyword(s):

Permanent Magnet ◽

Lateral Force ◽

Torque Ripple ◽

Analytical Models ◽

Permanent Magnet Synchronous Machines ◽

Axial Flux ◽

Cogging Torque ◽

Precise Calculation ◽

Analytical Tools ◽

2D And 3D

A comparison between different analytical and finite-element (FE) tools for the computation of cogging torque and torque ripple in axial flux permanent-magnet synchronous machines is made. 2D and 3D FE models are the most accurate for the computation of cogging torque and torque ripple. However, they are too time consuming to be used for optimization studies. Therefore, analytical tools are also used to obtain the cogging torque and torque ripple. In this paper, three types of analytical models are considered. They are all based on dividing the machine into many slices in the radial direction. One model computes the lateral force based on the magnetic field distribution in the air gap area. Another model is based on conformal mapping and uses complex Schwarz Christoffel (SC) transformations. The last model is based on the subdomain technique, which divides the studied geometry into a number of separate domains. The different types of models are compared for different slot openings and permanent-magnet widths. One of the main conclusions is that the subdomain model is best suited to compute the cogging torque and torque ripple with a much higher accuracy than the SC model.

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Simulation-Based Tolerance and Assemblability Analyses of Assemblies With Multiple Pin/Hole Floating Mating Conditions

Volume 3: 25th Computers and Information in Engineering Conference, Parts A and B ◽

10.1115/detc2005-85398 ◽

2005 ◽

Cited By ~ 4

Author(s):

Zhengshu Shen ◽

Jami J. Shah ◽

Joseph K. Davidson

Keyword(s):

Tolerance Analysis ◽

Virtual Manufacturing ◽

Product Development Process ◽

3D Analysis ◽

Dimensional Problem ◽

Press Fit ◽

Simulation Based ◽

The Difference ◽

2D And 3D ◽

Mating Conditions

Development of tolerance analysis methods that are consistent with the ASME and ISO GD&T (geometric dimensioning and tolerancing) standards is a challenging task. Such methods are the basis for creating computer-aided tools for 3D tolerance analysis and assemblability analysis. These tools, along with the others, make it possible to realize virtual manufacturing in order to shorten lead-time and reduce cost in the product development process. Current simulation tools for 3D tolerance analysis and assemblability analysis are far from satisfactory because the underlying variation algorithms are not fully consistent with the GD&T standards. Better algorithms are still to be developed. Towards that goal, this paper proposes an improved simulation-based approach to tolerance and assemblability analyses for assemblies with pin/hole floating mating conditions in mechanical products. A floating pin/hole mating condition is the one where the mating pin should be able to “float” within the mating hole, and thus press-fit is not necessary for the parts to assemble properly. When multiple pin/hole mating pairs are involved in a product, the feasibility of assembly needs to be analyzed. This paper will introduce a more complete method of analyzing assemblability for such assemblies. In most cases, a 3D (3-dimensional) problem can be simplified to 1D (1-dimensional) or 2D (2-dimensional) problem, with the loss of some accuracy. To make a comparison and find out how accurately 1D and 2D analyses can approximate 3D analysis, this paper will provide the variation algorithms for 1D, 2D and 3D simulations. The algorithms developed account not only for bonus/shift tolerances but also for feasibility of assembling. These algorithms are extendable to consider other different GD&T specifications. The assemblability criteria proposed is generally applicable to any assemblies with pin/hole floating mating conditions. Case studies are provided to demonstrate the algorithms developed. The comparison study shows quantitatively the difference in the results from 1D, 2D and 3D simulation based analyses.

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Characterization of stripline circuit by planar circuit/equivalent network and demonstration of its validity by 1d, 2d and 3d analysis for practical structures

IEEE MTT-S International Microwave Symposium Digest, 2005. ◽

10.1109/mwsym.2005.1516861 ◽

2006 ◽

Author(s):

Jui-pang Hsu ◽

T. Hiraoka ◽

T. Ogawa

Keyword(s):

3D Analysis ◽

Equivalent Network ◽

Planar Circuit ◽

2D And 3D

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2D and 3D Analysis of Magnetocardiographic Data in the Evaluation of the Ventricular Repolarization Changes under Exercise Stress Test in Patients with CAD

World Journal of Cardiovascular Diseases ◽

10.4236/wjcd.2014.48050 ◽

2014 ◽

Vol 04 (08) ◽

pp. 399-404 ◽

Cited By ~ 2

Author(s):

Illya Chaikovsky ◽

Leonid Stadnyuk ◽

Georg Mjasnikov ◽

Anatoly Kazmirchuk ◽

Sergy Sofienko ◽

...

Keyword(s):

Stress Test ◽

Exercise Stress Test ◽

Ventricular Repolarization ◽

Exercise Stress ◽

3D Analysis ◽

2D And 3D

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Comparative analysis of 2D and 3D distance measurements to study spatial genome organization

10.1101/076893 ◽

2016 ◽

Cited By ~ 1

Author(s):

Elizabeth H. Finn ◽

Gianluca Pegoraro ◽

Sigal Shachar ◽

Tom Misteli

Keyword(s):

Genome Organization ◽

Spatial Organization ◽

Theoretical Models ◽

3D Analysis ◽

Distance Measurements ◽

Accuracy And Precision ◽

Distance Distributions ◽

Cell Type Specific ◽

Spatial Genome Organization ◽

2D And 3D

ABSTRACTThe spatial organization of eukaryotic genomes is non-random, cell-type specific, and has been linked to cellular function. The investigation of spatial organization has traditionally relied extensively on fluorescence microscopy. The validity of the imaging methods used to probe spatial genome organization often depends on the accuracy and precision of distance measurements. Imaging-based measurements may either use 2 dimensional datasets or 3D datasets including the z-axis information in image stacks. Here we compare the suitability of 2D versus 3D distance measurements in the analysis of various features of spatial genome organization. We find in general good agreement between 2D and 3D analysis with higher convergence of measurements as the interrogated distance increases, especially in flat cells. Overall, 3D distance measurements are more accurate than 2D distances, but are also more prone to noise. In particular, z-stacks are prone to error due to imaging properties such as limited resolution along the z-axis and optical aberrations, and we also find significant deviations from unimodal distance distributions caused by low sampling frequency in z. These deviations can be ameliorated by sampling at much higher frequency in the z-direction. We conclude that 2D distances are preferred for comparative analyses between cells, but 3D distances are preferred when comparing to theoretical models in large samples of cells. In general, 2D distance measurements remain preferable for many applications of analysis of spatial genome organization.

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Cogging Torque Reduction in Brushless Motors by a Nonlinear Control Technique

Energies ◽

10.3390/en12112224 ◽

2019 ◽

Vol 12 (11) ◽

pp. 2224 ◽

Cited By ~ 8

Author(s):

Pierpaolo Dini ◽

Sergio Saponara

Keyword(s):

Permanent Magnet ◽

Electric Drive ◽

Feedback Linearization ◽

Permanent Magnets ◽

Position Control ◽

Angular Position ◽

Control Technique ◽

Electrical Machine ◽

Brushless Motors ◽

Cogging Torque

This work addresses the problem of mitigating the effects of the cogging torque in permanent magnet synchronous motors, particularly brushless motors, which is a main issue in precision electric drive applications. In this work, a method for mitigating the effects of the cogging torque is proposed, based on the use of a nonlinear automatic control technique known as feedback linearization that is ideal for underactuated dynamic systems. The aim of this work is to present an alternative to classic solutions based on the physical modification of the electrical machine to try to suppress the natural interaction between the permanent magnets and the teeth of the stator slots. Such modifications of electric machines are often expensive because they require customized procedures, while the proposed method does not require any modification of the electric drive. With respect to other algorithmic-based solutions for cogging torque reduction, the proposed control technique is scalable to different motor parameters, deterministic, and robust, and hence easy to use and verify for safety-critical applications. As an application case example, the work reports the reduction of the oscillations for the angular position control of a permanent magnet synchronous motor vs. classic PI (proportional-integrative) cascaded control. Moreover, the proposed algorithm is suitable to be implemented in low-cost embedded control units.

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