coordinate system
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Author(s):  
Dániel Bíró ◽  
Franz Diwoky ◽  
Erich Schmidt

Purpose The aim of the paper is to investigate the impacts of simplifications of a reduced-order simulation model of squirrel cage induction machines (SCIMs) by numerical experiments. Design/methodology/approach Design of setups to isolate the main influences on the results of the reduced-order model of SCIMs. Results of time-stepping finite element calculations are used as benchmark. Findings Whereas neglecting eddy current effects and the assumption of a sinusoidal rotor current distribution leads to acceptable deviations in regular inverter operation, the sampling and interpolation of the machine parameters in a two-axis coordinate system considerably deteriorate the model accuracy. Using a polar coordinate system for this purpose is expected to significantly improve the model quality. Originality/value Preparing the ground for a successful, both fast and accurate simulation model of SCIMs as parts of electrified drivetrains.


2022 ◽  
Author(s):  
Arkady Poliakovsky

We investigate Lorentzian structures in the four-dimensionalspace-time, supplemented either by a covector field of thetime-direction or by a scalar field of the global time. Furthermore,we propose a new metrizable model of the gravity. In contrast to theusual Theory of General Relativity where all ten components of thesymmetric pseudo-metrics are independent variables, the presentedhere model of the gravity essentially depend only on singlefour-covector field, restricted to have only three-independentcomponents. However, we prove that the Gravitational field, ruled bythe proposed model and generated by some massive body, resting andspherically symmetric in some coordinate system, is given by apseudo-metrics, which coincides with thewell known Schwarzschild metric from the General Relativity. TheMaxwell equations and Electrodynamics are also investigated in theframes of the proposed model. In particular, we derive the covariantformulation of Electrodynamics of moving dielectrics andpara/diamagnetic mediums.


Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 148
Author(s):  
Nikita Andriyanov ◽  
Ilshat Khasanshin ◽  
Daniil Utkin ◽  
Timur Gataullin ◽  
Stefan Ignar ◽  
...  

Despite the great possibilities of modern neural network architectures concerning the problems of object detection and recognition, the output of such models is the local (pixel) coordinates of objects bounding boxes in the image and their predicted classes. However, in several practical tasks, it is necessary to obtain more complete information about the object from the image. In particular, for robotic apple picking, it is necessary to clearly understand where and how much to move the grabber. To determine the real position of the apple relative to the source of image registration, it is proposed to use the Intel Real Sense depth camera and aggregate information from its depth and brightness channels. The apples detection is carried out using the YOLOv3 architecture; then, based on the distance to the object and its localization in the image, the relative distances are calculated for all coordinates. In this case, to determine the coordinates of apples, a transition to a symmetric coordinate system takes place by means of simple linear transformations. Estimating the position in a symmetric coordinate system allows estimating not only the magnitude of the shift but also the location of the object relative to the camera. The proposed approach makes it possible to obtain position estimates with high accuracy. The approximate root mean square error is 7–12 mm, depending on the range and axis. As for precision and recall metrics, the first is 100% and the second is 90%.


Author(s):  
M. J. Sani ◽  
I. A. Musliman ◽  
A. Abdul Rahman

Abstract. Geographic information system (GIS) is known traditionally for the modelling of two-dimensional (2D) geospatial analysis and therefore present information about the extensive spatial framework. On the other hand, building information modelling (BIM) is digital representation of building life cycle. The increasing use of both BIM and GIS simultaneously because of their mutual relationship, as well as their similarities, has resulted in more relationships between both worlds, therefore the need for their integration. A significant purpose of these similarities is importing BIM data into GIS to significantly assist in different design-related issues. However, currently this is challenging due to the diversity between the two worlds which includes diversity in coordinate systems, three-dimensional (3D) geometry representation, and semantic mismatch. This paper describes an algorithm for the conversion of IFC data to CityGML in order to achieve the set goal of sharing information between BIM and GIS domains. The implementation of the programme developed using python was validated using an IFC model (block HO2) of a student’s hostel, Kolej Tun Fatima (KTF). The conversion is based on geometric and semantic information mapping and the use of 3D affine transformation of IFC data from local coordinate system (LCS) to CityGML world coordinate system (WCS) (EPSG:4236). In order to bridge the gap between the two data exchange formats of BIM and GIS, we conducted geometry and semantic mapping. In this paper, we limited the conversion of the IFC model on level of details 2 (LOD2). The conversion will serve as a bridge toward the development of a software that will perform the conversion to create a strong synergy between the two domains for purpose of sharing information.


2022 ◽  
Author(s):  
Andrew Jones ◽  
F. William Townes ◽  
Didong Li ◽  
Barbara E Engelhardt

Spatially-resolved genomic technologies have allowed us to study the physical organization of cells and tissues, and promise an understanding of the local interactions between cells. However, it remains difficult to precisely align spatial observations across slices, samples, scales, individuals, and technologies. Here, we propose a probabilistic model that aligns a set of spatially-resolved genomics and histology slices onto a known or unknown common coordinate system into which the samples are aligned both spatially and in terms of the phenotypic readouts (e.g., gene or protein expression levels, cell density, open chromatin regions). Our method consists of a two-layer Gaussian process: the first layer maps the observed samples' spatial locations into a common coordinate system, and the second layer maps from the common coordinate system to the observed readouts. Our approach also allows for slices to be mapped to a known template coordinate space if one exists. We show that our registration approach enables complex downstream spatially-aware analyses of spatial genomics data at multiple resolutions that are impossible or inaccurate with unaligned data, including an analysis of variance, differential expression across the z-axis, and association tests across multiple data modalities.


Author(s):  
Robert Ward ◽  
Burak Sencer ◽  
Bryn Jones ◽  
Erdem Ozturk

Abstract This paper presents a novel real-time interpolation technique for 5-axis machine tools to attain higher speedand accuracy. To realize computationally efficient real-time interpolation of 6DOF tool motion, a joint workpiece-machine coordinate system interpolation scheme is proposed. Cartesian motion of the tool centre point (TCP) isinterpolated in the workpiece coordinate system (WCS), whereas tool orientation is interpolated in the machinecoordinate system (MCS) based on the finite impulse response (FIR) filtering. Such approach provides several ad-vantages: i) it eliminates the need for complex real-time spherical interpolation techniques, ii) facilitates efficientuse of slower rotary drive kinematics to compensate for the dynamic mismatch between Cartesian and rotary axesand achieve higher tool acceleration, iii) mitigates feed fluctuations while interpolating near kinematic singulari-ties. To take advantage of such benefits and realize accurate joint WCS-MCS interpolation scheme, tool orientationinterpolation errors are analysed. A novel approach is developed to adaptively discretize long linear tool movesand confine interpolation errors within user set tolerances. Synchronization errors between TCP and tool orienta-tion are also characterized, and peak synchronization error level is determined to guide the interpolation parameterselection. Finally, blending errors during non-stop continuous interpolation of linear toolpaths are modelled andconfined. Advantages of the proposed interpolation scheme are demonstrated through simulation studies and vali-dated experimentally. Overall, proposed technique can improve cycle times up to 10% while providing smooth and accurate non-stop real-time interpolation of tool motion in 5-axis machining.


Author(s):  
Tianyun Yuan ◽  
Yu Song ◽  
Gerald A. Kraan ◽  
Richard HM Goossens

Abstract Measuring the motions of human hand joints is often a challenge due to the high number of degrees of freedom. In this study, we proposed a hand tracking system utilizing action cameras and ArUco markers to continuously measure the rotation angles of hand joints. Three methods were developed to estimate the joint rotation angles. The pos-based method transforms marker positions to a reference coordinate system (RCS) and extracts a hand skeleton to identify the rotation angles. Similarly, the orient-x-based method calculates the rotation angles from the transformed x-orientations of the detected markers in the RCS. In contrast, the orient-mat-based method first identifies the rotation angles in each camera coordinate system using the detected orientations, and then, synthesizes the results regarding each joint. Experiment results indicated that the repeatability errors with one camera regarding different marker sizes were around 2.64 to 27.56 degrees and 0.60 to 2.36 degrees using the marker positions and orientations respectively. When multiple cameras were employed to measure the joint rotation angles, the angles measured by using the three methods were comparable with that measured by a goniometer. Despite larger deviations occurred when using the pos-based method. Further analysis indicated that the results of using the orient-mat-based method can describe more types of joint rotations, and the effectiveness of this method was verified by capturing hand movements of several participants. Thus it is recommended for measuring joint rotation angles in practical setups.


2022 ◽  
Vol 12 ◽  
Author(s):  
Weixing Liu ◽  
Gui Chen ◽  
Junyang Xie ◽  
Tianhao Liang ◽  
Chunyi Zhang ◽  
...  

Objectives: To develop and evaluate a new coordinate system for MRI of the vestibular system.Methods: In this study, 53 internal auditory canal MRI and 78 temporal bone CT datasets were analyzed. Mimics Medical software version 21.0 was used to visualize and three-dimensionally reconstruct the image data. We established a new coordinate system, named W–X, based on the center of the bilateral eyeballs and vertex of the bilateral superior semicircular canals. Using the W–X coordinate system and Reid's coordinate system, we measured the orientations of the planes of the anterior semicircular canal (ASCC), the lateral semicircular canal (LSCC), and the posterior semicircular canal (PSCC).Results: No significant differences between the angles measured using CT and MRI were found for any of the semicircular canal planes (p > 0.05). No statistical differences were found between the angles measured using Reid's coordinate system (CT) and the W–X coordinate system (MRI). The mean values of ∠ASCC & LSCC, ∠ASCC & PSCC, and ∠LSCC & PSCC were 84.67 ± 5.76, 94.21 ± 3.81, and 91.79 ± 5.22 degrees, respectively. The angle between the LSCC plane and the horizontal imaging plane was 15.64 ± 3.92 degrees, and the angle between the PSCC plane and the sagittal imaging plane was 48.79 ± 4.46 degrees.Conclusion: A new W–X coordinate system was developed for MRI studies of the vestibular system and can be used to measure the orientations of the semicircular canals.


2021 ◽  
pp. 224-230
Author(s):  
Konstantin Amelin ◽  
Vladimir Maltsev

In the modern world, UAVs (unmanned aerial vehicles) are increasingly used in everyday life in solving civilian tasks. One of the main applications of UAVs is data collection with their reference to a given coordinate system. For example, for the task of aerial photography, it is necessary to accurately link each image to the global coordinate system. In addition to the exact location of coordinates, it is worth the exact movement of a given route, to collect data of exactly those places that are needed. Thus, it is very important to ensure the minimum deviation of the UAV from the given route under the conditions of external disturbances (wind disturbances) acting on it. The article describes a procedure for assessing wind speed and direction for a UAV control system using the SPSA method. The simulation results of the algorithm operation, confirmed during flight tests on an ultralight UAV with an ardupilot autopilot, are presented.


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