Wyniki wyszukiwania - BazTech

1

Research on the Motion Features Model for Underwater Targets with Multiple Highlights and Multiple Micro-Motion Forms

Sun Tongjing, Zhou Zihan, Peng Dongliang

Archives of Acoustics

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2024

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Vol. 49, nr 2

199--208

EN

Motion characterization, including Doppler and micro-Doppler, is crucial for the detection and identification of high-speed underwater targets. Under high-frequency and short-range conditions, underwater targets cannot be simply regarded as single highlight targets as they exhibit a complex structure with multiple scattering centers accompanied by distinct micro-motions. To address this multi-highlight and multi-micro-motion scenario, a model is proposed to characterize the motion features of underwater targets. Firstly, a mathematical model is established to represent the micro-Doppler features based on the single-highlight model. Subsequently, considering the overlap of multiple highlight echoes caused by the high-speed translation of the target and the long pulse detection signal, precise representation is achieved by setting motion positions and calculating time delays within the model. The results represent the echoes of moving targets with multiple highlights and micromotions. Finally, a time-frequency analysis method is employed to extract motion features and estimate target parameters, thereby validating the accuracy and effectiveness of the proposed model. This research provides a theoretical foundation for the modeling of underwater moving targets.

2

Peg-on-hole: fundamental principles of motion of a peg leaning on a horizontal hole edge

Chernyakhovskaya L. B., Simakov D. A.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 4

49--59

EN

This paper presents a solution to the problem of a peg leaning on the edge of a horizontal hole at three points. The object of the interest is the motion in the course of automated peg-in-hole assembly. The complex motion of a peg is described in two degrees of freedom. These degrees of freedom are planar motion and rotational motion. Planar motion provides parts alignment via a change of nutation angle. Rotational motion occurs around a hole axis. It is described by a precession angle. The kinematic analysis of these was performed. Based on this analysis the directions of the peg velocities at the contact points were established. The directions of forces acting on the peg at these points were also determined. The system of Dynamic Differential Equations of the generalized coordinates was derived. This system determines the equations of the peg motion and dynamic reactions. During rotational motion, the forces acting on the peg at contact points are shown to be significantly reduced. This reduction improves the conditions of parts alignment and increases the assembly quality.

3

Efektywność rozdzielania modelowej mieszaniny w tryjerze obiegowym

Jadwisieńczak K., Choszcz D., Konopka S.

Inżynieria Rolnicza

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2010

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R. 14, nr 4

73-80

PL

W pracy przedstawiono wyniki badań skuteczności rozdzielania modelowej mieszaniny składającej się z cząstek długich (ziaren żyta) i krótkich (nasion gorczycy) w nowym tryjerze z powierzchnią roboczą w postaci ściętego stożka wprowadzonego w dodatkowy ruch wokół osi obiegu. Przedstawiono wpływ ruchu złożonego, kąta ustawienia roboczej krawędzi rynienki oraz zasilania stożka mieszaniną na jakość procesu separacji. Opracowano matematyczne umożliwiające prognozowanie wskaźniki oceny jakości rozdzielania mieszaniny.

EN

The work presents results of tests of effectiveness of separation of the model mixture consisting of long particles (rye grains) and short particles (mustard grains) in the new trieur with the working surface in the form of a truncated zone set in additional motion around the circulation axis. The impact of complex motion, the angle of setting of the working edge of the trough and the supply of the mixture to the cone on the quality of the separation process was presented. Mathematical indicators of evaluation of the quality of the mixture separation process were elaborated for the purpose of easier forecasting.