Motion Simulation of Key Components in a Package Machine

2012 ◽  
Vol 557-559 ◽  
pp. 2303-2306
Author(s):  
Shu Bin Kan
Keyword(s):  
Structural Parameters ◽  
Center Of Mass ◽  
Motion Simulation ◽  
Software Environment ◽  
Optimization Result ◽  
Adams Software ◽  
Motion Characteristic ◽  
The Moment ◽  
Selection Of

The motion characteristic of key components is a decisional factor to the working reliability and stability of a package machine. In this paper, the motion simulation of a key component is carried out in the ADAMS software environment. By analysis of the force, variance of the center-of-mass and the moment of the component, the mutation point in the motion is found, and then the structure is optimized by selection of different structural parameters. The optimization result shows a significant improvement for the reliability and stability of the whole machine.

Research of Baseball’s Best Batting Position Changes with the Selection of Material of Baseball

2013 ◽  
Vol 690-693 ◽  
pp. 1826-1830
Author(s):  
Li Ping Du ◽  
Wu Li ◽  
Wen Sheng Han
Keyword(s):  
Major League Baseball ◽  
Center Of Mass ◽  
Original Material ◽  
Sweet Spot ◽  
Collision Model ◽  
Exit Speed ◽  
The Moment ◽  
Definition Of ◽  
Selection Of ◽  
Parameters Calculation

From the aspect of the fastest exit speed of the ball and through the collision model of mechanics, we analyzed the best hitting point which results in the fastest exit speed of the ball and the change of the best hitting point. Based on this model, we gave a very practical definition of the sweet spot, and we also found out the effect of the baseball bat’s material on the sweet spot. The distances from the best hitting point to the end of the baseball bat result from the three different materials, which are the bat’s original material, aluminum and the corked material. Through the sensitivity analysis, three parameters affecting the hitting position resulting in the ball’s fastest exit speed are the weight of the bat, the center of mass and the moment-of-inertia. In the process of the three parameters’ calculation, the infinitesimal method is used. As can be found out that the length of the sweet spot results from the corked and the aluminum are much longer than results from the original material. The longer the length of sweet spot, the possibility that the hitter hits the fast ball is higher. Also ball hit by the aluminum bat is faster than that hit by the bat made out of the original material. The above analysis can explain that why the aluminum bat and corked bat are prohibited by Major League Baseball

MULTISTAGE ROCKET FLIGHT SIMULATION

2019 ◽  
pp. 105-107
Author(s):  
A. S. Busygin ◽  
А. V. Shumov
Keyword(s):  
State Vector ◽  
Center Of Mass ◽  
Flight Simulation ◽  
Continuous Change ◽  
Information Tools ◽  
The Earth ◽  
Proposed Model ◽  
Piecewise Continuous ◽  
The Moment ◽  
Simulated Object

The paper considers a method for simulating the flight of a multistage rocket in Matlab using Simulink software for control and guidance. The model takes into account the anisotropy of the gravity of the Earth, changes in the pressure and density of the atmosphere, piecewise continuous change of the center of mass and the moment of inertia of the rocket during the flight. Also, the proposed model allows you to work out various targeting options using both onboard and ground‑based information tools, to load information from the ground‑based radar, with imitation of «non‑ideality» of incoming target designations as a result of changes in the accuracy of determining coordinates and speeds, as well as signal fluctuations. It is stipulated that the design is variable not only by the number of steps, but also by their types. The calculations are implemented in a matrix form, which allows parallel operations in each step of processing a multidimensional state vector of the simulated object.

scholarly journals Modeling, comparison and evaluation of one-DOF six-bar bioinspired jumping leg mechanisms

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199295
Author(s):  
Ziqiang Zhang ◽  
Qi Yang ◽  
Xingkun Liu ◽  
Chuanzhong Zhang ◽  
Jinnong Liao
Keyword(s):  
Center Of Mass ◽  
Principal Component ◽  
Analysis Method ◽  
Index Distribution ◽  
Inertial Moment ◽  
Structure Index ◽  
Mean And Variance ◽  
Research Objects ◽  
Leg Mechanisms ◽  
Selection Of

One degree-of-freedom (DOF) jumping leg has the advantages of simple control and high stiffness, and it has been widely used in bioinspired jumping robots. Compared with four-bar jumping leg, six-bar jumping leg mechanism can make the robot achieve more abundant motion rules. However, the differences among different configurations have not been analyzed, and the choice of configurations lacks basis. In this study, five Watt-type six-bar jumping leg mechanisms were selected as research objects according to the different selection of equivalent tibia, femur and trunk link, and a method for determining the dimension of the jumping leg was proposed based on the movement law of jumping leg of locust in take-off phase. On this basis, kinematics indices (sensitivity of take-off direction angle and trunk attitude angle), dynamics indices (velocity loss, acceleration fluctuation, and mean and variance of total inertial moment) and structure index (distribution of center of mass) were established, and the differences of different configurations were compared and analyzed in detail. Finally, according to the principal component analysis method, the optimal selection method for different configurations was proposed. This study provides a reference for the design of one DOF bioinspired mechanism.

DIFFERENTIAL EQUATIONS FOR TRAIN STARTING WITH ELASTIC CONNECTIONS

2021 ◽  
Vol 2 ◽  
pp. 18-26
Author(s):  
I.P. POPOV
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Friction Force ◽  
Static Friction ◽  
Longitudinal Vibrations ◽  
Maximum Tension ◽  
Inert Mass ◽  
The Moment ◽  
Elastic Couplings ◽  
Selection Of

The starting mode for the train is the most difficult. An effective method of pulling is the selection of coupling clearances. In this case, the cars are set in motion sequentially and the inert mass, as well as the static friction force immediately at the moment of starting, are minimal. This method has two significant drawbacks - a small fixed value of the gaps in the couplings and the shock nature of the impulse transfer. These disadvantages can be avoided by using elastically deformable couplings. The aim of this work is to construct a mathematical model of "easy" starting of a train with elastic couplings. The softening of the train start-off mode is essentially due to the replacement of the simultaneous start-off of the sections with alternate ones. To exclude longitudinal vibrations of the composition, after reaching the maximum tension of the coupling, the possibility of its harmonic compression should be mechanically blocked.

Efficient Treatment of Gyroscopic Bodies in the Recursive Solution of Multibody Dynamics Equations

2008 ◽  
Vol 3 (4) ◽  
Author(s):  
Martin M. Tong
Keyword(s):  
Center Of Mass ◽  
Solution Process ◽  
Body System ◽  
Efficient Treatment ◽  
Composite Body ◽  
Recursive Solution ◽  
System A ◽  
Principal Axes ◽  
Solution Methods ◽  
The Moment

This paper presents an efficient treatment of gyroscopic bodies in the recursive solution of the dynamics of an N-body system. The bodies of interest include the reaction wheels in satellites, wheels on a car, and flywheels in machines. More specifically, these bodies have diagonal inertia tensors. They spin about one of its principal axes, with the moment of inertia along the transverse axes identical. Their center of mass lies on the spin axis. Current recursive solution methods treat these bodies identically as any other body in the system. The proposition here is that a body with gyroscopic children can be collectively treated as a composite body in the recursive solution process. It will be shown that this proposition improves the recursive solution speed to the order(N−m) where m is the number of gyroscopic bodies in the system. A satellite with three reaction wheels is used to illustrate the proposition.

Influences of Diaphragm Springs on Operation Performances of Sight-Stabilizing Mechanism

2011 ◽  
Vol 211-212 ◽  
pp. 384-388
Author(s):  
Gui Mei Guo ◽  
Lin Hong
Keyword(s):  
Rigid Body ◽  
Structural Parameters ◽  
Angular Displacement ◽  
Kinematics And Dynamics ◽  
Analysis Method ◽  
Structure Form ◽  
Simulation Results ◽  
Fix Point ◽  
The Moment

Sight-stabilizing mechanisms controlled by diaphragm springs and other damping elements is an important subordinate system of airborne sight stabilizing System. The performances of sight-stabilizing system depend on the characteristics of kinematics and dynamics of the system in a great extent. Among various external moments acting on the rod of the manipulator, such as those moments caused by damper, positioning spring, and restoration spring, the forces by diaphragm springs are most obvious. According to the structure form and motion peculiarity, the rod can be equivalent to a rigid body turning around a fix point. Simulation results reveal that the moment of the restoration spring to the rod is proportional to the angular displacement, and that the moment is the most prominent factor influencing the operating performances among all these moments. Through reasonable adjustments of structural parameters of the restoration spring, the performances of the sight-stabilizing system can be improved greatly; the analysis method provides a basis for guiding the design of concerned structural parameters of sight-stabilizing system.

A distributional theory for asymptotic expansions

1990 ◽  
Vol 428 (1875) ◽  
pp. 399-430 ◽  
Keyword(s):  
Asymptotic Expansions ◽  
Asymptotic Series ◽  
Generalized Functions ◽  
The Moment ◽  
The One ◽  
Topological Tensor Products ◽  
Multidimensional Integrals ◽  
Vector Valued ◽  
Selection Of ◽  
Mathematics And Physics

We present various techniques for the asymptotic expansions of generalized functions. We show that the moment asymptotic expansions hold for a very wide variety of kernels such as generalized functions of rapid decay and rapid oscillations. We do not use Mellin transform techniques as done by previous authors in the field. Instead, we introduce a direct approach that not only solves the one-dimensional problems but also applies to various multidimensional integrals and oscillatory kernels as well. This approach also helps in the development of various asymptotic series arising in diverse fields of mathematics and physics. We find that the asymptotic expansions of generalized functions depend on the selection of suitable spaces of test functions. Accordingly, we have exercised special care in classifying the spaces and the distributions defined on them. Furthermore, we use the theory of topological tensor products to obtain the expansions of vector-valued distributions. We present several examples to illustrate that many classical results follow in a simple manner. For instance, we derive from our results the asymptotic expansions of certain series considered by Ramanujan.

scholarly journals IMPORTANCE OF CLASSICAL MORPHOLOGY IN THE DIAGNOSIS OF MYELODYSPLASTIC SYNDROME

2015 ◽  
Vol 7 ◽  
pp. e2015035 ◽  
Author(s):  
Rosangela Invernizzi ◽  
Federica Quaglia ◽  
Matteo Giovanni Della Porta
Keyword(s):  
Molecular Techniques ◽  
Classification Systems ◽  
World Health ◽  
Hematopoietic Stem ◽  
Morphological Alterations ◽  
Diagnosis And Classification ◽  
The Moment ◽  
Health Organization ◽  
Selection Of

Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders characterized by dysplastic, ineffective, clonal and neoplastic hematopoiesis. MDS represent a complex hematological problem: differences in disease presentation, progression and outcome  have necessitated the use of classification systems to improve diagnosis, prognostication and treatment selection. However, since a single biological or genetic reliable diagnostic marker has not yet been discovered for MDS, quantitative and qualitative dysplastic morphological alterations of bone marrow precursors and of peripheral blood cells are still fundamental for diagnostic classification. In this paper World Health Organization (WHO) classification refinements and current minimal diagnostic criteria proposed by expert panels are highlighted and related problematic issues are discussed. The recommendations should facilitate diagnostic and prognostic evaluations in MDS and selection of patients for new effective targeted therapies. Although in the future morphology should be supplemented with new molecular techniques, the morphological approach, at least for the moment, is still the cornerstone for the diagnosis and classification of these disorders.

Volume change of the ocular lens during accommodation

2007 ◽  
Vol 293 (2) ◽  
pp. C797-C804 ◽  
Author(s):  
R. Gerometta ◽  
A. C. Zamudio ◽  
D. P. Escobar ◽  
O. A. Candia
Keyword(s):  
Structural Parameters ◽  
Center Of Mass ◽  
Physiological Solution ◽  
Volume Determination ◽  
Cross Sectional ◽  
Lens Fibers ◽  
Human Lenses ◽  
Lens Surface ◽  
Shape Changes ◽  
Anterior Posterior

During accommodation, mammalian lenses change shape from a rounder configuration (near focusing) to a flatter one (distance focusing). Thus the lens must have the capacity to change its volume, capsular surface area, or both. Because lens topology is similar to a torus, we developed an approach that allows volume determination from the lens cross-sectional area (CSA). The CSA was obtained from photographs taken perpendicularly to the lenticular anterior-posterior (A-P) axis and computed with software. We calculated the volume of isolated bovine lenses in conditions simulating accommodation by forcing shape changes with a custom-built stretching device in which the ciliary body-zonulae-lens complex (CB-Z-L) was placed. Two measurements were taken (CSA and center of mass) to calculate volume. Mechanically stretching the CB-Z-L increased the equatorial length and decreased the A-P length, CSA, and lens volume. The control parameters were restored when the lenses were stretched and relaxed in an aqueous physiological solution, but not when submerged in oil, a condition with which fluid leaves the lens and does not reenter. This suggests that changes in lens CSA previously observed in humans could have resulted from fluid movement out of the lens. Thus accommodation may involve changes not only in capsular surface but also in volume. Furthermore, we calculated theoretical volume changes during accommodation in models of human lenses using published structural parameters. In conclusion, we suggest that impediments to fluid flow between the aquaporin-rich lens fibers and the lens surface could contribute to the aging-related loss of accommodative power.

scholarly journals Review of the Literature on Latin America in Ketab-e-Jom’eh

2019 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Jom’ehToloo Riazi
Keyword(s):  
Latin American ◽  
Historical Context ◽  
Influential Factors ◽  
Review Of The Literature ◽  
Literature And Society ◽  
Revolutionary Movements ◽  
The Moment ◽  
Interpretative Approach ◽  
Symbolic Approach ◽  
Selection Of

This paper aims to analyze a weekly magazine called Ketab-e-Jom’eh (Friday’s Book) and the reflection of Latin American’s revolutionary movements in it. Ketab-e-Jom’eh, published from July 26, 1979, to May 22, 1980, was supervised by a number of the most legendary Iranian authors and poets, such as Ahmad Shamloo1 and Gholam Hossein Saedi. I focus on the way a particular perspective on Latin American movements is constructed and perpetuated among Ketab-e-Jom’eh’s lectors. With a symbolic approach, I analyze those texts through their symbolic representation in the Iranian society, which requires me to study those symbols and their concomitant relevance in Iran. Eventually, I will use an interpretative approach to examine this magazine’s ideologically motivated articles in the broader context of the Iranian society with its particular traits. The dialectic relationship between literature and society helps us understand literature as the product of social conditions and influential factors in society. The position that I develop here echoes Louis de Bonald’s belief that “through a careful reading of any nation’s literature ‘one could tell what this people had been’” (as cited in Hall, 1979, p. 13). I employ such an expansive horizon to scrutinize the selection of literature on Latin American guerillas. I shall unfold the magazine’s ideological orientation from the angle of the context in which it is used. I aim to show that the historical context of the Iranian society at the moment gives those articles specific meanings. In pursuit of my goals, I will recontextualize the articles to determine their primary significance in the Iran of the 1970s and 1980s.

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