Determination of the Instantaneous Pole Axes in Single-DOF Spherical Mechanisms

2008 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
A Algorithm ◽  
Planar Mechanisms ◽  
Spherical Mechanisms ◽  
Kinematic Behavior ◽  
General Method

In spherical mechanisms, the instantaneous pole axes play the same role as the instant centers in planar mechanisms. Notwithstanding this, they are not fully exploited to study the kinematic behavior of spherical mechanisms as the instant centers are for planar mechanisms. The first step to make their use possible and friendly is the availability of efficient techniques to determine them. This paper presents a general method to determine the instantaneous pole axes in single-dof spherical mechanisms as a function of the mechanism configuration. The presented method is directly deduced from a algorithm already proposed by the author for the determination of the instant centers in single-dof planar mechanisms.

A general algorithm for analytically determining all the instantaneous pole axis locations in single-DOF spherical mechanisms

2011 ◽  
Vol 225 (9) ◽  
pp. 2062-2075 ◽  
Author(s):  
R Di Gregorio
Keyword(s):  
Degree Of Freedom ◽  
General Algorithm ◽  
Planar Mechanisms ◽  
Spherical Mechanisms ◽  
Kinematic Analyses ◽  
General Method

In spherical mechanisms (SMs), instantaneous pole axes (IPAs) play the same role as instant centres in planar mechanisms. Their use in kinematic analyses requires general techniques to determine them. In the literature, such techniques have not been proposed yet. That is why they are not used for studying the kinematics of SMs in all the problems whose planar counterparts are efficiently solved by exploiting instant centres’ properties. This article aims to fill this lack of techniques. For SMs with one degree of freedom (DOF), a general method to analytically locate all the IPAs as a function of the mechanism configuration is presented. The presented method is directly deduced from an algorithm already proposed by the author for the determination of the instant centres in single-DOF planar mechanisms.

Singularities of Single-DOF Spherical Mechanisms Identified by Means of Pole Axes’ Properties

2010 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Singularity Analysis ◽  
Systems Of Equations ◽  
Planar Mechanisms ◽  
Planar Mechanism ◽  
Geometric Conditions ◽  
Spherical Mechanisms ◽  
Spherical Mechanism ◽  
General Method

Instantaneous pole axes (IPAs) play, in spherical-mechanism kinematics, the same role as instant centers in planar-mechanism kinematics. IPA-based techniques have not been proposed yet for the singularity analysis of spherical mechanisms, even though instant-center-based algorithms have been already presented for planar mechanisms’ singularity analysis. This paper addresses the singularity analysis of single-dof spherical mechanisms by exploiting the properties of pole axes. A general method for implementing this analysis is presented. The presented method relies on the possibility of giving geometric conditions for any type of singularity, and it is the spherical counterpart of an instant-center-based algorithm previously proposed by the author for single-dof planar mechanisms. It can be used to generate systems of equations useful either for finding the singularities of a given mechanism or to synthesize mechanisms that have to match specific requirements about the singularities.

MANUFACTURE INVESTIGATION OF CARTRIDGE WITH BOTTOM-MOST PART FLANGE BY DIRECT EXTRUSION WITH COUNTERPUNCH. REPORT 13. DETERMINATION OF DEFORMED STATE UNDER STRAITENED EXTRUSION IN FOURTH CENTRAL AREA OF PLASTIC DEFORMATION

2020 ◽  
Vol 0 (4) ◽  
pp. 43-51
Author(s):  
A. L. Vorontsov ◽  
◽  
I. A. Nikiforov ◽  
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Central Area ◽  
Direct Extrusion ◽  
Deformed State ◽  
Cumulative Deformation ◽  
The Given ◽  
General Method

Formulae have been obtained that are necessary to calculate cumulative deformation in the process of straitened extrusion in the central area closed to the working end of the counterpunch. The general method of plastic flow proposed by A. L. Vorontsov was used. The obtained formulae allow one to determine the deformed state of a billet in any point of the given area. The formulae should be used to take into account the strengthening of the extruded material.

Solving the Kinematics of Planar Mechanisms

1998 ◽  
Author(s):  
Charles W. Wampler
Keyword(s):  
Eigenvalue Problem ◽  
Complex Plane ◽  
System Of Equations ◽  
Polynomial Equations ◽  
Input Output ◽  
Planar Mechanisms ◽  
General Method

Abstract This paper presents a general method for the analysis of planar mechanisms consisting of rigid links connected by rotational and/or translational joints. After describing the links as vectors in the complex plane, a simple recipe is outlined for formulating a set of polynomial equations which determine the locations of the links when the mechanism is assembled. It is then shown how to reduce this system of equations to a standard eigenvalue problem, or if preferred, a single resultant polynomial. Both input/output problems and tracing-curve equations are treated.

A New Method and Automatic Generation for Dynamic Analysis of Complex Planar Mechanisms Based on the Ordered Single-Opened-Chains

1994 ◽  
Author(s):  
Jian-Qing Zhang ◽  
Ting-Li Yang
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Equation ◽  
Automatic Generation ◽  
The Other ◽  
New Method ◽  
Complex Mechanism ◽  
Planar Mechanisms ◽  
Spatial Mechanisms ◽  
General Dynamic

Abstract This work presents a new method for kinetostatic analysis and dynamic analysis of complex planar mechanisms, i.e. the ordered single-opened-chains method. This method makes use of the ordered single-opened chains (in short, SOC,) along with the properties of SOC, and the network constraints relationship between SOC,. By this method, any planar complex mechanism can be automatically decomposed into a series of the ordered single-opened chains and the optimal structural decomposition route (s) can be automatically selected for dynamic analysis, the paper present the dynamic equation which can be used to solve both the kinetostatic problem and the general dynamic problem. The main advantage of the proposed approach is the possibility to reduce the number of equations to be solved simultaneously to the minimum, and its high automation as well. The other advantage is the simplification of the determination of the coefficients in the equations, and thus it maybe result in a much less time-consuming algorthem. The proposed approach is illustrated with three examples. The presented method can be easily extended to the dynamic analysis of spatial mechanisms.

Model Verification of Mixed Dynamic Systems

1978 ◽  
Vol 100 (2) ◽  
pp. 266-273 ◽  
Author(s):  
J. D. Chrostowski ◽  
D. A. Evensen ◽  
T. K. Hasselman
Keyword(s):  
Experimental Data ◽  
Parameter Estimation ◽  
Dynamic Systems ◽  
Statistical Parameter ◽  
Model Verification ◽  
Passive Networks ◽  
Parameter Values ◽  
Basic Configuration ◽  
General Method

A general method is presented for using experimental data to verify math models of “mixed” dynamic systems. The term “mixed” is used to suggest applicability to combined systems which may include interactive mechanical, hydraulic, electrical, and conceivably other types of components. Automatic matrix generating procedures are employed to facilitate the modeling of passive networks (e.g., hydraulic, electrical). These procedures are augmented by direct matrix input which can be used to complement the network model. The problem of model verification is treated in two parts; verification of the basic configuration of the model and determination of the parameter values associated with that configuration are addressed sequentially. Statistical parameter estimation is employed to identify selected parameter values, recognizing varying degrees of uncertainty with regard to both experimental data and analytical results. An example problem, involving a coupled hydraulic-mechanical system, is included to demonstrate application of the method.

The Role of Improved K-Means Clustering Algorithm in the Motion Parameters Determination of Breaker's Moving Contact

2014 ◽  
Vol 960-961 ◽  
pp. 905-909
Author(s):  
Yu Tao Xu ◽  
Shu Tao Zhao ◽  
Dan Jiang ◽  
Jian Feng Ren
Keyword(s):  
Clustering Algorithm ◽  
Circuit Breaker ◽  
A Algorithm ◽  
Use Of Time ◽  
Moving Contact ◽  
Center Point ◽  
Movement Distance ◽  
Motion Parameters

High voltage circuit breaker's motion parameters of the moving contact is one of the key performance indicators in the evaluated of breaker. By means of extracting color features of LW10B-252 circuit breaker by image segmentation, then determining its center point of the minimum circumscribed rectangle, getting the movement distance of center point and the use of time in adjacent images, realization motion parameter's measurement of the moving contact. This paper presents a algorithm based on improved k-means clustering algorithm to extract the color characteristics of the mechanical linkage of breaker, at the same time contrast with classical OTSU method and RGB color segmentation method. Experimental results show that the k-means clustering algorithm have a better segmentation result.

Modal Velocity-Based Multiaxial Fatigue Damage Evaluation Using Simplified Finite Element Models

2020 ◽  
Vol 87 (11) ◽  
Author(s):  
Kurthan Kersch ◽  
Elmar Woschke
Keyword(s):  
Finite Element ◽  
Fatigue Damage ◽  
Cross Section ◽  
Multiaxial Fatigue ◽  
Finite Element Models ◽  
Damage Evaluation ◽  
Geometric Factors ◽  
The Relationship ◽  
General Method

Abstract This work proposes a new method for the fatigue damage evaluation of vibrational loads, based on preceding investigations on the relationship between stresses and modal velocities. As a first step, the influence of the geometry on the particular relationship is studied. Therefore, an analytic expression for Euler Bernoulli beams with a non-constant cross section is derived. Afterward, a general method for obtaining geometric factors from finite element (FE) models is proposed. In order to ensure a fast fatigue damage evaluation, strongly simplified FE-models are used for the determination of both factors and measurement locations. The entire method is demonstrated on three mechanical structures and indicates a better compromise between effort and accuracy than existing methods. For all examples, the usage of velocities and geometric factors obtained from simplified FE models enables a sufficient fatigue damage calculation.

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