scholarly journals Generalized Singularity Analysis of Snake-Like Robot

2018 ◽  
Vol 8 (10) ◽  
pp. 1873 ◽  
Author(s):  
Shunsuke Nansai ◽  
Masami Iwase ◽  
Hiroshi Itoh
Keyword(s):  
Singularity Analysis ◽  
Common Point ◽  
Analysis Method ◽  
Link Length ◽  
New Model ◽  
Singular Configurations ◽  
Singular Configuration ◽  
The One

The purpose of this paper is to elucidate a generalized singularity analysis of a snake-like robot. The generalized analysis is denoted as analysis of singularity of a model which defines all designable parameters such as the link length and/or the position of the passive wheel as arbitrary variables. The denotation is a key point for a novelty of this study. This paper addresses the above new model denotation, while previous studies have defined the designable parameters as unique one. This difference makes the singularity analysis difficult substantively. To overcome this issue, an analysis method using redundancy of the snake-like robot is proposed. The proposed method contributes to simplify singularity analysis concerned with the designable parameters. The singular configurations of both the model including side-slipping and the one with non side-slipping are analyzed. As the results of the analysis, we show two contributions. The first contribution is that a singular configuration depends on designable parameters such as link length as well as state values such as relative angles. The second contribution is that the singular configuration is characterized by the axials of the passive wheels of all non side-slipping link. This paper proves that the singular configuration is identified as following two conditions even if the designable parameters are chosen as different variables and the model includes side-slipping link. One is that the axials of passive wheels of all non side-slipping links intersect at a common point. Another one is that axials of passive wheels of all non side-slipping links are parallel.

Singularity Analysis of Serial Robot-Manipulators

1996 ◽  
Vol 118 (4) ◽  
pp. 520-525 ◽  
Author(s):  
A. Karger
Keyword(s):  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Singularity Analysis ◽  
Singular Set ◽  
Singular Configurations ◽  
Special Cases ◽  
Serial Robot ◽  
Singular Configuration ◽  
Actual Configuration

This paper is devoted to the description of the set of all singular configurations of serial robot-manipulators. For 6 degrees of freedom serial robot-manipulators we have developed a theory which allows to describe higher order singularities. By using Lie algebra properties of the screw space we give an algorithm, which determines the degree of a singularity from the knowledge of the actual configuration of axes of the robot-manipulator only. The local shape of the singular set in a neighbourhood of a singular configuration can be determined as well. We also solve the problem of escapement from a singular configuration. For serial robot-manipulators with the number of degrees of freedom different from six we show that up to certain exceptions singular configurations can be avoided by a small change of the motion of the end-effector. We also give an algorithm which allows to determine equations of the singular set for any serial robot-manipulator. We discuss some special cases and give examples of singular sets including PUMA 560.

A New Approach for Singularity Analysis and Closeness Measurement to Singularities of Parallel Manipulators

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Xin-Jun Liu ◽  
Chao Wu ◽  
Jinsong Wang
Keyword(s):  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Challenging Problem ◽  
Performance Indices ◽  
New Approach ◽  
Singular Configurations ◽  
Different Types ◽  
Force Transmissibility ◽  
Singular Configuration

Singularity analysis is one of the most important issues in the field of parallel manipulators. An approach for singularity analysis should be able to not only identify all possible singularities but also explain their physical meanings. Since a parallel manipulator is always out of control at a singularity and its neighborhood, it should work far from singular configurations. However, how to measure the closeness between a pose and a singular configuration is still a challenging problem. This paper presents a new approach for singularity analysis of parallel manipulators by taking into account motion/force transmissibility. Several performance indices are introduced to measure the closeness to singularities. By using these indices, a uniform “metric” can be found to represent the closeness to singularities for different types of nonredundant parallel manipulators.

Singularity Analysis of 3-DOF Planar Parallel Mechanisms via Screw Theory

2003 ◽  
Vol 125 (3) ◽  
pp. 573-581 ◽  
Author(s):  
Ilian A. Bonev ◽  
Dimiter Zlatanov ◽  
Cle´ment M. Gosselin
Keyword(s):  
Screw Theory ◽  
Singularity Analysis ◽  
Point Of View ◽  
Mobile Platform ◽  
Parallel Mechanisms ◽  
Singular Configurations ◽  
Revolute Joints ◽  
Singular Configuration

This paper presents the results of a detailed study of the singular configurations of 3-DOF planar parallel mechanisms with three identical legs. Only prismatic and revolute joints are considered. From the point of view of singularity analysis, there are ten different architectures. All of them are examined in a compact and systematic manner using planar screw theory. The nature of each possible singular configuration is discussed and the singularity loci for a constant orientation of the mobile platform are obtained. For some architectures, simplified designs with easy to determine singularities are identified.

scholarly journals Sensitivity Analysis of the Orthoglide: A Three-DOF Translational Parallel Kinematic Machine

2005 ◽  
Vol 128 (2) ◽  
pp. 392-402 ◽  
Author(s):  
Stéphane Caro ◽  
Philippe Wenger ◽  
Fouad Bennis ◽  
Damien Chablat
Keyword(s):  
Design Parameters ◽  
Analysis Method ◽  
Parallel Kinematic Machine ◽  
Vector Method ◽  
End Effector ◽  
Singular Configurations ◽  
Parallel Kinematic ◽  
Position And Orientation ◽  
The One ◽  
Three Degree Of Freedom

In this paper, two complementary methods are introduced to analyze the sensitivity of a three-degree-of-freedom (3-DOF) translational parallel kinematic machine (PKM) with orthogonal linear joints: the Orthoglide. Although these methods are applied to a particular PKM, they can be readily applied to 3-DOF Delta-Linear PKM such as ones with their linear joints parallel instead of orthogonal. On the one hand, a linkage kinematic analysis method is proposed to have a rough idea of the influence of the length variations of the manipulator on the location of its end-effector. On the other hand, a differential vector method is used to study the influence of the length and angular variations in the parts of the manipulator on the position and orientation of its end-effector. Besides, this method takes into account the variations in the parallelograms. It turns out that variations in the design parameters of the same type from one leg to another have the same effect on the position of the end-effector. Moreover, the sensitivity of its pose to geometric variations is a minimum in the kinematic isotropic configuration of the manipulator. On the contrary, this sensitivity approaches its maximum close to the kinematic singular configurations of the manipulator.

Singularity analysis and avoidance of a planar parallel mechanism with kinematic redundancy under a fixed orientation

2020 ◽  
pp. 095440622097671
Author(s):  
Haibo Qu ◽  
Lanqing Hu ◽  
Sheng Guo
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Singularity Analysis ◽  
Kinematic Redundancy ◽  
Comparison Analysis ◽  
Singularity Avoidance ◽  
Singular Configurations ◽  
Fixed Orientation ◽  
Free Transition ◽  
Singular Configuration

In this paper, the singularity of a planar mechanism with kinematic redundancy is studied. First, the architecture of the mechanism and the concept schematic diagram for singularity avoidance are stated. Next, inverse kinematics model of the planar parallel mechanism with kinematic redundancy is established. For determining the unique inverse solution of the mechanism under certain initial installation configuration, a comparison analysis based on the strategy tree and the virtual prototype is performed. Then, based on the obtained Jacobian matrices and the singular condition, the workspace-singularity map and two singular configurations of the mechanism are drawn. Finally, with the obtained workspace-singularity map, a singularity-free transition layer and an aisle can be found to perform to singularity avoidance, even if the initial designed trajectory passing through the second kind of singularity. Three tasks are carried out to illustrate that the workspace boundary and singular configuration can be changed by adjusting the kinematic redundant actuated parameter.

Singular Configuration and Workspace of a Parallel Manipulator With New Architecture

2000 ◽  
Author(s):  
Abbas Fattah ◽  
Mojtaba Oghbaei
Keyword(s):  
Parallel Manipulator ◽  
Singularity Analysis ◽  
Kinematic Constraint ◽  
Constraint Equations ◽  
Singular Configurations ◽  
Input And Output ◽  
Points Of View ◽  
Singular Configuration

Abstract In this paper singularity analysis and workspace of a 3DOF parallel manipulator with new architecture are studied. Singular configurations of the manipulator at hand are analysed first. To this end, upon differentiating the kinematic constraint equations of the manipulator with respect to time, the relation between input and output speeds is obtained in terms of two kinds of Jacobians. These two Jacobians are then used to determine singular configurations. Next the workspace of the manipulator is studied from two points of view.

Getting Over Athens

2018 ◽  
Author(s):  
Nicolas Wiater
Keyword(s):  
Roman Empire ◽  
The Other ◽  
The Political ◽  
New Model ◽  
Dionysius Of Halicarnassus ◽  
The One

This chapter examines the ambivalent image of Classical Athens in Dionysius of Halicarnassus’ Roman Antiquities. This image reflects a deep-seated ambiguity of Dionysius’ Classicist ideology: on the one hand, there is no question for Dionysius that Athenocentric Hellenicity failed, and that the Roman empire has superseded Athens’ role once and for all as the political and cultural centre of the oikoumene. On the other, Dionysius accepted Rome’s supremacy as legitimate partly because he believed (and wanted his readers to believe) her to be the legitimate heir of Classical Athens and Classical Athenian civic ideology. As a result, Dionysius develops a new model of Hellenicity for Roman Greeks loyal to the new political and cultural centre of Rome. This new model of Greek identity incorporates and builds on Classical Athenian ideals, institutions, and culture, but also supersedes them.

Cycles in symbol production? A new model to explain concentration, diversity and innovation in the music industry

Popular Music ◽  
1995 ◽  
Vol 14 (1) ◽  
pp. 55-93 ◽  
Author(s):  
Michael Christianen
Keyword(s):  
Negative Correlation ◽  
Music Industry ◽  
The Other ◽  
Recording Industry ◽  
Cultural Goods ◽  
New Model ◽  
Advantages And Disadvantages ◽  
Factors Influencing ◽  
Using Data ◽  
The One

With the publication of the article ‘Cycles in symbol production’ (Peterson and Berger 1975) a discussion started concerning the advantages and disadvantages of the production of cultural goods under market conditions. The analysis by Peterson and Berger showed a negative correlation between concentration in the recording industry, on the one hand, and the diversity and innovativeness of the music, on the other. Repetition of the analysis using data from the 1980s (Burnett 1990; Lopes 1992) has shown that for this period Peterson and Berger's hypotheses should be rejected. Is there a connection between concentration and diversity and innovation? Are there cycles in symbol production? There seems to be no conclusive answer. In this article, I will attempt to clear up this matter. First, I will repeat the analysis of the relation between concentration and diversity/innovation, using the same model as Peterson and Berger, but with different definitions for the variables concentration, diversity and innovation. Then I will suggest a new model, which can be helpful in uncovering other factors influencing diversity and innovation in the music industry. I will come to that later. Let me first give the reader a brief overview of previous research.

scholarly journals A New Model Approach for Convective Wall Heat Losses in DQMOM-IEM Simulations for Turbulent Reactive Flows

2018 ◽  
Vol 141 (5) ◽  
Author(s):  
Yeshaswini Emmi ◽  
Andreas Fiolitakis ◽  
Manfred Aigner ◽  
Franklin Genin ◽  
Khawar Syed
Keyword(s):  
Experimental Data ◽  
Heat Losses ◽  
Reacting Flow ◽  
Jet Flame ◽  
New Model ◽  
Turbulent Reactive Flows ◽  
Novel Method ◽  
The One ◽  
The Impact ◽  
Model Approach

A new model approach is presented in this work for including convective wall heat losses in the direct quadrature method of moments (DQMoM) approach, which is used here to solve the transport equation of the one-point, one-time joint thermochemical probability density function (PDF). This is of particular interest in the context of designing industrial combustors, where wall heat losses play a crucial role. In the present work, the novel method is derived for the first time and validated against experimental data for the thermal entrance region of a pipe. The impact of varying model-specific boundary conditions is analyzed. It is then used to simulate the turbulent reacting flow of a confined methane jet flame. The simulations are carried out using the DLR in-house computational fluid dynamics code THETA. It is found that the DQMoM approach presented here agrees well with the experimental data and ratifies the use of the new convective wall heat losses model.

scholarly journals KAJIAN MAKNA: MIHRAB MASJID KONTEMPORER AL-IRSYAD KOTA BARU PARAHYANGAN

2018 ◽  
Vol 1 (2) ◽  
pp. 292
Author(s):  
RYANTY DERWENTYANA NAZHAR
Keyword(s):  
Religious Beliefs ◽  
Analysis Method ◽  
Religious Ideology ◽  
Sign Structure ◽  
The One ◽  
Meaning Analysis

Al-Irsyad mosque at Kota Baru Parahyangan is a religious building that has the power of narrative and full of meaning. The elements of interior and exterior are designed by the architect to deliver messages to users. One element of the interior which is the orientation for the user is the Mihrab. Mihrab of this mosque has a unique concept of shape and philosophy. The concept can contain messages that can even up on the ideology that is intended for users who use the facility, and when elements of the space is interpreted (signified), then it becomes a sign (sign). Meaning analysis method that is used is combined with analysis of the typology of signs and sign structure, that will produce a more powerful meaning of the sign. Mihrab Al-Irsyad mosque is one part of a whole section of the mosque, but its role is very important for conveying message, especially message that regarding religious ideology, which is expressed in symbols. Mihrab Al-Irsyad Kota Baru Parahyangan try to use elements of the space as a mark to describe the expression "Quranic", so that each element is applied within the mihrab has a meaning derived from the meaning that comes from the verses of the Qur'an as a source of knowledge for the Islam follower. Expression of space that is designed solely to strengthen the religious beliefs of the congregation of the mosque on infinity, the one, and the greatness of God. Keywords: mihrab; mosque; semiotic; sign

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