scholarly journals Recursive Dynamic Algorithm of Open-Chain Multibody System

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Ming Lu ◽  
Wenbin Gu ◽  
Jianqing Liu ◽  
Zhenxiong Wang ◽  
Zhisheng Jing ◽  
...  
Keyword(s):  
Multibody Systems ◽  
Multibody System ◽  
Structural Characteristics ◽  
Open Chain ◽  
Widespread Application ◽  
Dynamic Algorithm ◽  
Generalized Coordinates ◽  
The Relationship ◽  
Kane Method ◽  
Partial Velocity

Open-chain multibody systems have been extensively studied because of their widespread application. Based on the structural characteristics of such a system, the relationship between its hinged bodies was transformed into recursive constraint relationships among the position, velocity, and acceleration of the bodies. The recursive relationships were used along with the Huston-Kane method to select the appropriate generalized coordinates and determine the partial velocity of each body and to develop an algorithm of the entire system. The algorithm was experimentally validated; it has concise steps and low susceptibility to error. Further, the algorithm can readily solve and analyze open-chain multibody systems.

Inverse Dynamics of Constrained Multibody Systems

1990 ◽  
Vol 57 (3) ◽  
pp. 750-757 ◽  
Author(s):  
J. T. Wang
Keyword(s):  
Multibody Systems ◽  
Inverse Dynamics ◽  
Multibody System ◽  
Coefficient Matrix ◽  
Force Term ◽  
Constraint Forces ◽  
Kinematic Constraints ◽  
Constrained Multibody Systems ◽  
Orthogonal Complement Matrix ◽  
Partial Velocity

A method for analyzing constrained multibody systems is presented. The method is applicable to a class of problems in which the multibody system is subjected to both force and kinematic constraints. This class of problems cannot be solved by using the classical methods. The method is based upon the concept of partial velocity and generalized forces of Kane’s method to permit the choice of constraint forces for fulfilling both kinematic and force constraints. Thus, the constraint forces or moments at convenient points or bodies may be specified in any desired form. For many applications, the method also allows analysts to choose a constant coefficient matrix for the undetermined force term to greatly reduce the burden of repeatedly computing its orthogonal complement matrix in solving the differential algebraic dynamic equations. Two examples illustrating the concepts are presented.

A Recursive Algorithm for Solving the Generalized Velocities From the Momenta of Flexible Multibody Systems

2008 ◽  
Author(s):  
Martin M. Tong
Keyword(s):  
Numerical Solution ◽  
Multibody Systems ◽  
Multibody System ◽  
Recursive Algorithm ◽  
Mass Matrix ◽  
Direct Methods ◽  
Flexible Multibody Systems ◽  
Hamiltonian Form ◽  
Generalized Coordinates ◽  
Flexible Multibody

The computation of the generalized velocities from the generalized momenta of a multibody system is a part of the numerical solution of the dynamics equations when they are given in the Hamiltonian form. The states of these equations are the generalized coordinates and momenta, (q, p). The generalized velocity, q˙, is defined by q˙ = J−1p, where J is the system mass matrix. The effort in solving q˙ by direct methods is order(N3) where N is the number of bodies in the system. This paper presents an order(N) recursive algorithm to compute q˙ for flexible multibody systems.

Dynamics of Multibody Systems With Variable Kinematic Structure

1986 ◽  
Vol 108 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Y. A. Khulief ◽  
A. A. Shabana
Keyword(s):  
Multibody Systems ◽  
Multibody System ◽  
Kinematic Structure ◽  
The Finite Element Method ◽  
Flexible Bodies ◽  
Generalized Coordinates ◽  
Structure Changes ◽  
Dynamics Of Multibody Systems ◽  
Analysis Scheme ◽  
Deformation Modes

The problem of predicting the dynamic behavior of a general multibody system subject to kinematic structure changes is addressed using a mixed set of Lagrangian coordinates. Changes in the kinematic structure may occur smoothly or accompanied by a change in the system momenta. The finite element method is employed to estimate the modal characteristics of flexible bodies. An automated pieced-interval computational scheme that accounts for the change in the dynamic characteristics due to the imposition of new sets of constraints on the boundaries of flexible components is developed. The resulting change in the deformation modes and the associated change in basis of the configuration space requires a new set of generalized coordinates for each subinterval of the analysis. A numerical example is used to demonstrate the analysis scheme developed in this paper.

Optimal Design of Lightweight Machines Using Flexible Multibody System Dynamics

2012 ◽  
Author(s):  
Robert Seifried ◽  
Alexander Held
Keyword(s):  
Energy Efficiency ◽  
Multibody Systems ◽  
Multibody System ◽  
Tracking Error ◽  
Dynamic Loads ◽  
Crucial Issue ◽  
Flexible Multibody ◽  
Dynamical Simulations ◽  
Tracking Behavior ◽  
Robotic Applications

In many machine and robotic applications energy efficiency is an increasingly crucial issue. In order to achieve energy efficiency lightweight structural designs are necessary. However, undesired elastic deformations might occur due to the light wight design. In order to achieve good system performance the actual dynamic loads must be taken into account in the design of the system’s components. In this paper optimization approaches for lightweight machine designs are employed to improve the tracking behavior the systems. Thereby, fully dynamical simulations of flexible multibody systems are coupled with both shape or topology optimization for the elastic members of the multibody system. It is shown, that by these approaches the end-effector trajectory tracking error of light wight manipulators can be decreased significantly.

Flexible Multibody Dynamics Formulation by Hamilton’s Equations

2010 ◽  
Author(s):  
Martin M. Tong
Keyword(s):  
Multibody Dynamics ◽  
Multibody System ◽  
Mass Matrix ◽  
Equations Of Motion ◽  
Flexible Multibody Dynamics ◽  
Flexible Body ◽  
Flexible Multibody System ◽  
Generalized Coordinates ◽  
Flexible Multibody ◽  
The Matrix

Numerical solution of the dynamics equations of a flexible multibody system as represented by Hamilton’s canonical equations requires that its generalized velocities q˙ be solved from the generalized momenta p. The relation between them is p = J(q)q˙, where J is the system mass matrix and q is the generalized coordinates. This paper presents the dynamics equations for a generic flexible multibody system as represented by p˙ and gives emphasis to a systematic way of constructing the matrix J for solving q˙. The mass matrix is shown to be separable into four submatrices Jrr, Jrf, Jfr and Jff relating the joint momenta and flexible body mementa to the joint coordinate rates and the flexible body deformation coordinate rates. Explicit formulas are given for these submatrices. The equations of motion presented here lend insight to the structure of the flexible multibody dynamics equations. They are also a versatile alternative to the acceleration-based dynamics equations for modeling mechanical systems.

Minimum Energy Control of Multibody Systems Utilizing Storage Elements

2009 ◽  
Author(s):  
Werner Schiehlen ◽  
Makoto Iwamura
Keyword(s):  
Multibody Systems ◽  
Optimal Trajectory ◽  
Design Method ◽  
Equations Of Motion ◽  
Minimum Energy ◽  
Operating Time ◽  
Minimum Energy Control ◽  
Robot Systems ◽  
Optimal Design Method ◽  
The Relationship

In this paper, we consider the problem to minimize the energy consumption for controlled multibody systems utilizing passive elastic elements for energy storage useful for robot systems in manufacturing. Firstly, based on the linearized equations of motion, we analyze the relationship between the consumed energy and the operating time, and the optimal trajectory using optimal control theory. Then, we verify the analytical solution by comparing with the numerical one computed considering the full nonlinear dynamics. After that we derive a condition for the operating time to be optimal, and propose the optimal design method for springs. Finally, we show the effectiveness of the design method by applying it to a 2DOF manipulator.

scholarly journals РАСПРЕДЕЛЁННАЯ ОБРАЗНОСТЬ: ИМАГИНАТИВНЫЕ ПРАКТИКИ СОВРЕМЕННОЙ КУЛЬТУРЫ

2020 ◽  
Author(s):  
Ilya Inishev
Keyword(s):  
Structural Characteristics ◽  
Point Of View ◽  
Main Theme ◽  
Contemporary Culture ◽  
Normative Claim ◽  
Political Implications ◽  
Core Feature ◽  
And Control ◽  
The Relationship ◽  
Regime Characteristic

В статье идёт речь о формах образного, которые во всё возрастающей степени становятся характерными для современной культуры. Центральная характеристика этих форм – распределённость в пространстве и времени, их способность сопровождать нас практически повсеместно, не будучи привязанными к каким-либо организационным формам. Распределённые разновидности образного противопоставляются «традиционным», нераспределённым образам, «репрезентирующим» некоторое идентифицируемое содержание. Одна из базовых черт нераспределенного образного – заключённое в нём нормативное притязание, затрагивающее не только способы его интерпретации, но и телесные практики воспринимающего «субъекта», релевантные для его восприятия. В отличие от репрессивного характера нераспределённого образа, являющегося его структурной характеристикой, связанной с характерным для него режимом восприятия, распределённая образность базируется не на редукции и контроле телесности воспринимающего, но – напротив – на интенсификации (и в этом смысле эмансипации) его эмоционально-телесного самоприсутствия. В диахронической перспективе отношение между нераспределённой и распределённой образностью опосредовано сложной социально-исторической и материально-технологической динамикой развитого и позднего модерна. Реконструкция этой динамики позволяет выстроить генетическую связь (континуальность) между нераспределённой и распределённой образностью. В синхронической перспективе распределённая и нераспределенная разновидности образности генерируют несовместимые типы опыта с взаимоисключающими структурными характеристиками и социально-политическими импликациями (дискретность).Main theme of the article are the types of imagery becoming increasingly characteristic of contemporary culture. The core feature of these types is their being distributed across time and space, their ability to accompany us virtually everywhere, without being tied to any organizational form. Distributed imagery opposes “traditional”, non-distributed images “representing” some identifiable subject-matter. One of the essential traits of non-distributed imagery is its normative claim addressing not only the ways of its interpretation but also bodily practices of the perceiving subject, relevant for experiencing images of this kind. In contrast to the inherent oppressiveness of non-distributed image connected to a perceptual regime characteristic of it, the distributed imagery draws not on reduction and control of body of the perceiving subject but – on the contrary – on intensifying (and in this sense, on emancipating) its bodily emotional self-presence. From a diachronic point of view, the relationship between distributed and non-distributed imageries is mediated by quite a complicated socio-historical and material-technological dynamic of the developed and late modernity. Reconstruction of this dynamic enables us to identify the genetic interrelation (continuity) between non-distributed and distributed imagery. From a synchronic point of view, distributed and non-distributed imagery forms generate incompatible experience types with mutually exclusive structural characteristics and social-political implications (discontinuity).

Structural Characteristics of the Sulfur Linkage in Natural Rubber Vulcanizates

1957 ◽  
Vol 30 (2) ◽  
pp. 397-405 ◽  
Author(s):  
L. C. Bateman ◽  
R. W. Glazebrook ◽  
C. G. Moore ◽  
R. W. Saville
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Mechanism ◽  
Structural Characteristics ◽  
Complex Mixture ◽  
Open Chain ◽  
Organic Bases ◽  
Zinc Salts ◽  
Natural Rubber Vulcanizates ◽  
Polar Reaction ◽  
Cyclic Sulfide

Abstract Polyisoprenes react with sulfur both intramolecuarly and intermolecularly to yield cyclic sulfides and crosslinked sulfides, respectively. The structures of these have been examined for the reaction of the di-isoprene, 2,6-dimethylocta-2,6-diene, with sulfur at 140°. The cyclic sulfides consist of the two saturated compounds (I) and (II) and the two unsaturated compounds (III) and (IV). The crosslinked sulfide consists of a complex mixture in which unsaturated open chain and saturated and unsaturated cyclic sulfide structures have been identified. The structures of these products suggest a polar reaction mechanism, and also that hydrogen sulfide participates in the reaction. The influence of organic bases, the sulfurizing agent, reaction temperature, and zinc salts on the nature of the sulfur linkage is discussed.

Flash translation layer: a review and bibliometric analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuhan Luo ◽  
Mingwei Lin
Keyword(s):  
Structural Characteristics ◽  
Development Trend ◽  
Comprehensive Analysis ◽  
Content Type ◽  
Fundamental Information ◽  
New Ideas ◽  
The Development Trend ◽  
The Relationship ◽  
Research Hotspots

PurposeThe purpose of this paper is to make an overview of 474 publications and 512 patents of FTL from 1987 to 2020 in order to provide a conclusive and comprehensive analysis for researchers in this field, as well as a preliminary knowledge of FTL for interested researchers.Design/methodology/approachFirstly, the FTL algorithms are classified and its functions are introduced in detail. Secondly, the structures of the publications are analyzed in terms of the fundamental information and the publication of the most productive countries/regions, institutions and authors. After that, co-citation networks of institutions, authors and papers illustrated by VOS Viewer are given to show the relationship among those and the most influential of them is further analyzed. Then, the characteristics of the patent are analyzed based on the basic information and classification of the patent and the most productive inventors. In order to obtain research hotspots and trends in this field, the time-line review and citation burst detection of keywords carried out by Cite Space are made to be visual. Finally, based on the above analysis, it draws some other important conclusions and the development trend of this field.FindingsThe research on FTL algorithm is still the top priority in the future, and how to improve the performance of SSD in the era of big data is one of the research hotspots.Research limitations/implicationsThis paper makes a comprehensive analysis of FTL with the method of bibliometrics, and it is valuable for researchers can quickly grasp the hotspots in this area.Originality/valueThis article draws the structural characteristics of the publications in this field and summarizes the research hotspots and trends in this field in recent years, aiming to inspire new ideas for researchers.

Dynamics Modeling of Elastic Multibody Systems Using Kane’s Method As Applied to a Flexible Robot

1997 ◽  
Author(s):  
Ali Meghdari ◽  
Farbod Fahimi
Keyword(s):  
Multibody Systems ◽  
Equations Of Motion ◽  
Component Mode Synthesis ◽  
Flexible Robot ◽  
Dynamics Modeling ◽  
Generalized Coordinates ◽  
Kane’S Method ◽  
Kane's Method ◽  
Elastic Multibody Systems ◽  
Elastic Form

Abstract Generalization of Kane’s equations of motion for elastic multibody systems is considered. Initially, finite element techniques are used to generate the elastic form of generalized coordinates. Then, the number of elastic coordinates are reduced by the component mode synthesis. Finally, Kane’s method is applied to obtain the equations of motion of such systems. Using this method, dynamic model of an elastic robot with one degree of freedom is presented.

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