A Study on the Dynamic Analysis of Flexible and Rigid Link System

1999 ◽  
Author(s):  
Naoki Sugano ◽  
Koichi Honke ◽  
Etsujiro Imanishi ◽  
Kazuo Hashimoto
Keyword(s):  
Dynamic Analysis ◽  
Geometric Nonlinearity ◽  
Rigid Bodies ◽  
Total System ◽  
Topological Information ◽  
Flexible Bodies ◽  
Link Structure ◽  
Rigid Link ◽  
Dependent Variables ◽  
Nonlinearity Effect

Abstract In this paper, the dynamic analysis of link structures including both flexible and rigid bodies is developed. The model for flexible bodies is based on FEM theory, and geometric nonlinearity effect is taken into account. Moreover, in the flexible rigid link structure, dependent variables are eliminated using topological information. The equation of the total system obtained in this study is in the form of ODE and can be solved efficiently.

Application of Euler Parameters to the Dynamic Analysis of Three-Dimensional Constrained Mechanical Systems

1982 ◽  
Vol 104 (4) ◽  
pp. 785-791 ◽  
Author(s):  
P. E. Nikravesh ◽  
I. S. Chung
Keyword(s):  
Differential Equations ◽  
Dynamic Analysis ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Influence Coefficient ◽  
Variable Order ◽  
Total System ◽  
Euler Parameters ◽  
Generalized Coordinates ◽  
Dependent Variables

This paper presents a computer-based method for formulation and efficient solution of nonlinear, constrained differential equations of motion for spatial dynamic analysis of mechanical systems. Nonlinear holonomic constraint equations and differential equations of motion are written in terms of a maximal set of Cartesian generalized coordinates, three translational and four rotational coordinates for each rigid body in the system, where the rotational coordinates are the Euler parameters. Euler parameters, in contrast to Euler angles or any other set of three rotational generalized coordinates, have no critical singular cases. The maximal set of generalized coordinates facilitates the general formulation of constraints and forcing functions. A Gaussian elimination algorithm with full pivoting decomposes the constraint Jacobian matrix, identifies dependent variables, and constructs an influence coefficient matrix relating variations in dependent and indpendent variables. This information is employed to numerically construct a reduced system of differential equations of motion whose solution yields the total system dynamic response. A numerical integration algorithm with positive-error control, employing a predictor-corrector algorithm with variable order and step size, integrates for only the independent variables, yet effectively determines dependent variables.

Dynamic Analysis of Lifting Mechanism Based on Rigid-Flexible Coupling

2013 ◽  
Vol 849 ◽  
pp. 411-416
Author(s):  
Xu Kun Ge ◽  
Da Wei Liu ◽  
Bin Tian
Keyword(s):  
Finite Element Analysis ◽  
Dynamic Analysis ◽  
Coupling Model ◽  
Rigid Bodies ◽  
Element Analysis ◽  
Flexible Coupling ◽  
Flexible Bodies ◽  
Flexible System ◽  
Lift Mechanism ◽  
Hinge Points

To obtain realistic dynamic characteristics of the lifting mechanism, the liftarm and drawbar were regarded as flexible bodies. The modal neutral file (MNF) of liftarm and drawbar were obtained from modal analysis conducted by finite element analysis (FEA) software MSC.Patran/Nastran . Then the MNF were translated into ADAMS, a rigid-flexible coupling model of the lift mechanism was built by replacing the rigid bodies with MNF. The forces of each hinge points in the rigid-flexible system, which were obtained from dynamic analysis, were compared with the rigid ones. The results showed that forces obtained from the rigid-flexible system were smaller than the rigid ones, which provided a reference for the design and improvement of the lifting mechanism.

Dynamic Analysis of Vehicle Trunk Lid with 4-Bar Link Structure

2007 ◽  
Author(s):  
Kap-Seung Choi ◽  
Sang-Ki Park ◽  
Hak-Min Wang ◽  
Yeong-Hun Jin ◽  
Chae-Wook Lim ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Link Structure

Modeling of Flexible Bodies for Dynamic Analysis of Multi-Body Dynamic Systems Using Ritz Vectors

1991 ◽  
Author(s):  
Henry T. Wu ◽  
Neel K. Mani
Keyword(s):  
Dynamic Analysis ◽  
Mechanical Systems ◽  
Normal Modes ◽  
Flexible Bodies ◽  
Static Correction ◽  
Ritz Vectors ◽  
Regeneration Procedure ◽  
Efficient Vector ◽  
Multi Body ◽  
Body Dynamic

Abstract Vibration normal modes and static correction modes have been previously used to model flexible bodies for dynamic analysis of mechanical systems. The efficiency and accuracy of using these modes to model a system depends on both the flexibility of each body and the applied loads. This paper develops a generalized method for the generation of a set of Ritz vectors to model flexible bodies for dynamic analysis of multi-body mechanical systems. The Ritz vectors are generated using the distribution of dynamic loading on a flexible body. Therefore they form the most efficient vector basis for the spatial distribution of the loadings. The Ritz vectors can be re-generated when the system undergoes significant changes of its configuration and the regeneration procedure is inexpensive. The combinations of vibration normal modes and the proposed Ritz vectors thus form more efficient and accurate vector bases for the modeling of flexible bodies for dynamic analysis.

Formulation of the Equations of Motion of RRPR Robot Manipulator

2000 ◽  
Author(s):  
Hazem Ali Attia ◽  
Tarek M. A. El-Mistikawy ◽  
Adel A. Megahed
Keyword(s):  
Dynamic Analysis ◽  
Efficient Solution ◽  
Robot Manipulator ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
Second Law ◽  
Equivalent System ◽  
Constraint Forces ◽  
Dynamic Formulation ◽  
System Of Particles

Abstract In this paper the dynamic analysis of RRPR robot manipulator is presented. The equations of motion are formulated using a two-step transformation. Initially, a dynamically equivalent system of particles that replaces the rigid bodies is constructed and then Newton’s second law is applied to derive their equations of motion. The equations of motion are then transformed to the relative joint variables. Use of both Cartesian and joint variables produces an efficient set of equations without loss of generality. For open chains, this process automatically eliminates all of the non-working constraint forces and leads to an efficient solution and integration of the equations of motion. The results of the simulation indicate the simplicity and generality of the dynamic formulation.

Recursive Method for the Dynamic Analysis of Open-Loop Flexible Multibody Systems

2003 ◽  
Author(s):  
Yunn-Lin Hwang
Keyword(s):  
Dynamic Analysis ◽  
Multibody Systems ◽  
Equations Of Motion ◽  
Open Loop ◽  
Flexible Multibody Systems ◽  
Recursive Method ◽  
Flexible Bodies ◽  
System Equations ◽  
Generalized Newton ◽  
Time Invariant

The main objective of this paper is to develop a recursive method for the dynamic analysis of open-loop flexible multibody systems. The nonlinear generalized Newton-Euler equations are used for flexible bodies that undergo large translational and rotational displacements. These equations are formulated in terms of a set of time invariant scalars, vectors and matrices that depend on the spatial coordinates as well as the assumed displacement fields, and these time invariant quantities represent the dynamic coupling between the rigid body motion and elastic deformation. The method to solve for the equations of motion for open-loop systems consisting of interconnected rigid and flexible bodies is presented in this investigation. This method applies recursive method with the generalized Newton-Euler method for flexible bodies to obtain a large, loosely coupled system equations of motion. The solution techniques used to solve for the system equations of motion can be more efficiently implemented in the vector or digital computer systems. The algorithms presented in this investigation are illustrated by using cylindrical joints that can be easily extended to revolute, slider and rigid joints. The basic recursive formulations developed in this paper are demonstrated by two numerical examples.

The Mobility Equation and the Solvability of Joint Forces/Torques in Dynamic Analysis

1992 ◽  
Vol 114 (2) ◽  
pp. 257-262 ◽  
Author(s):  
Shin-Min Song ◽  
Xiaochun Gao
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Rigid Bodies ◽  
Walking Machines ◽  
Spatial Mechanisms ◽  
Joint Forces ◽  
Simple Rules ◽  
Redundant Actuators

The mobility equation has been applied to predict the indeterminacy of unknown joint forces/torques in static analysis. In this paper, the mobility equation is modified to investigate the solvability of joint forces/torques of spatial mechanisms in dynamic analysis. Each factor which may contribute to indeterminacy is discussed and is explicitly expressed in the equation. With the modifications, the mobility equation can be applied to a system with or without redundant actuators. Together with the concept of subspaces and a few simple rules, the mobility equation can be used to identify the solvability of every joint unknown, as well as the equations which are required for the solutions, under the assumption of rigid bodies. This method can be used as a guidance of dynamic analysis in dealing with complicated systems such as walking machines and multi-fingered grippers.

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