scholarly journals Dynamic analysis of a system of hinge-connected rigid bodies with nonrigid appendages

1973 ◽  
Vol 9 (12) ◽  
pp. 1473-1487 ◽  
Author(s):  
Peter W. Likins
Keyword(s):  
Dynamic Analysis ◽  
Rigid Bodies

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.

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.

Dynamic Analysis and Parametric Excitation of a Multi-Span Beam Structure Coupled With a Sequence of Moving Rigid Bodies

2018 ◽  
Author(s):  
Hao Gao ◽  
Bingen Yang
Keyword(s):  
Rigid Body ◽  
Dynamic Analysis ◽  
Parametric Resonance ◽  
Degrees Of Freedom ◽  
Coupled System ◽  
Rigid Bodies ◽  
Time Varying ◽  
Beam Structure ◽  
Assumed Mode Method ◽  
Mode Method

Dynamic analysis of a multi-span beam structure carrying moving rigid bodies is essentially important in various engineering applications. With many rigid bodies having different speeds and varying inter-distances, number of degrees of freedom of the coupled beam-moving rigid body system is time-varying and the beam-rigid body interaction is thus complicated. Developed in this paper is a method of extended solution domain (ESD) that resolves the issue of time-varying number of degrees and delivers a consistent mathematical model for the coupled system. The governing equation of the coupled system is derived with generalized assumed mode method through use of exact eigenfunctions and solved via numerical integration. Numerical simulation shows the accuracy and efficiency of the proposed method. Moreover, a preliminary study on parametric resonance on a beam structure with 10 rigid bodies provides guidance for future development of conditions on parametric resonance induced by moving rigid bodies, which can be useful for operation of certain coupled structure systems.

Applied Technology in Dynamics Study for Projecting Deployment of a New Anti-Riot Net

2014 ◽  
Vol 977 ◽  
pp. 425-430
Author(s):  
Yong Yuan Li ◽  
Lei Fang ◽  
Hong Bo Chen
Keyword(s):  
Rigid Body ◽  
Dynamic Analysis ◽  
Drag Coefficient ◽  
Rigid Bodies ◽  
Dynamic Equations ◽  
Test Results ◽  
Dynamics Modeling ◽  
Applied Technology ◽  
Simulation Results ◽  
Equivalent Method

In this paper, Dynamic analysis for the process of opening net is studied base on a new anti-riot device, focusing on the problem that dynamics modeling of fully compliant anti-riot net during the process, a new equivalent method is proposed. This method regards the anti-riot net as a variable drag coefficient rigid body, and regards four traction heads as a suppositional traction head, so the process of opening net can be transformed to the problem for movement of two rigid bodies, furthermore, the dynamic equations for the process of opening net was derived from this method. These equations are used to simulate the process of opening net; the simulation results are compared with test results to verify the practicability of the method.

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 Step-by-Step

1998 ◽  
Vol 120 (08) ◽  
pp. 61-62
Author(s):  
Yi Sug Kwon
Keyword(s):  
Dynamic Analysis ◽  
Computer Aided Design ◽  
Degrees Of Freedom ◽  
Rigid Bodies ◽  
Operating Conditions ◽  
Industrial Systems ◽  
High Rise ◽  
Front End ◽  
Design Software ◽  
Aided Design

This article discusses about engineers who are relying on mechanical simulations to improve their understanding of loading and operating conditions with high-rise escalators gain in popularity. To model an escalator design’s steps for dynamic analysis, LG engineers simplified the mechanical system by applying the drive directly to the upper terminal gear and the driving pulley without the motor. To model an escalator’s continuous elastic handrail, LG engineers divided it into 127 discrete rigid bodies, resulting in a total of 381 independent degrees of freedom. Two friction contact elements for each handrail body are applied to prevent rotational motion of the handrail. LG Industrial Systems managers decided to expand the number of engineers at the company with access to the simulation model. They assigned LG engineers to work with Computer Aided Design Software, Inc. (CADSI), of Coralville, Iowa analysts to develop a front end to DADS that simplifies the process of developing a custom escalator model.

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.

scholarly journals A Two-Dimensional Discrete Model for Dynamic Analysis of Belt Transmission with Dry Friction

2014 ◽  
Vol 61 (4) ◽  
pp. 571-593
Author(s):  
Krzysztof Kubas
Keyword(s):  
Dynamic Analysis ◽  
Dry Friction ◽  
Discrete Model ◽  
Equations Of Motion ◽  
Friction Model ◽  
Rigid Bodies ◽  
Friction Forces ◽  
Calculation Results ◽  
Model Of Friction ◽  
Belt Transmission

Abstract The paper presents a model for dynamic analysis of belt transmission. A twodimensional discrete model was assumed of a belt consisting of rigid bodies joined by translational and torsion spring-damping elements. In the model, both a contact model and a dry friction model including creep were taken into consideration for belt-pulley interaction. A model with stiffness and damping between the contacting surfaces was used to describe the contact phenomenon, whereas a simplified model of friction was assumed. Motion of the transmission is triggered under the influence of torque loads applied on the pulleys. Equations of motion of separate elements of the belt and pulleys were solved numerically by using adaptive stepsize integration methods. Calculation results are presented of the reaction forces acting on the belt as well as contact and friction forces between the belt body and pulley in the sample of the belt transmission. These were obtained under the influence of the assumed drive and resistance torques.

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