Statics and Grasp Stiffness Analysis of an Underactuated Cable-Truss Mechanism

2014 ◽  
Vol 597 ◽  
pp. 507-514
Author(s):  
Nan Wu ◽  
Rong Qiang Liu ◽  
Hong Wei Guo
Keyword(s):  
Driving Force ◽  
Virtual Work ◽  
Principle Of Virtual Work ◽  
Vector Method ◽  
Stiffness Analysis ◽  
Grasping Force ◽  
The Relationship

Although much literature is available on the statics and grasp stiffness analysis of underactuated mechanisms, little research has been done on them of the underactuated cable-truss mechanism. The underactuated cable-truss mechanism grasps the target in the form of envelopment. Considering the grasping characteristics of the mechanism, the research on the relationship between the grasping force and the driving force is extremely important, as well as the study of the grasp stiffness. The statics analysis of an underactuated cable-truss mechanism, constituted by five cable-truss units, was given by means of combining with the vector method and the principle of virtual work in this paper. To prove the correctness of the analysis, the simulation was presented. The stiffness of the cable-truss unit was defined and the curve, showing the influence of the proportion relationship between the essential parameters to the stiffness, was obtained. Then, the stiffness of the mechanism was discussed.

Mechanical Design and Dynamics Analysis on a Jumping Robot

2012 ◽  
Vol 476-478 ◽  
pp. 1112-1115
Author(s):  
Yi Li Zheng ◽  
Jin Hao Liu ◽  
Jiang Ming Kan
Keyword(s):  
Thrust Force ◽  
Virtual Work ◽  
Mechanical Design ◽  
Dynamics Analysis ◽  
Principle Of Virtual Work ◽  
Structure And Motion ◽  
Motion Characteristic ◽  
Jumping Robot ◽  
Exploration Mission ◽  
The Relationship

Aiming at the forest and wetland environment exploration mission, the mechanical structure and motion characteristic of a four-legs jumping robot are given particularly. Using the principle of virtual work states, the simplified dynamic model of one jumping leg is derived under some assumptions, and the relationship between the jumping height and thrust force of the leg is given and simulated. The simulation result have demonstrated the feasibility and validity of the theoretical analysis for the jumping robot.

The rigid S-type cable-suspended parallel robot design, modelling and analysis

Robotica ◽  
2014 ◽  
Vol 34 (9) ◽  
pp. 1948-1960 ◽  
Author(s):  
M. Filipovic ◽  
A. Djuric ◽  
Lj. Kevac
Keyword(s):  
Jacobian Matrix ◽  
Virtual Work ◽  
Kinematic Model ◽  
Parallel Robot ◽  
Model Verification ◽  
Robot Design ◽  
Principle Of Virtual Work ◽  
Lagrange Principle ◽  
Internal Forces ◽  
The Relationship

SUMMARYThis paper presents design, modelling and analysis of the selected Rigid ropes S-type Cable-suspended Parallel Robot (RSCPR). The characteristic of this system is its geometric construction which defines the kinematic model through the Jacobian matrix. The relationship between external and internal forces is defined by the Lagrange principle of virtual work. The Jacobian matrix is directly involved in the application of the Lagrange principle of virtual work and generation of the dynamic model of the RSCPR system. Selected examples of the CPR system types are analysed and the comparison of their results is presented. The software package named ORIGI has been developed for the RSCPR model verification.

Kinematic Optimization of a Redundantly Actuated Parallel Mechanism for Maximizing Active Stiffness and Workspace Using Taguchi Method

2009 ◽  
Author(s):  
Hyunpyo Shin ◽  
SungCheul Lee ◽  
Woosung In ◽  
Jay I. Jeong ◽  
Jongwon Kim
Keyword(s):  
Taguchi Method ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Virtual Work ◽  
Optimization Procedure ◽  
Kinematic Parameter ◽  
Response Analysis ◽  
Stiffness Analysis ◽  
Redundantly Actuated ◽  
The Relationship

We present an optimization procedure that uses the Taguchi method to optimize the mean stiffness and workspace of a redundantly actuated parallel mechanism. The kinematic parameters of a planar 2-DOF parallel manipulator are optimized to maximize the manipulator’s workspace and mean stiffness at the same time. Kinematic analysis is performed to obtain a constraint Jacobian and forward Jacobian. And stiffness analysis of the redundantly actuated parallel manipulator is performed based on the virtual work theorem. The Taguchi method is applied to separate the more influential and controllable variables from the less influential ones in the optimization procedure. In the first stage of optimization, the number of experimental variables is reduced by response analysis. And after the response analysis, quasi-optimal kinematic parameter group is obtained in the second stage of optimization. The optimization procedure was used to investigate the optimal kinematic parameter groups and the relationship between the length and the stiffness of the link.

The Statics Analysis and Verification of 3-DOF Parallel Mechanism Based on Two Methods

2013 ◽  
Vol 7 (2) ◽  
pp. 237-244 ◽  
Author(s):  
Guangda Lu ◽  
◽  
Aimei Zhang ◽  
Jing Zhou ◽  
Shigang Cui ◽  
...  
Keyword(s):  
Force Feedback ◽  
Jacobian Matrix ◽  
Virtual Work ◽  
Rehabilitation Robot ◽  
Principle Of Virtual Work ◽  
Equilibrium Equations ◽  
Vector Method ◽  
Ankle Rehabilitation ◽  
Moving Platform ◽  
Mathematical Relationships

Statics of the 3-RSS/S parallel ankle-rehabilitation robot is analyzed in this paper using two methods, i.e. the component vector method and the principle of virtual work. Static equilibrium equations based on component vector theory were established on a moving platform, and cranks of 3-RSS/S parallel Ankle-rehabilitation Robot, using this method, to obtain mathematical relationships between the external torque of moving platform and the output torque of three cranks. The velocity Jacobian matrix of the robot is calculated firstly using the principle of virtual work method, then the force Jacobian matrix is obtained based on the relationship between velocity Jacobian matrix and force Jacobian matrix. The results of the two methods are verified and found to be consistent by calculation, and the force Jacobian matrix of the robot is the basis of the force feedback control for the Ankle-rehabilitation Robot.

Analysis of magnetic force and dynamic characteristic for non-contact permanent magnet linear drive device

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1337-1345
Author(s):  
Chuan Zhao ◽  
Feng Sun ◽  
Junjie Jin ◽  
Mingwei Bo ◽  
Fangchao Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Dynamic Characteristic ◽  
Driving Force ◽  
Magnetic Circuit ◽  
Response Speed ◽  
Computation Method ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.

On the Mechanical Behavior of the Orthotropic Cord-Rubber Composite

1976 ◽  
Vol 4 (4) ◽  
pp. 219-232 ◽  
Author(s):  
Ö. Pósfalvi
Keyword(s):  
Mechanical Behavior ◽  
Uniaxial Tension ◽  
Elastic Properties ◽  
Large Deformations ◽  
Virtual Work ◽  
Poisson's Ratio ◽  
Principle Of Virtual Work ◽  
Effective Elastic Properties ◽  
Rubber Composite ◽  
Mooney Equation

Abstract The effective elastic properties of the cord-rubber composite are deduced from the principle of virtual work. Such a composite must be compliant in the noncord directions and therefore undergo large deformations. The Rivlin-Mooney equation is used to derive the effective Poisson's ratio and Young's modulus of the composite and as a basis for their measurement in uniaxial tension.

scholarly journals Discrete element model for general polyhedra

2021 ◽  
Author(s):  
Alfredo Gay Neto ◽  
Peter Wriggers
Keyword(s):  
Frictional Contact ◽  
Virtual Work ◽  
Particle Surface ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Principle Of Virtual Work ◽  
Dynamics Model ◽  
Railway Ballast ◽  
Multibody Dynamics Model

AbstractWe present a version of the Discrete Element Method considering the particles as rigid polyhedra. The Principle of Virtual Work is employed as basis for a multibody dynamics model. Each particle surface is split into sub-regions, which are tracked for contact with other sub-regions of neighboring particles. Contact interactions are modeled pointwise, considering vertex-face, edge-edge, vertex-edge and vertex-vertex interactions. General polyhedra with triangular faces are considered as particles, permitting multiple pointwise interactions which are automatically detected along the model evolution. We propose a combined interface law composed of a penalty and a barrier approach, to fulfill the contact constraints. Numerical examples demonstrate that the model can handle normal and frictional contact effects in a robust manner. These include simulations of convex and non-convex particles, showing the potential of applicability to materials with complex shaped particles such as sand and railway ballast.

Analytical Modelling of the Dynamics of the Four-Bar Mechanism: A Comparison of Some Methods

2018 ◽  
Author(s):  
J. P. Meijaard ◽  
V. van der Wijk
Keyword(s):  
Virtual Work ◽  
Equations Of Motion ◽  
Differential Algebraic Equations ◽  
Force Balance ◽  
Dynamic Force ◽  
Algebraic Equations ◽  
Principle Of Virtual Work ◽  
Principal Vector ◽  
Reaction Forces ◽  
Principal Points

Some thoughts about different ways of formulating the equations of motion of a four-bar mechanism are communicated. Four analytic methods to derive the equations of motion are compared. In the first method, Lagrange’s equations in the traditional form are used, and in a second method, the principle of virtual work is used, which leads to equivalent equations. In the third method, the loop is opened, principal points and a principal vector linkage are introduced, and the equations are formulated in terms of these principal vectors, which leads, with the introduced reaction forces, to a system of differential-algebraic equations. In the fourth method, equivalent masses are introduced, which leads to a simpler system of principal points and principal vectors. By considering the links as pseudorigid bodies that can have a uniform planar dilatation, a compact form of the equations of motion is obtained. The conditions for dynamic force balance become almost trivial. Also the equations for the resulting reaction moment are considered for all four methods.

Static analysis of spatial parallel manipulators by means of the principle of virtual work

2012 ◽  
Vol 28 (3) ◽  
pp. 385-401 ◽  
Author(s):  
J. Jesús Cervantes-Sánchez ◽  
José M. Rico-Martínez ◽  
Salvador Pacheco-Gutiérrez ◽  
Gustavo Cerda-Villafaña
Keyword(s):  
Static Analysis ◽  
Virtual Work ◽  
Parallel Manipulators ◽  
Principle Of Virtual Work

Optimal Design of Bi- and Multi-Stable Compliant Cellular Structures

2018 ◽  
Author(s):  
Quantian Luo ◽  
Liyong Tong
Keyword(s):  
Optimal Design ◽  
Virtual Work ◽  
Reaction Force ◽  
Nonlinear Finite Element ◽  
Cellular Structures ◽  
Stress And Strain ◽  
Principle Of Virtual Work ◽  
Stable States ◽  
Threshold Method ◽  
Element Analysis

This paper presents optimal design for nonlinear compliant cellular structures with bi- and multi-stable states via topology optimization. Based on the principle of virtual work, formulations for displacements and forces are derived and expressed in terms of stress and strain in all load steps in nonlinear finite element analysis. Optimization for compliant structures with bi-stable states is then formulated as: 1) to maximize the displacement under specified force larger than its critical one; and 2) to minimize the reaction force for the prescribed displacement larger than its critical one. Algorithms are developed using the present formulations and the moving iso-surface threshold method. Optimal design for a unit cell with bi-stable states is studied first, and then designs of multi-stable compliant cellular structures are discussed.

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