A method for force analysis of the overconstrained lower mobility parallel mechanism

2015 ◽  
Vol 88 ◽  
pp. 31-48 ◽  
Author(s):  
Yundou Xu ◽  
Wenlan Liu ◽  
Jiantao Yao ◽  
Yongsheng Zhao
Keyword(s):  
Parallel Mechanism ◽  
Force Analysis ◽  
Lower Mobility

Force analysis of the redundantly actuated parallel mechanism 2RPR+P considering different control methodologies

2021 ◽  
pp. 103783
Author(s):  
Yundou Xu ◽  
Ze Jiang ◽  
Zhongjin Ju ◽  
Zengzhao Wang ◽  
Wenlan Liu ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Force Analysis ◽  
Redundantly Actuated

Acceleration and Dexterity Performance Indices for 6-DOF and Lower-Mobility Parallel Mechanism

2004 ◽  
Author(s):  
X. J. Guo ◽  
F. Q. Chang ◽  
S. J. Zhu
Keyword(s):  
Parallel Mechanism ◽  
Robot Manipulator ◽  
Coefficient Matrix ◽  
Second Order ◽  
Influence Coefficient ◽  
Global Index ◽  
Performance Indices ◽  
First Order ◽  
Lower Mobility

On the basis of first-order and second-order kinematic influence coefficient matrices, dynamics characteristics indices for robot manipulator are presented in the paper. Different from indices before, these indices include not only the first-order kinematics influence coefficient matrix G, but also the second-order kinematic influence coefficient matrix H. Then with the global index, these indices can be used to guide the dynamics design.

Repelling-Screw Based Force Analysis of Origami Mechanisms

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Chen Qiu ◽  
Ketao Zhang ◽  
Jian S. Dai
Keyword(s):  
Parallel Mechanism ◽  
Screw Theory ◽  
Reaction Force ◽  
Theoretical Background ◽  
Force Analysis ◽  
Modeling Approach ◽  
Reaction Forces ◽  
Redundantly Actuated

This paper provides an approach to model the reaction force of origami mechanisms when they are deformed. In this approach, an origami structure is taken as an equivalent redundantly actuated mechanism, making it possible to apply the forward-force analysis to calculating the reaction force of the origami structure. Theoretical background is provided in the framework of screw theory, where the repelling screw is introduced to integrate the resistive torques of folded creases into the reaction-force of the whole origami mechanism. Two representative origami structures are then selected to implement the developed modeling approach, as the widely used waterbomb base and the waterbomb-based integrated parallel mechanism. With the proposed kinematic equivalent, their reaction forces are obtained and validated, presenting a ground for force analysis of origami-inspired mechanisms.

Analysis and Design of Lower-Mobility Parallel Mechanism of Non-Symmetrical Based on Variable Topology Theory

2011 ◽  
Vol 201-203 ◽  
pp. 1907-1912
Author(s):  
Rong Jiang Cui ◽  
Zong He Guo ◽  
Zi Xun Yin ◽  
Song Song Zhu
Keyword(s):  
Parallel Mechanism ◽  
Screw Theory ◽  
Parallel Mechanisms ◽  
Basic Variable ◽  
Analysis And Design ◽  
And Topology ◽  
Variable Topology ◽  
Lower Mobility ◽  
Branched Chain ◽  
Mechanism Theory

First, the branched-chain of parallel mechanism was Classified according to reciprocal screw theory. Then, the introduction of variable topology mechanism theory, with the characteristics of parallel mechanisms themselves, the definition and basic variable topology means of variable topology parallel mechanism were given. With evolutionary theory, the method to design lower-mobility parallel mechanisms of non-asymmetric was proposed based on variable topology mechanism theory .Taking 3-RPS as ideal mechanism and topology synthesis was carried out, besides 2-RPS mechanism were analyzed. The introduction of variable topology mechanism theory provided a theoretical basis and innovative approaches for the synthesis configuration of Lower-mobility parallel mechanisms of non-asymmetric.

scholarly journals Mobility analysis of a robotic cardiopulmonary resuscitation device

2021 ◽  
Author(s):  
Mahdi Ardestani ◽  
Mohsen Asgari
Keyword(s):  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Closed Form Solution ◽  
Parallel Manipulators ◽  
Optimization Method ◽  
Form Solution ◽  
Mobility Analysis ◽  
Chest Compressions ◽  
Singularity Problem ◽  
Lower Mobility

Abstract During chest compressions action, in CPR (CPR), the 2 arms of the rescuer constitute a parallel mechanism. Inspired by this performance, during this study a specific family of lower mobility parallel manipulators by employing a modified version of Delta robot is proposed for chest compressions in rescuing a patient. One of the biggest differences between this mechanism and the Delta parallel mechanism is that the position of the three active connections of the robot relative to each other has changed the geometry of the platforms. Also, it shapes the asymmetrical structure within the robot mechanism and its workspace. Another difference is due to the architectural optimization method considering the mixed performance index, which has been used during this mechanism to achieve a much better compromise between the manipulator dexterity and its workspace. Within the present paper, after introducing the architecture of the robot, a closed-form solution is developed for the kinematic problem and therefore the results are verified using MSC. Adams©. Then Jacobian matrix is generated to gauge the singularity problem of the proposed mechanism. then, the workspace of the robot is investigated and compared with the original Delta mechanism.

Motion/Force Transmission Analysis of Parallel Mechanisms With Planar Closed-Loop Subchains

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Kristan Marlow ◽  
Mats Isaksson ◽  
Jian S. Dai ◽  
Saeid Nahavandi
Keyword(s):  
Performance Measures ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Parallel Mechanisms ◽  
Force Transmission ◽  
Six Degrees Of Freedom ◽  
Lower Mobility ◽  
Transmission Ability

Singularities are one of the most important issues affecting the performance of parallel mechanisms. A parallel mechanism with less than six degrees of freedom (6DOF) is classed as having lower mobility. In addition to input–output singularities, such mechanisms potentially suffer from singularities among their constraints. Furthermore, the utilization of closed-loop subchains (CLSCs) may introduce additional singularities, which can strongly affect the motion/force transmission ability of the entire mechanism. In this paper, we propose a technique for the analysis of singularities occurring within planar CLSCs, along with a finite, dimensionless, frame invariant index, based on screw theory, for examining the closeness to these singularities. The integration of the proposed index with existing performance measures is discussed in detail and exemplified on a prototype industrial parallel mechanism.

Dynamics Analysis of 3-PPR Planar Parallel Mechanism Including Friction

2014 ◽  
Vol 1006-1007 ◽  
pp. 265-270
Author(s):  
Ying Mei ◽  
Xiao Xue Gao ◽  
Jie Song
Keyword(s):  
Mechanical Model ◽  
Parallel Mechanism ◽  
Dynamics Analysis ◽  
Kinematic Pair ◽  
Force Analysis

In order to obtain actual dynamics equation of 3-PPR planar parallel mechanism, established mechanical model of kinematic pair including friction, carried on force analysis of 3-PPR planar parallel mechanism including friction. Then according to the Kane equation established the dynamics equation of 3-PPR planar parallel mechanism including friction.

Stiffness Design, Analysis and Validation of a Parallel-Mechanism Equivalent Suspension System

2015 ◽  
Author(s):  
Chen Qiu ◽  
Ketao Zhang ◽  
Jing Shan Zhao ◽  
Jian S. Dai
Keyword(s):  
Parallel Mechanism ◽  
Optimization Design ◽  
Screw Theory ◽  
Suspension System ◽  
Force Analysis ◽  
Design Constraint ◽  
Kinematic Design ◽  
Simulation Validation ◽  
Element Simulation ◽  
Stiffness Design

This paper provides a systematic approach to design a vehicle’s independent suspension system. In this approach, multi-link type suspension is selected. By treating it as a parallel mechanism, both the kinematic design and force analysis are conducted in the same framework of screw theory. Regarding the kinematic design, constraint-based approach is used to find suitable layouts of constraint limbs in accordance with desired degree of freedom. In the force analysis, stiffness matrix of the suspension mechanism is developed, leading to the deformation and stress analysis under various critical loads. The developed formulae are further utilized to design suitable suspension mechanism, followed by finite-element-simulation validation as well as optimization design to reduce the resulted maximum stresses.

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