Structural Synthesis Based on POC Set for Lower-Mobility Non-overconstrained Parallel Mechanisms

2015 ◽  
pp. 327-338
Author(s):  
Xiaorong Zhu ◽  
Xin Yao ◽  
Huiping Shen ◽  
Chen Sun ◽  
Tingli Yang
Keyword(s):  
Parallel Mechanisms ◽  
Structural Synthesis ◽  
Lower Mobility

Forward/Reverse Velocity and Acceleration Analysis for a Class of Lower-Mobility Parallel Mechanisms

2006 ◽  
Vol 129 (4) ◽  
pp. 390-396 ◽  
Author(s):  
Si J. Zhu ◽  
Zhen Huang ◽  
Hua F. Ding
Keyword(s):  
Kinematic Analysis ◽  
Jacobian Matrix ◽  
Hessian Matrix ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Analysis Method ◽  
Rear Part ◽  
Lower Mobility ◽  
Acceleration Analysis

This paper proposes a novel kinematic analysis method for a class of lower-mobility mechanisms whose degree-of-freedom (DoF) equal the number of single-DoF kinematic pairs in each kinematic limb if all multi-DoF kinematic pairs are substituted by the single one. For such an N-DoF (N<6) mechanism, this method can build a square (N×N) Jacobian matrix and cubic (N×N×N) Hessian matrix. The formulas in this method for different parallel mechanisms have unified forms and consequently the method is convenient for programming. The more complicated the mechanism is (for instance, the mechanism has more kinematic limbs or pairs), the more effective the method is. In the rear part of the paper, mechanisms 5-DoF 3-R(CRR) and 5-DoF 3-(RRR)(RR) are analyzed as examples.

Mobility analysis and structural synthesis of a class of spatial mechanisms with coupling chains

Robotica ◽  
2015 ◽  
Vol 34 (11) ◽  
pp. 2467-2485 ◽  
Author(s):  
Wen-ao Cao ◽  
Huafeng Ding ◽  
Ziming Chen ◽  
Shipei Zhao
Keyword(s):  
Structural Analysis ◽  
Parallel Mechanisms ◽  
Mobility Analysis ◽  
Structural Synthesis ◽  
Systematic Method ◽  
General Methodology ◽  
Spatial Mechanisms ◽  
Analysis And Synthesis

SUMMARYThis paper presents a systematic method for dealing with mobility analysis and structural synthesis of a class of important spatial mechanisms with coupling chains, which involve more complex coupling relations than spatial parallel mechanisms. First, an approach to the establishment of the motion screw equation of the class of mechanisms is derived. Then, a general methodology for mobility analysis along with detection of rigid substructures is proposed based on the motion screw equation. Third, the principle of structural synthesis of the class of mechanisms is established on the basis of the method of mobility analysis. Finally, some novel spatial mechanisms with coupling chains are synthesized, illustrating the effectiveness of the method. The study of the paper will benefit structural analysis and synthesis of more complex spatial mechanisms with coupling chains.

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.

Parallel mechanisms with decoupled rotation of the moving platform in planar motion

2009 ◽  
Vol 224 (3) ◽  
pp. 709-720 ◽  
Author(s):  
G Gogu
Keyword(s):  
Translational Motion ◽  
Planar Motion ◽  
Parallel Mechanisms ◽  
Structural Synthesis ◽  
Linear Transformations ◽  
New Family ◽  
Current Article ◽  
Moving Platform ◽  
First Time

The current article presents a new family of T2R1-type spatial parallel mechanisms (PMs) with decoupled and unlimited rotation of the moving platform in planar motion. The moving platform performs two independent translations (T2) and one independent unlimited rotation (R1) whose axis is perpendicular to the plane of translations. A method is proposed for structural synthesis of T2R1-type PMs based on the theory of linear transformations. The moving platform has unlimited rotational capabilities and is decoupled with respect to translational motion. To the best of the author's knowledge, this article presents for the first time solutions of T2R1-type spatial PMs with decoupled and unlimited rotation of the moving platform in planar motion.

A Family of Novel Lower-Mobility Decoupled Parallel Mechanisms

2007 ◽  
Author(s):  
Daxing Zeng ◽  
Sijun Zhu ◽  
Zhen Huang
Keyword(s):  
Real Time ◽  
Basic Feature ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Real Time Control ◽  
Motion Feature ◽  
Time Control ◽  
Fixed Base ◽  
Lower Mobility ◽  
Moving Platform

This paper presents a family of novel lower-mobility decoupled parallel mechanisms (DPMs), which consists of one 5-DOF (degree of freedom) DPM, two 4-DOF DPMs, three 3-DOF DPMs, and three 2-DOF DPMs. The basic feature of this family is that the moving platform and the fixed base of the DPMs are connected by two limbs and the motion of the moving platform is fully decoupled. Then the constraint screw method is used to analyze the motion feature of all DPMs presented in this paper. The mobility of these DPMs has also been calculated by the Modified Grubler-Kutzbach criterion. All the DPMs in this paper are simple and no computation is required for real-time control.

Rigid-Flexibility Modeling and Simulations of Lower-Mobility Parallel Mechanisms

2013 ◽  
Vol 681 ◽  
pp. 224-228
Author(s):  
Yang Qiang ◽  
Geng Hua Wang ◽  
Bian Ji ◽  
Luo Hao
Keyword(s):  
3D Model ◽  
Vibration Mode ◽  
Geometric Model ◽  
Flexible Body ◽  
Parallel Mechanisms ◽  
Modeling And Simulations ◽  
Ansys Software ◽  
Adams Software ◽  
Lower Mobility ◽  
Rigid Component

Considering the flexibility performance of lightweight slender axle in Delta parallel mechanisms, the effects of the elastic deformation on the kinematic accuracy of the mechanism are calculated based on the virtual prototype technology. Firstly, the 3D model of the mechanism is built via ADAMS software. Secondly, the geometric model of the driving rod is imported into ANSYS software to get meshed and generate the modal neutral files. Then, getting back to ADAMS, the original rigid component is replaced with the flexible body which constraint and driving is added to lately. At last, the rigid-flexibility hybrid model of the mechanism is built. Each frequency and vibration mode of the flexible body is calculated, using the simulation capabilities of the software. Furthermore, changes in motion accuracy of the mechanism under the effect of the force-elastic coupling are analyzed comparatively.

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.

Sign in / Sign up

Export Citation Format

Share Document