scholarly journals Parallel Manipulators with Lower Mobility

10.5772/5030 ◽  
2006 ◽  
Author(s):  
Raffaele Di
Keyword(s):  
Parallel Manipulators ◽  
Lower Mobility

scholarly journals Dimensional Synthesis of a Novel 3-URU Translational Manipulator Implemented through a Novel Method

Robotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Parallel Manipulators ◽  
Geometric Parameters ◽  
Dimensional Synthesis ◽  
Positioning Precision ◽  
Platform Motion ◽  
Operational Space ◽  
Lower Mobility ◽  
Novel Method ◽  
Block Diagonal

A dimensional synthesis of parallel manipulators (PMs) consists of determining the values of the geometric parameters that affect the platform motion so that a useful workspace with assigned sizes can be suitably located in a free-from-singularity region of its operational space. The main goal of this preliminary dimensioning is to keep the PM far enough from singularities to avoid high internal loads in the links and guarantee a good positioning precision (i.e., for getting good kinematic performances). This paper presents a novel method for the dimensional synthesis of translational PMs (TPMs) and applies it to a TPM previously proposed by the author. The proposed method, which is based on Jacobians’ properties, exploits the fact that TPM parallel Jacobians are block diagonal matrices to overcome typical drawbacks of indices based on Jacobian properties. The proposed method can be also applied to all the lower-mobility PMs with block diagonal Jacobians that separate platform rotations from platform translations (e.g., parallel wrists).

Dynamic Modelling of Lower Mobility Parallel Manipulators

2019 ◽  
pp. 292-298
Author(s):  
Haitao Liu ◽  
Weifeng Chen ◽  
Tian Huang ◽  
Huafeng Ding ◽  
Andres Kecskemethy
Keyword(s):  
Dynamic Modelling ◽  
Parallel Manipulators ◽  
Lower Mobility

A General Approach for Geometric Error Modeling of Lower Mobility Parallel Manipulators

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Haitao Liu ◽  
Tian Huang ◽  
Derek G. Chetwynd
Keyword(s):  
Systematic Approach ◽  
Parallel Manipulators ◽  
Geometric Error ◽  
Error Modeling ◽  
Kinematic Calibration ◽  
Accuracy Improvement ◽  
Linear Map ◽  
Homogeneous Transformation Matrix ◽  
Lower Mobility ◽  
Source Errors

This paper presents a general and systematic approach for geometric error modeling of lower mobility manipulators. The approach can be implemented in three steps: (1) development of a linear map between the pose error twist and source errors within an individual limb using the homogeneous transformation matrix method; (2) formulation of a linear map between the pose error twist and the joint error intensities of a lower mobility parallel manipulator; and (3) combination of these two models. The merit of this approach lies in that it enables the source errors affecting the compensatable and uncompensatable pose accuracy of the platform to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for the accuracy improvement achievable by suitable measures, i.e., component tolerancing in design, manufacturing and assembly processes, and kinematic calibration. Three typical and well-known parallel manipulators are taken as examples to illustrate the generality and effectiveness of this approach.

Dynamic Modelling of Lower-Mobility Parallel Manipulators Using the Boltzmann-Hamel Equations

2015 ◽  
pp. 157-165 ◽  
Author(s):  
Oscar Altuzarra ◽  
Philipp Marcel Eggers ◽  
Francisco J. Campa ◽  
Constantino Roldan-Paraponiaris ◽  
Charles Pinto
Keyword(s):  
Dynamic Modelling ◽  
Parallel Manipulators ◽  
Lower Mobility ◽  
Boltzmann Hamel Equations

New Indices for Optimal Design of Redundantly Actuated Parallel Manipulators

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Qinchuan Li ◽  
Ningbin Zhang ◽  
Feibo Wang
Keyword(s):  
Optimal Design ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Mean Value ◽  
Transmission Performance ◽  
Transmission Index ◽  
Redundantly Actuated ◽  
Lower Mobility ◽  
Six Dof ◽  
Force Transmissibility

Redundantly actuated parallel manipulators (PMs) receive growing interest due to their reduced singularity and enlarged workspace. This paper proposes new indices for optimal design and analysis of redundantly actuated PMs by evaluating their motion/force transmissibility. First, we proposed a method to extract a multi-DOF (degrees-of-freedom) redundantly actuated PM into several subsidiary one-DOF PMs with two or more actuators by locking some actuators in an ergodic manner. Then, a new index of output transmission performance is proposed by investigating the mean value of the instantaneous power produced by the multiple actuation wrenches and one twist of the moving platform of one-DOF PMs. A local transmission index (LTI) is defined as the minimum value of the index of output and input transmission performance. A global transmission index (GTI) is then established based on the LTI. The proposed LTI and GTI are coordinate-free and have clear physical interpretation. Finally, the validity and universality of the new indices are demonstrated by optimization and analysis of redundantly actuated lower-mobility PMs with extra articulated six-DOF or limited-DOF limbs.

A Dual Space Approach for Force/Motion Transmissibility Analysis of Lower Mobility Parallel Manipulators

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Haitao Liu ◽  
Manxin Wang ◽  
Tian Huang ◽  
Derek G. Chetwynd ◽  
Andrés Kecskeméthy
Keyword(s):  
Systematic Approach ◽  
Local Maximum ◽  
Parallel Manipulators ◽  
Joint Space ◽  
Unified Framework ◽  
Different Types ◽  
Indeterminate Form ◽  
Lower Mobility ◽  
Space Approach ◽  
Dimensional Optimization

By drawing on the duality of twist space and wrench space, this paper presents a general and systematic approach for force/motion transmissibility analysis of lower mobility nonredundant and nonoverconstrained parallel manipulators. This leads to the formulation of a complete and justifiable model that enables the force/motion transmissibility analysis to be integrated into a unified framework under the umbrella of a homogenous and decoupled linear transformation that maps the coordinates of the platform wrench/twist in the joint space to its natural coordinates in the operation space. Utilizing the penalty method to avoid the indeterminate form “0/0” when the local maximum of a virtual coefficient approaches zero, a set of dimensionally homogeneous transmission indices is proposed which can be employed for precisely representing the closeness to different types of singularities defined in twist space as well as for dimensional optimization. An example is given to illustrate the effectiveness of this approach.

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.

Type Synthesis of 2-DOF Rotational Parallel Manipulators With an Equal-Diameter Spherical Pure Rolling Motion

2013 ◽  
Author(s):  
Kang Wu ◽  
Jingjun Yu ◽  
Guanghua Zong ◽  
Xianwen Kong
Keyword(s):  
Theoretical Model ◽  
Parallel Manipulators ◽  
Rolling Motion ◽  
Geometrical Parameters ◽  
Graphic Method ◽  
Type Synthesis ◽  
Pure Rolling ◽  
Lower Mobility ◽  
Two Degree Of Freedom ◽  
Conventional Type

Two-degree-of-freedom (2-DOF) rotational parallel manipulators (RPMs) have been widely used in pointing devices and robot wrists. This paper focuses on a class of 2-DOF RPMs achieving an equal-diameter spherical pure rolling motion (ESPRM) around the base. At first, a theoretical model of spherical pure rolling motion is analyzed and the characteristic of the associated constraint space is derived. Taking the Omni-Wrist III as a typical 2-DOF RPMs with an equal-diameter spherical pure rolling motion, mappings between the geometry and the motion are established and eight useful constraint conditions are derived which will be instructive for the type synthesis. Then, with focus on symmetrical structures, nine classes of 2-DOF RPMs with equal-diameter spherical pure rolling motion are synthesized based on the graphic method. Most of these RPMs have already been used in practice. Unlike the conventional type synthesis of lower-mobility parallel manipulators in literatures, some geometrical parameters of links, in addition to the distributions of joints and limbs, are taken into consideration in the type synthesis in this paper. This proposed research may help produce novel architectures.

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