Solving Driving Forces of 2(3-SPR) Serial-Parallel Manipulator by CAD Variation Geometry Approach

2006 ◽  
Vol 128 (6) ◽  
pp. 1349-1351 ◽  
Author(s):  
Yi Lu ◽  
Bo Hu
Keyword(s):  
Computer Aided Design ◽  
Parallel Manipulator ◽  
Driving Forces ◽  
Virtual Work ◽  
Central Force ◽  
Virtual Displacement ◽  
Novel Approach ◽  
Computer Aided ◽  
Design Variation ◽  
Aided Design

A novel 2(3-SPR) serial-parallel manipulator is proposed. A novel approach for solving driving forces of the 2(3-SPR) parallel manipulator is proposed by using the virtual work theory and the computer aided design variation geometry. The solving procedure of this method is divided into following steps: First, constitute an initial simulation mechanism by using link dimension chains and driving dimensions of driving limbs; and then constitute a workloads simulation mechanism by using central force and central torque on initial simulation mechanism; finally constitute the force/torque simulation mechanism by giving a virtual displacement to one of the driving limbs, so that the virtual displacement about force and torque can be drawn, the driven force of this driven limb can be calculated by using the virtual work theory. In the same way, the others driven forces can be gotten.

Solving elastic deformation of some parallel manipulators with linear active legs using computer-aided design variation geometry

2013 ◽  
Vol 227 (12) ◽  
pp. 2810-2824 ◽  
Author(s):  
Yi Lu ◽  
Cong Cong ◽  
Chen Liwei ◽  
Peng Wang
Keyword(s):  
Elastic Deformation ◽  
Computer Aided Design ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Elastic Deformations ◽  
Deformation Equation ◽  
Computer Aided ◽  
Force Transformation ◽  
Design Variation ◽  
Aided Design

It has been a significant and challenging issue to determine the elastic deformation of parallel manipulators for their precision analysis and control. A new method is proposed and studied for solving the elastic deformation of some parallel manipulators with linear active legs using computer-aided design variation geometry. First, an original simulation mechanism of a parallel manipulator is constructed; each of the vectors in the force transformation matrix of the parallel manipulators is constructed by this simulation mechanism. The active/constrained wrench and their pose are determined based on the Newton–Euler formulation. Second, the elastic deformed dimensions of the active legs are determined based on the elastic deformation equation and the active/constrained wrench. Third, a new simulation mechanism of this parallel manipulator is constructed by replacing the original dimensions of active legs with the deformed dimensions of active legs and the elastic deformations of parallel manipulators are solved using the pose difference between the original and new simulation mechanisms. Finally, two parallel manipulators are illustrated and their elastic deformations are solved and verified by both analytic approach and finite element method.

Determination of the Workspace of a Three-Degrees-of-Freedom Parallel Manipulator Using a Three-Dimensional Computer-Aided-Design Software Package and the Concept of Virtual Chains1

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Andrew Johnson ◽  
Xianwen Kong ◽  
James Ritchie
Keyword(s):  
Computer Aided Design ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Graphical Representation ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Workspace Analysis ◽  
Computer Aided ◽  
Aided Design

The determination of workspace is an essential step in the development of parallel manipulators. By extending the virtual-chain (VC) approach to the type synthesis of parallel manipulators, this technical brief proposes a VC approach to the workspace analysis of parallel manipulators. This method is first outlined before being illustrated by the production of a three-dimensional (3D) computer-aided-design (CAD) model of a 3-RPS parallel manipulator and evaluating it for the workspace of the manipulator. Here, R, P and S denote revolute, prismatic and spherical joints respectively. The VC represents the motion capability of moving platform of a manipulator and is shown to be very useful in the production of a graphical representation of the workspace. Using this approach, the link interferences and certain transmission indices can be easily taken into consideration in determining the workspace of a parallel manipulator.

Analyses of kinematics, statics, and workspace of a 3-RRPRR parallel manipulator and its three isomeric mechanisms

2008 ◽  
Vol 222 (9) ◽  
pp. 1829-1837 ◽  
Author(s):  
B Hu ◽  
Y Lu
Keyword(s):  
Computer Aided Design ◽  
Parallel Manipulator ◽  
Analytical Approach ◽  
Displacement Velocity ◽  
Active Force ◽  
Kinematic Characteristics ◽  
Computer Aided ◽  
Analytical Formulae ◽  
The Common ◽  
Aided Design

A novel 3-RRPRR parallel manipulator with three pure translational movements and a relative larger workspace is proposed. Its three isomeric mechanisms 3-RR PU, 3-R PRU, and 3-U PU with three pure translational movements are constructed by varying dimensions of some links. Their common kinematic characteristics, workspace, and singularity are analysed, the active force and the constrained torque are solved. First, a simulation mechanism of the 3-RR PRR manipulator is created, and its kinematics, singularity, and workspace are analysed by using an analytical approach and a computer-aided design (CAD) variation geometry approach. Second, the common analytical formulae for solving the displacement, velocity, and acceleration of the four manipulators are derived. Third, the formulae for solving the active forces and constrained torques of the 3-RR PRR manipulator are derived. The analytic-solved results are verified by their simulation mechanisms.

Solving reachable workspace of some parallel manipulators by computer-aided design variation geometry

2008 ◽  
Vol 222 (9) ◽  
pp. 1773-1781 ◽  
Author(s):  
Y Lu ◽  
Y Shi ◽  
B Hu
Keyword(s):  
Computer Aided Design ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Six Degrees Of Freedom ◽  
Reachable Workspace ◽  
Spline Curves ◽  
Computer Aided ◽  
Design Variation ◽  
Aided Design ◽  
The Given

To shape the workspace of some novel parallel manipulators (PMs) is significant. A novel computer-aided design (CAD) variation geometry approach is proposed to shape and solve the reachable workspace of some PMs with three to six degrees of freedom (DOFs). Some basic techniques are described for designing the simulation mechanism and solving the reachable workspace. The simulation mechanisms of some PMs with three to six DOFs are created. When varying the driving dimensions of the active legs in the given extent, the simulation mechanisms vary correspondingly, and the position components of the moving platform are solved automatically. By transferring the position solutions into spatial spline curves in the simulation mechanism, all the boundary surfaces of the workspace can be created and visualized dynamically. Comparing with analytic approaches for solving workspace, the CAD variation geometry approach is simple, straightforward, accurate, and repeatable.

scholarly journals 3D Multi-Material Printing of an Anthropomorphic, Personalized Replacement Hand for Use in Neuroprosthetics Using 3D Scanning and Computer-Aided Design: First Proof-of-Technical-Concept Study

Prosthesis ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 362-370
Author(s):  
Jana Baron ◽  
Simon Hazubski ◽  
Andreas Otte
Keyword(s):  
Computer Aided Design ◽  
Concept Study ◽  
Hand Model ◽  
Flexible Material ◽  
Novel Approach ◽  
Computer Aided ◽  
Flexible Part ◽  
3D Printed ◽  
Material Printing ◽  
Aided Design

Background: This paper presents a novel approach for a hand prosthesis consisting of a flexible, anthropomorphic, 3D-printed replacement hand combined with a commercially available motorized orthosis that allows gripping. Methods: A 3D light scanner was used to produce a personalized replacement hand. The wrist of the replacement hand was printed of rigid material; the rest of the hand was printed of flexible material. A standard arm liner was used to enable the user’s arm stump to be connected to the replacement hand. With computer-aided design, two different concepts were developed for the scanned hand model: In the first concept, the replacement hand was attached to the arm liner with a screw. The second concept involved attaching with a commercially available fastening system; furthermore, a skeleton was designed that was located within the flexible part of the replacement hand. Results: 3D-multi-material printing of the two different hands was unproblematic and inexpensive. The printed hands had approximately the weight of the real hand. When testing the replacement hands with the orthosis it was possible to prove a convincing everyday functionality. For example, it was possible to grip and lift a 1-L water bottle. In addition, a pen could be held, making writing possible. Conclusions: This first proof-of-concept study encourages further testing with users.

A Sensitivity Approach for Eliminating Clashes From Computer Aided Design Model Assemblies

2014 ◽  
Vol 14 (3) ◽  
Author(s):  
Mohammad Shaheer Zubairi ◽  
Trevor T. Robinson ◽  
Cecil G. Armstrong ◽  
Danielle S. Soban
Keyword(s):  
Computer Aided Design ◽  
Optimum Combination ◽  
Substantial Cost ◽  
Manufacture Product ◽  
Novel Approach ◽  
Product Function ◽  
Computer Aided ◽  
Sensitivity Approach ◽  
Model Assemblies ◽  
Aided Design

Clashes occur when components in an assembly unintentionally violate others. If clashes are not identified and designed out before manufacture, product function will be reduced or substantial cost will be incurred in rework. This paper introduces a novel approach for eliminating clashes by identifying which parameters defining the part features in a computer aided design (CAD) assembly need to change and by how much. Sensitivities are calculated for each parameter defining the part and the assembly as the change in clash volume due to a change in each parameter value. These sensitivities give an indication of important parameters and are used to predict the optimum combination of changes in each parameter to eliminate the clash. Consideration is given to the fact that it is sometimes preferable to modify some components in an assembly rather than others and that some components in an assembly cannot be modified as the designer does not have control over their shape. Successful elimination of clashes has been demonstrated in a number of example assemblies.

scholarly journals Innovative approach to computer-aided design of horizontal axis wind turbine blades

2016 ◽  
Vol 4 (2) ◽  
pp. 98-105 ◽  
Author(s):  
Seyed Farhad Hosseini ◽  
Behnam Moetakef-Imani
Keyword(s):  
Wind Turbine ◽  
Computer Aided Design ◽  
Turbine Blades ◽  
Hausdorff Metric ◽  
Horizontal Axis ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Novel Approach ◽  
Computer Aided ◽  
Aided Design

Abstract The design of horizontal axis wind turbine (HAWT) blades involves several geometric complexities. As a result, the modeling of these blades by commercial computer-aided design (CAD) software is not easily accomplished. In the present paper, the HAWT blade is divided into structural and aerodynamic surfaces with a G1 continuity imposed on their connecting region. The widely used method of skinning is employed throughout the current work for surface approximation. In addition, to ensure the compatibility of section curves, a novel approach is developed based on the redistribution of input airfoil points. In order to evaluate deviation errors, the Hausdorff metric is used. The fairness of surfaces is quantitatively assessed using the standard strain energy method. The above-mentioned algorithms are successfully integrated into a MATLAB program so as to enhance further optimization applications. The final surfaces created by the procedure developed during the present study can be exported using the IGES standard file format and directly interpreted by commercial CAD and FE software. Highlights A new skinning approach is presented based on redistribution of input data points. The developed skinning method is successfully applied to the design of horizontal axis wind turbine blades. It has been shown that the blade surface constructed using the developed method is fair and visually pleasing. Special attention has been paid to construct a smooth surface in the transition area between the root and the section with maximum chord.

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