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.

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.

A NUMERICAL SIMULATION INVESTIGATION OF THE HYDRODYNAMIC MOTIONS OF A SHIP ADVANCING IN WAVES

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
D C Lo ◽  
D T Su ◽  
J T Lin
Keyword(s):  
Computer Aided Design ◽  
Degrees Of Freedom ◽  
Fluid Dynamic ◽  
Wave Interaction ◽  
Six Degrees Of Freedom ◽  
Ship Model ◽  
Computer Aided ◽  
Cad Tool ◽  
Aided Design ◽  
Wave Incidence

This study establishes a relationship diagram of the ship-wave interaction under a ship advancing in waves. A finite difference method based on volume of fluid (VOF) principles was used to simulate the hydrodynamic motions of a ship advancing in waves. A ship model was constructed using a computer aided design (CAD) tool. The computational fluid dynamic (CFD) technique was used to calculate the hydrodynamic motions effect of a ship sailing in waves at varying angles of incidence. This study investigates a number of significant related parameters, such as the speed of the ship model, the various wave incidence angles, the wave height, and the navigation time. A chart is also used to show the flow field, and changes in the six degrees of freedom motion and continually compare changes in the drag force.

scholarly journals WORKSPACE ANALYSIS AND OPTIMIZATION OF THE PARALLEL ROBOTS BASED ON COMPUTER-AIDED DESIGN APPROACH

2020 ◽  
Vol 18 (1) ◽  
pp. 079
Author(s):  
Badreddine Aboulissane ◽  
Larbi El Bakkali ◽  
Jalal El Bahaoui
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Parallel Robots ◽  
Design Parameters ◽  
Reachable Workspace ◽  
Design Variables ◽  
Computer Aided ◽  
Aided Design

This paper provides workspace determination and analysis based on the graphical technique of both spatial and planar parallel manipulators. The computation and analysis of workspaces will be carried out using the parameterization and three-dimensional representation of the workspace. This technique is implemented in CAD (Computer Aided Design) Software CATIA workbenches. In order to determine the workspace of the proposed manipulators, the reachable region by each kinematic chain is created as a volume/area; afterwards, the full reachable workspace is obtained by the application of a Boolean intersection function on the previously generated volumes/areas. Finally, the relations between the total workspace and the design parameters are simulated, and the Product Engineering Optimizer workbench is used to optimize the design variables in order to obtain a maximized workspace volume. Simulated annealing (SA) and Conjugate Gradient (CG) are considered in this study as optimization tools.

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.

A method of version merging for computer-aided design files based on feature extraction

2010 ◽  
Vol 225 (2) ◽  
pp. 463-471 ◽  
Author(s):  
C Sun ◽  
D Guo ◽  
H Gao ◽  
L Zou ◽  
H Wang
Keyword(s):  
Feature Extraction ◽  
Computer Aided Design ◽  
Application Programming Interface ◽  
Difference Set ◽  
Computer Aided ◽  
Application Programming ◽  
Feature Difference ◽  
The Difference ◽  
Aided Design ◽  
The Given

In order to manage the version files and maintain the latest version of the computer-aided design (CAD) files in asynchronous collaborative systems, one method of version merging for CAD files is proposed to resolve the problem based on feature extraction. First of all, the feature information is extracted based on the feature attribute of CAD files and stored in a XML feature file. Then, analyse the feature file, and the feature difference set is obtained by the given algorithm. Finally, the merging result of the difference set and the master files with application programming interface (API) interface functions is achieved, and then the version merging of CAD files is also realized. The application in Catia validated that the proposed method is feasible and valuable in engineering.

Computer Aided Design of Ultrasonic Test by Numerical Simulation

2021 ◽  
Vol 1164 ◽  
pp. 97-104
Author(s):  
Réka Erdei ◽  
Zoltán Bézi ◽  
Csaba Takács
Keyword(s):  
Computer Aided Design ◽  
Grain Orientation ◽  
Ultrasonic Test ◽  
Probability Of Detection ◽  
Test Method ◽  
Dissimilar Metal ◽  
Computer Aided ◽  
Aided Design ◽  
The Given ◽  
Sophisticated Technology

Ultrasonic tests of dissimilar metal welds require extremely sophisticated technology. The complexity of the test is caused by the grain orientation and difficult accessibility of the weld and it is therefore necessary to redound the examinations by simulation. This study details some application possibilities of CIVA software and presents an example of the evaluation of the procedure used for the given test method with probability of detection curves.

A Solution to the Missing-View Problem for Polyhedral Solids

1991 ◽  
Author(s):  
Y. L. Srinivas ◽  
Debasish Dutta
Keyword(s):  
Machine Vision ◽  
Computer Aided Design ◽  
Partial Information ◽  
Connectivity Matrix ◽  
Automated Inspection ◽  
Vertex Connectivity ◽  
Computer Aided ◽  
Inspection Systems ◽  
Aided Design ◽  
The Given

Abstract An algorithm for generating the missing view corresponding to a given pair of orthoghonal views of a polyhedral solid is presented. The solution involves reconstructing the solids from the partial information given and then generating the missing view. The input is a vertex connectivity matrix describing the given views. Reconstruction of solids from incomplete orthographic views will have applications in computer-aided design, machine vision and automated inspection systems.

Mechanical/Naval Design of an Underwater Remotely Operated Vehicle (ROV) for Surveillance and Inspection of Port Facilities

2007 ◽  
Author(s):  
Juan A. Rami´rez ◽  
Rafael E. Va´squez ◽  
Luis B. Gutie´rrez ◽  
Diego A. Flo´rez
Keyword(s):  
Visual Information ◽  
Computer Aided Design ◽  
Degrees Of Freedom ◽  
Remotely Operated Vehicle ◽  
Port Facilities ◽  
Computer Aided ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Aided Design ◽  
And Control

This paper presents the mechanical/naval design process of an underwater remotely operated vehicle (ROV), required to obtain reliable visual information, used for surveillance and maintenance of ship shells and underwater structures of Colombian port facilities. The design was divided into four main subsystems: mechanical/naval, hardware, software and guidance, navigation and control. The most relevant design constraints were evaluated considering environmental conditions, dimensional restrictions, hydrostatics, hydrodynamics, degrees of freedom and the availability of instrumentation and control hardware. The mechanical/naval design was performed through an iterative process by using computational tools, including Computer Aided Design CAD, Computer Aided Engineering CAE, Computational Fluid Dynamics CFD and a high level programming environment. The obtained design ensures that the reliable operation of the robot will be achieved by using a consistent construction process. The new ROV constitutes an innovative product in Colombia, and it will be used for surveillance and oceanographic research tasks.

Performance atlases of the workspace for planar 3-DOF parallel manipulators

Robotica ◽  
2000 ◽  
Vol 18 (5) ◽  
pp. 563-568 ◽  
Author(s):  
Xin-Jun Liu ◽  
Jinsong Wang ◽  
Feng Gao
Keyword(s):  
Physical Model ◽  
Optimum Design ◽  
Computer Aided Design ◽  
Solution Space ◽  
Parallel Manipulators ◽  
Performance Characteristics ◽  
Performance Criteria ◽  
Computer Aided ◽  
Aided Design

The design of the robotic mechanisms is most important because they determine the performance characteristics of the robots. This paper concerns the issue of computer-aided design (CAD) for planar 3-DOF parallel robotic mechanisms by means of the physical model of the solution space, which can be used systematically to express the relationships between the performance criteria and all link lengths of one type of the robtic mechanism. The performance atlases of the workspace volume for the manipulators are plotted in the physical model of the solution space. The characteristics of the distribution of the workspace shapes in the physical model of the solution space are presented. The results are useful for the optimum design of the robotic mechanisms. This paper proposes a new way for robotic CAD.

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