scholarly journals Synthesis and Analysis of a Novel Linkage Mechanism with the Helical Motion of the End-Effector

Robotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 53
Author(s):  
Alexey Fomin ◽  
Daniil Petelin ◽  
Andreas Jahr
Keyword(s):  
Computer Aided Design ◽  
Functional Performance ◽  
Cad Model ◽  
Kinematic Scheme ◽  
Linkage Mechanism ◽  
End Effector ◽  
Kinematic Chains ◽  
Cyclic Movement ◽  
Physical Prototype ◽  
Aided Design

The proposed study is focused on the development of a novel modification of the slider-crank mechanism, the kinematic scheme of which is organized by coupling planar and spatial (screw) kinematic chains. The structure of this mechanism provides the end-effector with a cyclic movement along a helicoidal trajectory, while all other links have planar motions. A kinematic analysis of the synthesized mechanism is discussed in this study. The motion variables of the end-effector at different pitches in the screw joints are determined analytically and numerically. Based on the mechanism’s kinematic scheme, its assembling computer-aided design (CAD) model has been created, in accordance with which a physical prototype has been built. A functional performance of the prototype is studied by comparing the displacements of its end-effector with analogical displacements of the CAD model. The question of the technological application of the developed mechanism for spring winding and various objects’ screwing has been considered in this study.

scholarly journals Virtual and Physical Prototyping of Reconfigurable Parallel Mechanisms with Single Actuation

2021 ◽  
Vol 11 (15) ◽  
pp. 7158
Author(s):  
Alexey Fomin ◽  
Daniil Petelin ◽  
Anton Antonov ◽  
Victor Glazunov ◽  
Marco Ceccarelli
Keyword(s):  
Computer Aided Design ◽  
Screw Theory ◽  
Complex Geometry ◽  
Kinematic Chain ◽  
Parallel Mechanisms ◽  
Mobility Analysis ◽  
Kinematic Chains ◽  
Physical Prototype ◽  
Detailed Computer ◽  
Aided Design

The paper presents novel models of reconfigurable parallel mechanisms (RPMs) with a single active degree-of-freedom (1-DOF). The mechanisms contain three to six identical kinematic chains, which provide three (for the tripod) to zero (for the hexapod) uncontrollable DOFs. Screw theory is applied to carry out mobility analysis and proves the existence of controllable and uncontrollable DOFs of these mechanisms. Each kinematic chain in the synthesized mechanisms consists of planar and spatial parts. Such a design provides them with reconfiguration capabilities even when the driving link is fixed. This allows reproduction of diverse output trajectories without using additional actuators. In this paper, the model of a mechanism with six kinematic chains (hexapod) has been virtually and physically prototyped. The designing and assembling algorithms are developed using the detailed computer-aided design (CAD) model, which was further used to carry out kinetostatic analysis considering complex geometry of mechanism elements and friction among all contacting surfaces of joints. The developed virtual prototype and its calculation data have been further applied to fabricate mechanism elements and assemble an actuated full-scale physical prototype for future testing.

scholarly journals Automatized Evaluation of Students’ CAD Models

2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Computer Application ◽  
Test Cases ◽  
Cad Model ◽  
Computer Solution ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

The article describes an attempt to address the automatized evaluation of student three-dimensional (3D) computer-aided design (CAD) models. The driving idea was conceptualized under the restraints of the COVID pandemic, driven by the problem of evaluating a large number of student 3D CAD models. The described computer solution can be implemented using any CAD computer application that supports customization. Test cases showed that the proposed solution was valid and could be used to evaluate many students’ 3D CAD models. The computer solution can also be used to help students to better understand how to create a 3D CAD model, thereby complying with the requirements of particular teachers.

Design and Fabrication of Stirling Engine for Solar Power Application

2021 ◽  
Vol 143 (11) ◽  
Author(s):  
Muhammad Hassan ◽  
Hussain Ahmed Tariq ◽  
Muhammad Anwar ◽  
Talha Irfan Khan ◽  
Asif Israr
Keyword(s):  
Computer Aided Design ◽  
Peak Power ◽  
Stirling Engine ◽  
Working Fluid ◽  
Cad Model ◽  
Stroke Length ◽  
And Performance ◽  
Power Application ◽  
Aided Design ◽  
Alpha Type

Abstract This paper showcases the designing, fabrication, and performance evaluation of 90-deg alpha-type Stirling engine. The diameters of the hot and cold cylinder are 50 mm and 44 mm, respectively, with a stroke length of 70 mm. The computer-aided design (CAD) model is developed by keeping in mind the ease of manufacturing, maintenance, bearing replacements, and lubrication. After fabrication, the engine is tested by heating the hot cylinder with air as a working fluid. The engine delivered peak power of 155 watts at the temperature of 1123 K and 968 K for hot and cold cylinders, respectively. This developed prototype can be commissioned with the solar parabolic concentrator in the future based on the smooth operation while delivering power.

Laser Additive Manufacturing

3D Printing ◽  
2017 ◽  
pp. 154-171 ◽  
Author(s):  
Rasheedat M. Mahamood ◽  
Esther T. Akinlabi
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Cad Model ◽  
Laser Additive Manufacturing ◽  
Computer Aided ◽  
Manufacturing Technologies ◽  
Aided Design

Laser additive manufacturing is an advanced manufacturing process for making prototypes as well as functional parts directly from the three dimensional (3D) Computer-Aided Design (CAD) model of the part and the parts are built up adding materials layer after layer, until the part is competed. Of all the additive manufacturing process, laser additive manufacturing is more favoured because of the advantages that laser offers. Laser is characterized by collimated linear beam that can be accurately controlled. This chapter brings to light, the various laser additive manufacturing technologies such as: - selective laser sintering and melting, stereolithography and laser metal deposition. Each of these laser additive manufacturing technologies are described with their merits and demerits as well as their areas of applications. Properties of some of the parts produced through these processes are also reviewed in this chapter.

Computer aided design (CAD) model search and retrieval using frequency domain file conversion

2020 ◽  
Vol 36 ◽  
pp. 101554
Author(s):  
Wenjin Li ◽  
Gary Mac ◽  
Nektarios Georgios Tsoutsos ◽  
Nikhil Gupta ◽  
Ramesh Karri
Keyword(s):  
Frequency Domain ◽  
Computer Aided Design ◽  
Cad Model ◽  
Model Search ◽  
Computer Aided ◽  
Aided Design ◽  
Search And Retrieval

A Reverse Compensation Framework for Shape Deformation in Additive Manufacturing

2016 ◽  
Author(s):  
Kai Xu ◽  
Tsz-Ho Kwok ◽  
Yong Chen
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Shape Deformation ◽  
Cad Model ◽  
Complex Deformation ◽  
Physical Measurements ◽  
Building Process ◽  
Aided Design ◽  
Thermal Cooling ◽  
And Control

Shape deformation is an important issue in additive manufacturing (AM) processes such as the projection-based Stereolithography. Volumetric shrinkage and thermal cooling during the photopolymerization process combined with other factors such as the layer-constrained building process lead to complex deformation that is difficult to predict and control. In this paper, a general reverse compensation method and related computation framework are presented to reduce the shape deformation of AM fabricated parts. During the reverse compensation process, the shape deformation is calculated based on physical measurements of shape deformation. A novel method for identifying the correspondence between the deformed shape and the given nominal computer-aided design (CAD) model is presented based on added markers. Accordingly, a new CAD model based on the shape deformation and related compensation is computed. The intelligently revised CAD model by going through the same building process can result in a fabricated part that is close to the nominal CAD model. Two test cases have been designed to demonstrate the effectiveness of the presented method and the related computation framework. The shape deformation in terms of L2- and L∞-norm based on measuring the geometric errors is reduced by 40–60%.

Toward Effective Mechanical Design Reuse: CAD Model Retrieval Based on General and Partial Shapes

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Min Li ◽  
Y. F. Zhang ◽  
J. Y. H. Fuh ◽  
Z. M. Qiu
Keyword(s):  
Computer Aided Design ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Cad Model ◽  
Model Retrieval ◽  
Cad Models ◽  
Feature Based ◽  
Novel Method ◽  
Aided Design ◽  
Model Similarity

In product design, a large proportion of three-dimensional (3D) computer-aided design (CAD) models can be reused to facilitate future product development due to their similarities in function and shape. This paper presents a novel method that incorporates modeling knowledge into CAD model similarity assessment to improve the effectiveness of reuse-oriented retrieval. First, knowledge extraction is performed on archived feature-based CAD models to construct feature dependency directed acyclic graph (FDAG). Second, based on the FDAG subgraph decomposition, two useful component partitioning approaches are developed to extract simplified essential shapes and meaningful subparts from CAD models. Third, the extracted shapes and their FDAG subgraphs are indexed. Finally, the indexed shapes that are similar to user-sketched queries are retrieved to reuse, and FDAG information of the retrieved shapes is provided as redesign suggestions. Experimental results suggest that the incorporation of modeling knowledge greatly facilitates CAD model retrieval and reuse. Algorithm evaluations also show the presented method outperforms other 3D retrieval methods.

A CAD Template Approach to Support Web-Based Customer Centric Product Design

2005 ◽  
Vol 5 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Zahed Siddique ◽  
Karunakar Boddu
Keyword(s):  
Product Design ◽  
Design Process ◽  
Mass Customization ◽  
Computer Aided Design ◽  
Cad Model ◽  
Entire Family ◽  
Web Based ◽  
Computer Aided ◽  
Aided Design ◽  
Configurable Products

In order to provide products that can be tailored to the need of the customer, it is necessary to integrate the customer into the design process. In this paper we present a mass customization computer-aided design (CAD) framework that helps to integrate the customer into the design of user-configurable products. A template approach, which considers both modularity and scaling, is utilized to concisely represent a CAD model of the entire family. The system accepts user selections and parameters to automatically create a CAD model of the customized product in real time and then shows the model to the user. The system is implemented using PRO/ENGINEER and demonstrated through customization of bicycle frames.

Curvature Estimation for Metrology of Non-Rigid Parts

2013 ◽  
Author(s):  
Ali Aidibe ◽  
Souheil-Antoine Tahan
Keyword(s):  
Residual Stresses ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Cad Model ◽  
New Approach ◽  
Profile Deviation ◽  
Defect Area ◽  
Computer Aided ◽  
Curvature Estimation ◽  
Aided Design

At the end of the manufacturing process, engineers need to know if a manufactured part fits its computer-aided design (CAD) model and how is the amplitude of inherent variation of manufacturing process. Non-rigid parts, at free state condition, may have a significant different form than their CAD model due to gravity loads; residual stresses induced distortion and/or assembly load. Today, a complicated and expensive specialized fixture is needed to conform these parts. To tackle the above challenges, we present in this paper a new approach for metrology of fixtureless non-rigid parts. This approach combines the curvature properties of manufactured parts with the extreme value statistic test as identification method to distinguish profile deviation due to the manufacturing process from part’s deformation due to the flexibility of the part and to determine whether the tolerance fits the CAD model or no. This approach is tested on simulated typical industrial sheet metal giving satisfying results in terms of percentage of errors in defect area and in peak profile deviation estimated.

Design of a Novel Statically Balanced Mechanism for Laparoscope Holders With Decoupled Positioning and Orientating Manipulation

2014 ◽  
Author(s):  
Chin-Hsing Kuo ◽  
Shao-Jung Lai
Keyword(s):  
Parallel Mechanism ◽  
Design Procedure ◽  
Static Balance ◽  
Cad Model ◽  
End Effector ◽  
Surgical Incision ◽  
Physical Prototype ◽  
Position And Orientation ◽  
Insertion Length ◽  
Kinematic Properties

This paper presents a novel mechanism concept of laparoscope holders used for minimally invasive surgery (MIS). The mechanism is made of a parallelogram linkage and a parallel mechanism, which respectively serve as a robotic positioning arm and an orientating wrist of the holder. Due to its special geometry, the mechanism possesses several interesting kinematic properties. First, the laparoscope, which is held by the end-effector, can illustrate a remote center-of-motion (RCM) kinematics at the surgical incision point. Second, the position of the RCM point is solely defined by the parallelogram, whereas the orientation and insertion length of the laparoscope are governed by the parallel mechanism. Such an arrangement suggests a decoupled positioning and orientating manipulation for the holder, which is clinically helpful in laparoscopic MIS. Third, the overall mechanism including the parallelogram linkage and the parallel mechanism can be perfectly statically balanced at any configuration within the workspaces by using common linear springs. In other words, no electrical actuation or mechanical locks are required for making the laparoscope rest at any position and orientation. The design procedure for static balancing is detailed in the paper, and the theoretically perfect static balance of the mechanism is verified by a numerical example and computer simulation. Furthermore, a CAD model of the holder is constructed for evaluating its workspaces and a physical prototype is built up and tested. As a result, the prototyped holder is fully statically balanced within a sufficient workspace for practical MIS environment.

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