Workspace atlases for the computer aided design of the Delta robot

2003 ◽  
Vol 217 (8) ◽  
pp. 861-869 ◽  
Author(s):  
X-J Liu ◽  
J Wang ◽  
H Zheng
Keyword(s):  
Physical Model ◽  
Optimum Design ◽  
Computer Aided Design ◽  
Solution Space ◽  
Parallel Robots ◽  
New Method ◽  
Performance Criteria ◽  
Computer Aided ◽  
Aided Design

Parallel robots lead to complex kinematics equations, so determination of their workspaces is a challenging issue. The workspace of a robot is not fully characterized by its volume alone; the workspace shape is an important aspect as well. In this paper, the geometric determination of the workspace for Delta robots is presented. The workspace (workspace volume and workspace shape) for the robots is studied systematically in ‘the physical model of the solution space’, which is a useful tool to express relationships between the performance criteria and all link lengths of one type of robotic mechanism. Performance atlases of the workspace volume for the robots 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 as well. The physical model of the solution space presents a new method for the computer aided design (CAD) of robotic mechanisms. The results are very useful for obtaining the optimum design of robotic mechanisms.

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.

Designing of Outriggers for the Needs of the Vehicles Stability Testing

2018 ◽  
Vol 875 ◽  
pp. 71-76
Author(s):  
Victor Kryaskov ◽  
Andrey Vashurin ◽  
Anton Tumasov ◽  
Alexey Vasiliev
Keyword(s):  
Coefficient Of Friction ◽  
Computer Aided Design ◽  
Strength Analysis ◽  
Direct Impact ◽  
Stability Testing ◽  
Supporting Surface ◽  
Stability Tests ◽  
Computer Aided ◽  
Aided Design

This paper is dedicated to the issues of designing of outriggers for avoidance of vehicle tilting during its stability tests. An analysis of existing types of outriggers was done by authors as well as legislative requirements on them. The reliable and well-timed operation of outriggers largely depends on the height of their positioning on a vehicle. In order to determine this important parameter a special methodic of determining the tipping angle of the vehicle with the use of computer-aided design (CAD) was composed by authors. The article also contains some main principles of strength analysis of the structure a very important part of which became the necessity of determination of coefficient of friction between the outrigger sliders and the supporting surface. This coefficient has a direct impact on the value of transverse forces appearing at the ends of outrigger beams.

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.

Feature Edge Extraction Via Angle-Based Edge Collapsing and Recovery

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Soji Yamakawa ◽  
Kenji Shimada
Keyword(s):  
Adverse Effects ◽  
Computer Aided Design ◽  
Region Growing ◽  
New Method ◽  
Small Radius ◽  
Edge Extraction ◽  
Line Segments ◽  
Computer Aided ◽  
Downstream Processes ◽  
Aided Design

This paper presents a new method for extracting feature edges from computer-aided design (CAD)-generated triangulations. The major advantage of this method is that it tends to extract feature edges along the centroids of the fillets rather than along the edges where fillets are connected to nonfillet surfaces. Typical industrial models include very small-radius fillets between relatively large surfaces. While some of those fillets are necessary for certain types of analyses, many of them are irrelevant for many other types of applications. Narrow fillets are unnecessary details for those applications and cause numerous problems in the downstream processes. One solution to the small-radius fillet problem is to divide the fillets along the centroid and then merge each fragment of the fillet with nonfillet surfaces. The proposed method can find such fillet centroids and can substantially reduce the adverse effects of such small-radius fillets. The method takes a triangulated geometry as input and first simplifies the model so that small-radius, or “small,” fillets are collapsed into line segments. The simplification is based on the normal errors and therefore is scale-independent. It is particularly effective for a shape that is a mix of small and large features. Then, the method creates segmentation in the simplified geometry, which is then transformed back to the original shape while maintaining the segmentation information. The groups of triangles are expanded by applying a region-growing technique to cover all triangles. The feature edges are finally extracted along the boundaries between the groups of triangles.

scholarly journals COMPLEX USAGE OF 4D INFORMATION MODELLING CONCEPT FOR BUILDING DESIGN, ESTIMATION, SHEDULING AND DETERMINATION OF EFFECTIVE VARIANT

2006 ◽  
Vol 12 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Vladimir Popov ◽  
Saulius Mikalauskas ◽  
Darius Migilinskas ◽  
Povilas Vainiūnas
Keyword(s):  
Computer Aided Design ◽  
Information Technologies ◽  
Investment Project ◽  
Building Design ◽  
Product Lifecycle Management ◽  
Information Modeling ◽  
Information Modelling ◽  
Computer Aided ◽  
Aided Design

With the growth of information technologies in the field of construction industry, the concept of CAD (Computer Aided Design), which denotes just design operations using a computer acquires a new meaning and changes the contents lightening design process based on product modelling and further numerical simulation construction process and facility managing. New definitions as Building Information Modelling (BIM) and Product Lifecycle Management (PLM) are more and more usable as the definition of a new way approaching the design and documentation managing of building projects. The presented computer aided design technology based on the concept of graphical ‐ information modeling of a building, is combined with resource demand calculations, comparison of alternatives and determination of duration of all the stages of investment project life. The software based on this combined 4D PLM model is to be created as a means to manage effectively the investment project, starting from planning, designing, economical calculations, construction and afterwards to manage the finished building and to utilize it.

A Method of Determining the Direction of Two Dimensional Curves

2014 ◽  
Vol 980 ◽  
pp. 159-164
Author(s):  
F. Wang ◽  
R.K.F. Abdelmaguid ◽  
H.M.A. Hussein
Keyword(s):  
Computer Aided Design ◽  
Tangent Vector ◽  
Two Dimensional ◽  
Linear Algorithm ◽  
Complete Cycle ◽  
Angular Change ◽  
Computer Aided ◽  
Aided Design ◽  
Relationship Of

Two-dimensional curves are represented by a list of vertices and other parameters that control the shape or curvature of the segments. In computer programming to deal with closed two-dimensional curves, it is often required to know the direction of the curve, which is reflected by the sequence of the vertex data. It can be anticlockwise or clockwise. This paper presents a robust, linear algorithm to determine the direction of a closed two-dimensional curve, by computing the total angular change of a tangent vector travelling along the curve for a complete cycle. A new, robust linear algorithm is proposed for the determination of the positional relationship of a point to a two-dimensional curve. For curves that consist of line and arc segments, which are most commonly used in engineering applications in computer aided design, the paper presents algorithms and procedures for solving the above problems.

Optimum Design of Radial-Flow Impellers

1989 ◽  
Vol 203 (4) ◽  
pp. 229-232
Author(s):  
G S Ray ◽  
B K Sinha ◽  
S Majumdar
Keyword(s):  
Optimum Design ◽  
Centrifugal Force ◽  
Computer Aided Design ◽  
High Speed ◽  
Radial Flow ◽  
Design Stage ◽  
Early Design ◽  
Early Design Stage ◽  
Computer Aided ◽  
Aided Design

The paper presents a procedure of computer aided design of high-speed impellers. The configurations are obtained using programs for the strength under the influence of centrifugal force within given constraints. The method provides a tool for optimizing stresses at an early design stage.

A Novel Model for the Tolerancing of Nonrigid Part Assemblies in Computer Aided Design

2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Mehdi Tlija ◽  
Anis Korbi ◽  
Borhen Louhichi ◽  
Abdelmajid Benamara
Keyword(s):  
Computer Aided Design ◽  
Tolerance Analysis ◽  
Physical Factors ◽  
Worst Case ◽  
Manufacturing Defects ◽  
Computer Aided ◽  
Aided Design ◽  
Novel Model

In the design step, the realistic modeling of the product represents an industrial requirement and a digital muck up (DMU) improvement. Thus, the tolerance integration in the computer aided design (CAD) model with the neglect of important physical factors, such as the components’ deformations during the mounting and assembly operation, causes a deviation between the numerical and the realistic models. In this regard, this paper presents a new model for the tolerance analysis of CAD assemblies based on the consideration of both manufacturing defects and deformations. The dimensional and geometrical tolerances are considered by the determination of assemblies’ configurations with defects based on the worst case tolerancing. The finite elements (FEs) simulation is realized with realistic models. An algorithm for updating the realistic mating constraints, between rigid and nonrigid parts, is developed. The case study of an assembly with planar and cylindrical joints is presented.

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