Implementation and Evaluation of Mixed Model Representation of Virtual Objects in a Haptic Based Virtual Assembly Platform

2017 ◽  
Author(s):  
Germánico González Badillo ◽  
Hugo I. Medellín-Castillo ◽  
Víctor E. Espinoza López
Keyword(s):  
Mixed Model ◽  
Virtual Assembly ◽  
Model Representation ◽  
Dynamic State ◽  
Assembly System ◽  
Assembly Systems ◽  
Assembly Process ◽  
Virtual Objects ◽  
Physics Simulation ◽  
Simulation Engines

Virtual assembly systems have become popular in recent years due to its ability to simulate natural interaction between parts and ease of manipulation by the user. One of the most relevant technologies used in virtual assembly systems are haptic devices that provide force feedback and allow simulating real word conditions, such as weight, inertia, texture and collisions. Physics simulation engines (PSE) are another important tool used to simulate a realistic behavior in virtual assembly systems by enabling the effect of gravity and collision response of the virtual objects, resulting in a real world behavior. However, the use of haptic systems together with physics simulation engines is costly in terms of computing resources. This cost is mainly associated to collision detection between virtual objects, and increases when the shapes represented within the PSE are more complex, resulting in a poor performance of the virtual assembly system, making very difficult to simulate the assembly of complex parts or use several parts in the assembly. The present work shows a new algorithm to simulate complex objects, by using a different representation of the same object according with its dynamic state during the assembly process. The results show that the use of mixed model representation reduce the computing time when assembling objects, thus improving the performance of the virtual assembly system and finally allowing a better comfort and performance of the user during the assembly process. The system HAMS (Haptic Assembly and Manufacturing System) was used for the experimental validation, also the simulation of four assembly tasks that simulate real assembly objects, has been conducted.

Physics Engines Evaluation Based on Model Representation Analysis

2014 ◽  
Author(s):  
Germánico González Badillo ◽  
Hugo I. Medellín Castillo ◽  
Theodore Lim ◽  
Víctor E. Espinoza López
Keyword(s):  
Virtual Environments ◽  
Dynamic Behavior ◽  
Collision Detection ◽  
Model Representation ◽  
Virtual Object ◽  
Virtual Objects ◽  
Physics Simulation ◽  
Representation Method ◽  
Assembly Tasks ◽  
Simulation Engines

Virtual environments (VE) are becoming a popular way to interact with virtual objects in several applications such as design, training, planning, etc. Physics simulation engines (PSE) used in games development can be used to increase the realism in virtual environments (VE) by enabling the virtual objects with dynamic behavior and collision detection. There exist several PSE available to be integrated with VE, each PSE uses different model representation methods to create the collision shape and compute virtual object dynamic behavior. The performance of physics based VEs is directly related to the PSE ability and its method to represent virtual objects. This paper analyzes different freely available PSEs — Bullet and the two latest versions of PhysX (v2.8 and 3.1) — based on their model representation algorithms, and evaluates them by performing various assembly tasks with different geometry complexity. The evaluation is based on the collision detection performance and their influence on haptic-virtual assembly process. The results have allowed the identification of the strengths and weaknesses of each PSE according to its representation method.

3D Object Representation for Physics Simulation Engines and its Effect on Virtual Assembly Tasks

2012 ◽  
Author(s):  
Germanico Gonzalez ◽  
Hugo I. Medellin ◽  
Theodore Lim ◽  
James M. Ritchie ◽  
Raymond C. W. Sung
Keyword(s):  
Collision Detection ◽  
Object Representation ◽  
Virtual Assembly ◽  
Detection Algorithm ◽  
Convex Decomposition ◽  
Virtual Objects ◽  
Detection Algorithms ◽  
Physics Simulation ◽  
Assembly Tasks ◽  
Simulation Engines

Physical based modelling (PBM) uses physics simulation engines (PSE) to provide the dynamic behaviour and collision detection of virtual objects in virtual environments emulating the real world. There exists a variety of PSEs, each one with pros and cons according to the application in which they are employed. Each physics engine uses its proprietary collision detection algorithm. Collision detection is a key aspect of assembly tasks and its performance is dependent on the way virtual objects are represented. In general, objects can be divided into two groups: convex and concave, the latter being the most common and challenging for collision detection algorithms. This study reports on three different methods to represent concave objects. GIMPACT, Hierarchical Approximate Convex Decomposition (HACD) and Approximate Convex Decomposition (ACD), which are evaluated and compared based on their collision detection performances. An exact convex decomposition algorithm, named as ConvexFT, is also proposed and analyzed in this paper. Finally the performance of the three existing methods and the ConvexFT proposed approach are compared in order to assess which model representation algorithm is best suited for haptic-virtual assembly tasks.

A Human-Centered Virtual Assembly System

2009 ◽  
Vol 16-19 ◽  
pp. 796-800 ◽  
Author(s):  
Peng Chen ◽  
Ping Jun Xia ◽  
Yue Dong Lang ◽  
Ying Xue Yao
Keyword(s):  
Motion Capture ◽  
Virtual Assembly ◽  
Optimization Method ◽  
Virtual Manufacturing ◽  
Assembly System ◽  
Assembly Process ◽  
New Approach ◽  
Assembly Operation ◽  
Assembly Design ◽  
Human Modeling

Virtual manufacturing technology has become an effective method for decision and planning in manufacturing. Due to ergonomics problems are widely concerned in assembly design planning, a human-centered virtual assembly system framework is proposed for ergonomics analysis for assembly operation in this paper. The six-layer framework integrates virtual human modeling, motion capture and recognition, ergonomics evaluation and virtual assembly process planning as an organic whole. Data exchanging and system function are discussed based on this framework. The work in virtual reality (VR) technology, motion capture technology, ergonomics method and optimization method for implementing the system is also described. The framework would provide a new approach for the combination of virtual manufacturing and ergonomics analysis in the future.

Study on Desktop Virtual Assembly System for Interactive Assembly Process Planning

2010 ◽  
Vol 426-427 ◽  
pp. 371-375
Author(s):  
Dan Zhang ◽  
Guang Ming Jiao ◽  
Dun Wen Zuo ◽  
Jian Xie ◽  
J.P. Li ◽  
...  
Keyword(s):  
Process Planning ◽  
Process Design ◽  
Virtual Assembly ◽  
Data Conversion ◽  
Assembly System ◽  
Assembly Process ◽  
Assembly Process Planning ◽  
Key Technologies ◽  
Assembly Operations ◽  
Assembly Models

Aiming at the shortcomings of traditional assembly process design and immersive virtual assembly system, the architecture of Desktop Virtual Assembly System (DVAS) for interactive assembly process planning is presented. The key technologies such as data conversion and reconstruction of assembly models, assembly intention recognition and assembly control navigation are studied. The lightweight storage of assembly models’ data and the intelligent constraints recognition are realized. The problem of assembly operations resulted from the lack of immersion is solved by movement navigation. The algorithms were proposed and applied to the DVAS prototype, and an application case is studied to demonstrate the effectiveness of the system.

scholarly journals A new methodology to evaluate the performance of physics simulation engines in haptic virtual assembly

2014 ◽  
Vol 34 (2) ◽  
pp. 128-140 ◽  
Author(s):  
Germanico Gonzalez-Badillo ◽  
Hugo I. Medellin-Castillo ◽  
Theodore Lim ◽  
James M. Ritchie ◽  
Raymond C.W. Sung ◽  
...  
Keyword(s):  
Force Feedback ◽  
Weight Perception ◽  
Virtual Assembly ◽  
Third Party ◽  
Task Completion ◽  
Dynamic Complexity ◽  
Content Type ◽  
Simulation Engine ◽  
Physics Simulation ◽  
Simulation Engines

Purpose – In this study, a new methodology to evaluate the performance of physics simulation engines (PSEs) when used in haptic virtual assembly applications is proposed. This methodology can be used to assess the performance of any physics engine. To prove the feasibility of the proposed methodology, two-third party PSEs – Bullet and PhysXtm – were evaluated. The paper aims to discuss these issues. Design/methodology/approach – Eight assembly tests comprising variable geometric and dynamic complexity were conducted. The strengths and weaknesses of each simulation engine for haptic virtual assembly were identified by measuring different parameters such as task completion time, influence of weight perception and force feedback. Findings – The proposed tests have led to the development of a standard methodology by which physics engines can be compared and evaluated. The results have shown that when the assembly comprises complex shapes, Bullet has better performance than PhysX. It was also observed that the assembly time is directly affected by the weight of virtual objects. Research limitations/implications – A more comprehensive study must be carried out in order to evaluate and compare the performance of more PSEs. The influence of collision shape representation algorithms on the performance of haptic assembly must be considered in future analysis. Originality/value – The performance of PSEs in haptic-enabled VR applications had been remained as an unknown issue. The main parameters of physics engines that affect the haptic virtual assembly process have been identified. All the tests performed in this study were carried out with the haptic rendering loop active and the objects manipulated through the haptic device.

Research and Development of CA6140 Virtual Assembly System

2014 ◽  
Vol 621 ◽  
pp. 558-563
Author(s):  
X.M. Li ◽  
Ya Lin Shen ◽  
L.H. Zhu
Keyword(s):  
Employee Training ◽  
Virtual Assembly ◽  
3D Models ◽  
Assembly System ◽  
Motion Simulation ◽  
Virtual Technology ◽  
Working Principle ◽  
Programming Software ◽  
Indispensable Tool ◽  
Visual Basic 6.0

On the basis of analyzing assembly process of main structural components in CA6140 lathe, 3D models for those components were established with CAD software UGNX6.0. Virtual assembly and motion simulation of the structure parts were performed with virtual technology. A set of virtual assembly system of CA6140 engine lathe was developed with programming software Visual Basic 6.0. It contains six main modules about spindle box, feed box, apron, tailstock, turret, etc. Dynamic simulation and motion simulation of the corresponding components in entity lathe can be realized, respectively. And also, mechanical structure, working principle, assembly relation between different components and motion transmission process of the lathe can be realistically reproduced with the system. This virtual assembly system not only can be used to analyze and transform old products, but also can be used in new products development, and to some extent, can be used to replace the prototype. It is an indispensable tool in the employee training and mechanical engineering activities.

Study on Mixed Assembly Modeling of Rigid and Flexible Parts for Aerospace Product Virtual Assembly

2010 ◽  
Vol 431-432 ◽  
pp. 9-12 ◽  
Author(s):  
Dan Zhang ◽  
Dun Wen Zuo ◽  
Guang Ming Jiao ◽  
Jian Xie ◽  
Hua Lin Zhou ◽  
...  
Keyword(s):  
Hierarchical Model ◽  
Graph Model ◽  
Virtual Assembly ◽  
Assembly Process ◽  
Assembly Model ◽  
Assembly Modeling ◽  
Cable Harness ◽  
Modeling Process ◽  
Flexible Parts ◽  
And Storage

According to the characteristics of aerospace product, the model representation and storage of the rigid part and cable harness is proposed. The Dendritic Correlative Model of Mixed Assembly of Rigid and Flexible Parts (DCMMA-RFP) is introduced based on the hierarchical model and graph model. The assembly model which realizes the lightweight storage can clearly represent the hierarchy relation and assembly process of aerospace products. The assembly modeling process in the virtual assembly environment is detailed described. Finally the effectiveness of DCMMA-RFP is verified by an example.

The Modeling and Locating Technology of Assembly\Disassembly Tools in Virtual Environment

2013 ◽  
Vol 483 ◽  
pp. 229-233
Author(s):  
Yi Liu ◽  
Shi Qi Li ◽  
Jun Feng Wang
Keyword(s):  
Real Time ◽  
Virtual Environment ◽  
Virtual Assembly ◽  
Vector Model ◽  
Assembly System ◽  
Virtual Scene ◽  
Matching Constraints ◽  
Point Vector

This paper presents a feasible approach for modeling and locating of assembly\disassembly tools in the virtual scene: First, a novel point-vector model for tool is presented by means of abstracting the locating constraints of tools; Then, the mapping relationship for locating constraints between tools and parts is detailed; Finally, the best matching constraints algorithm is proposed on basis of point-vector model, which can calculate the locating constraints to the triangle model of part in real time. The proposed method has been integrated in the virtual assembly system to solve practical assembly problems.

The Research of Virtual Assembly of Cotton Picker Roller Based on Virtual Reality

2010 ◽  
Vol 156-157 ◽  
pp. 496-499
Author(s):  
Wen Lei Sun ◽  
Yu Shan Cao ◽  
Wei Sun
Keyword(s):  
Virtual Reality ◽  
Three Dimensional ◽  
Virtual Assembly ◽  
Assembly Process ◽  
Software Environment ◽  
Virtual Scene ◽  
Mapping Software ◽  
Three Dimensional Mapping ◽  
Cotton Picker ◽  
Dimensional Mapping

This paper took the roller of a new cotton picker as the example, drew its various parts and assemblyed overally in the three-dimensional mapping software environment of UG, imported the models into the virtual reality assembly platform by the interface between UG and VAPlatform, added the virtual hand and carried through the virtual assembly in the virtual scene based on the certain assembly restriction in UG. The paper realized the visualization of the assembly path, offered the foundation for the feasible assembly path, and finally obtained the reasonable assembly process, provided a set of reasonable operation guide for the workers to assemble the cotton pickers.

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