A Tool/Part/Human Interaction Model for Assembly in Virtual Environments

2000 ◽  
Author(s):  
Uma Jayaram ◽  
Hrishikesh Tirumali ◽  
Sankar Jayaram ◽  
Kevin Lyons
Keyword(s):  
Interaction Model ◽  
Virtual Assembly ◽  
Physical Reality ◽  
Human Interaction ◽  
Design Environment ◽  
Hand Part ◽  
Significant Step ◽  
Tool Accessibility ◽  
Tool Motion ◽  
Assembly Operations

Abstract Current virtual assembly environments primarily allow assembly operations involving pick and place manipulations with hands. In some applications, assembly tools snap onto screws and are constrained. Some non-immersive systems create tool motion script models for the tool to execute the assembly operation. The inclusion of tools and realistic tool operations is a significant step in creating a better virtual assembly environment. We propose a technique to model hand held tools and the corresponding assembly operations in a virtual environment. Intermediate-location constraints and tool engagement constraints obtained from the CAD model are used to model the intermediate positions and engagements of a fastener tool, tool-part, and base-part. In addition, tool-based motion dependent on the rotation of the tool and the pitch of the thread has been achieved for a fastener part This allows us to simulate the physical reality of these interactions without using expensive collide, penetrate, correct, and align methods. The tools and tool/hand/part interactions have been modeled and tested in a virtual assembly and design environment successfully. This capability also allows tool accessibility and tool operability to be verified.

Virtual Assembly Design Environment

1995 ◽  
Author(s):  
Hugh I. Connacher ◽  
Sankar Jayaram ◽  
Kevin Lyons
Keyword(s):  
Virtual Reality ◽  
Research Effort ◽  
New Technology ◽  
Natural Extension ◽  
Virtual Assembly ◽  
Software Systems ◽  
Design Environment ◽  
Cad System ◽  
Assembly Design ◽  
Design And Manufacturing

Abstract Virtual reality is a technology which is often regarded as a natural extension to 3D computer graphics with advanced input and output devices. This technology has only recently matured enough to warrant serious engineering applications. The integration of this new technology with software systems for engineering, design and manufacturing will provide a new boost to the field of computer-aided engineering. One aspect of design and manufacturing which may be significantly affected by virtual reality is design for assembly. This paper presents the ideas behind a current research effort aimed at creating a virtual assembly design environment and integrating that environment with a commercial, parametric CAD system.

MIVAS: A Multi-Modal Immersive Virtual Assembly System

2004 ◽  
Author(s):  
Huagen Wan ◽  
Shuming Gao ◽  
Qunsheng Peng ◽  
Guozhong Dai ◽  
Fengjun Zhang
Keyword(s):  
Virtual Environments ◽  
Large Scale ◽  
Force Feedback ◽  
User Interaction ◽  
Virtual Assembly ◽  
Research Area ◽  
Optimization Techniques ◽  
Assembly System ◽  
Assembly Operations ◽  
Assembly Constraints

Evaluation and planning of assembly processes in virtual environments have become an active research area in engineering community. However, planning of complex assemblies in virtual environments, especially large-scale virtual environments, is still hindered by limitations like unnatural user interaction, insufficient frame rates, and deficiencies in processing of assembly constraints. In this paper, we present MIVAS, a Multi-modal Immersive Virtual Assembly System. By viewing the virtual assembly system as a finite state machine, we incorporate tracked devices, force feedback dataglove, voice commands, human sounds, fully immersive 4-sided CAVE, together with optimization techniques for both complex assembly models and assembly operations to provide for engineers an intuitive and natural way of assembly evaluation and planning. Testing scenarios on disassembling different components of an intelligent hydraulic excavator are described. Special attention is paid upon such technical issues as interface between CAD packages and the CAVE virtual environment, natural and intuitive user interaction including realistic virtual hand interaction and force feedback, intelligent navigation for assembly operations, and real-time display of complex assemblies.

scholarly journals Dynamics of resource production and utilisation in two-component biosphere-human and terrestrial carbon systems

2007 ◽  
Vol 11 (2) ◽  
pp. 875-889 ◽  
Author(s):  
M. R. Raupach
Keyword(s):  
Soil Carbon ◽  
Interaction Model ◽  
Human Interaction ◽  
Resource Utilisation ◽  
State Variables ◽  
Oscillatory Behaviour ◽  
Stable States ◽  
Random Forcing ◽  
Plant Soil ◽  
Two Component

Abstract. This paper analyses simple models for "production-utilisation" systems, reduced to two state variables for producers and utilisers, respectively. Two modes are distinguished: in "harvester" systems the resource utilisation involves active seeking on the part of the utilisers, while in "processor" systems, utilisers function as passive material processors. An idealised model of biosphere-human interactions provides an example of a harvester system, and a model of plant and soil carbon dynamics exemplifies a processor system. The biosphere-human interaction model exhibits a number of features in accord with experience, including a tendency towards oscillatory behaviour which in some circumstances results in limit cycles. The plant-soil carbon model is used to study the effect of random forcing of production (for example by weather and climate fluctuations), showing that with appropriate parameter choices the model can flip between active-biosphere and dormant-biosphere equilibria under the influence of random forcing. This externally-driven transition between locally stable states is fundamentally different from Lorenzian chaos. A behavioural difference between two-component processor and harvester systems is that harvester systems have a capacity for oscillatory behaviour while processor systems do not.

Research on Knowledge-Based Virtual Assembly Planning

2007 ◽  
Vol 10-12 ◽  
pp. 435-439
Author(s):  
Bin Wang ◽  
D.F. Liu ◽  
P. Wang ◽  
Q.S. Xie
Keyword(s):  
Engineering Design ◽  
Virtual Assembly ◽  
Assembly Planning ◽  
Design Domain ◽  
Assembly Rules ◽  
Assembly Sequence ◽  
Design Environment ◽  
Assembly Design ◽  
Knowledge Based ◽  
Assembly Method

In order to find an optimum assembly sequence in engineering design domain, a knowledge-based virtual assembly approach was put forward. Virtual assembly design environment was also introduced, and knowledge representation models for virtual assembly rules and cases are introduced and studied respectively. A side-center virtual assembly method was applied to avoid the occurrence of assembly interference. Finally, a case was employed to demonstrate the practicality of knowledge-based virtual assembly planning.

scholarly journals Limiting Performance Analysis of Underwater Shock Isolation of a System with Biodynamic Response Using Genetic Algorithm

2000 ◽  
Vol 7 (5) ◽  
pp. 321-332 ◽  
Author(s):  
Z. Zong ◽  
K.Y. Lam ◽  
Tessa Gan
Keyword(s):  
Genetic Algorithm ◽  
Large Scale ◽  
Optimization Problem ◽  
Optimization Problems ◽  
Interaction Model ◽  
Human Interaction ◽  
Optimization Scheme ◽  
Underwater Shock ◽  
Shock Isolation ◽  
Very High

Biodynamic response of shipboard crew to underwater shock is of a major concern to navies. An underwater shock can produce very high accelerations, resulting in severe human injuries aboard a battleship. Protection of human bodies from underwater shock is implemented by installing onboard isolators. In this paper, the optimal underwater shock isolation to protect human bodies is studied. A simple shock-structure-isolator-human interaction model is first constructed. The model incorporates the effect of fluid-structure interaction, biodynamic response of human body, isolator influence. Based on this model, the optimum shock isolation is then formulated. The performance index and restriction are defined. Thirdly, GA (genetic algorithm) is employed to solve the formulated optimization problem. GA is a powerful evolutionary optimization scheme suitable for large-scale and multi-variable optimization problems that are otherwise hard to be solved by conventional methods. A brief introduction to GA is given in the paper. Finally, the method is applied to an example problem and the limiting performance characteristic is obtained.

A Conceptual Framework to Support Natural Interaction for Virtual Assembly Tasks

2011 ◽  
Author(s):  
Judy M. Vance ◽  
Georges Dumont
Keyword(s):  
Virtual Assembly ◽  
Human Interaction ◽  
Phase Model ◽  
Natural Interaction ◽  
Two Phase ◽  
Immersive Virtual Environment ◽  
Product Models ◽  
Design And Manufacturing ◽  
Cad Models ◽  
Assembly Tasks

Over the years, various approaches have been investigated to support natural human interaction with CAD models in an immersive virtual environment. The motivation for this avenue of research stems from the desire to provide a method where users can manipulate and assemble digital product models as if they were manipulating actual models. The ultimate goal is to produce an immersive environment where design and manufacturing decisions which involve human interaction can be made using only digital CAD models, thus avoiding the need to create costly preproduction physical prototypes. This paper presents a framework to approach the development of virtual assembly applications. The framework is based on a Two Phase model where the assembly task is divided into a free movement phase and a fine positioning phase. Each phase can be implemented using independent techniques; however, the algorithms needed to interface between the two techniques are critical to the success of the method. The paper presents a summary of three virtual assembly techniques and places them within the framework of the Two Phase model. Finally, the conclusions call for the continued development of a testbed to compare virtual assembly methods.

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