Virtual Reality Interactive Design Utilizing Meshless Stress Re-Analysis

Interactive design gives engineers the ability to modify the shape of a part and immediately see the changes in the part’s stress state. Virtual reality techniques are utilized to make the process more intuitive and collaborative. The results of a meshless stress analysis are superimposed on the original design. As the engineer modifies the design using subdivision volume free-form deformation, the stress state for the modified design is computed using a Taylor series approximation. When the designer requests a more accurate analysis, a stress re-analysis technique based on the pre-conditioned conjugate gradient method is used with parallel processing to quickly compute an accurate approximation of the stresses for the new design

A Virtual Reality Environment for Synthesizing Spherical Four-bar Mechanisms

This paper describes the development of a virtual reality environment which facilitates the design of spherical four-bar mechanisms. A short discussion of spherical mechanism design theory and computer-aided mechanism design is followed by a description of the virtual environment and the development and operation of the SphereVR program. The virtual environment allows the user to naturally interact with the input data and specify the design parameters while operating in a three-dimensional environment. We see this development as a logical extension of existing graphics-based spatial design software. The need for a three-dimensional design space is driven by the difficulty in specifying design inputs and constraints for a spatial problem using a two-dimensional interface. In addition, once the mechanism has been created, the virtual environment provides the opportunity for the user to visually verify that the mechanism will perform the desired three-dimensional motion

Implementing Speech Recognition in Virtual Reality

Virtual Reality (VR) is becoming an important tool in the engineering product development process. The virtual environment provides the user with the ability to interact with three-dimensional digital representations of products using natural head and hand motions. While interacting with digital objects in VR seems natural, the use of traditional two-dimensional menu systems does not always provide a convenient interface to controlling task specifications in the three-dimensional space. New human-computer-interfaces are needed for this emerging VR design tool. This paper will present the details of implementing a speaker-independent, command and control, speech recognition menuing system for a virtual reality application. The menuing system will be described as it is incorporated into a virtual environment for the design of spatial mechanisms. Design and technical issues involved in the interface creation process are discussed and the resulting interaction system is described

Effectiveness of Haptic Sensation for the Evaluation of Virtual Prototypes

Virtual reality techniques provide a unique new way to interact with three-dimensional digital objects. Virtual prototyping refers to the use of virtual reality to obtain evaluations of designs while they are still in digital form before physical prototypes are built. While the state-of-the-art in virtual reality relies mainly on the use of stereo viewing and auditory feedback, commercial haptic devices have recently become available that can be integrated into the virtual environment to provide force feedback to the user. This paper outlines a study that was performed to determine whether the addition of force feedback to the virtual prototyping task improved the ability of the participants to make design decisions. Seventy-six people participated in the study. The specific task involved comparing the location and movement of two virtual parking brakes located in the virtual cockpit of an automobile. The results indicate that the addition of force feedback to the virtual environment did not increase the accuracy of the participants’ answers, but it did allow them to complete the task in a shorter time. This paper describes the purpose, methods, and results of the study

Interactive Product Development and Haptics in Virtual Reality with VrM3d

The VrM3d design tool has been created to investigate the utility of interactive design in virtual reality with force feedback. VrM3d uses two iterative stress approximation methods for reanalyzing part geometry as it is deformed as well as mesh-free analysis to avoid mesh distortion issues, subdivision volume free-form deformation for shape changes, fast collision detection routines, and haptic feedback tied to stress analysis results for shape manipulation. The application runs in virtual reality on a variety of platforms, from desktop computers to the C6 virtual environment at Iowa State University

Virtual Hand Representations to Support Natural Interaction in Immersive Environment

Immersive Computing Technology (ICT) offers designers the unique ability to evaluate human interaction with product design concepts through the use of stereo viewing and 3D position tracking. These technologies provide designers with opportunities to create virtual simulations for numerous different applications. In order to support the immersive experience of a virtual simulation, it is necessary to employ interaction techniques that are appropriately mapped to specific tasks. Numerous methods for interacting in various virtual applications have been developed which use wands, game controllers, and haptic devices. However, if the intent of the simulation is to gather information on how a person would interact in an environment, more natural interaction paradigms are needed. The use of 3D hand models coupled with position-tracked gloves provide for intuitive interactions in virtual environments. This paper presents several methods of representing a virtual hand model in the virtual environment to support natural interaction

Using VPS (VoxMap Pointshell) as the Basis for Interaction in a Virtual Assembly Environment

Realistic part interaction is an important component of an effective virtual assembly application. Both collision detection and part interaction modeling are needed to simulate part-topart and hand-to-part interactions. This paper presents a comparison of several common collision detection algorithms and examines the VoxMap Pointshell (VPS) method as it is used in an application to evaluate proposed assembly methods. Results from several performance tests on VPS are presented. VPS was found to provide realistic collisions and physicallybased modeling interaction with excellent performance. This paper concludes by presenting how VPS has been implemented to handle multiple dynamic part collisions and two-handed assembly using the 5DT dataglove in a projection screen virtual environment

Modeling of Hydraulic Hose Paths

Hydraulic hoses are key components used to transfer power in heavy industrial machinery. The routing of these hoses is currently performed late in the product design process because no accurate physical models of the hoses exist that allow designers to predict the path the hoses will follow when installed in the machine. Designers must either guess the path the hose will take based on prior experience or wait until the first product prototype is built in order to experiment with the hose routes. This paper describes the use of ADAMS, a commercially available dynamic modeling package, to predict hose paths. The hose path model was verified by comparing the predicted paths to the paths of real hoses

A Conceptual Framework to Support Natural Interaction for Virtual 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

VEMECS: A virtual reality interface for spherical mechanism design

Mechanisms are one of the fundamental elements used by engineers in the design of machines. The design or synthesis of these elements has been studied for hundreds of years. More recently, the focus of kinematic synthesis research has been in reformatting the graphical synthesis methods into an analytical form compatible with computer processing. One of the thrusts of this research concentrates on the human/computer interface (HCI) between the user and the computer design software. The work presented in this paper addresses this issue of developing a new HCI for mechanism design based on virtual reality techniques. Current computer-aided mechanism design can be seen in the areas of analysis, topological, and dimensional synthesis (Erdman 1995). In each of these areas, the trend is toward developing user interfaces that are more compatible with the cognitive and perceptual nature of the designer. Mechanism synthesis computer programs like KINSYN (Rubel et al . 1977), LINCAGES-4 (Erdman and Riley 1981) and SPHINX (Larochelle et al . 1993) utilize the traditional HCI of monitor, keyboard and mouse. More recently, virtual reality (VR) is being examined as a natural human interface for mechanism design. Osborn (1994) developed the first virtual environment for the synthesis of spherical four-bar mechanisms, SphereVR, which used the Newton-Raphson iterative approach to solve the design equations. This paper takes a slightly different approach by combining the reliable and robust solution algorithms of SPHINX1.0 with VR technology. VR is used for all interaction, manipulation, and navigation throughout the design process, while SPHINX1.0 computational routines are used for computing the solution mechanisms. Natural and intuitive skills of the designer are used through reliance on a head tracked three-dimensional display and three-dimensional interaction. The result is a program called VEMECS (Virtual Environment MEChanism Synthesis). This paper outlines the organization and operation of VEMECS, and concludes with a discussion of the lessons learned in development and implementation of this approach