PROTOTYPING AND DESIGN FOR ASSEMBLY ANALYSIS USING MULTIMODAL VIRTUALENVIRONMENTS

The goal of this work is to investigate whether estimates of ease of p art handling and part insertion can be provided by multimodal simulati on using virtual environment (VE) technology, rather than by using con ventional table-based methods such as Boothroyd and Dewhurst Charts. T he long term goal is to extend CAD systems to evaluate and compare alt ernative designs using Design for Assembly Analysis. A unified physica lly based model has been developed for modeling dynamic interactions a mong virtual objects and haptic interactions between the human designe r and the virtual objects. This model is augmented with auditory event s in a multimodal VE system called the Virtual Environment for Design for Assembly (VEDA). The designer sees a visual representation of the objects, hears collision sounds when objects hit each other and can fe el and manipulate the objects through haptic interface devices with fo rce feedback. Currently these models are 2D in order to preserve inter active update rates. Experiments were conducted with human subjects us ing two-dimensional peg-in-hole apparatus and a VEDA simulation of the same apparatus. The simulation duplicated as well as possible the wei ght, shape, size, peg-hole clearance, and frictional characteristics o f the physical apparatus. The experiments showed that the Multimodal V E is able to replicate experimental results in which increased task co mpletion times correlated with increasing task difficulty (measured as increased friction, increased handling distance combined with decreas ed peg-hole clearance). However, the Multimodal VE task completion tim es are approximately two times the physical apparatus completion times . A number of possible factors for this temporal discrepancy have been identified but their effect has not been quantified. Copyright (C) 19 97 Elsevier Science Ltd.