Experiments Using Multimodal Virtual Environments in Design for Assembly Analysis

The goal of this work is to investigate whether estimates of ease of part handling and part insertion can be provided by multimodal simulation using virtual environment (VE) technology. The long-term goal is to use this data to extend computer-aided design (CAD) systems in order to evaluate and compare alternate designs using design for assembly analysis. A unified, physically-based model has been developed for modeling dynamic interactions and has been built into a multimodal VE system called the Virtual Environment for Design for Assembly (VEDA). The designer sees a visual representation of objects, hears collision sounds when objects hit each other, and can feel and manipulate the objects through haptic interface devices with force feedback. Currently these models are 2D in order to preserve interactive update rates. Experiments were conducted with human subjects using a two-dimensional peg-in-hole apparatus and a VEDA simulation of the same apparatus. The simulation duplicated as well as possible the weight, shape, size, peg-hole clearance, and fictional characteristics of the physical apparatus. The experiments showed that the multimodal VE is able to replicate experimental results in which increased task completion times correlated with increasing task difficulty (measured as increased friction, increased handling distance, and decreased peg-hole clearance). However, the multimodal VE task completion times are approximately twice those of the physical apparatus completion process. A number of possible factors have been identified, but the effect of these factors has not been quantified.