Predicting the Image Stability Rating for an Automotive Side View Mirror System

Reflected image stability is the fundamental parameter used in the automotive industry to measure rearview mirror performance. Unfortunately it has always been necessary to wait until production units were designed, tooled, and built before the stability could be evaluated. The purpose of this paper is to develop a theoretical model based on experimental analysis that would predict a mirror's performance before the design ever left the computer environment. Benefits of revising a virtual design via such a model would be significant and include: reduction in life cycle timing, lower total tool costs, and higher customer satisfaction. Through observation, three basic factors affecting mirror stability were determined; resonant frequency, total deflection, and the moment created by the wind effect. Next, computer level manipulation was performed on each factor via modal analysis, finite element analysis (FEA) and computational fluid dynamics (CFD). Correlation was then established between each factor and the stability performance rating. Six case studies along with regression analysis and analysis of variance were utilized to create the individual stability equations.