Virtual Road Load Data Acquisition in Practice at General Motors 2011-01-0025

Measured vehicle loads have traditionally been used as the basis for development of component, subsystem and vehicle level durability tests. The use of measured loads posed challenges due to the availability of representative hardware, scheduling, and other factors. In addition, stress was placed on existing procedures and methods by aggressive product development timing, variety in tuning and equipment packages, and higher levels of design optimization. To meet these challenges, General Motors developed new processes and technical competencies which enabled the direct substitution of analytically synthesized loads for measured data. This process of Virtual Road Load Data Acquisition (vRLDA) enabled (a) conformance to shortened product development cycles, (b) greater consistency between design targets and validation requirements, and (c) more comprehensive data. Further, the vRLDA process was predicated on accurately quantified vehicle components, with the analytical model serving to aggregate the component models. As a result, a change in focus from a single comprehensive measurement (RLDA) to characterization and verification of individual components developed. The technical demands, timing implications, and a brief history of application are discussed.