Evaluation of Vehicle Drag Parameters From Coastdown Experiments Conducted Under Nonideal Environmental Conditions

Abstract

Parameter identification by optimization forms the analytical basis for extracting road load information from well controlled coastdown tests. Specific attention is given to the effects of both biased and random errors as may be caused by environmental disturbances, road conditions, inaccurate parameteric input, or signal and instrument noise. As a consequence, experimental conditions can be identified and quantitative criteria established for either avoiding or correcting such errors. Test results are presented which support the methodology and conclusions.