A Graphical Representation of Road Profile Characteristics

Load data representing severe customer usage is required during the chassis development process. One area of current research is the use of road profiles for predicting chassis loads. The most direct method of predicting these loads is to run dynamic simulations of the vehicle using numerous road profiles as the excitation. This onerous task may be avoided, and a greatly reduced number of simulations would be required, if roads having similar characteristics can be grouped. Currently, road profiles are characterized by their spectral content. It has been noted by several researches, however, that road profiles are generally nonstationary signals that contain significant transient events and are not well described in the spectral domain. The objective of this work, then, is to develop a method by which the characteristics of the road can be captured by describing these constitutive transient events. Additionally, the representation developed in this work lends itself to a graphical characterization of the road profile. This allows the characteristics of a road to be immediately apparent by inspection. The insight gained from this representation is clearly demonstrated through examples. The implications of using this graphical representation are then discussed in terms of chassis load prediction, the chassis development process, and durability test schedule development. The graphical representation developed in this work allows the characteristics of road profiles to be quickly compared, to scrutinize differences in the nature of road profiles, and to group roads with similar characteristics.