OPTIMIZED CHASSIS STABILITY RELATIVE TO DYNAMIC TERRAIN PROFILES IN A SELF-PROPELLED SPRAYER MULTIBODY DYNAMICS MODEL

Multibody dynamics (MBD) models are continuing to be valuable for engineering design and product develop-ment, especially regarding subsystem optimization. Most MBD optimization processes begin with a sensitivity analysis of treatment factors and levels to understand how uncertainty in model inputs can be attributed to different sources of uncer-tainty within model outputs; however, this study developed a new MBD methodology to automatically determine the opti-mized dynamic chassis suspension responses on each corner of the vehicle from a single simulation for a self-propelled sprayer model as the chosen application use-case. This technique leveraged a prismatic joint (with a high spring stiffness and damping coefficient) connected between the chassis mainframe and the simplified optimization tire to create a distance constraint that held the chassis body at a near-consistent height above the ground. Then the solver optimized the response of the chassis suspension system to maintain a stable chassis platform relative to the terrain beneath it as the vehicle trav-ersed across dynamic terrain conditions. This optimization response was also accomplished by replacing the baseline chas-sis suspension components with a free-floating cylinder, which permitted the unrestricted, optimized motion needed to keep the chassis body at a near-level position with respect to the roll and pitch profiles of the terrain. For a simulation with an aggressive terrain configuration, the analysis showed that an optimized suspension system resulted in a 46% decrease in operator comfort and a 19.5% increase in overall boom height stability as the boom height control system better maintained a dynamic position closer to the specified target height.