Optimized Chassis Stability Relative to Dynamic Terrain Profiles in a Self-Propelled Sprayer Multibody Dynamics Model

Highlights This study presented a new optimization methodology using a prismatic joint with high stiffness and damping. The virtual suspension model contained the main bodies, an optimization subsystem, and a free-floating cylinder. Under aggressive terrain, an optimized chassis platform resulted in a 19.5% increase in boom height stability. Abstract. Multibody dynamics (MBD) models are continuing to be valuable for engineering design and product development, 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 uncertainty within model outputs; however, this study developed a new MBD methodology to automatically determine the optimized 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 traversed across dynamic terrain conditions. This optimization response was also accomplished by replacing the baseline chassis 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. Keywords: Boom height, Chassis suspension, Multibody dynamics (MBD), Optimization, Prismatic joint, Simulation, Terrain.