Vehicle dynamics are well understood by both academic researchers and automotive industries. And while modeling and simulation tools are still underutilized, they are becoming more frequently used in the vehicle design process. However, there is still lacking an overall design methodology that can link and integrate in a systematic fashion the design tasks of individual components or systems such that the vehicle performs as intended with a minimal number of design iterations. A process called Target Cascading, applied in the early stages of vehicle design, might serve as this systematic design methodology. In this paper, Target Cascading is evaluated for its ability to propagate top-level design specifications down to specifications for various subsystems and components in a vehicle design problem. More specifically, general ride and handling targets are set for a vehicle and these are cascaded down through the suspension, tire pressure and spring design levels by partitioning the original problem into a hierarchical set of subproblems. At a given level, an optimization problem is formulated to minimize deviations from the proposed targets and thus achieve intersystem compatibility. A coordination strategy links all subproblem decisions so that the overall supersystem performance targets are met. Results are presented that demonstrate Target Cascading’s utility in unearthing tradeoffs and incompatibilities among initial targets early in the vehicle development cycle. Throughout the paper, the Target Cascading process is compared to traditional vehicle design strategies for achieving ride and handling targets. Target Cascading appears to be a promising systematic technique for the design of vehicles to meet ride and handling specifications.

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