Development of a consistent continuum of the dimensional parameters of a vehicle for optimization and simulation

Parametric vehicle modeling permits rapid iteration and optimization of vehicles in the conceptual design phase. A significant portion of vehicle design can be optimized parametrically without knowing specific details based on computer-aided design. Many overall characteristics of a vehicle such as the curb mass, the location of the center of gravity, the key dimensions, the occupant packaging, and the cargo volume can be assessed and improved at the parametric level. Targets for the vehicle such as the 0–60 mile/h acceleration time, the stopping distance, the fuel economy, the low-speed turn radius and aspects of the vehicle dynamics and handling can also be determined to a high level of confidence. In developing the vehicle’s dimensions for a parametric model it is recommended that a vehicle is built up using an ‘inside-out’ approach centered on effective knowledge-based occupant packaging. This work develops a continuum of the dimensional parameters which tie the vehicle’s internal and external dimensions together; it employs a combination of industry standard dimensions and component dimensions defined by the present authors, which make up the outside dimensions of the overall vehicle. In order to develop and optimize models for a desired vehicle type and size class, a knowledge base of typical values for the key dimensional parameters of a vehicle was compiled using a combination of data sources and field measurements. These values provide a useful starting point for the vehicle design and optimization process. They also increase optimization effectiveness, reducing the likelihood of local minima and maxima, and ensure that optimization begins within a valid design space.