The Vehicle Terrain Performance Lab (VTPL) has adopted a holistic approach toward its research, investigating all aspects of vehicle-terrain interactions, and using a broad range of measurement, analysis, and modeling tools. This approach allows the researchers to broaden their expertise while gaining a deeper understanding of the fundamental issues that are involved in improving vehicle system performance.
The vehicles being studied include passenger cars and trucks, commercial vehicles, military vehicles, motorcycles, and more. Critical components of the vehicle system are studied in detail: tires, dampers, and other chassis and steering components. Racetracks, proving grounds, highways, residential streets, and off-road trails are all important terrain to be studied. Understanding how the terrain and the vehicle interact to affect performance is the founding research goal of the lab.
Understanding the vehicle responses resulting from a vehicle traversing terrain is critical in predicting and improving vehicle system performance. This requires a thorough understanding of tire dynamics, chassis design, and vehicle dynamics, and the ability to accurately model these dynamics. Vehicle performance includes the prediction of objective metrics for handling, chassis durability and reliability, and the development of durability testing schedules. Performance can also be the subjective perception of a passenger when traveling in a vehicle; in which case haptics, bio-dynamics, and psychometrics are crucial.
Areas of Expertise
Stochastic models are developed to characterize terrain surfaces and describe their physical characteristics. The ability to characterize terrain is critical for pavement health monitoring and durability test schedule development, for example. These mathematical models are also used to create synthetic terrain surfaces. The synthetic terrain is used whenever it is impractical to simulate very long test sections, or when simulating terrain variations that exist in the real operating conditions is important. Auto-Regressive models, Markov Chains, Hidden Markov Models, Wavelets, Kriging, and Morphological filtering are in development.
The VTPL performs empirical and analytical modeling of the vehicle and tire. Nonlinear multi-body dynamic models are developed to understand the vehicle responses to the terrain. Tires are tested to determine nonlinear characteristics, such as the enveloping properties, and models are developed based on these empirical results. For example, characteristic constraint modes are used to capture tire deformations, with the resulting modes used in a nonlinear model to predict loading.
The VTPL applies its expertise in terrain measurement and modeling, and vehicle and component modeling, to improve vehicle system performance. Improvements can be made to ride and handling metrics, durability test schedules, and subjective performance metrics. Psychometric studies quantifying the perceptions and preferences of drivers to subjective performance metrics such as ride quality have been conducted. The comprehensive suite of measurement, analysis, and modeling tools and expertise – developed by the VTPL – results in accurate predictions of a vehicle’s performance early in the development cycle enables better-informed, less-costly, and more product-focused design decisions that ultimately lead to better vehicles, tires and roads.