|
Vehicle Terrain Performance Laboratory
Technical Overview
Mission
The mission of the VTPL is to improve vehicle system performance by studying the interactions between vehicles and terrain.
Scope Location
The lab 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 off-road and military vehicles, motorcycles, and more. Critical components of the vehicle system are studied in detail: tires, dampers, and other chassis and steering components. Of equal interest to the lab is the terrain that vehicles traverse. Terrain includes the on-road driving experience and harsh off-road conditions. The on-road driving experience includes test tracks, highway travel, and rough city streets. Off-road terrain may be deformable surfaces such as soil, snow, and sand, or non-deformable surfaces such as rocks and fallen trees.
Understanding the loading that results from a vehicle traversing terrain is the first step in studying the performance. This seminal issue requires a thorough understanding of terramechanics, tire/soil interactions, tire dynamics, chassis design, and vehicle dynamics. Performance can also be the subjective response of a passenger when traveling in a vehicle; in which case haptics, bio-dynamics, and psychometrics will be investigated. These are just a few examples of the many performance issues that the Vehicle Terrain Performance Laboratory is pursuing.
Our mission is pursued through research in four areas of expertise:
Terrain Measurement
Terrain surface measurements are achieved using the Vehicle Terrain Measurement System (VTMS). The VTMS is a state-of-the-art test bed for integrating technologies from different disciplines, allowing researchers to validate their theoretical and computation work with experimental data. The system is capable of scanning the complete topology of the terrain surface, in 3 dimensions, while simultaneously tracking the position, orientation, and speed of the vehicle. The VTMS provides millimeter the precision required for high-fidelity vehicle simulations for validation of vehicle and tire models, tuning of chassis components, and performance predictions.
Terrain Modeling
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.
Vehicle Modeling
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.
Performance Prediction
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.
Location
The Vehicle Terrain Performance Laboratory is located in the Charles Hawkins Research Center directly adjacent to the IALR. This new facility has 2000 sq. ft. of dedicated vehicle research space including a vehicle hoist and vehicle exhaust ports.
|
