Aerodynamic Crosswind Sensitivity Analysis
L. D. Metz*
University of Illinois

Automobile behavior and control are studied in the presence of significant crosswinds. Qualitative and quantitative measures of performance have been modeled and results compiled for a variety of vehicles (automobiles, sport/utility vehicles, vans, and pick-up trucks).

Dynamics of Vehicles Braked at the Emergency Limit
L. D. Metz*
University of Illinois

Vehicles with locked wheels exhibit both yaw and lateral instability in addition to roughly longitudinal deceleration. This work focuses on calculation of vehicle trajectories under such conditions.

Enhancement of Road Vehicle Performance through Aerodynamic Tuning
L. D. Metz*
University of Illinois

Road vehicle aerodynamics has up to now been concentrated on drag reduction. This work examines potential handling and braking performance improvements that could be made through proper use of vehicle aerodynamics. The practicality of the enhancements is also addressed in light of packaging and styling considerations.

Flat Tire Vehicle Dynamics
L. D. Metz*
University of Illinois

This work examines the vehicle dynamics associated with a single flat tire at various locations on automobiles. Fixed control and active steering vehicle dynamic response are studied. Effects associated with understeer/oversteer, tire capabilities, and vehicle inertial properties are included. Effects of underinflation of a pair of tires are also included. A road vehicle and a racing car are examined.

Active Air Suspension for Commercial Vehicles
R. L. Ruhl,* J. V. Medanic
University of Illinois

Commercial vehicles typified by a Class 8 tractor and trailer have, by necessity, a high mass center. Rollover frequency goes up exponentially with decreased rollover threshold. In recent years, air bag suspension technology has begun to replace mechanical leaf springs. Current control technology attempts to provide closed loop position control on ride height and to deliberately ignore road transients in the interest of reduced air consumption. This research attempts to determine the feasibility of sensing incipient roll and to provide a stabilizing roll moment by lateral biasing of air bag pressure.