GPS-Based, Mobility Power Analysis of Military Vehicles with the WES Model

Abstract

Accurately quantifying the necessary power for locomotion is of principle concern when designing military, agricultural, construction, and mining vehicles that operate in an off-road environment. As a result, there is a need to better quantify the power and duty cycle requirements for a vehicle during certain operating conditions. To meet this demand, a GPS-based mobility power and duty cycle analysis is one approach that may accurately predict the power requirements of off-road vehicles. The motion resistance force generated at the wheel/track and soil interface is quantified via the U.S. Army Engineer Waterways Experiment Station's (WES) tractive performance model where the motion resistance force is a function of the tire geometry, the steering angle of the steered wheels, and the soil's cone index (CI). Initial application of the mobility power concept began when the wheeled Stryker vehicles and Amphibious Assault Vehicles (AAV) were equipped with GPS receivers and data acquisition equipment while conducting maneuvers in an off-road environment with a known CI. The mobility power analysis was applied to the GPS tracking data to identify the mobility power and duty cycle characteristics of the vehicles. The Stryker and AAV's average mobility power requirement was 37.4 and 198.7 kW respectively. By varying the soil's cone index value, it was determined that the motion resistance power increased substantially when less than 1000 kPa .