Heavy Truck Vehicle Dynamics and Parameter Estimation



The NCAT pavement test track is a Civil Engineering research facility at Auburn University whose primary function is to perform accelerated asphalt wear studies. The facility performs these studies on a 1.7 mile oval test track constructed with various asphalts on which they run five Class-8 long haul tractor-trailers 16 hrs a day, 5 days a week, for approximately two year test periods. During the inaugural construction of the NCAT asphalt test track, fuel economy decreased as the test period elapsed. When fuel economy was compared to the measured track roughness (measured in the International Roughness Index or IRI) there seemed to be a trend showing that as roughness increased, fuel economy decreased. This trend has motivated further research to rule out other external factors that may have contributed to this trend.

The GPS and Vehicle Dynamics lab was approached to research the heavy truck vehicle dynamics as they traversed the track and investigate various properties that may effect fuel economy. The project’s main thrust involves estimating various vehicle parameters within the longitudinal dynamics, such as the vehicle’s rolling resistance, air drag force, and mass. Various estimation techniques are used to identify the vehicle’s properties without disturbing the trucks primary research function of asphalt degradation. This work also evaluates these techniques in the presence of sensor noise, all with a goal to identify types of asphalt composition, construction and condition that results in the best fuel economy. This work also has applications to many advanced truck systems, which could benefit from improved vehicle parameter estimation.

Figure 1:


Vehicle and In-Cab Data Acquisition

Figure 2:


Longitudinal Dynamics Model