Articulated Vehicle Yaw Stability During Braking – A Parametric Study

An efficient model for simulating articulated vehicle dynamics for yaw stability during heavy braking is developed. The system’s governing equations are derived using Lagrange’s Equations, eliminating the need for any assumptions concerning forces at the tractor-trailer hitch. Detailed parametric results are presented. Six important dimensionless parameter groups affecting yaw stability are identified. Parametric plots based upon numerical simulations, are presented and a yaw stability limit criterion is defined to evaluate the simulation results. The graphical results show that increasing trailer braking consistently increases stability, while increasing the trailer to tractor weight-ratio decreases stability assuming balanced tractor braking. The most influential parameter affecting vehicle stability is the trailer fore/aft C.G. position.