On nonlinear yaw-roll-pitch model of the dynamics of log hauling trucks

A full nonlinear yaw-roll-pitch model of the dynamics of log hauling trucks is developed based on Kane's equations. All the joint stiffnesses, suspens ion springs and dampers, and the vertical compliance of the tyres are consi dered in the model. The relationships amongst the articulation angles betwe en the vehicle units, the sliding length of the drawbar, and the bounce of the trailing unit at the pintle hook joint, relative to the leading unit, h ave been introduced into the governing equations of motion. The orthogonal complement array and the zero eigenvalue method are used to deal with the c losed-loop constraint equation. The numerical results for directional respo nses of the system are checked against measured responses in field tests. A comparison of the results of the yaw-roll-pitch and a nonlinear yaw model is also carried out. The sensitivity of the handling performance due to cha nges in the magnitude of the mass and the location of the mass centre of th e payload and the stiffness and cornering characteristics of the tyres are investigated.