Vertical Dynamics Modeling and Simulation of a Six-Wheel Unmanned Ground Vehicle

Vertical dynamics modeling and simulation of a six-wheel unmanned military vehicle (MULE) studied in this paper. The Common Mobility Platform (CMP) chassis provided mobility, built around an advanced propulsion and articulated suspension system gave the vehicle ability to negotiate complex terrain, obstacles, and gaps that a dismounted squad would encounter. Aiming at modeling of vehicle vertical dynamics, basic and geometrical parameters defined and degrees-of-freedom specified on a compromise between accuracy and complexity of two models. Equations of motion provided on two linear and nonlinear 5-degree-of-freedom models using two different modeling methods. There is good agreement between time responses of two presented models. The main differences of two models observed in articulated suspension degrees-of-freedom while the vehicle subjected to high frequency maneuvers that cause severe oscillations on wheels and arms in comparison to vehicle body due to lower mass and inertia properties. The linear model can be used to design a controller and the nonlinear to predict vehicle motion more accurately. Sensitivity analysis of the influential parameters is also presented to specify effects of different parameters. Results of this study may be used to design articulated suspension and making next frequency analyses.