Vertical Dynamics of a Fully Independent Suspension Vehicle
Rodrigo Veronese Moreira1; Alberto Paiva1
1 Universidade Federal Fluminense
doi:10.20906/CPS/CON-2016-1410
Resumo
Vehicle dynamics has been a point of great interest since the very beginning, when vehicles started to evolve in the early 1900's. Since then, a lot of physical models have been proposed - from the simple quarter-car model up to all-inclusive vehicle models. Moreover, localized refinement of these models may be introduced to scrutinize some desired features. With no doubts, commercial packages play an outstanding role to simulate more elaborated models. Nevertheless, handmade-implemented numerical codes enable thorough dynamical analyses. This paper presents a complete vehicle model, where the physical archetype consists of a seven-degree of freedom (DOF) system; where three of them are associated with the bounce, pitch and roll displacements of the vehicle chassis, while the four remaining DOF's are related to the independent suspension unsprung masses. To solve the resulting set of ordinary differential equations, the fourth-order Runge-Kutta method is employed. The parameters adopted in the simulations are related to a 4x2 commercial light truck, including empirical nonlinear performance curves for the front and rear suspension stiffness and damping, provided by a specific manufacturer. The numerical results consider three different pavement conditions - namely: a cobblestone road; a speed bump and a hole on the road. Besides, changes in the dynamical response are investigated through comparisons regarding: loaded/unloaded truck configurations and linear/nonlinear suspension elements (spring and damper), as well as variations in the performance curves for these elements.
Palavras-chave: Vehicle dynamics; fully independent suspension; nonlinear stiffness and damping