Influence of the distances between the axles in the vertical dynamics of a military vehicle equipped with magnetorheological dampers 2018-36-0232

While traveling on any type of ground, the damper of a vehicle has the critical task of attenuating the vibrations generated by its irregularities, to promote safety, stability, and comfort to the occupants. To reach that goal, several passive dampers projects are optimized to embrace a bigger frequency range, but, by its limitations, many studies in semiactive and active dampers stands out by promoting better control of the vehicle dynamics behavior. In the case of military vehicles, which usually have more significant dimensions than the common ones and can run on rough or unpaved lands, the use of semi-active or active dampers reveals itself as a promising alternative. Motivated by that, the present study performs an analysis of the vertical dynamics of a wheeled military vehicle with four axles, using magnetorheological dampers. This study is made using a configuration of the distances between the axles of the vehicle, which is chosen from five available options. The proposed model uses the power flow concept to establish the kinematics relationships of the subsystems, and thus determinate the causality relationships among the components. In order to reduce the oscillations from the road input, a modeling of a magnetorheological suspension was combined using the hyperbolic tangent model operated by a fuzzy logic control. The computational implementation was developed in MATLAB® software Simulink version R2018a to reproduce the model using block diagram. The experiments resulted in a reduction of the chassis responses against the obstacle imposed. Despite the non-linearities and multiple system variables, intelligent control combined with a semi-active suspension improves the vehicle performance, especially at low speeds, reducing bounce and pitch oscillations. To conclude, the results presented are relevant and serve as a basis for the theoretical and experimental development of semi-active suspension designs for military vehicles.