Three suspension structures including the parallel vertical suspension (PVS), the
horizontal parallel suspension (HPS), and the negative stiffness element added
into suspension (NSES) of the driver’s seat are proposed to improve the driver’s
ride comfort of off-road vehicles. Based on the dynamic models of the PVS, HPS,
and NSES established and simulated under the same random excitations of the cab
floor, the effect of the design parameters of the proposed models is analyzed,
and the design parameters are then optimized to evaluate their isolation
performance. The indexes of the root-mean-square (r.m.s) accelerations of the
vertical seat direction, pitching seat angle, and rolling seat angle are used as
the objective functions. The study results indicate that the dynamic parameters
of the PVS, HPS, and NSES greatly affect the driver’s ride comfort while their
geometrical dimensions insignificantly affect the driver’s ride comfort. With
the dynamic parameters of the PVS, HPS, and NSES optimized, the r.m.s seat
acceleration in the vertical direction with the NSES is strongly reduced by
74.0% in comparison with the HPS; while the r.m.s accelerations of the pitching
seat angle and rolling seat angle with the PVS are greatly decreased by 99.1%
and 99.8% compared to the NSES. Therefore, the ride comfort of the driver’s seat
is remarkably improved by using the NSES while the driver’s seat shaking is
obviously ameliorated by using the PVS. To enhance the ride comfort and reduce
the shaking of the driver’s seat, a combination of the PVS and NSES should be
applied to the seat suspension of off-road vehicles.
