Enhancing the ride comfort of off-road vibratory rollers with seat suspension using optimal quasi-zero stiffness

Abstract

The research proposes a new design of the seat suspension equipped with the quasi-zero stiffness (QZS) and hydraulic mount (HM) of the cab isolation system to improve the ride comfort of off-road vibratory rollers. To assess the ride comfort of the vehicle using the QZS and the HM, a dynamic model of the off-road vibratory roller is built and researched under various interactions of the drum/wheel and off-road terrain. Based on the multi-objective genetic algorithms, the design parameters of the QZS are also optimized to further enhance the vehicle’s ride comfort. The QZS optimized (QZSO)’s efficiency and the ride comfort of the off-road vibratory roller are analyzed based on the indexes of the seat displacement and acceleration; and the cab’s pitching and rolling acceleration. The experimental investigation is then carried out to verify the accuracy of the mathematical model and research result. The investigation result indicates that with the QZSO applied on the seat isolation, the Root-Mean-Square and Power-Spectral-Density of the acceleration responses of the seat and cab are greatly decreased compared to the seat isolation without the QZS in both the time and frequency regions. Particularly, the Root-Mean-Square acceleration of the seat is remarkably decreased by 61.7% when the vehicle is moving and 67.5% when the vehicle is working. Consequently, this research can provide a valuable reference and knowledge for the application of the QZSO on the driver’s seat suspension of off-road vehicles to optimize ride comfort.

Ride performance of driver’s seat suspension system using various dynamics models

“…To further enhance the isolation performance of the seat suspension, the damping parameter c s of the seat suspension added by the NSE-SM should be controlled. This is also the reason that the NSE and NSE-SM were researched and embedded into the seat suspension, [9][10][11][12][13][14][15][16][17][18][19][20] concurrently, the damping coefficients of the vehicle suspension systems were independently controlled. [2][3][4][5][6][7][8] However, combining both the NSE-SM and the control of the damping coefficient c s for the seat suspension has not been considered.…”

“…In order to further improve the ride comfort of the driver, the model of the negative-stiffness-element (NSE), [9][10][11] model of the magnetic-negative-stiffness damper, 12,13 and model of the quasi-zero-stiffness 14 had been studied and embedded into the driver's seat suspension. The effect of the dynamic parameters, geometrical dimension ratios, and stiffness ratio of the NSE on the ride performance was also analyzed based on the dimensionless characteristics between the restoring force/dynamic stiffness and displacement of the seat suspension.…”

“…However, comparative research between the NSE-SM and NSE has also not been performed yet. Moreover, in all the above researches of the seat suspension equipped with the NSE and NSE-SM, [9][10][11][12][13][14][15][16]19,20 a simple model of the seat suspension was mostly applied to evaluate the performance of the NSE and NSE-SM. In the actuality, the seat suspension is installed on the vehicle floor, thus, a dynamics model of the vehicle should also be applied to fully evaluate the isolation performance of the seat suspension models.…”

“…The effect of the dynamic parameters, geometrical dimension ratios, and stiffness ratio of the NSE on the ride performance was also analyzed based on the dimensionless characteristics between the restoring force/dynamic stiffness and displacement of the seat suspension. 15,16 The different structures of the NSE including the stiffness elements designed by the steel springs, air pistons, or curved mount spring rollers 10,11,17,18 were simulated and analyzed the performance of the seat suspension. The study results indicated that the seat suspension embedded by the NSE not only remarkably decreased the seat’s displacement and acceleration but also reduced the power spectral density seat’s acceleration at the low frequency.…”

“…1,5,21 Furthermore, with the NSE embedded into the driver’s seat suspension, the stiffness elements were mainly designed by the pairs of the steel springs or pneumatic springs in the horizontal direction and symmetrical to obtain the quasi-zero stiffness and decrease the vibration of the driver’s seat. 10,11,17,18 As we all know, in all suspension systems of the vehicle, cab, or seat, the dampers must be added to the suspension systems to generate the damping force and extinguish the vibrations. If the stiffness elements of the two horizontal springs in the NSE are replaced by the damping elements (DE) of the dampers, will the isolation performance of the seat suspension system be better?…”