Isolation Efficiency of Vehicle Seat Suspension with Three Quasi-Zero Stiffness Models

This study proposes three different models of the quasi-zero stiffness (QZS) using the horizontal spring (QZS-HS), air piston (QZS-AP), and roller spring (QZS-RS) for the seat suspension of the vehicle to improve ride comfort. A dynamic model of the two-axle vehicle with the seat suspension added by the different QZS models has been established under the various excitations of the road surface. The design parameters of the different QZS models have been optimized to enhance the isolation efficiency and ride comfort. The indexes of the root mean square of the displacement (z_ws), acceleration (a_ws), and power spectral density acceleration (maximum PSD) of the driver's seat have been chosen to evaluate the vehicle's ride comfort and the isolation efficiency of three different QZS models. The results indicate that the seat suspension equipped with the different QZS models greatly improves the ride comfort in comparison with the seat suspension without the QZS. Also, the isolation efficiency of three different QZS models has been greatly affected by their design parameters. With the design parameters of the different QZS models optimized by the genetic algorithm, the stable value of the dimensionless restoring force of the optimal QZS-AP is lower than that of both the optimal QZS-HS and optimal QZS-RS. Particularly, under the random excitation of the road surface, the z_ws, a_ws, and maximum PSD have been greatly decreased by 41.4%, 73.8%, and 94.4% in comparison with the seat suspension without the QZS, respectively. Therefore, the optimal QZS-AP should be applied to enhance the driver's ride comfort and health.