###### Abstract
prove the vibration isolation effect, especially the low-frequency vibration isolation effect. [PERSON] et al. [10] first used negative stiffness in the mechanical design of a leaf spring to reduce the total stiffness of the system. South Korean researchers [PERSON] et al. [11] developed a seat vibration isolation mechanism with negative stiffness based on a thin shell theory with theoretical derivation and experimental verification, which achieved good results. [PERSON] et al. [12] studied the dynamics and power flow behavior of a nonlinear vibration isolation system with a negative stiffness mechanism, derived the nonlinear dynamic equations of the system, and obtained the frequency response function of the system under harmonic excitation by using the average method. [PERSON] et al. [13] used a type of bending mounted spring roller mechanism as a negative stiffness calibrator in parallel with a vertical linear spring to design a passive nonlinear isolator, and analyzed the dynamic characteristics of the isolator. [PERSON] et al. [14] developed a vibration absorber of positive and negative stiffness elastic elements in parallel using the principle of counteracting each other, in which its stiffness was arbitrarily low. [PERSON] et al. [15] studied a new type of vibration isolation system with positive and negative stiffness in parallel, which had higher support stiffness and lower motion stiffness. The natural frequency could be reduced by adjusting the magnitude of force at both ends of the negative stiffness mechanism and the vibration isolation effect was improved significantly. [PERSON] et al. [16] proposed a new type of vibration isolation system with a negative stiffness damping device (NSD) attached to an ordinary vibration isolation layer, and discussed the effect of the NSD on the performance of the vibration isolation system. In recent years, many studies have been conducted on negative stiffness structures [17; 18; 19; 20; 21; 22; 23; 24; 25]. However, there are few in-depth studies in the literature on the negative stiffness structure for cab seats of construction machinery vehicles. Therefore, there is a need to design an accurate seat suspension system with NSS characteristics and to determine the most ideal parameters of the system according to the space size of the cab seat, and to analyze its dynamic characteristics. In this study, the static analysis and dynamic analysis of a cab seat suspension system based on a negative stiffness structure are presented. First, the theoretical model of a seat suspension system is established, and different structural parameters and their influences on dynamic stiffness are subsequently discussed in order to determine the most ideal configuration of the parameter range of the suspension system. In addition, a nonlinear dynamic model of a quasi-zero-stiffness system with inerter elements (QZS-IE) is established, and the primary response and the stability are analyzed. The vibration suppression effects of the QZS-IE system and parameter studies are described by comparing the QZS-IE system with a quasi-zero-stiffness system. The results should accelerate the application of the QZS-IE system in construction machinery cab seats and improve the ride comfort of drivers.