Analysis of a passive scissor-like structure isolator with quasi-zero stiffness for a seating system vibration-isolation application

It is widely known that vibration is a mechanical motion phenomenon where a mass point oscillates around an equilibrium point. Vibrations are a source of discomfort and are extremely harmful to vehicle drivers and passengers. The motivations of this research are to develop an innovative vehicle seating suspension system to isolate vibrations transmitted to vehicle drivers and passengers and to improve ride comfort to ensure that their health is not negatively impacted and to improve the working efficiency of the driver. An innovative design of a passive multi-degree-of-freedom vibration isolator is presented in a truck seat suspension system where a Stewart platform configuration with a six-degree-of-freedom (6-DOF) isolation system is used rather than the traditional Stewart platform. A scissor-like structure (SLS) is used as one of the supporting legs to provide a nonlinear system with quasi-zero stiffness (QZS). Vibration is effectively attenuated without a loss of the system's load capacity. The effects of structural parameters in the proposed system are studied to determine how to adjust the parameters to achieve better vibration-isolation performance. The results reveal that a SLS supporting leg with a small assembly angle, more layers, a shorter link length and less spring stiffness has led to better vibration isolation and higher system stability than the conventional baseline supporting structure.