QZS-Mcpherson Suspension And Its Dynamic Characteristics

Automotive vibrations caused by uneven pavement are usually associated withlow frequency and large amplitude. In comparison with traditional linear vibrationisolations, a quasi-zero-stiffness (QZS) vibration isolation system can perform betterin isolation for the above mentioned vibration. This thesis proposes the idea ofcombining a QZS isolator with McPherson suspension of vehicle, and studies thefeasibility of applications in vehicle suspension systems. Based on this idea, aroller-cam type of QZS vibration isolator was designed for McPherson suspensionwithout increase of installation space. The characteristic of the roller-cam QZS isinvestigated. Further, a five degrees of freedom model of vehicle was constructed, andthe isolation performance of the QZS McPherson suspension is analyzed based onrandom road profiles.In addition, automotive ADAMS models are established for simulations ofdynamic responses of vehicles on random excitations of road. Compared with theRMS value of the acceleration at the seat, the result proves that QZS vibration isolatorhas a better isolation performance than the linear isolators. Then the study is extendedto optimal design of the QZS suspension, where the pre-compression of horizontalspring of the QZS vibration isolator is selected to be the design variable and theoptimal value of the design variable is of8.5mm. The experiment of the roller-camQZS model has been carried out. For periodic excitation, the QZS isolator canperform isolation in a wider range of low-frequency and without involving resonance.For random excitation, the QZS vibration isolator outperforms the linear isolator aswell. The experimental results also verified that the isolation performance becomesbetter even when excitation increases, implying that QZS vibration suspension couldhave deliver better comfort ability.