Ellipsograph-derived vibration isolator with stiffness mode switching

Achieving effective low-frequency vibration suppression remains a persistent goal in vibration engineering. In recent decades, the emergence of quasi-zero stiffness (QZS) isolation methods has highlighted performance advantages surpassing traditional linear vibration isolation systems, showing promising applications in ultra-precision fields. This study presents a class of low-frequency isolation devices utilizing an elastic ellipsograph-derived mechanism. The stiffness attribute can be switched among QZS, constant-zero stiffness (CZS), and linear stiffness (LS), and the device can reduce the sensitivity of vibration isolators to payloads, thereby adapting to varying load scenarios. Firstly, the conceptual inspiration and modular design of the ellipsograph-derived vibration isolator (EDVI) is introduced. A static mechanical model is subsequently developed based on the EDVI structure, enabling convenient adjustment among different stiffness attributes via preload modification. Then, the equivalent dynamic model of the EDVI is established, and the response behaviors and parameter effects on the isolation performance are analyzed. Based on the manufactured EDVI prototype, the static and dynamic testing systems are constructed, and the correctness and effectiveness of the proposed method are verified experimentally. The proposed isolator configuration and stiffness adjustment strategy provide an innovative approach to low-frequency isolation, offering new technical solutions for engineering challenges.