Design and analysis of a tunable electromagnetic lever-type anti-resonant vibration isolator

Abstract

To broaden the effective vibration suppression band of a typical dynamic anti-resonant vibration isolator (DAVI), a tunable lever-type anti-resonant vibration isolator has been designed, theoretically investigated, and experimentally verified. An anti-resonant frequency occurs within the device when the inertial force generated by the levered mass cancels the spring force. By controlling the electromagnetic spring so as to adjust the system’s equivalent stiffness, the anti-resonant frequency of the electromagnetic lever-type anti-resonant vibration isolator (EM-LVI) can be tuned to coincide with the excitation frequency in real time. A broad stopband where the vibration is sufficiently suppressed can be provided by the EM-LVI for low-frequency applications. Due to the lever’s amplifying effect, the EM-LVI can modify the equivalent stiffness of the system with a small electromagnetic stiffness, which provides a viable approach to the design of lightweight isolators. Theoretical and experimental results demonstrate that the tuning bandwidth increases along with the lever amplification ratio. With the advantages of a wide stopband and a high vibration suppression level, the proposed EM-LVI exhibits significant advantages in suppressing low-frequency vibration in a finite-frequency band and has been successfully validated by experimental prototypes for its beneficial performance in low-frequency vibration suppression.