A Linear Electromagnetic Negative Stiffness Spring Based on Antagonistic Force

Quasi-zero stiffness (QZS) vibration isolators based on negative stiffness have been widely used due to their excellent low-frequency isolation performance. However, the nonlinearity of negative stiffness leads to the nonlinear behavior of vibration isolators, especially under large excitation, which can lead to the deterioration of vibration isolation performance. This paper proposes a linear electromagnetic negative stiffness spring based on antagonistic force, which has the advantages of long linear stroke, large tunable range, and high energy efficiency. Based on the equivalent magnetic circuit method, an electromagnetic force model was established and verified by both simulation and experiment. The influence of parameters such as air gap on stiffness characteristics was studied. The experiment proves that the designed electromagnetic negative stiffness mechanism has a linear stroke of
$\pm 0.005$
m and a tunable range of
$\pm$
8086 Nm-
¹
. The linear electromagnetic negative stiffness spring proposal will expand the application of QZS isolators.