Structural optimization and experiment of a semi-active hourglass-type electromagnetic isolator with negative resistance shunt circuit

The present work proposed a semi-active electromagnetic isolator with negative resistance shunt circuit to improve isolation performance on micro-vibration. By an innovative combination of an hourglass-type displacement amplifier and electromagnetic mechanism with negative resistance shunt circuit, the proposed isolator can not only solve the difficulty for electromagnetic isolators to isolation micro-amplitude vibration but also achieve a significant electromechanical coupling effect to obtain excellent vibration isolation performance by a self-sensing method. First, the design of the isolator and motion relationship are presented. Then, the electromechanical coupling dynamic model of the isolator is established. Moreover, the angle of the hourglass-type displacement amplifier is optimized, and the influence of the negative resistance on the additional damping ratio and system stability is explored. Finally, the isolator was manufactured and several experiments were carried on. The experiment results demonstrated that the isolator has an excellent isolation performance. And meanwhile, the comparison between experiment and simulation also indicated the correctness of the model.