Multi-modal vibration control using a synchronized switch based on a displacementswitching threshold

Abstract

A new semi-active method for multi-mode vibration control using the nonlinearsynchronized switch damping (SSD) approach based on a displacement switching thresholdis proposed in this paper. Several extensions of the SSD approach, including SSDI (SSD oninductance), SSDV (SSD on a voltage source), enhanced SSDV, and adaptive SSDV, havebeen developed to improve the control of the single-mode vibration, but the weaknessof the SSD approach for multi-modal vibration control has not been solved. Inall these extensions of the SSD approach, the switch is controlled by the samealgorithm, that is, it reverses the voltage of the piezoelectric element at all extrema ofdisplacement. This switching algorithm is effective in single-mode control, but it leads toover-frequent switching in multi-mode control. In the method proposed in thisstudy, an improved switching algorithm based on a displacement threshold, whichprevents the switch in the shunt circuit from over-frequent on-and-off actions andaccordingly increases the converted energy to improve the control performance, isproposed. The switching algorithm is applied to an SSDI system and used in thevibration damping of a beam with two excited modes. Compared to the classicalSSDI approach, the control performance of the first mode is improved from 3.7 to18.2 dB, but that of the second mode is slightly worse, having changed from 3.46 to2.6.