Experimental comparisons of two detection methods for semi-passive piezoelectric structural damping

Recently, the so-called Synchronized Switch Damping on Inductor (SSDI) have been intensively investigated and discussed. The SSDI technique heavily relies on switching signals, which is synchronously generated by extrema detection. This article presents a comprehensive experimental comparison between two displacement extrema detections named as voltage peak detection and zero-velocity crossing detection. The experimental results show that the peak voltage detector enjoys high robustness with a single piezoelectric patch, but the phase lag degrades damping performance. On the contrary, zero-velocity crossing detection has less phase lag, but the high sensitivity to velocity fluctuation induces multiple voltage inversions, which deteriorates damping performance of SSDI. To overcome this drawback, an enhanced zero-velocity detection using the synthetic inductor is presented to strengthen the detector's robustness at the cost of larger phase lag. It is demonstrated that the enhanced version has sufficient robustness, and shows the great advantage over peak voltage detection at low excitation level, although the advantage is gradually reduced with increasing of excitation level.