Enhanced Vibration Damping by Means of a Negative Capacitance

Abstract

The use of shunt of piezoelectric transducers to damp mechanical vibrations is an interesting approach thanks to its low cost and the light weight of the actuators used. Among the different ways to build the shunt impedance, the use of negative capacitances is very attractive because it allows for high damping performances with low power required by the control system. Negative capacitances do not exist in the actual world but they can be designed and built using circuits based on operational amplifiers. The use of shunt circuits based on a negative capacitance coupled to a resistance allows to have a broadband control. This paper explains how to increase the bandwidth of the controller by adding to such a shunt circuit an inductance. The dynamics of the controlled system is solved analytically and the reason why the introduction of the inductance is able to give the mentioned improvement is made clear also using numerical simulations. Furthermore, this improvement also allows to increase the attenuation performance. The conditions necessary to assure the stability of the electro-mechanical system are found and explained.

Enhancement of the broadband vibration attenuation of a resistive piezoelectric shunt

“…Particularly, the aim of the present paper is to show how to improve the attenuation provided by an RNC shunt on a given frequency range by modifying the shunt impedance (which is a topic addressed also in other works (Berardengo et al, 2016a; Oshmarin et al, 2019) in the literature), more specifically by adding an inductance in the shunt circuit. While an inductor is usually used for mono-modal control, here it is used to the aim of improving the broadband attenuation provided by the RNC shunt.…”