IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 57, NO. 5, MAY2008 907 Vibration Damping Using CCII-Based Inductance Simulators Giuseppe Ferri, Senior Member, IEEE, Nicola Guerrini, Ernesto Silverii, and Amabile Tatone Abstract—In this paper, we present an application of second- generation current-conveyor (CCII)-based active inductance simulators to mechanical vibration damping. The oscillation amplitude of a metallic beam, which is near some resonant fre- quencies, can be reduced by converting mechanical energy into electrical energy through a piezoelectric transducer that is bonded to the beam. An electric circuit, which is made up of the piezo- electric transducer, a resistance, and an inductance, accomplishes the task of dissipating the energy. To this end, the natural fre- quency of the circuit should be close to the natural frequency of interest of the mechanical system. The high value that is requested for the inductance (thousands of henrys) can only be achieved through an inductance-simulator circuit. In the literature, the circuit implementations of the inductance simulators are typically based on operational amplifiers, such as the Antoniou circuit. In this paper, we make use of the CCIIs, which allow us to obtain both grounded and floating equivalent inductances that work within a regulated frequency range from three to four decades. The effectiveness of the traditional inductance simulators and CCII- based simulators is discussed, comparing the responses of an experimental mechanical–electrical system, with different circuit implementations, through experimental results. The use of series- resistance compensation, which is obtained through the use of a suitable topology based on the CCIIs, in the implementation of the equivalent inductance, allows one to obtain the best vibra- tion damping, as confirmed by measurements, for all the natural mechanical frequencies of the realized system. Index Terms—Inductance simulators, passive control, piezo- electric shunt damping, second-generation current-conveyor (CCII)-based circuit, vibration damping. I. I NTRODUCTION T ECHNOLOGICAL advances have led to the design of thin, flexible, and lightweight structures. Vibration damp- ing is an important issue in such mechanical systems. An effective reduction of mechanical vibrations is a key factor in positioning systems, noise reduction, and, in general, in increasing reliability and durability of mechanical structures. Both active and passive controls are used in vibration damping. A drawback of the active control is the so-called spillover. This is completely absent in the passive control [1] where, typically, Manuscript received August 5, 2005; revised November 12, 2007. G. Ferri is with the Department of Electrical and Information Engineering, University of L’Aquila, 67040 L’Aquila, Italy (e-mail: ferri@ing.univaq.it). N. Guerrini is with Rutherford Appleton Laboratory, Oxford, U.K. E. Silverii and A. Tatone are with the Department of Structural, Water, and Soil Engineering, University of L’Aquila, 67040 L’Aquila, Italy (e-mail: e.silverii@tiscali.it; tatone@ing.univaq.it). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TIM.2007.913762 Fig. 1. Mechanical–electrical system. a piezoelectric transducer, which is bonded to the surface of a metallic beam, is connected to a resistance and to an inductance simulator. This circuit accomplishes the task of converting mechanical energy into electrical energy and then dissipating that energy through an electric resistance (Fig. 1). The required inductance value depends on the oscillating mode that we want to damp. It is of thousands of henrys if the operating frequency is as low as 10 Hz. While new active inductors have been presented in the literature [2]–[5], the interest in designing and studying inductance simulators for low-frequency applications has increased. Analog designers face inductance integration with some difficulties in terms of both silicon area and inductance values. Low inductances are integrated through a strip of a conductive material, and their value is about 1 nH/mm. This method is not practicable for high inductive values, where a solenoid with a magnetic flux inside is only used for high-frequency applications. In order to implement high inductive values for low-frequency applications, it is mandatory to find new circuit solutions. Inductance simulators generate equivalent inductive behavior from capacitances, resistances, and active components (typically voltage amplifiers). In the literature, the most efficient impedance simulator (in terms of nonidealities) was proposed by Antoniou in 1969 [6], which is based on the classical voltage operational am- plifier and some passive components (resistances and capac- itances). This simulator only gives an equivalent grounded inductance, which has only one terminal that is free, and presents a series resistance so that the equivalent inductance is not a pure inductance. In more recent years, a new ap- proach, which considers current as reference instead of volt- age, has become increasingly important and studied. Based on this new philosophy, different active blocks have been implemented [7]–[11], and one of the most popular blocks is represented by a second-generation current conveyor (CCII). 0018-9456/$25.00 © 2008 IEEE