Shunted Piezoelectric Transducers Research Articles

Frequency tuning and automatic frequency tracking of shunted piezoelectric transducers

Piezoelectric ultrasonic transducers, vital in medical devices and aerospace, often face challenges like resonant frequency shifts and impedance variations affecting their operational efficiency. This paper introduces a shunted piezoelectric transducer which could tune itself by digitally programmable inductance. A transformer and inductance-capacitance matching network ensures enhanced compatibility and impedance management. Proposing a fuzzy PI-based phase control method achieves resonant frequency tracking, synchronizing operational frequency with the transducer. In contrast to traditional methods, our approach enables faster and more precise fine-tuning, detecting and rectifying real-world deviations for optimal performance. A comprehensive experimental validation, based on fundamental knowledge analysis, confirms the feasibility and superiority of our proposed method, and the commonly encountered issues of resonance frequency deviation and impedance variation in high-power piezoelectric transducer applications can be effectively mitigated.

Calibration of multiple shunted piezoelectric transducers with correction for residual modes and shunt interactions

Piezoelectric shunt damping can be used for efficient vibration mitigation of a single or multiple vibration modes of a structure. Several analytical tuning expressions have been derived for numerous circuit topologies for a single shunt. However, when multiple shunted piezoelectric transducers are attached to a flexible structure, their individual interactions alongside the spill-over from residual modes affect the calibration accuracy. In this paper, explicit correction terms that represent these effects are presented for multiple shunted piezoelectric transducers targeting a single vibration mode. The correction terms are obtained from the evaluation of effective electromechanical coupling factors, while proper balancing between shunts follows from an assumed proportionality between shunt forces. The proposed correction method is applicable to general shunt architectures, for which tuning is available when targeting a single-degree-of-freedom structure. Its ability to regain nearby optimal damping properties is illustrated numerically for the classic series RL shunt.

Vibration attenuation band tuning by active stiffness control of local resonators of metamaterials

This paper presents a design of metamaterials with a broader bandgap by active stiffness control of local resonators. A series of cantilever beams are connected to the host structure, serving as local resonators to open the bandgap for vibration attenuation. The piezoelectric transducers bonded on the cantilever beams are shunted to a negative capacitance-negative inductance series circuit (NCNL). The variation of the effective modulus of the piezoelectric sample when connected to NCNL is discussed. In addition, the effect of the NC circuit and negative capacitance in series with positive inductance (NC-L) circuit on the effective modulus of shunted piezoelectric transducers is also analyzed for comparison. By tuning the NCNL circuit, the elastic modulus of the beam-type resonator exhibits frequency-dependent, which will achieve active stiffness tuning. Subsequently, the transmittance analysis of a metamaterial beam with active stiffness resonators is conducted using finite element method. The finite element results show that a broader attenuation band can be achieved by properly selecting the parameters of NC-NL circuits. This work provides a promising method for effective vibration attenuation using metamaterials.

Vibration damping of aircraft propeller blades using shunted piezoelectric transducers

Gas turbine engine blades experience vibrations due to the flow disturbances, these vibrations are critical to the engine durability and performance. Piezoelectric transducers (sensors and actuators) have been used for engine blade vibrations damping either through a passive or active vibration control. The propeller blades are part of turboprop engine and considered as one of the main source of turboprop engine vibrations. Piezoelectric blade damping ideas have been studied by other researchers for fan blades and compressor blades. In this research a vibration damping procedure using piezoelectric transducers applied to an unmanned aerial vehicle (UAV) composite propeller. Experimental investigation introduces an approach for the propeller vibration damping using piezoelectric transducers in conjunction with appropriate shunt circuit. Three thin piezoelectric transducers macro fiber composite (MFC) type PZT-5A are surface-mounted on the propeller, one at each blade. These transducers are placed at locations of high modal strain areas for the propeller first mode at each blade, where these locations are identified by finite element numerical simulation. Electronic resonance shunt circuit, resistor-inductor-capacitor type, for the piezoelectric transducers is designed and experimentally developed such that effective vibration suppression of the propeller is achieved. The experimental and numerical investigations in this research illustrate that piezoelectric transducers with appropriate shunt circuit reduces the aircraft propeller vibrations.

Fast Attitude Maneuver of a Flexible Spacecraft with Passive Vibration Control Using Shunted Piezoelectric Transducers

This paper is concerned with designing a bang-bang control input to perform a quick rotational maneuver of a rigid spacecraft hub connected with flexible appendages. The control design is based on only the rigid body mode making it very simple to design and at the same time achieve the quickest maneuver possible. The induced vibrations are suppressed using piezoelectric transducers bonded to the appendages and connected to an electric circuit with the objective of converting the vibrational energy to electrical energy and then dissipating it using passive electric elements, such as a resistance and an inductor. The proposed control design method is applied to a spacecraft containing a rigid hub and flexible appendages. The attitude control torque is produced using either the reaction wheels contained inside the rigid hub or jet thrusters mounted outside it. The control design process starts with deriving the nonlinear partial differential equations of motion for the spacecraft using Hamilton’s principle which accounts for the electromechanical coupling and the presence of resistive or resistive-inductive circuits. To simplify the analysis, the nonlinear ordinary differential equations of motion are then obtained using the assumed mode method. The effectiveness of the control design method is numerically tested on a spacecraft that is required to perform a quick attitude maneuver and, simultaneously, suppress the induced vibrations. The simulations show a quick and accurate maneuver has been achieved combined with very low levels of vibrations resulting from the reduced coupling between flexible and rigid motions as well as the damping added as a result of the passive shunt circuit. Furthermore, the resistance-inductance shunt circuit is shown to be more effective in damping the vibrations than the resistance shunt circuit.

Reducing Uncertainty in Shunt Damping by Model-Predictive Product Stiffness Control in a Single Point Incremental Forming Process

The stiffness of metal formed products strongly affects the dynamic behavior of structures in which they are integrated. Forming processes underlie short and long-term variations which cause the stiffness to be uncertain.In the application of resonant shunted piezoelectric transducers for vibration attenuation, uncertain stiffness may cause significant reduction in the vibration attenuation performance due to imprecise tuning. In the past, large efforts were made to control one or more geometrical feature of products while weightier features that cause uncertainty have not been addressed.In this paper, a single point incremental forming process of a membrane-like spring element on a servo press with a 3 degrees of freedom drive system is investigated. This spring element is used in a beam support for lateral vibration attenuation with resonant shunted transducers as well as axial buckling stabilization.To reduce uncertainty caused by process variations, an offline closed-loop control of product stiffness is presented. Different product and forming criteria are integrated into a control approach based on an optimization routine. By making use of a model-based prediction of the product properties, the approach shows how to realize a multi-objective control.

Vibration and noise control using shunted piezoelectric transducers: A review

Abstract Among various strategies developed for the attenuation of noise and vibration in mechanical structures, piezoelectric shunt damping, which consists in connecting piezoelectric transducers integrated in a structure to electric or electronic circuits, is a promising alternative for use in small- and mid-scale structural components. Despite the fact that the shunt damping technology has been investigated for quite a long time, it is recognized that its application to real-world structures still requires developments aiming at improving its effectiveness and range of application under unavoidable practical constraints. As a result, research on improved solutions related to piezoelectric shunt damping is still very active. Due to the very nature of the piezoelectric shunt damping, it becomes clear that further improvements must consider both mechanical and electrical/electronic aspects. Based on the current state-of-the-art, this paper provides a systematic literature review of different piezoelectric shunt damping strategies developed for the attenuation of vibration and noise in mechanical systems, including an assessment of the basic principles underlying the electromechanical behavior, as well as design procedures and numerical modeling of piezoelectric shunt damping devices applied to elastic vibrating systems. Emphasis is placed on the various types of shunt circuits, including the traditional passive resonant circuits, multimode resonant circuits, adaptive tuning circuits, switching circuits, and negative capacitance. The strategies for location and shape of the piezoelectric transducers is also discussed. A variety of applications recently reported in the scientific literature and in patents are presented. An assessment is made about more significant recent achievements and technological issues to be faced in further developments.

Passive vibration control of flexible spacecraft using shunted piezoelectric transducers

This paper is devoted to the attitude and vibration control of spacecraft containing flexible appendages. It entails an investigation of a passive control strategy which consists in connecting piezoelectric transducers bonded to the flexible elements to electric circuits in such a way that the vibration energy, once converted into electrical energy, is transferred and partially dissipated into the electric circuit. This strategy enables to circumvent some difficulties involved in active control such as instability and the necessity of a large amount of hardware, which can be critical in space applications. One considers an artificial satellite model composed of a hub, a reaction wheel used for angular position control and two identical flexible panels, which contain piezoelectric patches symmetrically bonded to their surfaces. The equations of motion are derived based on the Assumed Modes approach, accounting for the electromechanical coupling and the presence of two types of circuits (resistive, and resistive–inductive). The effectiveness of the control strategy suggested is assessed by means of numerical simulations of a satellite undergoing an angular position correction commanded by proportional–derivative torque applied by the reaction wheel. The results demonstrate that the panel vibrations levels and coupling between flexible and rigid-body motions are significantly reduced for both types of circuits considered, such effectiveness being greater for resistive–inductive shunt circuits.

Energy harvesting module for the improvement of the damping performance of autonomous synchronized switching on inductance

Shunted piezoelectric transducers can be used to dissipate vibration energy of a host structure. The synchronized switch damping on inductance is a shunting technique characterized by a nearly rectangular shape of the resulting voltage on the transducer being in antiphase with the structure’s velocity. As for these systems, previous studies have reported the strong relationship between the dissipated energy and the slope of the voltage signal occurring during the switch. This implies that any electrical losses have to be minimized in order to increase the slope of the voltage signal and, thus, the damping performance. The rate of change of the voltage represents a critical issue for autonomous shunts, where the switch can be inefficient because the power for switching the circuit is not supplied by an external source but is supplied by the vibrating structure itself. In this study, a new technique for improving the damping performance of autonomous synchronized switch damping on inductance is proposed based on controlling the switch with a square wave signal that reduces its electrical losses. An experimental validation of the proposed shunting technique is carried out in order to assess the performance in both the cases of a single-tone and multimodal responses of the structure.

Structural multi-modal damping by optimizing shunted piezoelectric transducers

The capacity of different auto-supplied devices using shunted piezoelectric circuits are studied here to improve structural damping by avoiding implementation of complex and heavy control devices. The presented technique uses a dedicated numerical piezo-mechanical model combining both mechanical and electrical coupling parameters. An original methodology are also introduced for optimizing the parameters of electrical shunt circuits connected to piezoelectric elements and also structural locations of these integrated transducers. The results, experimentally validated (on beams and a plate), demonstrate that vibrations can be significantly reduced when shunted piezoelectric devices are mounted on a real structure. Finally, the proposed methodology is used for optimizing shape and location of the shunted piezoelectric patches to damp several modes of a plate.

Structural multi-modal damping by optimizing shunted piezoelectric transducers

The capacity of different auto-supplied devices using shunted piezoelectric circuits are studied here to improve structural damping by avoiding implementation of complex and heavy control devices. The presented technique uses a dedicated numerical piezo-mechanical model combining both mechanical and electrical coupling parameters. An original methodology are also introduced for optimizing the parameters of electrical shunt circuits connected to piezoelectric elements and also structural locations of these integrated transducers. The results, experimentally validated (on beams and a plate), demonstrate that vibrations can be significantly reduced when shunted piezoelectric devices are mounted on a real structure. Finally, the proposed methodology is used for optimizing shape and location of the shunted piezoelectric patches to damp several modes of a plate.

Modal Synthesis and Dynamical Condensation Methods for Accurate Piezoelectric Systems Impedance Computation

This article proposes a new, simple and efficient approach, allowing one to reduce and construct piezoelectric super elements guaranteeing an accurate representation of the electrical impedance without the need for static correction. This allows the electronic coupling to be fully addressed in the optimization of passive shunted piezoelectric transducers, energy harvesting piezoelectric systems or dense distributed transducers. The model obtained through this approach is also versatile, of small size, and is therefore quite tractable for use in intensive computation algorithms. Two example systems are used to demonstrate the numerical accuracy and convergence properties of the proposed approach.

Optimization of damping and absorbing performance of shunted piezo elements utilizing negative capacitance

In this paper, the effect of negative capacitance in damping and absorbing systems using shunted piezoelectric transducers is analyzed. Different passive and semi-active configurations of networks have been compared in a general, normalized form, highlighting the influence of the general electromechanical coupling coefficient and the negative capacitance. Commonly used criteria for passive networks are adapted to the general configuration with negative capacitance resulting in optimal parameters. The damping and absorbing performance of optimal passive and semi-active networks are compared. With optimal parameter for negative capacitance, an upper limit for maximum appearing amplitude in the frequency response function (FRF) can be given. Results are verified experimentally using a test rig.

A survey of recent innovations in vibration damping and control using shunted piezoelectric transducers

Research on shunted piezoelectric transducers, performed mainly over the past decade, has generated new opportunities for control of vibration and damping in flexible structures. This is made possible by the strong electromechanical coupling associated with modern piezoelectric transducers. In vibration control applications, a piezoelectric transducer is bonded to, or embedded in a base structure. As the structure deforms, the piezoelectric element strains and converts a portion of the structural vibration energy into electrical energy. By shunting the piezoelectric transducer to an electrical impedance, a part of the induced electrical energy can be dissipated. Hence, the impedance acts as a means of extracting mechanical energy from the base structure. This paper reviews recent research related to the use of shunted piezoelectric elements for vibration damping and control. In particular, the paper presents an overview of the literature on piezoelectric shunt damping and discusses recent observations on the feedback nature of piezoelectric shunt damping systems.