Vector Control of Piezoelectric Transducers and Ultrasonic Actuators

This paper presents the implementation of a novel vibration amplitude control and resonant frequency tracking for piezoelectric transducers (PTs) and ultrasonic motors (USMs). It is based on a generalization of the vector control method to the PT and the USM, which is explained in the first part. We show that two independent controllers with a similar structure are required: one tracks the resonant frequency and the second controls the amplitude. We then present the implementation into a low-cost digital signal processing controller with a sampling period of 200 µs. Experimental results on a Langevin transducer achieved a time response of 20 ms approximately, and the generality of the method is further demonstrated on a 2-D tactile stimulator at the end of this paper

A match coefficient approach for damage imaging in structural components by ultrasonic synthetic aperture focus

Ultrasonic Synthetic Aperture Focus (SAF) techniques are commonly used to image structural defects. In this paper, a variation of SAF based on ideas borrowed from Matched Field Processing (MFP) is evaluated to reduce artifacts and sidelobes of the resulting images. In particular, instead of considering the full RF ultrasonic waveforms for the SAF time backpropagation, only selected features from the waveforms are utilized to form a “data vector” and a “replica” (expected) vector of MFP. These vectors are adaptive for the pair of transmitter-receiver and the focus point. The image is created as a matched filter between these two vectors. Experimental results are shown for an isotropic and homogenous metallic plate with simulated defects, probed by six piezoelectric patches used as receivers or transmitters

Damage identification in structural health monitoring: a brief review from its implementation to the Use of data-driven applications

The damage identification process provides relevant information about the current state of a structure under inspection, and it can be approached from two different points of view. The first approach uses data-driven algorithms, which are usually associated with the collection of data using sensors. Data are subsequently processed and analyzed. The second approach uses models to analyze information about the structure. In the latter case, the overall performance of the approach is associated with the accuracy of the model and the information that is used to define it. Although both approaches are widely used, data-driven algorithms are preferred in most cases because they afford the ability to analyze data acquired from sensors and to provide a real-time solution for decision making; however, these approaches involve high-performance processors due to the high computational cost. As a contribution to the researchers working with data-driven algorithms and applications, this work presents a brief review of data-driven algorithms for damage identification in structural health-monitoring applications. This review covers damage detection, localization, classification, extension, and prognosis, as well as the development of smart structures. The literature is systematically reviewed according to the natural steps of a structural health-monitoring system. This review also includes information on the types of sensors used as well as on the development of data-driven algorithms for damage identification.Peer ReviewedPostprint (published version

Dynamics of piezoceramics-based mass and force actuators for rotating machines

In the past decade, it has become more and more common to install active vibration control devices on rotating systems like grinding machines, tooling centers, industrial fans and drive shafts. In the present research, two innovative actuation concepts for such devices are evaluated. The first device is a force actuator based on piezoceramic fibers, which has a low power consumption and high dynamic range. The second device is a mass redistribution actuator based on two piezoelectric ultrasonic motors, which is smaller and faster than conventional electromagnetic devices. At the basis of the analysis are rotor dynamic finite element models including actuators, sensors and feedback controllers. In simulations and experiments with device one, feedback control and scheduled feedforward control are considered. It is shown experimentally that the unbalance response at a critical speed can be reduced by some 97%. In experiments with device two, the positioning speed is determined

Smart materials application on high performance sailing yachts for energy harvesting

Piezoelectric patches are bounded on a keel bulb in order to harvest vibration energy by converting electrical output. Unsteady computational fluid dynamics method is also used to find the structural boundary condition such as the hydrodynamic pressure fluctuation. Finite element analysis (FEM) is used to find structural and electrical responses

Design and dynamic modeling of piezoelectric laser beam shutters

The paper presents the results of numerical modelling and experiments of piezoelectric bimorph-type bending actuator for laser beam shutting system. Theoretical calculations are realized by using finite element method. The purpose of these calculations is to optimize geometric parameters of a piezoelectric bimorph, ensuring maximum resonant frequency of the first bending form and stability of oscillation amplitude. Experimental performance of piezoelectric actuators is compared with results of finite element simulations

Pjezorobotų trajektorijų valdymas nanopalydovų stabilizavimui

Rapid industrial advancement requires novel ideas, new scientific approaches and effective technologies that would ensure quality and precision. Application of piezoelectric actuators in robotics opens many possibilities to create systems with extreme precision and control. A very important step in the development of autonomous robots is the formation of motion trajectories. Classical interpolation methods used for formation of the trajectories are suitable only when robots have wheels, legs or other parts for motion transmission. Piezorobots that are analyzed in this dissertation have no additional components that create motion, only contact points with the static plane. Therefore, traditional motion formation methods are not suitable and a problem arises how to define motion trajectory of such device. The aim of this work is to create a trajectory control algorithm of multi-degrees-of-freedom piezorobot used for nanosatellite stabilization. In order to achieve the objective, the following tasks had to be solved: to analyze constructions of precise piezorobots, their operating principles and motion formation methods; to analyze stabilization problems of satellites and application of multi-degrees-of-freedom piezorobots for nanosatellite stabilization; to create piezorobots’ motion formation algorithms according to electrode excitation schemes, to perform an experimental research; to determine quantitative characteristics of the constructed piezorobots and their motion trajectories. The introduction describes the importance and novelty of this thesis, goals of this work, its practical value and defended statements. The first chapter analyses the principals of ultrasonic devices, gives a thorough review of constructions of ultrasonic devices with multi-degrees-of-freedom. The second chapter provides a review of satellite stabilization principles and how multi-degrees-of-freedom piezorobots can be applied for nanosatellite stabilization. Motion formation methods for ultrasonic devices with multi-degrees-of-freedom are presented. The third chapter presents the detailed analysis of different piezorobots. In the fourth chapter experimental results are provided. Trajectory planning of piezorobot is shown, results are compared to numerical calculations performed in the third chapter. The conclusions about applicability of piezorobots’ motion formation algorithms according to electrode excitation schemes are given. Seven articles focusing on the subject of the dissertation have been published, two presentations on the subject have been presented in conferences at international level. The research for the dissertation has been funded by the Lithuanian State Science and Studies Foundation: European Regional Development Fund, Project No. DOTSUT-234 and Research Council of Lithuania, Project No. MIP-084/2015.Dissertatio

Numerical simulation and validation of ultrasonic de-icing system

This work presents the analytic and experimental research of de-icing method with piezoelectric transducer as actuators. For the reason of flight conditions like altitude, high and humidity. To meet the requirements for flight, deicing measures must be taken in consideration. There are lots of existing deicing methods, but the main problem is that the loss of power with them is very big increasing the consumption of fuel and decreasing the efficiency of the flight. With the development of piezoelectric ceramic technology, shear vibration deicing is more concerned for their low power consumption. Shear stress between surface and ice is generated by the forced vibration which is driven by piezoelectric. The device achieves the deicing purpose activating resonant frequencies of a structure using piezoelectric ceramic actuators to generate enough shear stress at the interface, between the surface and ice, to break the adhesion stress between them. In this study, we study the effect of shear stress generated for different distances between ceramic piezoelectric, and then analyze the relations of the shear stress and frequency. First, a numerical method was validated to assist the design of such systems. Numerical simulations were performed for the case of a flat plate testing the natural modes and harmonic response by the software ANSYS, which proves the feasibility to remove ice by piezoelectric ceramic actuator in theory. And then, validated experimentally. The model was then used to study important design parameters such as actuator positioning and the distance between them