Active Vibration Control Of Piezo Stack Actuator With Consideration To Hysteresis And Saturation Effects

Tindak balas penggerak piezo bertindih dari segi daya-sesaran-pecutan sebagai fungsi pengujaan voltan dan frekuensi diukur bagi menentukan ciri-ciri histeresis dan ketepuan yang boleh diwakili oleh persamaan kuadratik polinomial. Ketepuan daya, sesaran dan pecutan berlaku daripada 400 Hz sehingga 500 Hz untuk 400 V voltan pengujaan. Ciri-ciri histeresis dan ketepuan ini kemudiannya digunakan di dalam sistem kawalan getaran aktif dan mengakibatkan pengurangan ralat sebanyak 50 - 67 %. Ini membuktikan kepentingan memasukkan histeresis dan ketepuan penggerak di dalam reka bentuk sistem kawalan getaran aktif. Pengukuran kebolehpindahan menunjukkan julat frekuensi berkesan pada 250 - 450 Hz. Kebolehgunaan secara praktikal sistem kawalan getaran aktif telah disiasat dengan menggunakannya pada mesin pencanai elektrik yang berkelajuan nominal 25000 rpm dan kebolehpindahan getaran berkurangan sebanyak 91 %. Penambahbaikan telah dicapai menggunakan model histeresis lelurus bersama-sama tiga skim anti-gegulung (pengapitan, pengiraan-belakang dan mod jejakan) untuk mengelakkan ketepuan voltan pantas pada penggerak piezo bertindih dan prestasinya telah dibandingkan dengan skim kawalan daya aktif. Hasil kajian menunjukkan sistem PID-kawalan daya aktif adalah lebih baik daripada PID-anti-gegulung dengan jumlah pengurangan kebolehpindahan getaran sebanyak 97.7 %. Getaran struktur boleh dihadkan supaya kurang daripada nilai tepu sesaran penggerak di dalam sistem kawalan getaran aktif dengan melakukan pengubahsuaian struktur dinamik dan ini telah menyebabkan perlebaran julat frekuensi berkesan kepada 200 - 510 Hz dengan pengurangan kebolehpindahan getaran sebanyak 96 % berbanding dengan reka bentuk asal. Di dalam penyelidikan ini, sumbangan utama adalah penentuan lengkungan histeresis dan ketepuan bagi penggerak piezo bertindih dari segi daya-sesaran-voltan sebagai fungsi pengujaan frekuensi. ________________________________________________________________________________________________________________________ The piezo stack actuator response in terms of force-displacement-acceleration as a function of the excitation voltage and frequency are measured to determine the hysteresis and saturation characteristics which are represented using quadratic polynomial equations. Saturation of force, displacement and acceleration occurred from 400 Hz to 500 Hz for the 400 V excitation voltages. These hysteresis and saturation characteristics are used in the active vibration control (AVC) system which resulted in error reduction of 50 - 67 %. This proves the importance of including the hysteresis and saturation of the actuator in the design of the AVC system. Transmissibility measurement showed the effective frequency range of 250 - 450 Hz. The practical applicability of the AVC system was investigated using an electric die grinder with a nominal speed of 25000 rpm and the vibration transmissibility was reduced by 91 %. Further improvement was achieved using the linearized hysteresis model together with three anti-windup schemes (clamping, back-calculation and tracking mode) to avoid fast voltage saturation of the piezo stack actuator and the performance was compared with the active force control (AFC) scheme. The results showed that the PID-AFC was superior to the PID-anti-windup schemes with a total vibration transmissibility reduction of 97.7 %. The vibration of the structure can be limited to be less than the saturation displacement of the actuator in the AVC system using the structural dynamic modification (SDM) and this has resulted in a wider effective frequency range of 200 - 510 Hz with the vibration transmissibility reduction of 96 % when compared with the initial design. In this research, the main contribution is the determination of the hysteresis and saturation curves of the piezo stack actuator in terms of force-displacement-voltage relationship as a function of excitation frequencies

Design of passive piezoelectric damping for space structures

Passive damping of structural dynamics using piezoceramic electromechanical energy conversion and passive electrical networks is a relatively recent concept with little implementation experience base. This report describes an implementation case study, starting from conceptual design and technique selection, through detailed component design and testing to simulation on the structure to be damped. About 0.5kg. of piezoelectric material was employed to damp the ASTREX testbed, a 500kg structure. Emphasis was placed upon designing the damping to enable high bandwidth robust feedback control. Resistive piezoelectric shunting provided the necessary broadband damping. The piezoelectric element was incorporated into a mechanically-tuned vibration absorber in order to concentrate damping into the 30 to 40 Hz frequency modes at the rolloff region of the proposed compensator. A prototype of a steel flex-tensional motion amplification device was built and tested. The effective stiffness and damping of the flex-tensional device was experimentally verified. When six of these effective springs are placed in an orthogonal configuration, strain energy is absorbed from all six degrees of freedom of a 90kg. mass. A NASTRAN finite element model of the testbed was modified to include the six-spring damping system. An analytical model was developed for the spring in order to see how the flex-tensional device and piezoelectric dimensions effect the critical stress and strain energy distribution throughout the component. Simulation of the testbed demonstrated the damping levels achievable in the completed system

Study and Development of Mechatronic Devices and Machine Learning Schemes for Industrial Applications

Obiettivo del presente progetto di dottorato è lo studio e sviluppo di sistemi meccatronici e di modelli machine learning per macchine operatrici e celle robotizzate al fine di incrementarne le prestazioni operative e gestionali. Le pressanti esigenze del mercato hanno imposto lavorazioni con livelli di accuratezza sempre più elevati, tempi di risposta e di produzione ridotti e a costi contenuti. In questo contesto nasce il progetto di dottorato, focalizzato su applicazioni di lavorazioni meccaniche (e.g. fresatura), che includono sistemi complessi quali, ad esempio, macchine a 5 assi e, tipicamente, robot industriali, il cui utilizzo varia a seconda dell’impiego. Oltre alle specifiche problematiche delle lavorazioni, si deve anche considerare l’interazione macchina-robot per permettere un’efficiente capacità e gestione dell’intero impianto. La complessità di questo scenario può evidenziare sia specifiche problematiche inerenti alle lavorazioni (e.g. vibrazioni) sia inefficienze più generali che riguardano l’impianto produttivo (e.g. asservimento delle macchine con robot, consumo energetico). Vista la vastità della tematica, il progetto si è suddiviso in due parti, lo studio e sviluppo di due specifici dispositivi meccatronici, basati sull’impiego di attuatori piezoelettrici, che puntano principalmente alla compensazione di vibrazioni indotte dal processo di lavorazione, e l’integrazione di robot per l’asservimento di macchine utensili in celle robotizzate, impiegando modelli di machine learning per definire le traiettorie ed i punti di raggiungibilità del robot, al fine di migliorarne l’accuratezza del posizionamento del pezzo in diverse condizioni. In conclusione, la presente tesi vuole proporre soluzioni meccatroniche e di machine learning per incrementare le prestazioni di macchine e sistemi robotizzati convenzionali. I sistemi studiati possono essere integrati in celle robotizzate, focalizzandosi sia su problematiche specifiche delle lavorazioni in macchine operatrici sia su problematiche a livello di impianto robot-macchina. Le ricerche hanno riguardato un’approfondita valutazione dello stato dell’arte, la definizione dei modelli teorici, la progettazione funzionale e l’identificazione delle criticità del design dei prototipi, la realizzazione delle simulazioni e delle prove sperimentali e l’analisi dei risultati.The aim of this Ph.D. project is the study and development of mechatronic systems and machine learning models for machine tools and robotic applications to improve their performances. The industrial demands have imposed an ever-increasing accuracy and efficiency requirement whilst constraining the cost. In this context, this project focuses on machining processes (e.g. milling) that include complex systems such as 5-axes machine tool and industrial robots, employed for various applications. Beside the issues related to the machining process itself, the interaction between the machining centre and the robot must be considered for the complete industrial plant’s improvement. This scenario´s complexity depicts both specific machining problematics (e.g. vibrations) and more general issues related to the complete plant, such as machine tending with an industrial robot and energy consumption. Regarding the immensity of this area, this project is divided in two parts, the study and development of two mechatronic devices, based on piezoelectric stack actuators, for the active vibration control during the machining process, and the robot machine tending within the robotic cell, employing machine learning schemes for the trajectory definition and robot reachability to improve the corresponding positioning accuracy. In conclusion, this thesis aims to provide a set of solutions, based on mechatronic devices and machine learning schemes, to improve the conventional machining centre and the robotic systems performances. The studied systems can be integrated within a robotic cell, focusing on issues related to the specific machining process and to the interaction between robot-machining centre. This research required a thorough study of the state-of-the-art, the formulation of theoretical models, the functional design development, the identification of the critical aspects in the prototype designs, the simulation and experimental campaigns, and the analysis of the obtained results

Design of passive piezoelectric damping for space structures

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993.Includes bibliographical references (leaves 103-105).by Jack Barron Aldrich.M.S

The Fifth NASA/DOD Controls-Structures Interaction Technology Conference, part 1

This publication is a compilation of the papers presented at the Fifth NASA/DoD Controls-Structures Interaction (CSI) Technology Conference held in Lake Tahoe, Nevada, March 3-5, 1992. The conference, which was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense, was organized by the NASA Langley Research Center. The purpose of this conference was to report to industry, academia, and government agencies on the current status of controls-structures interaction technology. The agenda covered ground testing, integrated design, analysis, flight experiments and concepts

NASA Tech Briefs, March 2011

Topics covered include: Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation; Airborne Radar Interferometric Repeat-Pass Processing; Plug-and-Play Environmental Monitoring Spacecraft Subsystem; Power-Combined GaN Amplifier with 2.28-W Output Power at 87 GHz; Wallops Ship Surveillance System; Source Lines Counter (SLiC) Version 4.0; Guidance, Navigation, and Control Program; Single-Frame Terrain Mapping Software for Robotic Vehicles; Auto Draw from Excel Input Files; Observation Scheduling System; CFDP for Interplanetary Overlay Network; X-Windows Widget for Image Display; Binary-Signal Recovery; Volumetric 3D Display System with Static Screen; MMIC Replacement for Gunn Diode Oscillators; Feature Acquisition with Imbalanced Training Data; Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads; Carbon Nanotube-Based Structural Health Monitoring Sensors; Wireless Inductive Power Device Suppresses Blade Vibrations; Safe, Advanced, Adaptable Isolation System Eliminates the Need for Critical Lifts; Anti-Rotation Device Releasable by Insertion of a Tool; A Magnetically Coupled Cryogenic Pump; Single Piezo-Actuator Rotary-Hammering Drill; Fire-Retardant Polymeric Additives; Catalytic Generation of Lift Gases for Balloons; Ionic Liquids to Replace Hydrazine; Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings; Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger; Multi-Mission Power Analysis Tool; Correction for Self-Heating When Using Thermometers as Heaters in Precision Control Applications; Gravitational Wave Detection with Single-Laser Atom Interferometers; Titanium Alloy Strong Back for IXO Mirror Segments; Improved Ambient Pressure Pyroelectric Ion Source; Multi-Modal Image Registration and Matching for Localization of a Balloon on Titan; Entanglement in Quantum-Classical Hybrid; Algorithm for Autonomous Landing; Quantum-Classical Hybrid for Information Processing; Small-Scale Dissipation in Binary-Species Transitional Mixing Layers; Superpixel-Augmented Endmember Detection for Hyperspectral Images; Coding for Parallel Links to Maximize the Expected Value of Decodable Messages; and Microwave Tissue Soldering for Immediate Wound Closure

Gallium Nitride Integrated Microsystems for Radio Frequency Applications.

The focus of this work is design, fabrication, and characterization of novel and advanced electro-acoustic devices and integrated micro/nano systems based on Gallium Nitride (GaN). Looking beyond silicon (Si), compound semiconductors, such as GaN have significantly improved the performance of the existing electronic devices, as well as enabled completely novel micro/nano systems. GaN is of particular interest in the “More than Moore” era because it combines the advantages of a wide-band gap semiconductor with strong piezoelectric properties. Popular in optoelectronics, high-power and high-frequency applications, the added piezoelectric feature, extends the research horizons of GaN to diverse scientific and multi-disciplinary fields. In this work, we have incorporated GaN micro-electro-mechanical systems (MEMS) and acoustic resonators to the GaN baseline process and used high electron mobility transistors (HEMTs) to actuate, sense and amplify the acoustic waves based on depletion, piezoelectric, thermal and piezo-resistive mechanisms and achieved resonance frequencies ranging from 100s of MHz up to 10 GHz with frequency×quality factor (f×Q) values as high as 1013. Such high-performance integrated systems can be utilized in radio frequency (RF) and microwave communication and extreme-environment applications.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/135799/1/azadans_1.pd

Evolutionary design of controlled structures

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1997.Includes bibliographical references (p. 209-213).by Brett P. Masters.Ph.D