A robust loop-shaping approach to fast and accurate nanopositioning

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Butterworth Pattern-based Simultaneous Damping and Tracking Controller Designs for Nanopositioning Systems

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Optimal integral force feedback and structured PI tracking control : application for objective lens positioner

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A dual-loop tracking control approach to precise nanopositioning

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Enhanced Positioning Bandwidth in Nanopositioners via Strategic Pole Placement of the Tracking Controller

Funding: This research received no external funding.Peer reviewedPublisher PD

Sinteza H-beskonačno regulatora s unaprijednom granom za kompenzaciju histereze kod piezoelektričnih aktuatora

Piezoelectric actuators, widely used in different micro/nanopositioning applications, generally exhibit nonlinear hysteresis characteristics. The compensation of hysteretic behavior of piezoelectric actuators is mandatory for precise micro/nanopositioning. In this paper, nonlinear hysteresis effect is first characterized using the Prandtl-Ishlinskii hysteresis model. The inverse of the Prandtl-Ishlinskii hysteresis model is employed as a feed-forward controller to compensate for hysteresis nonlinearities of the piezoelectric actuator. Slight hysteresis nonlinearity is still observed in the experimental results due to small mismatch between the identified hysteresis model and the measured hysteresis loop. To further enhance the performance of the piezoelectric actuator in terms of mitigation of hysteresis nonlinearity and precise reference tracking, advanced robust full-order as well as fixed-order H-infinity feedback controllers are designed and applied to this actuator in the presence of feed-forward compensator. The experimental results verify the effectiveness of the proposed control scheme in achieving the improved tracking performance with peak-to-peak tracking error of less than 1% for the desired displacement of 12 um with tracking frequency of 10 Hz.Piezoelektrični aktuatori, rasprostranjeni u različitim primjenama mikro/nanopozicioniranja, općenito su izloženi nelinearnim histereznim karakteristikama. Kompenzacija histereznog ponašanja piezoelektričnih aktuatora nužna je za precizno mikro/nanopozicioniranje. Inverzni Prandtl-Ishlinskii histerezni model korišten je za unaprijednu kompenzaciju histereznih nelinearnosti piezoelektričnog aktuatora. Neznatna histerezna nelinearnost još uvijek je vidljiva u eksperimentalnim rezultatima zbog malog neslaganja između identificiranog histereznog modela i mjerene histerezne petlje. Za daljnje poboljšanje performansi piezoelektričnog aktuatora u smislu smanjenja histerezne nelinearnosti i preciznog slijeđenja reference, napredni robusni H-beskonačno regulatori punog i određenog reda sintetizirani su i primijenjeni na ovaj aktuator uz prisutnost unaprijednog kompenzatora. Eksperimentalni rezultati potvrđuju efektivnost predložene upravljačke strukture u postizanju poboljšanih performansi slijeđenja, uz vršnu vrijednost pogreške manju od 1% za ciljani pomak od 12 um s frekvencijom slijeđenja od 10 Hz

Generalizing Negative Imaginary Systems Theory to Include Free Body Dynamics: Control of Highly Resonant Structures with Free Body Motion

Negative imaginary (NI) systems play an important role in the robust control of highly resonant flexible structures. In this paper, a generalized NI system framework is presented. A new NI system definition is given, which allows for flexible structure systems with colocated force actuators and position sensors, and with free body motion. This definition extends the existing definitions of NI systems. Also, necessary and sufficient conditions are provided for the stability of positive feedback control systems where the plant is NI according to the new definition and the controller is strictly negative imaginary. The stability conditions in this paper are given purely in terms of properties of the plant and controller transfer function matrices, although the proofs rely on state space techniques. Furthermore, the stability conditions given are independent of the plant and controller system order. As an application of these results, a case study involving the control of a flexible robotic arm with a piezo-electric actuator and sensor is presented

Advances in Tracking Control for Piezoelectric Actuators Using Fuzzy Logic and Hammerstein-Wiener Compensation

first_page settings Open AccessArticle Advances in Tracking Control for Piezoelectric Actuators Using Fuzzy Logic and Hammerstein-Wiener Compensation by Cristian Napole 1,* [OrcID] , Oscar Barambones 1,* [OrcID] , Isidro Calvo 1 [OrcID] , Mohamed Derbeli 1 [OrcID] , Mohammed Yousri Silaa 1 [OrcID] and Javier Velasco 2 [OrcID] 1 System Engineering and Automation Deparment, Faculty of Engineering of Vitoria-Gasteiz, Basque Country University (UPV/EHU), 01006 Vitoria-Gasteiz, Spain 2 Fundación Centro de Tecnologías Aeronáuticas (CTA), Juan de la Cierva 1, 01510 Miñano, Spain * Authors to whom correspondence should be addressed. Mathematics 2020, 8(11), 2071; https://doi.org/10.3390/math8112071 Received: 23 October 2020 / Revised: 16 November 2020 / Accepted: 17 November 2020 / Published: 20 November 2020 (This article belongs to the Special Issue Fuzzy Applications in Industrial Engineering) Download PDF Browse Figures Abstract Piezoelectric actuators (PEA) are devices that are used for nano- microdisplacement due to their high precision, but one of the major issues is the non-linearity phenomena caused by the hysteresis effect, which diminishes the positioning performance. This study presents a novel control structure in order to reduce the hysteresis effect and increase the PEA performance by using a fuzzy logic control (FLC) combined with a Hammerstein–Wiener (HW) black-box mapping as a feedforward (FF) compensation. In this research, a proportional-integral-derivative (PID) was contrasted with an FLC. From this comparison, the most accurate was taken and tested with a complex structure with HW-FF to verify the accuracy with the increment of complexity. All of the structures were implemented in a dSpace platform to control a commercial Thorlabs PEA. The tests have shown that an FLC combined with HW was the most accurate, since the FF compensate the hysteresis and the FLC reduced the errors; the integral of the absolute error (IAE), the root-mean-square error (RMSE), and relative root-mean-square-error (RRMSE) for this case were reduced by several magnitude orders when compared to the feedback structures. As a conclusion, a complex structure with a novel combination of FLC and HW-FF provided an increment in the accuracy for a high-precision PEA.This research was funded by Basque Government and UPV/EHU projects