• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.349-352
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• 1997

A Piezoelectric actuator yields hysteresis effect due to its composed ferroelectric. Hysteresis nonlinearity is neglected when a piezoelectric actuator moves with short stroke. However when it moves with long stroke and high frequency, the hysteresis nonlinearity can not be neglected. The hysteresis nonlinearity of piezoelectric actuator degrades the control performance in precision position control. In this paper, in order to improve the control performance of piezoelectric actuator, an inverse modeling scheme is proposed to compensate the hysteresis nonlinearity problem. And feedforward-feedforward-feedback controller is proposed to give a good tracking performance. The Feedforward controller is inverse hysteresis model, and PID control is sued as a feedback controller. To show the feasibility of the proposed controller and hysteresis modeling, some experiments have been carried out. It is concluded hat the proposed control scheme gives good tracking performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.85-88
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• 2000

In this paper, the ultra precision positioning system for piezoelectric actuator using hysteresis compensation has been developed. Piezoelectric actuators exhibit limited accuracy in tracking control due to their hysteresis nonlinearity. The main purpose of the proposed controller is to compensate the hysteresis nonlinearity of the piezoelectric actuator. The controller is composed of a PD, hysteresis compensation and neural network part in parallel manner, at first, the excellent tracking performance of the neural network controller was verified by experiments and was compared with the classical PD controller.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1052-1055
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• 1996

Piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, serious hysteresis nonlinearity of the actuator deteriorates its precise positioning capability. Evenworse, its hysteresis nonlinearity changes as the actuator input frequency varies. In this study, a simple feedforward scheme is proposed and tested through experiments for precision position control when the variance of the system input frequency is significant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.219-224
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• 1996

Piezoelectric actuators exhibit limited accuracy in tracking control due to their hysteresis nonlinearity. In this study a digital tracking control approach for a piezoelectric actuator based on incorporating a feedback linearization loop with a PID feedback controller is presented. The hysteresis nonlinearity of the piezoelectric actuator is modeled in the feedback compensation loop using the Maxwell slip model. Experiments were performed on a piezoelectric 2-axis linear positioner for tracking linearly decaying sinusoidal waveforms and circles. The experimental results show that the tracking control performance is noticeably improved by augmenting the feedback loop with a model of hysteresis in the feedback compensation loop.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.736-746
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• 2002

There has been a great demand for smart actuators in the field of micro-machines. However, the control accuracy of smart actuators, e.g., a shape memory alloy(SMA) and a piezoceramic actuator, is limited due to the inherent hysteresis nonlinearity. The Preisach hysteresis model has emerged as an appropriate model f3r the behavior of those smart actuators. Yet it is still not easy to construct a practical model of hysteresis using the classical Preisach model. Accordingly, in this paper, we propose a new simple method for modeling of the hysteresis nonlinearity of SMA. Using only the proportional relation of the major loop of hysteresis, the proposed method makes the computation of the Preisach model easy. We prove the efficacy of the proposed model through the comparative the experimentation with the classical Preisach model.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.162-167
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• 2005

The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that are cost less and faster than previous semiconductor processes have been developed for the production of electric paper and RFID(Radio Frequency IDentification). The system proposed in this study prints by spraying the molten metal. And this system consist of a nozzle, heating furnace, operating actuator and an XYZ 3-axis stage. As an operating system, the piezoelectric(PZT) actuator is a very useful tool for position control of the metal printing system. However, the PZT actuator has a hysteresis nonlinearity due to the ferroelectric characteristics of the PZT element. This hysteresis causes problem position control characteristics in the system and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. In order to reduce the hysteresis nonlinearity of the PZT actuator, this proposed a inverse hysteresis model and a mathematic modeling method that can express the geometric relationship between voltage and displacement. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good tracking performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.189-193
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• 1996

Piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, serious hysteresis nonlinearity of the actuator deteriorates its open loop positioning capability. Generally, a nonlinear hysteresis model is used in feedforward loop to improve positioning accuracy. In this study, however, a simple lead compensator is proposed as a substitution for a complex nonlinear hysteresis model and tested through experiments for precision position control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1074-1078
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• 2005

In precision positioning applications, such as scanning tunneling microscopy and diamond turning machines [1], it is often required that actuators have nanometer resolution in displacement, high stiffness, and fast frequency response. These requirements are met by the use of piezoceramic actuators. A major limitation of piezoceramic actuators, however, is their lack of accuracy due to hysteresis nonlinearity and drift. The maximum error due to hysteresis can be as much as 10-15% of the path covered if the actuators are run in an open-loop fashion. Hence, the accurate control of piezoceramic actuators requires a control strategy that incorporates some form of compensation for the hysteresis. One approach is to develop an accurate model of the hysteresis and the use the inverse as a compensator. The Preisach model has frequently been employed as a nonlinear model for representing the hysteresis, because it encompasses the basic features of the hysteresis phenomena in a conceptually simple and mathematically elegant way. In this paper, a new numerical inversion scheme of the Preisach model is developed with an aim of compensating hysteresis in piezoceramic actuators. The inversion scheme is implemented using the first-order reversal functions and is presented in a recursive form. The inverted model is then incorporated in an open-loop control strategy that regulates the piezoceramic actuator and compensates for hysteretic effects. Experimental results demonstrate satisfactory regulation of the position of the piezoceramic actuator to the desired trajectories.

• Structural Engineering and Mechanics
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• v.6 no.5
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• pp.473-484
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• 1998

The first and second moments of response variables for SDOF systems with hysteretic nonlinearity are obtained by a direct linearization procedure. This adaptation in the implementation of well-known statistical linearization methods, provides concise, model-independent linearization coefficients that are well-suited for numerical solution. The method may be applied to systems which incorporate any hysteresis model governed by a differential constitutive equation, and may be used for zero or non-zero mean random vibration. The implementation eliminates the effort of analytically deriving specific linearization coefficients for new hysteresis models. In doing so, the procedure of stochastic analysis is made independent from the task of physical modeling of hysteretic systems. In this study, systems with three different hysteresis models are analyzed under various zero and non-zero mean Gaussian White noise inputs. Results are shown to be in agreement with previous linearization studies and Monte Carlo Simulation.

• Smart Structures and Systems
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• v.33 no.2
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• pp.133-143
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• 2024

Piezoelectric (PZT) actuators have been widely used in precision positioning fields for their excellent displacement resolution. However, due to the inherent characteristics of piezoelectric actuators, hysteresis has been proven to greatly reduce positioning performance. In this paper, five mathematical hysteretic models based on activation function are proposed to characterize the nonlinear hysteresis characteristics of piezoelectric actuators. Then the performance of the proposed models is verified by particle swarm optimization (PSO) algorithm and the experiment data. Thirdly, the fitting performance of the proposed models is compared with the classical Bouc-Wen model. Finally, the performance of the five proposed models in modelling hysteresis nonlinearity of piezoelectric drivers is compared, in terms of RMSE, MAPE, SAPE and operation efficiency, and relevant suggestions are given.