Creep Of Piezoelectric Actuator Research Articles

Comprehensive compensation of dynamic hysteresis and creep for piezoelectric actuator

This paper addresses the modeling of dynamic hysteresis and creep in piezoelectric actuators, and employs feedforward open-loop control based on inverse models to compensate for hysteresis and creep phenomena. The comprehensive model consists of quasi-dynamic and dynamic components. The quasi-dynamic model combines the quasi-dynamic Prandtl–Ishlinskii (PI) model with an PI-based linear time-invariant model, while the dynamic part utilizes the auto-regressive exogenous model. The model accurately describes creep and dynamic hysteresis with modeling errors of less than 0.01 μm and 0.14 μm, respectively. The inversion of the comprehensive model has been proven to exhibit unique convergence. Under inverse feedforward control, the improvement in dynamic hysteresis and hysteresis with creep can be achieved at 94% and 83%, respectively. The comprehensive model proposed in this paper accurately describes the dynamic hysteresis and creep phenomena in piezoelectric actuators and realizes open-loop compensation control, achieving precise actuation of piezoelectric actuators.

Model Reduction for Optimized Online Compensation of Hysteresis and Creep in Piezoelectric Actuators

In this brief, a strategy is proposed for the identification, starting from experimental measurements on piezoelectric actuators, of all the parameters of the recently proposed power-law hysteresis and creep model. The algorithm allows trading off modeling accuracy and speed of the inverse model (compensator) implemented in a digital device. An analysis of the relationships among parameters and their effects on modeling and circuit performances is also carried out. The proposed strategy is tested on two piezoelectric actuators, showing that the obtained models are able to fulfill the circuit specifications.

SVD‐Based Accurate Identification and Compensation of the Coupling Hysteresis and Creep Dynamics in Piezoelectric Actuators

AbstractIn this paper, the coupling hysteresis and creep in piezoelectric actuators are identified and compensated for accurate tracking. First, we present the coupling hysteresis and creep model in smart actuators. Next, a complete identification strategy is designed according to the properties of the Preisach model. Then, an approach for parameter updating of the coupling model is provided. With the identified hysteresis and creep, the model‐based inversion compensation is designed. Finally, we apply the model identification and compensation to a piezoelectric stage to demonstrate the effectiveness of the proposed approaches. Significant reduction of the tracking error is achieved with the model‐based inversion feedforward compensator in which the relative errors at 10 Hz and 50 Hz are reduced to 1.85% and 4.53%, respectively. In addition, the model‐based feedforward is augmented with an integral feedback controller. With the composite controller, the relative errors at 10 Hz and 50 Hz are reduced to 0.42% and 3.04%, respectively.

Real-time compensation control for hysteresis and creep in IPMC actuators

Hysteresis and creep hinder the effective use of IPMC in sensors and actuators. In order to cope with these disadvantageous effects, a fundamental approach is inverse compensation. This paper presents a hybrid model of hysteresis and creep in piezoelectric actuator, which is constructed by Preisach operator and creep operator. Then, the corresponding inverse models for both hysteresis and creep are developed. Based on the obtained inverse model, a method for real-time compensation of the hysteresis and creep of piezoelectric actuator is applied to the control of system nonlinearities. The efficiency of this new model and the method of real-time inverse control are demonstrated by simulation and experiment based on an IPMC actuator. Using this control concept, the tracking errors caused by hysteretic and creep effects are reduced by approximately one order of magnitude, the result verified the validity of the model and effectiveness of the controller.

An integrated physical model that characterizes creep and hysteresis in piezoelectric actuators

In this paper, a model that can precisely portray hysteresis and creep in piezoelectric actuators is proposed. The model, which is originally constructed using bond-graph representation, describes the actuator’s various physical effects and energy interaction between physical domains. Specifically, the model utilizes a parallel connection of Maxwell-slip elements and a nonlinear spring to describe hysteresis, and a series connection of Kelvin–Voigt units to describe creep. Using the experimental data, the constitutive relation of the nonlinear spring and the parameters of linear, physical elements in the model can be systematically identified via the linear programming method. To further account for the frequency-dependent hysteresis behavior, a dynamic damper is incorporated. By analyzing the model, the influence of initial strain/charges on the creep response is revealed and an initialization procedure is devised to eliminate such an influence. An inverse model control, in the sense of feedback linearization, is constructed based on the identified model to make the actuator track reference trajectories. Experiments show that both creep and hysteresis are effectively cancelled and accurate tracking of selected reference trajectories is achieved.

Application of capacitor insertion method to scanning tunneling microscopes

The capacitor insertion method to compensate for hysteresis and creep in piezoelectric actuators is applied to scanning tunneling microscopes. By inserting a capacitor in series with the piezoelectric actuator, hysteresis and creep can be greatly reduced or eliminated. After the principle of the method is reviewed, a structure of a scanning tunneling microscope used here is described. A calibration grid for scanning electron microscopes (2000 lines/mm) can be imaged with greatly reduced distortion by inserting capacitors in series with the piezoelectric actuators, which consist of an x-y-z scanner of the microscope. Furthermore the method can be used to reduce the sensitivity of the x-y-z movements of the scanner because an applied voltage is divided between an inserted capacitor and a piezoelectric actuator. Hence, using suitably small capacitors, atomic-scale images of Kish-graphite can be easily obtained with the same microscope.