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An enhanced Bouc-Wen model for characterizing rate-dependent hysteresis of piezoelectric actuators
摘要： A classical Bouc-Wen model is widely applied in hysteresis modeling and compensation for piezoelectric ceramic actuators. However, the classical Bouc-Wen model cannot characterize rate-dependent hysteresis under excitations at high frequencies precisely. In this paper, an enhanced Bouc-Wen model is developed by introducing the frequency of input voltage based on the classical Bouc-Wen model. A number of experiments were conducted to characterize the rate-dependent hysteresis of piezoelectric ceramic actuators under sinusoidal excitations at a range of 1–150 Hz. The measured data were used to demonstrate the validity of the developed model. A method of parameter estimation based on the Matlab/Simulink parameter estimation tool is adopted to identify the parameters of models. The comparisons of experiments and simulations show that the developed model can describe rate-dependent hysteresis more accurately than the classical Bouc-Wen model. The modeling errors of the developed model were decreased by nearly 75% compared with that of the classical Bouc-Wen model. The root-mean-square error of the developed model is controlled in 0.1719 μm.
关键词： parameter estimation,Bouc-Wen model,rate-dependent hysteresis,piezoelectric actuators
更新于2025-09-04 15:30:14
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Strain-Mediated Substrate Effect on the Dielectric and Ferroelectric Response of Potassium Sodium Niobate Thin Films
摘要： If piezoelectric thin films sensors based on K0.5Na0.5NbO3 (KNN) are to achieve commercialization, it is critical to optimize the film performance using low-cost scalable processing and substrates. Here, sol–gel derived KNN thin films are deposited using a solution with 5% of potassium excess on Pt/TiO2/SiO2/Si and Pt/SrTiO3 substrates, and rapid thermal annealed at 750 ?C for 5 min. Despite an identical film morphology and thickness of ~335 nm, an in-plane stress/strain state is found to be tensile for KNN films on Pt/TiO2/SiO2/Si, and compressive for those on Pt/SrTiO3 substrates, being related to thermal expansion mismatch between the substrate and the film. Correspondingly, KNN films under in-plane compressive stress possess superior dielectric permittivity and polarization in the parallel-plate-capacitor geometry.
关键词： stress/strain,ferroelectric hysteresis,dielectric properties,KNN thin films,sol–gel,thermal expansion
更新于2025-09-04 15:30:14
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Lack of correlation between C-V hysteresis and capacitance frequency dispersion in accumulation of metal gate/high- <i>k</i> /n-InGaAs metal-oxide-semiconductor stacks
摘要： The correlation between capacitance-voltage hysteresis and accumulation capacitance frequency dispersion of metal gate/high-k/n-InGaAs metal-oxide-semiconductor stacks is experimentally assessed. Samples fabricated employing forming gas annealing (FGA) or substrate air exposure to obtain different densities of defects were thoroughly characterized and the results were compared with previous literature on the topic. Results indicate a lack of correlation between capacitance-voltage hysteresis and accumulation capacitance dispersion with frequency, suggesting that defects with remarkably different kinetics are involved in each phenomenon. This is assessed through the dependence of the capacitance-voltage hysteresis with DC bias and stress time, observing that permanent interface defect depassivation under bias has no effect on the hysteresis width after stress. Overall, capacitance-voltage hysteresis probes slow trapping mechanisms throughout the oxide and the bandgap, which are consistent with the negative charge trapping characteristic of the current-time curves for FGA samples at constant voltage stress. Instead, accumulation capacitance frequency dispersion probes defects with short trapping/detrapping characteristic times that can be linked to the stress induced leakage current of air exposed samples under constant DC stress. Experimental results indicate that each effect must be assessed separately due to the large difference in the kinetics of the probed defects.
关键词： metal-oxide-semiconductor stacks,forming gas annealing,defects,metal gate/high-k/n-InGaAs,trapping mechanisms,capacitance-voltage hysteresis,accumulation capacitance frequency dispersion
更新于2025-09-04 15:30:14