Shuying Cao

Optimization of hysteresis parameters for the Jiles-Atherton model using a genetic algorithm

A dynamic model with hysteretic nonlinearity for magnetostrictive actuators has been established, combined with the Jiles-Atherton model. The hysteresis parameters for the model have been optimized using the genetic algorithm (GA). Simulation and experimental results demonstrated the effectiveness of the model and parameter identification approach.

Dynamic Strain Model With Eddy Current Effects for Giant Magnetostrictive Transducer

Based on the Jiles-Atherton model and transducers structural dynamics principle, the magnetoelastic dynamic strain model of giant magnetostrictive transducer is founded. This model takes into account the eddy current losses and the variety of stress. Simulation results are in a good agreement with the experimental ones. This indicates that the dynamic strain model can characterize the magnetization intensity and strain behavior at different frequency. The proposed model is suitable to describe the relation between the applied field and the output vibration at a wide range of exciting frequency

Hybrid genetic algorithms for parameter identification of a hysteresis model of magnetostrictive actuators

In this paper, we present an improved hysteresis model for magnetostrictive actuators. To obtain optimal parameters of the model, we study two distinct hybrid strategies: namely, employing a gradient algorithm as a local search operation of a genetic algorithm (GA), and taking the best individual of a GA as the initial value of a gradient algorithm. Here, two different gradient algorithms, a well-known Levenberg-Marquardt algorithm (LMA) and a novel Trust-Region algorithm (TRA), are investigated. Finally, the proposed four hybrid genetic algorithms (HGAs) are applied to identify parameters of the improved model. The simulation and experimental results show the performances of the HGAs and the improved hysteresis model.

Hysteresis compensation for giant magnetostrictive actuators using dynamic recurrent neural network

According to the hysteresis characteristics of the giant magnetostrictive actuator (MA), a dynamic recurrent neural network (DRNN) is constructed as the inverse hysteresis model of the MA, and an on-line hysteresis compensation control strategy combining the DRNN inverse compensator and a proportional derivative (PD) controller is used for precision position tracking of the MA. Simulation results validate the excellent performances of the proposed strategy

Modeling dynamic hysteresis for giant magnetostrictive actuator using hybrid genetic algorithm

This paper establishes a simple and novel dynamic hysteresis model for giant magnetostrictive actuator by considering the eddy current loss, anomalous loss and structural dynamic mechanical behavior of the actuator. To obtain parameters of the model, a hybrid genetic algorithm is proposed. Comparisons between the experimental and calculated results show the validity and practicability of the model

Structure, Curie temperature, and magnetostriction of SmZn1−xMnx alloys

The structure, Curie temperature, and magnetostriction of SmZn1-xMnx polycrystalline crystals were investigated by x-ray diffraction, vibrating-sample magnetometer, and standard strain gauge techniques. It is found that SmZn1-xMnx alloys are nearly a single Sm(Zn,Mn) phase with the CsCl-type cubic structure up to x=0.2. The Curie temperature of SmZn1-xMnx alloys quickly increases with increasing Mn when x <= 0.05 and gradually does in the range of 0.05 < x <= 0.2. The substitution of Mn for Zn in the SmZn compound has a marked effect on improving the Curie temperature and makes it reach 255 K when x=0.2. The magnetization of SmZn1-xMnx alloys increases with increasing Mn content in the range of 0 < x <= 0.2 and the magnetostriction increases in the range of 0 < x <= 0.15. (c) 2006 American Institute of Physics.

A numerical model of displacement for giant magnetostrictive actuator

A numerical model of displacement for a giant magnetostrictive actuator was founded. According to the model and the measured magnetic characteristic of giant magnetostrictive material, the relation between input current and output displacement for the actuator was calculated by means of the finite element method. A comparison between the calculating result and experimental one for the actuator was carried out and it was found that they were in agreement well. This demonstrates that the numerical model can be used for the design of giant magnetostrictive actuators.

Dynamic Characteristics of Galfenol Cantilever Energy Harvester

Based on the Armstrong model and the established electromechanical model of a Galfenol cantilever energy harvester, a nonlinear dynamic model is proposed to describe the mechanical-magneto-electro coupled characteristics of the device. Comparisons between the experimental and calculated results show that the proposed model can provide a reasonable qualitative indication of data trends, and can predict the effects of the acceleration excitation, the load resistance, and the bias magnetic field on the output performance of the device, thus has very strong practicability.

Phase diagram of the iron-rich portion in the iron–gallium–aluminum ternary system

Abstract The isothermal section at 650°C and the vertical section Fe-(Ga0.75Al0.25) of the Fe-rich portion in the Fe – Ga – Al ternary system were determined using optical microscopy, scanning electron microscopy, energy dispersion X-ray spectroscopy, X-ray diffraction and differential thermal analysis. The isothermal section of the Fe-rich portion consists of 4 single-phase regions: A2, B2, D03, D019, and 4 two-phase regions: A2 + B2, A2 + D03, D03 + D019 and B2 + D019. No fcc L12 phase region occurs in the isothermal section of the Fe-rich portion. The vertical section Fe-(Ga0.75Al0.25) of the Fe-rich portion consists of 3 single-phase regions: A2, B2 and D03, 4 two-phase regions: A2 + D03, D03 + D019, A2 + L12 and D03 + L12, and 2 three-phase regions: D03 + D019 + L12 and A2 + D03 + L12.

An Equivalent Circuit Model and Energy Extraction Technique of a Magnetostrictive Energy Harvester

This paper proposes a distributed parameter equivalent circuit model of a magnetostrictive energy harvester, where the mechanical parameters and the mechanical-electro coupled terms are represented by electronic components. Based on the model, the harvester system with any energy extraction circuit (EEC) can be modeled in a circuit simulator for system-level evaluation and design. Comparisons between the measured and calculated results show that the proposed model can provide reasonable data of the harvester at low acceleration levels, and support the physical understanding of the dynamic behaviors for the harvester. In addition, the harvester system with a self-powered EEC is constructed, and its whole performances are effectively predicted. These prove that the proposed model can analyze and design the harvester system with both complicated mechanical structure and practical EEC, thus has very strong practicability.