Search

In this study, an integrative giant magnetostrictive material-based electro-hydrostatic actuator (GMEHA) was designed. Firstly, the uniform of magnetic field distribution on giant magnetostrictive material rod was obtained by using finite element method, i.e. the nonuniformity of the axis and radial direction magnetic field intensity were less than 3% and 0.05%, respectively. Secondly, the flow rate model through the reed valve model was established in COMSOL Multiphysics software, and the relevant properties of reed valves were studied. Thirdly, the dynamic mathematical model of GMEHA was systematically established based on the operational principles of the GMEHA, accordingly, and the simulation model of GMEHA was built in Matlab/Simulink. Finally, the model and simulation results were subsequently verified with the experimental data, which indicates the effective output stroke of the designed GMEHA reached 70 mm, and the maximum no-load output flow was 0.85 L/min at approximately 250 Hz with the best working frequency; the blocked force was nearly 120 N. These results demonstrated the accuracy of the theoretical model and provided a foundation for the design and optimization of the GMEHA. [ABSTRACT FROM AUTHOR]

A theoretical magnetic field intensity model within giant magnetostrictive material was presented. This model was established just like the reluctance model, while could describe the non-uniform distribution flexibly for its integral form. This model employed magnetic circuit theorem calculating the mean of the magnetic field, while used a normalized function describing the distributing character. The distributing function was determined by Biot--Savart law and relative permeability of the material. The model was validated with the help of the experimental device. At last, the fitting degree of the model with the tested results in predicting the performance of the actuator is researched. [ABSTRACT FROM AUTHOR]

A giant magnetostrictive actuator is designed with strong bias magnetic field. The influence of the strong bias field is introduced, and the corresponding exciting input signal is selected. Magnetic reluctance estimation, approximate linearity between the strain and magnetic field, and a mass–spring–damper system assumption are employed to analyze the actuator’s displacement with low-frequency signal input. An experimental system is designed, and properties of the proposed actuator are tested. With the help of square wave test, appropriate direction of exciting signal for the magnetostrictive actuator is determined. With the help of sinusoidal wave test, the established model is validated and the relationship between the maximum value of the displacement and of the current is analyzed. With exciting frequency lower than 200 Hz, the errors between the calculating and testing results are within 1.0 m, which validates the model. [ABSTRACT FROM AUTHOR]

This article presents a new iterative learning control algorithm based on inverse model to decrease the hysteresis-caused tracking error of a giant magnetostrictive actuator. The first iteration input is calculated by the inverse model of the giant magnetostrictive actuator system according to the desired output. Compared to a standard iterative learning control algorithm—in which the first iteration input usually is proportional to the desired output—the proposed algorithm converges more rapidly. Performance of the approach is demonstrated both theoretically and experimentally. The experimental results show that the inverse model–based iterative learning control converges about twice as fast as standard iterative learning control and reduces the hysteresis-caused error of giant magnetostrictive actuator to 0.5% of the total displacement range, which is comparable to the noise level of sensor measurement. Two sets of model parameters were identified by 0–1.5 and 0–5 V major hysteresis loop, respectively, and evaluated. The best convergence rate is obtained with the former case. [ABSTRACT FROM PUBLISHER]

In various leading-edge technology areas, such as semiconductor manufacturing, the requirement for micro-vibration control is increasing. The authors have developed an active six-degrees-of-freedom (6-DOF) micro-vibration control system using an off the shelf, giant magnetostrictive (GMS) actuator. The efficiency of the active micro-vibration control system using a GMS actuator has been verified through several control experiments. However, the active micro-vibration control approach has not previously been applied to actual precision measuring equipment. Therefore, the control performance of such systems has not been verified on a practical application. In this study, an active 6-DOF micro-vibration control system using GMS actuators is developed and applied to buildings in order to provide micro-level-vibration-free space for a focused ion beam (FIB). The outline of the system, the design of the control system, and the results of experimental verification are described. In this application of the active micro-vibration control system, the design of the active micro-vibration control system is carried out taking several factors into consideration. Vibration measurements made after adjusting the micro-vibration control system confirm that the table satisfies the specified requirement and that a clear FIB image is obtained under high-magnification observation. [ABSTRACT FROM AUTHOR]