Design And Research Of Micro-Actuator With Large Displacement Based On GMM And Flexible Hinge

The giant magnetostrictive material (GMM) has developed rapidly from the 20th century, which has widely influence on the scientific comprehensive competitive power. GMM has the advantages of high resolution, strain, output force, quick response and energy density, and it has a broad prospect in army-civil dual-use. Because of rich rare earth resources in China, study on giant magnetostrictive actuator (GMA) has a positive role in promoting the development of rare earth material. Currently, research on GMA mostly focused on the micro-displacement actuator. In order to expand application, the large displacement actuator is manufactured in this paper, which has combined GMM with differential displacement amplifier. And its key technical problems are studied in both theoretic and experiment.Using the micro-actuator technology as background, the present situation of GMA research is discussed in this paper, also including GMM, magnetostrictive principle, physical effect and its application.Based on the operating characteristics of GMM, the large displacement micro-actuator is manufactured, including the selection of GMM rod, the design of coil, magnetic circuit structure, preloading structure, temperature control structure, and displacement amplifier structure and so on.After understanding the electromagnetic field analysis theory of ANSYS software, the three-dimensional finite element model of the designed actuator is established. The analysis result shows that the design of magnetic circuit field is reasonable. The magnetization distributed on the GMM rod has a less loss which can meet the needs. Meanwhile, the relationship between the axial distribution of driving magnetic field and material of shell, output shaft, and end cover is analyzed, which is significance for the optimization of magnetic circuit field.The flexible structure is employed in the whole displacement amplifier, and the mechanical model of the fillet flexible hinge is established. Some structural parameters, such as minimum thickness, straight beam length and fillet radius, have impact on its deflection and tensile stiffness, and the influence is analyzed in this paper. All the above provide a theoretical basis for determining structural parameters of flexible hinge. The static and modal analysis of displacement amplifier is implemented by finite element method. Its result shows that the amplification factor, input and output stiffness can be realized as constants, and its intension can meet the needs while amplification factor is 6.8 and input displacement is 80μm.The magnetic-mechanical coupling relationship of GMM rod is described by piezomagnetic equation. The dynamic characteristic of large displacement micro-actuator is analyzed by its dynamic model simulation. The result shows that time-domain and frequency-domain performance of the designed actuator is superior. Meanwhile, the analysis of the relationship between its structure and dynamic characteristic can provide a basis for its dynamic design and optimization.The test and experiment research of the designed micro-actuator characteristics is implemented in this paper, including magnetic field, output displacement, stability, displacement amplifier performance. The result shows that the three-dimensional finite element model and its analysis of micro-actuator via ANSYS is correct; the amplifier factor of displacement amplifier structure via ANSYS is equal to experiment; the steady-state output also equal to experiment.