Concept Of A Novel Nano Displacement Magnetostrictive Actuator With Self-Sensing Function

Giant magnetostrictive materials can be used in the micro driving or sensing system for that the shape of materials changes under the different external magnetic field, which is called one effect of magnetostriction. As for the common Terfenol-D bars, the magnetostriction is expressed by the length change in the direction of the magnetic field, and the value of length change is too small to be detected. This paper presents a design of nano scale driving and measuring system which utilizes the thick film resistor (TFR) strain gauge mounted on the surface of Terfenol-D bar to measure the strain change of giant magnetostrictive materials directly, the in-situ measuring method has better flexibility and sensibility than indirect measuring methods such as capacitor sensor or other displacement measuring devices. A DSP based weak signal processing system has been developed to excite the micro displacement sensing system and calculate the strain of Terfenol-D bars from the signal output from thick film strain gauge instantly. The design scheme improves the resolution and accuracy of deformation measurement of the Terfenol-D bar, which is fundamental to the control of system and fulfills the requirements of real-time precise driving or sensing.