Yu Huang, Yue Xue Xia, Dian Hua Lin, Kui Yao, and Leong Chew Lim, “Large Stroke High Fidelity PZN-PT Single Crystal “Stake” Actuator,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol. 64, No. 10, pp. 1617-1624, 2017. (10.1109/TUFFC.2017.2735800)
Abstract:
A new piezoelectric actuator design, called “Stake” actuator, is proposed and demonstrated in this work. As an example, the stake actuator is made of four d32–mode PZN-5.5%PT single crystals, each of 25mmL x8mmW x 0.4mmT in dimensions, bonded with the aid of polycarbonate (PC) edge guide-cum-stiffeners into a square-pipe configuration for improved bending and twisting strengths and capped with top and bottom pedestals made of 1.5 mm thick anodized aluminium. The resultant stake actuator measured 9 mm x 9 mm x 28 mm. The hollow structure is a key design feature, which optimizes single crystal usage efficiency and lowers the overall cost of the actuator. The displacement-voltage responses, blocking forces, resonance characteristics of the fabricated stake actuator, as well as the load and temperature effects, are measured and discussed. Since d32 is negative for [011]-poled single crystal, the “Stake” actuator contracts in the axial direction when a positive polarity field is applied to the crystals. Biased drive is thus recommended when extensional displacement is desired. The single crystal stake actuator has negligible (0.13% when driven up to +300V (i.e., 0.75 kV/mm), which is close to the rhombohedral-to- orthorhombic transformation field (ERO) of 0.85 kV/mm of the single crystal used. The stake actuator displays a stroke of -36.5 µm (at +300V) despite its small overall dimensions, and has a blocking force of 114 N. The single crystal d32 stake actuator fabricated displays more than 30% larger axial strain than the state-of-the-art PZT stack actuators of comparable length as well as moderate blocking forces. Said actuators are thus ideal for applications when large displacements with simple open loop control are preferred.
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Funding Info:
Authors would like to thank Dynamic Lab in National University of Singapore and Institute of Materials Research and Engineering for their supports in equipment and experiments. Authors would also like to thank Microfine Material Technologies for his support in material supply.