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Sensors 2014, 14(7), 12399-12409; doi:10.3390/s140712399
Article

Wireless Displacement Sensing of Micromachined Spiral-Coil Actuator Using Resonant Frequency Tracking

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Received: 20 May 2014; in revised form: 6 July 2014 / Accepted: 7 July 2014 / Published: 10 July 2014
(This article belongs to the Section Physical Sensors)
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Abstract: This paper reports a method that enables real-time displacement monitoring and control of micromachined resonant-type actuators using wireless radiofrequency (RF). The method is applied to an out-of-plane, spiral-coil microactuator based on shape-memory-alloy (SMA). The SMA spiral coil forms an inductor-capacitor resonant circuit that is excited using external RF magnetic fields to thermally actuate the coil. The actuation causes a shift in the circuit’s resonance as the coil is displaced vertically, which is wirelessly monitored through an external antenna to track the displacements. Controlled actuation and displacement monitoring using the developed method is demonstrated with the microfabricated device. The device exhibits a frequency sensitivity to displacement of 10 kHz/µm or more for a full out-of-plane travel range of 466 µm and an average actuation velocity of up to 155 µm/s. The method described permits the actuator to have a self-sensing function that is passively operated, thereby eliminating the need for separate sensors and batteries on the device, thus realizing precise control while attaining a high level of miniaturization in the device.
Keywords: wireless displacement sensing; spiral-coil; micro-electro-mechanical systems; microactuators; resonant circuit wireless displacement sensing; spiral-coil; micro-electro-mechanical systems; microactuators; resonant circuit
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Ali, M.S.M.; AbuZaiter, A.; Schlosser, C.; Bycraft, B.; Takahata, K. Wireless Displacement Sensing of Micromachined Spiral-Coil Actuator Using Resonant Frequency Tracking. Sensors 2014, 14, 12399-12409.

AMA Style

Ali MSM, AbuZaiter A, Schlosser C, Bycraft B, Takahata K. Wireless Displacement Sensing of Micromachined Spiral-Coil Actuator Using Resonant Frequency Tracking. Sensors. 2014; 14(7):12399-12409.

Chicago/Turabian Style

Ali, Mohamed S.M.; AbuZaiter, Alaa; Schlosser, Colin; Bycraft, Brad; Takahata, Kenichi. 2014. "Wireless Displacement Sensing of Micromachined Spiral-Coil Actuator Using Resonant Frequency Tracking." Sensors 14, no. 7: 12399-12409.



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