An electro-thermally activated rotary micro-positioner for slider-level dual-stage positioning in hard disk drives
Lau, Gih Keong
Tan, Cheng Peng
Chong, Nyok Boon
Date of Issue2016
School of Mechanical and Aerospace Engineering
Slider-level micro-positioners are useful to assist a voice coil motor to perform fine head positioning over a Tb/in2 magnetic disk. Recently, a new kind of slider-level micro-positioner was developed using the thermal unimorph of the Si/SU8 composite. It has the advantages of a very small footprint and high mechanical resonant frequency, but its stroke generation is inadequate, with a 50 nm dynamic stroke at 1 kHz. There is a need for a larger thermally induced stroke. This paper presents a rotary design of an electrothermal micro-positioner to address the stroke requirements without consuming more power or decreasing the mechanical resonant frequency. Experimental studies show the present rotary design can produce a six-fold larger displacement, as compared to the previous lateral design, while possessing a 35 kHz resonant frequency. In addition, simple analytical models were developed to estimate: (i) the rotational stiffness and system's natural frequency, (ii) thermal unimorph bending and stage rotation, and (iii) the system's thermal time constant for this rotary electro-thermal micro-positioner. This study found that this rotary electro-thermal micro-positioner can meet the basic stroke requirement and high mechanical resonant frequency for a moving slider, but its thermal cut-off frequency needs to be increased further.
dual stage actuator
dual stage actuator
Journal of Micromechanics and Microengineering
© 2016 IOP Publishing Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Micromechanics and Microengineering, IOP Publishing Ltd. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1088/0960-1317/26/3/035016].