Dynamic characterization of dual stage micro actuator

• Main Author: Chua, Siong Pau
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechatronics
• Online Access: http://hdl.handle.net/10356/60918
• Institution: Nanyang Technological University

The importance of storage capacity in a hard disk drive (HDD) grows over the years. One way to increase the capacity is to improve the tracking performance of the read/write head. In order to achieve that, micro thermal actuator is introduced which has more accuracy for driving the head to read or write on the right track. In thermal actuation, the resonant frequency and sensitivity achieved can be much higher than the other actuation technology. In addition, the strain caused by the heat can produced a higher lateral motion at a small amount of voltage. This report presents the characteristic of a micro thermal actuator for dynamic performance. The thermal micro actuator uses thermal expansion of polymer to move a stage, which carry the slider. This polymer composite actuator consists of two benders that will alternatively activate the head position by different thermal expansion. Thus created a lateral motion to drive the slider when voltage is applied that cause resistive heating. Therefore, it is important to measure the displacement cause by the bending. As the micro actuator is too small to be measured, Laser Doppler Vibrometer (LDV) is used instead to obtain the lateral displacement cause by heating. The actuator was driven at 100Hz interval to see whether lateral displacement at a higher frequency. In this experiment, a voltage of 5 volt will be driving the actuator to act as the heating source. The results showed that the actuator can only achieve up to 2000Hz frequency. It may due to the fast response made from the actuator that the instrument is unable to capture. Other factors like the source of disturbance can also affect the output result from the LDV.