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Detection method of shock caused by stick slip

IP.com Disclosure Number: IPCOM000215874D
Publication Date: 2012-Mar-14
Document File: 2 page(s) / 73K

Publishing Venue

The IP.com Prior Art Database

Abstract

Thermal stick-slip phenomenon is sudden sticking and slipping motion over materials caused by difference in thermal expansion. To detect such kind of shock, the shock sensor is utilized. According to decrease of the track width, the detection sensitivity should be higher. But, this leads mis-detection of the noise. Two or more shock sensors are located at around pivot shaft and at actuator. The average signal with predetermined delay can suppresses the noise. This increases shock detectability.

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Detection method of shock caused by stick slip

  Thermal stick-slip phenomenon is sudden sticking and slipping motion over materials caused by difference in thermal expansion. If a shock due to the phenomenon reaches to a head, there is a possibility to write information to an adjacent track faultily. The shock sensor is utilized to detect such kind of shock as shown in Fig. 1. According to decrease of the track width, the detection sensitivity should be higher. But, this leads mis-detection of the noise.

     To increase shock detectability, the additional sensors are attached on the actuator which the shock transmits through as shown Fig. 2. The signals from these sensors are added with some delay time. The delay time can be predetermined by the numerical analysis or measurement. Because the shocks always transmit the bearing even if the stick slip location is changed, the delay time does not differ much. Then the added signal is input to the window comparator. If the signal exceeds pre-determined threshold, then the write process is stopped. Addition of the two signals from the two shock sensors suppresses the noise and increases signal-to-noise ratio by 30%.

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Disclosed by Hitachi Corporation

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