METHOD FOR MEASURING FRICTION OF A PIVOT BEARING OF A MAGNETIC DISK DRIVE, AND AN APPARATUS THEREOF, PARTICULARLY REGARDING TO OBTAINING ACCURATE FRICTIONAL CHARACTERISTIC OF A PIVOT BEARING BY OBTAINING SPEED AND DISPLACEMENT MODEL TO INPUT OF AN ACTUATOR

摘要

PURPOSE: A method for measuring friction of a pivot bearing of a magnetic disk drive, and an apparatus thereof, particularly regarding to obtaining an accurate frictional characteristic of a pivot bearing by obtaining speed and displacement model to input of an actuator are provided to model non-linearity of a driving unit due to friction, and design a controller for compensating friction in designing a servo controller. CONSTITUTION: An output signal level in a time domain of speed and displacement is measured by applying the first low-frequency input signal in a predetermined voltage level to a rotary magnetic disk drive system. An output signal level in a time domain of speed and displacement is measured by applying the second input signal larger than the first input signal in a predetermined voltage level to the rotary magnetic disk drive system. Each output signal level in a time domain of speed and displacement is measured by applying the third to nth input signal in a predetermined voltage level to the rotary magnetic disk drive system. Characteristics of speed and displacement of the rotary magnetic disk drive system are modeled based on the result of the output signal levels. A frictional characteristic of a pivot bearing of a magnetic disk drive(100) is modeled based on the modeling of the characteristics of speed and displacement.