Slider vibrations induced by ramp-suspension interaction during the ramp loading process

In our previous experimental investigation of the ramp loading process for a 2.5 inch ramp-load disk drive employing a two beam laser Doppler vibrometer, we observed that the slider´s approach velocity was not controllable because of a vibrating motion that became excited as the suspension moved down the ramp. Here we study the source of this vibration and observe that it becomes excited each time when the slider reaches a certain location above the disk, and its amplitude is sometimes reduced at slower actuation speeds. By analyzing the frequency spectra of the slider´s pitch, roll and vertical translation during loading, we found that the vibration was primarily comprised of the last two modes. This motion was found to be correlated with the shape of the ramp. Modification of the ramp profile effectively reduced the vibration, resulting in a controllable approach velocity and a substantial reduction in slider-disk contacts during loading