Linear actuator for precise track following

A new air bearing linear actuator with a Voice Coil Motor (VCM) was investigated for a precise head track following in an Hard Disk Drive (HDD) magnetic recording tester system. The actuator has a servo bandwidth of two times as wide as that of a conventional HDD, due to a high stiffness without any friction. A low-pass filter was introduced to precisely monitor the step response behavior by reducing the relatively large noise of the used optical fiber sensor. The effect of the low-pass filter was investigated comparing with the other method. Track following accuracy was also tested by using a conventional 2.5-inch hard disk drive. The head installed on the actuator could follow on a track by using Position Error Signal (PES) from the servo pattern. When a Double Metal In Gap (D-MIG) head of 4 μm track-width was loaded on a disk rotating at 4200rpm, the tracking error could be compressed down to one-twentieth of the track-width. The tested system did not show any azimuth error of head-tracking due to the linear motion. In conclusion, the air-bearing linear actuator is suitable for a precise track following mechanism of a spin-stand tester for an HDD system.