Samsung Electronics Co., Ltd.

Tae Yeon Hwang

Young-Hoon Kim

Tho Pham

Seong-Woo Kang

Sang Hoon Chu

Yun-Sik Han

Dong-Ho Oh

Seong Hoon Kim

The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.

Servo controller method and apparatus for high tracks per inch hard disk drives using a delay accomodating state estimator

The inventors have discovered that aerodynamic forces contribute to disk fluttering. If the flow of air about these disk surfaces is unstable, the resulting aerodynamic forces can mechanically excite the disk surfaces, causing fluttering. The invention includes media enclosures constraining such aerodynamic effects, methods of making disk drives with these enclosures, the disk drives. This includes disk drives of at most 13 millimeters in height.

Media enclosures providing reduced air gap around disk drive media surfaces of a disk drive

Growing community of inventors

Kyunggi, South Korea

Tae Yeon Hwang