1. 1) HOROWITZ R. Dual-Stage Servo Systems and Vibration Compensation in Computer Hard Disk Drives. Control Engineering Practice. (2007) vol.15, no.3, p.291-305.
2. 2) CHEN Y. Iterative Learning Control and Repetitive Control in Hard Disk Drive Industry-A Tutorial. Proc. 45th IEEE Conf. Decision & Control 2006. (2006) p.2338-2351.
3. 3) SATO K. Micro/Macro Dynamic Characteristics of Mechanism with a Harmonic Speed Reducer and Precision Rotational Positioning Control Using Disturbance Observer. JSME International Journal Series C : Mechanical Systems, Machine Elements and Manufacturing. (2000) vol.42, no.2, p.318-325.
4. 4) SHIM H. An almost necessary and sufficient condition for robust stability of closed-loop systems with disturbance observer. Automatica. (2009) vol.45, no.11, p.296-299.
5. 5) ANDERSON B. D. O. Optimal control-Linear quadratic methods-. Prentice-Hall, Inc.. (1989)