Enhancing the Dynamic Response Servo Positioning System Using Internal Model Control Based Compensator: A Case Study of HDD (KEY IJP************294)

• Muoghalu, C. N.

Abstract

This paper presents improving the head position servo control system of hard disk drive (HDD) using adaptive mechanism. The dynamic model of HDD servomechanism was presented as a transfer function to describe the behaviour of the RW head position servo of the hard drive in a computer system. An internal model control tuned compensator was designed. Simulation analysis was conducted for conventional control state of the RW head positioning of the HDD. The performance of the system was largely impacted by cycling which resulted in instability and therefore maintaining accurate track for efficient read and write operation was not guaranteed. Notwithstanding fast response in terms of very much reduced rise time of 0.0373 s, the step response performance of the uncompensated system indicated high overshoot of 95.4% and extended settling time of 9.13 s. Besides, the system in this situation was not able to track the desired position, which in this case, is represented by a step input and thereby yielding a final value of 0.0113 that caused steady state error of 0.9887. With the introduction of the designed IMC based compensator, the performance of the system was largely improved such that the rise time, settling time, overshoot, and steady state error were: 0.283 s, 0.492 s, and 0 overshoot and steady- state error. Comparison with MRAC-PID and PID revealed the superiority of the IMC over the two previously implemented controllers.Keywords: Hard Disk Drive, Positioning System, Internal Model Control, PID.