Abstract
In the head positioning control of hard disk drives, the information of the head position is embedded radially on the magnetic disk that eliminates the capacity of the hard disk drive. So, if the quantity of this information is decreased, the capacity of the hard disk drive will then be increased. This means that the sampling period in the head positioning control must be lengthened. With long sampling period, it is also expected to cut the cost of A/D, D/A converter and processor for control.
In this paper, we apply the method of the sampled-data H∞ control theory to the following control (fine positioning for read/write data) of the hard disk drive with the aim to control using long sampling period. The sampled-data H∞ control theory can design the discrete-time controller which stabilizes the continuous-time plant with no approximations. For this reason, this method is effective when the sampling period is long.
The obtained performance of the sampled-data H∞ controller is then compared with that of the continuous-time H∞ based controller to show the effectiveness of our proposed method.
