Hard disk drive control by model based dual-rate controller. Computation saving by interlacing

This paper addresses the application of multirate control techniques to hard disk drives (HDD) single stage actuation. It applies a model-based dual-rate controller with computation saving at its implementation stage. The main goal is twofold: to study a new dual-rate control scheme in this kind of environment that, as it is known, provides the achievement of more storage space and to reach a saving in computation resources when using this specific dual-rate control. The dual-rate control is planed by considering an N times slower measurement -NT- but a faster frequency for control updating -T- being N a positive integer. The work introduces a new discrete lifting modelling step that allows to compute an exact frequency response that helps the controller implementation with computation saving by interlacing. A system output response improvement is obtained by using this methodology. A comparison with an usual single rate control including its implementation by interlacing is done based on a HDD laboratory set-up.