Lifted Frequency-Domain Identification of Closed-Loop Multirate Systems: Applied to Dual-Stage Actuator Hard Disk Drives

TL;DR

This paper introduces a frequency-domain system identification method for closed-loop multirate systems that uses only slow-rate output measurements, validated on a hard disk drive actuator.

Contribution

It develops a novel identification technique combining lifting and local modeling for accurate multirate system identification from limited data.

Findings

Accurately identifies multirate systems in a single experiment

Effective for closed-loop systems with multivariable dynamics

Validated on a hard disk drive actuator benchmark

Abstract

Frequency-domain representations are crucial for the design and performance evaluation of controllers in multirate systems, specifically to address intersample performance. The aim of this paper is to develop an effective frequency-domain system identification technique for closed-loop multirate systems using solely slow-rate output measurements. By indirect identification of multivariable time-invariant representations through lifting, in combination with local modeling techniques, the multirate system is effectively identified. The developed method is capable of accurate identification of closed-loop multirate systems within a single identification experiment, using fast-rate excitation and inputs, and slow-rate outputs. Finally, the developed framework is validated using a benchmark problem consisting of a multivariable dual-stage actuator from a hard disk drive, demonstrating its applicability and accuracy.