Discrete-Time Sliding Mode Control With Time-Varying Surface for Hard Disk Drives

• Published in: IEEE transactions on control systems technology Vol. 17; no. 1; pp. 175 - 183
• Main Authors: Qinglei Hu, Qinglei Hu, Chunling Du, Chunling Du, Lihua Xie, Lihua Xie, Youyi Wang, Youyi Wang
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-01-2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Computer science; control theory; systems; Control surfaces; Control system synthesis; Control systems; Control theory. Systems; Design engineering; Discrete-time sliding mode control (DSMC); Disk drives; Electronics; Exact sciences and technology; hard disk drives (HDDs); Hard disks; Miscellaneous; Optimal control; Proportional control; Resonance; Robust control; Robustness; Servomechanisms; Simulation; Sliding mode; Sliding mode control; Storage and reproduction of information; Studies; Switching; Time optimal; time-varying sliding surface; track following; track seeking; Discontinuity; Variable structure control; Sliding mode; track seeking; Control synthesis; track following; Discrete-time sliding mode control (DSMC); Chatter; Time varying system; Minimum time; Experimental design; hard disk drives (HDDs); Discrete time; Time curve; Feasibility; Hard disk; Servomechanism; Differential integral proportional control; time-varying sliding surface
• ISSN: 1063-6536; 1558-0865
• DOI: 10.1109/TCST.2008.922505

A time optimal-based discrete-time sliding mode control (DSMC) scheme with application to hard disk drives (HDDs) is developed in this study. In this approach, an approximate time optimal switching curve is adopted for the time-varying sliding mode design and the controller, which consists of an equivalent part and a discontinuous one, is designed such that the trajectory from any initial point is driven into a sliding region in the vicinity of the switching surface without chattering and thereafter remains inside it. By using the time-varying switching surface, one unified framework for both track seeking and following control is provided and smooth transition from seeking control to track following control is achieved as well. Simulation and experimental studies on the design of controller in HDDs were conducted to illustrate its feasibility and effectiveness. The simulation/experimental results demonstrate that the proposed scheme provides better performance during track seeking than the commonly used discrete-time proximate time-optimal servomechanism (PTOS) and sliding mode proximate time optimal servomechanism (SMPTOS). Moreover, the unified controller achieves better disturbance suppression in track-following than the proportional-integral-differential (PID) control.