Projected Phase-Plane Control of Flexible Structures with Applications to Hard Disk Drives

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

In this project, controllers are being developed for maneuvering flexible structures, with particular application to disk drive systems, where the flexibility of the read/write arm are being addressed. The control approach separates the non-flexible and flexible dynamics of the system. Because of the desire for fast read/write access times in disk drives, the approach starts with the time-optimal control for the non-flexible dynamics. Depending on how complex these non-flexible dynamics are, this time-optimal control may be solved analytically or numerically. The notions of input shaping are then used to address the flexible dynamics of the system, where a technique is being developed that incorporates the ideas of input shaping and time-optimal control to derive a feedback control law that causes flexible systems to track desired projected phase-plane trajectories that are constructed based upon state responses to shaped time-optimal control inputs. The research ideas proposed provide a clear methodology for deriving a complete theory for designing feedback controllers for multi-modal flexible structures, including non-ideal effects such as back EMF, inductance, and slew rate limitations. The PI's involvement with the Colorado Center for Information Storage (CCIS) ensures interaction with disk drive companies (such as Maxtor Corporation and Seagate Corporation) so that the techniques developed can be transferred successfully to industry. The results of this research are expected to make an impact in the disk drive industry and hence ultimately an impact on every computer user. Further, because several aspects of the basic approach are more general in nature, it is expected that the proposed research will impact other fields where structural flexibilities must be controlled.