1. Adaptive Robust Control F or Dual Stage Hard Drives استاد راهنما : جناب آقای دکتر حمید تقی راد هادی حاجی اقراری دانشجوی کارشناسی ارشد مهندسی برق –کنترل دانشگاه خواجه نصیرالدین طوسی Dr. Hamid D. Taghirad H.H.Eghrary MS Student of Electrical Engineering K.N.Toosi Univ.

2. 2end Seminar Presentation Introduction to Adaptive Robust Control Obstacles for Control Algorithm DesignObstacles for Control Algorithm Design Strategies for Performance Improvement Strategies for Performance Improvement Adaptive Robust Control (ARC) For a HDD Adaptive Robust Control (ARC) For a HDD  Adaptive Control  Robust Control ARC via Discontinuous Projection ARC via Discontinuous Projection ARC via Smooth Projection ARC via Smooth Projection Desired Compensation ARC Desired Compensation ARC Sunday, August 12,2007

3. Obstacles for Control Algorithm Design: Inherent Nonlinearity Modeling Uncertainty Unknown But Reproducible for example : Unknown parameters Unreproducable for example: model Disturbance

4. Strategies for Performance Improvement: Nonlinear Analysis And SynthesisNonlinear Analysis And Synthesis Nonlinear Control  Deal With Nonlinearity Directly : Nonlinear Control Fast Robust FeedbackFast Robust Feedback Effective for both reproducible and none Reproducible Uncertainities Controled Learning For Uncertainity ReductionControled Learning For Uncertainity Reduction Effective for Reproducible Uncertainities

5. Adaptive Robust Control (ARC) RobustAdaptive Drawbacks: Transient Performance of the system is not Clear. Unknown Nonlinear functions such as external disturbances are not considered. Drawbacks: Transient Performance of the system is not Clear. Unknown Nonlinear functions such as external disturbances are not considered. Reduce the model uncertainty Zero Tracking Error (Without High gain Feedback) Attenuate the effect of model uncertainties through robust feedback. Instantaneous Reaction

6. Deterministic Robust Control Use to Design Base Line Controller Guarantee  Transient Performance  Transient Performance  Prescribed final tracking accuracy  Prescribed final tracking accuracy Adaptive Control Used to Design Supervisor Improved  Asymptotic Input Tracking  Asymptotic Input Tracking

7. Conventional Adaptation Law  Estimated Parameters May not be Bounded Deterministic Robust Control  Requires Bounds On Uncertainties Modify The Conventional Adaptation Law Bounded Estimation Parameters

8. Adaptive Robust Control For Hard Disk Drive Servo System

9. Adaptive Control scheme: Robust Control scheme:

10. Adaptive Control scheme: Stability Analysis:  Lyapanov Function: Parameter Estimation Estimation Error

11. Results: Limitations Of Adaptive ControlLimitations Of Adaptive Control Transient Performance is Unknown Uncertain nonlinearity are not Considered

12. Robust Control scheme: More In Detail: Error Dynamics  Choose The such that:

13. Stability Analysis:  Lyapanov Function: Choose small such that: : Stable

14. Tracking Error Steady State ErrorSteady State Error

15. Decrease for decreasing Steady State Error Parameter Adaptation

16. Adaptive Robust Control

17. Conventional Adaptation Law  Estimated Parameters May not be Bounded Deterministic Robust Control  Requires Bounds On Uncertainties Modify The Conventional Adaptation Law Bounded Estimation Parameters

18. Adaptive Robust Control Via Discontinuous Projection

19. Remains in Decreases Increases Parameter Uncertainty Bounded via Adaptation Progress RobustControlProblem Solved Robust Control Problem Solved

20. Adaptive Robust Control Via Smooth Projection There is a Lyapanov Function : Stability is Guaranteed

21. Desired Compensation ARC Remind ARC Scheme Real Parameter Measurement ( Measurement Noise ) Static Feedback Desired Trajectory DynamicStabilizingFeedback

22. Desired Compensation ARC Regressors Dose not Depend On Measurements  Eliminate Measurement Noise Effect on Parameter Adaptation  Off-Line Regressors Calculation Fast Error Dynamic and Parameter Adaptation Facilitate Control Gain Tuning Process due to Separation of Robust Control And Parameter Adaptation Separation of Robust Control And Parameter Adaptation