Analysis and self-tuning control of dual stage servo with MEMS micro-actuators

Track following controllers for a dual-stage servo with a MEMS micro-actuator (MA) were designed using a decoupled pole placement methodology. The stability and performance robustness of the servo to MA resonance frequency variations were analyzed using μ-analysis for both an MIMO (when the MA relative position is available), and a SIMO (when the MA relative position is not available) design. Both designs are robust stable to the plant uncertainties. However, the MA resonance frequency variations have a significant detrimental effect on the error rejection performance of both controllers. A direct self-tuning algorithm was developed to compensate for the MA resonance frequency variations, when the MA´s relative position is available to the control system. Simulation results showed that the adaptive control parameters converge to their desired values, and nominal performance is restored