INTEGRATED SERVO-MECHANICAL DESIGN OF HIGH-PERFORMANCE MAGNETICALLY LEVITATED POSITIONING SYSTEMS FOR MULTI-AXIS NANOPOSITIONING

Abstract

Magnetic levitation (maglev) is critical in ultra-precision positioning. This dissertation presents the integrated design of maglev positioning systems for multi-axis nanopositioning. First, an integrated servo-mechanical design is proposed, where various control and mechanical specifications, e.g., robust stability, robust performance, and saturation, are formulated in an optimization about the design parameters in plant and controller. Second, a flexure-based parallel actuation dual-stage system is proposed for large stroke single-axis nanopositioning, and this system is then extended to 6-Degree-Of-Freedom (DOF) that a flexure-based dual-stage maglev positioner is proposed to improve the dynamic performance, where both of their fine stages are designed using the proposed integrated design approach. Next, a novel design of maglev positioner is proposed for unlimited stroke with high power efficiency, which avoids the major limitations of the existing designs. Furthermore, a novel finite-frequency robust performance control is presented to design the fixed-order controller for the 2-DOF maglev fine stage.