  The ever increasing need for performance results in increasingly rigorous
demands on throughput and positioning accuracy of high-precision motion
systems, which often suffer from position dependent effects that originate from
relative actuation and sensing of the moving-body. Due to the highly stiff
mechanical design, such systems are typically controlled using rigid body
control design approaches. Nonetheless, the presence of position dependent
flexible dynamics severely limits attainable position tracking performance.
This paper presents two extensions of the conventional rigid body control
framework towards active control of position dependent flexible dynamics.
Additionally, a novel control design approach is presented, which allows for
shaping of the full closed-loop system by means of structured $H_\infty$
co-design. The effectiveness of the approach is validated through simulation
using a high-fidelity model of a state-of-the-art moving-magnet planar
actuator.
