On modal observers for beyond rigid body $H_\infty$ control in high-precision mechatronics

TL;DR

This paper develops advanced control strategies for high-precision mechatronic systems, addressing flexible dynamics and employing structured $H_ abla$ co-design to improve positioning accuracy beyond traditional rigid body control methods.

Contribution

It introduces two extensions to rigid body control and a novel structured $H_ abla$ co-design approach for flexible dynamics in high-precision motion systems.

Findings

Enhanced control of flexible dynamics demonstrated in simulations

Structured $H_ abla$ co-design improves system performance

Validation on a high-fidelity model shows significant accuracy gains

Abstract

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.