Hans Butler

Control of high-precision mechatronic systems

This Lab focusses on control techniques in lithographic scanners, in particular related to high-accuracy positioning systems.

image

Research Profile

A distinction can be made based on motion range (“long” indicating meter-scale, “short” indicating mm scale), and accuracy (micrometer or sub-nanometer). Long-range actuators typically have a moderate accuracy but suffer from nonlinearities like friction, requiring compensation methods using adaptive or learning techniques. Nonlinearities also play a role when using piezo materials for actuation in high-accuracy applications, possibly simultaneously with using the material as sensor (“self-sensing”). Finally, control techniques to improve sub-nanometer positioning systems have to deal with position dependency, in particular in the observation of dynamic modes in the measurement system. This has led to position-dependent observers creating the option of increasing control bandwidth.

Meet some of our Researchers

Most important projects

  • Nanometer Accurate Positioning System (NAPAS)  having the goal of creating a long-stroke planar actuator with nanometer accuracy, using modelling and control techniques to reduce quasi-static deformations as well as position-dependent resonant behavior.
  • Impulse Feedforward techniques for time-varying positioning systems, in collaboration with ASML and Mechanical Engineering department.
  • Advanced Large range Piezo stage (ALP) Creating a piezo-driven wafer stage, in collaboration with HTSC and ASML.