Position control of a wafer stage


Funded by:

Marie Skłodowska-Curie Actions


Seyedeh Fatemeh Sharifi


Hans Zwart


CONFLEX consortium


The main aim of this project is to use the port-Hamiltonian approach for the modelling and control of the wafer stage. The port-based method is a unified frame work for the geometric description of systems in interaction with its environment, taking advantage of the intrinsic structure and physical properties of the system. The modeling, simulation and validation of the wafer stage as a Port-Hamiltonian system will be implemented in terms of accuracy and reliability.

The wafer stage is a flexible structure which is used in the manufacture of integrated circuits. It is a relatively heavy object whose position has to be controlled extremely accurately. Since the reference signal, i.e., the desired position of the wafer stage is known as a function of time, a feedforward control is usually applied. However, this will not correct for small errors, and thus an additional feedback controller is needed. 

The second goal of the project is to design an H2optimal controller for a time-varying port-Hamiltonian model. Since the full PDE model of the wafer stage may lead to controllers which are hard to implement, the port-Hamiltonian approach may lead to a combined feedforward and feedback controller for the position of the wafer stage satisfying given performance criteria which can be implemented.

Thus, the overall development concerning the project is the control of Port-Hamiltonian model of a wafer stage with the consideration of time varying parameters and nonlinear constraints (physical range limitations).