Design and Implementation of a New Three-DOF Electromagnetically Actuated Precision Positioning Stage with Flexure Mechanism

In this thesis, we present the novel design, control and implementation of a three degree-of-freedom (DOF) compact positioner with high resolution in tens of nanometer-scale precision positioning capacity and millimeter-level long travel range. According to the serial flexure mechanism design, whose motion comes from the elastic deformation of the flexure and the force allocation of five pairs of electromagnetic coils and permanent magnets, the precision positioner enables both horizontal and vertical actuations resulting in x-, y-, and z- motions respectively. Next, in order to improve the transient response and to suppress the vibration of the flexure suspension mechanism, an eddy current damper (ECD) is also applied as passive and noncontact resistance of vibration. In order to realize accurate feedback control, a laser interferometer sensing system is implemented to improve the positioning resolution of the stage.
For maintaining stability and robustness of the precision system, we implement a decentralized adaptive sliding mode controller (DASMC) overcoming the overall situations of unmodeled system dynamics and external noises. Finally, from the simulation and experimental results, satisfactory performance has been observed, which means that the designated objectives of this research have been successfully attained, namely, (1) long travel range (2) high positioning resolution and (3) fast response.