Development of a 2d positioning stage with submicrometric accuracy for metrological applications
- Autores: Marta Torralba Gracia
- Directores de la Tesis: J. A. Albajez (dir. tes.), José Antonio Yagüe Fabra (dir. tes.)
- Lectura: En la Universidad de Zaragoza ( España ) en 2015
- Idioma: español
- Tribunal Calificador de la Tesis: Juan José Aguilar Martín (presid.), Simone Carmignato (secret.), Eugen Trapet Herbert (voc.)
- Materias:
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- Resumen
This dissertation describes the development of a two-dimensional positioning stage for nanotechnology applications. Their design specifications are; nanometer resolution for displacement feedback, sub-micrometer position uncertainty and a 50 x 50 mm travel range in each axis. This performance is considered desirable for a broad variety of applications using the system as a common stage for different tasks (sample characterization, nanomanufacturing processes, nanoprobes calibration, etc.). Its first implemented tool to be used with this platform will be an atomic force microscope (AFM).
The design has been based on a review of state-of-art systems and applications, and incorporates precision engineering principles and desirable features of found in similar systems described in the literature. Thus, using commercial components when possible, the system has been optimized by finite element simulation, analyzing deformations and vibration modes of the complete system and individual parts. This final scheme is characterized by a three-layer and two-stage architecture, whose compactness optimizes the metrology task. As part of this design phase, an error budget analysis has been carried out to estimate positioning deviations, including all of the known error source contributions and their propagation around the metrology loop. In addition, this study proposes and provides procedures to apply a basic self-calibration technique for the 2D-measurement system.
The experimental part focuses on the first prototype assembly and systems initialization, such as the levitation scheme in charge of the moving platform suspension, and the measurement sensors that determine position in all six degrees-of-freedom of the moving platform. Furthermore, the behavior of the driving system, four linear motors, has been characterized, in order to determinate possible differences in terms of forces between theoretical and actual performance. Considering the 1D-setup, a control scheme has been proposed based on the experimental dynamic system characterization. The tuning of the suggested controller has been justified according to the requirements of settling times and step response damping factors, which has been probed by simulation of the whole closed loop. To conclude, the strategy for the 2D-stage has been also presented, considering all sensors and actuators, and including the future tasks for hardware and software implementation.
