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Thomas Dehaeze 2025-04-15 17:20:12 +02:00
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@ -12926,6 +12926,32 @@ Moreover, the systematic approach to system development and validation, along wi
:END: :END:
<<sec:test_conclusion>> <<sec:test_conclusion>>
The experimental validation detailed in this chapter confirms that the Nano Active Stabilization System successfully augments the positioning capabilities of the micro-station, thereby enabling full utilization of the ESRF's new light source potential.
A methodical approach was employed—first characterizing individual components and subsequently testing the integrated system—to comprehensively evaluate the NASS performance.
Initially, the Amplified Piezoelectric Actuators (APA300ML) were characterized, revealing consistent mechanical and electrical properties across multiple units.
The implementation of Integral Force Feedback was shown to add significant damping to the system.
Two models of the APA300ML were developed and validated: a simplified two degrees-of-freedom model and a more complex super-element extracted from finite element analysis.
Both models accurately represented the axial dynamics of the actuators, with the super-element model additionally capturing flexible modes.
The flexible joints were examined for geometric accuracy and bending stiffness, with measurements confirming compliance with design specifications.
The experimental values demonstrated good agreement with finite element predictions, validating the joint design and enabling accurate modeling of their behavior within the system.
The strut assembly process was optimized to ensure consistent performance across the six struts.
Dynamic testing revealed complex behavior in the transfer function from piezoelectric voltage to encoder displacement, attributed to misalignment between flexible joints and actuators.
This finding led to the strategic decision to mount encoders on the nano-hexapod plates rather than on the struts.
The nano-hexapod was then assembled and mounted on a suspended table to characterize its dynamic behavior.
The measurement setup enabled isolation of the hexapod's dynamics from potential influence of complex support dynamics.
The experimental frequency response functions exhibited good correlation with the multi-body model, confirming that the model can be used for control system design.
Finally, the complete NASS was validated on the ID31 beamline using a short-stroke metrology system.
The HAC-LAC control architecture successfully provided robust active damping of suspension modes and rejection of low-frequency disturbances across various payload conditions.
Comprehensive testing under typical experimental scenarios—including tomography scans, reflectivity scans, and diffraction tomography—demonstrated the NASS ability to maintain the positioning errors within specifications ($30\,\text{nm RMS}$ in lateral direction, $15\,\text{nm RMS}$ in vertical direction, and $250\,\text{nrad RMS}$ in tilt direction).
The system performed exceptionally well during vertical scans, though some limitations were identified during rapid lateral scanning and with heavier payloads.
With the implementation of an accurate online metrology system, the NASS will be ready for integration into the beamline environment, significantly enhancing the capabilities of high-precision X-ray experimentation on the ID31 beamline.
* TODO Conclusion and Future Work * TODO Conclusion and Future Work
<<chap:conclusion>> <<chap:conclusion>>