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Christophe's review of the conclusion

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Thomas Dehaeze 2025-04-21 10:06:52 +02:00
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@ -13742,7 +13742,8 @@ These simulations demonstrated the NASS concept could meet the nanometer-level s
Following the conceptual validation, the detailed design phase focused on translating the NASS concept into an optimized, physically realizable system.
Geometric optimization studies refined the Stewart platform configuration.
A hybrid modeling technique combining Finite Element Analysis (FEA) with multi-body dynamics simulation was applied and experimentally validated.
This approach enabled detailed optimization of components, such as amplified piezoelectric actuators and flexible joints, while efficiently simulating the complete system dynamics.
This approach enabled detailed optimization of components, such as Amplified Piezoelectric Actuators (APA) and flexible joints, while efficiently simulating the complete system dynamics.
By dedicating one stack of the APA specifically to force sensing, excellent collocation with the actuator stacks was achieved, which is critical for implementing robust decentralized IFF.
Work was also undertaken on the optimization of the control strategy for the active platform.
Instrumentation selection (sensors, actuators, control hardware) was guided by dynamic error budgeting to ensure component noise levels met the overall nanometer-level performance target.
@ -13764,7 +13765,7 @@ Systems like the micro-station can be conceptually modeled as interconnected sol
An interesting perspective is the development of methods for the automatic tuning of the multi-body model's stiffness matrix (representing the interconnecting spring stiffnesses) directly from experimental modal analysis data.
Such a capability would enable the rapid generation of accurate dynamic models for existing end-stations, which could subsequently be used for detailed system analysis and simulation studies.
***** Better addressing plant uncertainty coming from a change of payload
***** Better addressing plant uncertainty from a change of payload
For most high-performance mechatronic systems like lithography machines or atomic force microscopes, payloads inertia are often known and fixed, allowing controllers to be precisely optimized.
However, synchrotron end-stations frequently handle samples with widely varying masses and inertias – ID31 being an extreme example, but many require nanometer positioning for samples from very light masses up to 5kg.
@ -13779,7 +13780,7 @@ Potential strategies to be explored include adaptive control (involving automati
***** Control based on Complementary Filters
The control architecture based on complementary filters (detailed in Section ref:sec:detail_control_cf) has been successfully implemented in several instruments at the ESRF.
This approach has proven straightforward to implement and offers the valuable capability of modifying closed-loop behavior in real time, which proves advantageous for many applications.
This approach has proven to be straightforward to implement and offers the valuable capability of modifying closed-loop behavior in real time, which proves advantageous for many applications.
For instance, the controller can be optimized according to the scan type: constant velocity scans benefit from a $+2$ slope for the sensitivity transfer function, while ptychography may be better served by a $+1$ slope with slightly higher bandwidth to minimize point-to-point transition times.
Nevertheless, a more rigorous analysis of this control architecture and its comparison with similar approaches documented in the literature is necessary to fully understand its capabilities and limitations.
@ -13815,7 +13816,7 @@ Consequently, the underlying micro-station's own positioning accuracy has minima
Nevertheless, it remains crucial that the micro-station itself does not generate detrimental high-frequency vibrations, particularly during movements, as evidenced by issues previously encountered with stepper motors.
Designing a future end-station with the understanding that a functional NASS will ensure final positioning accuracy could allow for a significantly simplified long-stroke stage architecture, perhaps chosen primarily to facilitate the integration of the online metrology.
One possible configuration, illustrated in Figure ref:fig:conclusion_nass_architecture, would comprise a long-stroke Stewart platform providing the required mobility without generating high-frequency vibrations; a spindle that need not deliver exceptional performance but should be stiff and avoid inducing high-frequency vibrations (an air-bearing spindle might not be essential); and a short-stroke Stewart platform for correcting errors from the long-stroke stage and spindle.
One possible configuration, illustrated in Figure ref:fig:conclusion_nass_architecture, would comprise a long-stroke Stewart platform providing the required mobility without generating high-frequency vibrations; a spindle that needs not deliver exceptional performance but should be stiff and avoid inducing high-frequency vibrations (an air-bearing spindle might not be essential); and a short-stroke Stewart platform for correcting errors from the long-stroke stage and spindle.
#+name: fig:conclusion_nass_architecture
#+caption: Proposed alternative configuration for an end-station including the Nano Active Stabilization System