Adaptive vibration control method for double-crystal monochromator base on VMD and FxNLMS

Area of Science:

• Optics and Synchrotron Radiation Science
• Control Systems Engineering
• Applied Physics

Background:

• Double-crystal monochromators (DCMs) are essential optical components in synchrotron beamlines, critical for beam energy and position quality.
• Increasing performance of synchrotron light sources necessitates higher stability in DCMs to meet advanced research demands.
• Existing vibration control methods may not adequately address the complex, random engineering disturbances affecting DCMs.

Purpose of the Study:

• To develop and validate a novel adaptive vibration control method for enhancing the stability of double-crystal monochromators (DCMs).
• To ensure reliable DCM performance under dynamic and random engineering disturbances encountered in synchrotron environments.
• To improve the precision and quality of synchrotron beams by mitigating optical device instability.

Main Methods:

• Proposed a hybrid adaptive vibration control strategy combining variational modal decomposition (VMD) and filter-x normalized least mean squares (FxNLMS).
• Utilized a genetic algorithm to optimize VMD parameters (modal components k, penalty factor α) based on vibration signal sample entropy.
• Decomposed vibration signals into non-overlapping frequency bands, with each band individually controlled by an FxNLMS algorithm.

Main Results:

• The proposed VMD-FxNLMS method demonstrated high convergence accuracy in numerical simulations.
• Significant vibration suppression performance was achieved, confirming the method's effectiveness.
• Validation with experimentally measured DCM vibration signals confirmed the practical applicability and robustness of the control strategy.

Conclusions:

• The novel adaptive vibration control method effectively ensures DCM stability under random engineering disturbances.
• The combination of VMD for signal decomposition and FxNLMS for adaptive control offers superior vibration mitigation.
• This approach contributes to maintaining and improving the quality of synchrotron radiation beams for scientific research.