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Title: In-hardware demonstration of model-independent adaptive tuning of noisy systems with arbitrary phase drift

Abstract

In this work, an implementation of a recently developed model-independent adaptive control scheme, for tuning uncertain and time varying systems, is demonstrated on the Los Alamos linear particle accelerator. The main benefits of the algorithm are its simplicity, ability to handle an arbitrary number of components without increased complexity, and the approach is extremely robust to measurement noise, a property which is both analytically proven and demonstrated in the experiments performed. We report on the application of this algorithm for simultaneous tuning of two buncher radio frequency (RF) cavities, in order to maximize beam acceptance into the accelerating electromagnetic field cavities of the machine, with the tuning based only on a noisy measurement of the surviving beam current downstream from the two bunching cavities. The algorithm automatically responds to arbitrary phase shift of the cavity phases, automatically re-tuning the cavity settings and maximizing beam acceptance. Because it is model independent it can be utilized for continuous adaptation to time-variation of a large system, such as due to thermal drift, or damage to components, in which the remaining, functional components would be automatically re-tuned to compensate for the failing ones. We start by discussing the general model-independent adaptive scheme and howmore » it may be digitally applied to a large class of multi-parameter uncertain systems, and then present our experimental results.« less

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1193396
Report Number(s):
LA-UR-14-21532
Journal ID: ISSN 0168-9002; PII: S0168900214004227
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Additional Journal Information:
Journal Volume: 756; Journal Issue: C; Journal ID: ISSN 0168-9002
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 97 MATHEMATICS AND COMPUTING; 43 PARTICLE ACCELERATORS; linac; adaptive control; feedback control; model independent control; RF cavity; phase drift

Citation Formats

Scheinker, Alexander, Baily, Scott, Young, Daniel, Kolski, Jeffrey S., and Prokop, Mark. In-hardware demonstration of model-independent adaptive tuning of noisy systems with arbitrary phase drift. United States: N. p., 2014. Web. doi:10.1016/j.nima.2014.04.026.
Scheinker, Alexander, Baily, Scott, Young, Daniel, Kolski, Jeffrey S., & Prokop, Mark. In-hardware demonstration of model-independent adaptive tuning of noisy systems with arbitrary phase drift. United States. doi:10.1016/j.nima.2014.04.026.
Scheinker, Alexander, Baily, Scott, Young, Daniel, Kolski, Jeffrey S., and Prokop, Mark. Fri . "In-hardware demonstration of model-independent adaptive tuning of noisy systems with arbitrary phase drift". United States. doi:10.1016/j.nima.2014.04.026. https://www.osti.gov/servlets/purl/1193396.
@article{osti_1193396,
title = {In-hardware demonstration of model-independent adaptive tuning of noisy systems with arbitrary phase drift},
author = {Scheinker, Alexander and Baily, Scott and Young, Daniel and Kolski, Jeffrey S. and Prokop, Mark},
abstractNote = {In this work, an implementation of a recently developed model-independent adaptive control scheme, for tuning uncertain and time varying systems, is demonstrated on the Los Alamos linear particle accelerator. The main benefits of the algorithm are its simplicity, ability to handle an arbitrary number of components without increased complexity, and the approach is extremely robust to measurement noise, a property which is both analytically proven and demonstrated in the experiments performed. We report on the application of this algorithm for simultaneous tuning of two buncher radio frequency (RF) cavities, in order to maximize beam acceptance into the accelerating electromagnetic field cavities of the machine, with the tuning based only on a noisy measurement of the surviving beam current downstream from the two bunching cavities. The algorithm automatically responds to arbitrary phase shift of the cavity phases, automatically re-tuning the cavity settings and maximizing beam acceptance. Because it is model independent it can be utilized for continuous adaptation to time-variation of a large system, such as due to thermal drift, or damage to components, in which the remaining, functional components would be automatically re-tuned to compensate for the failing ones. We start by discussing the general model-independent adaptive scheme and how it may be digitally applied to a large class of multi-parameter uncertain systems, and then present our experimental results.},
doi = {10.1016/j.nima.2014.04.026},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
number = C,
volume = 756,
place = {United States},
year = {Fri Aug 01 00:00:00 EDT 2014},
month = {Fri Aug 01 00:00:00 EDT 2014}
}

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Cited by: 9works
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  • We present a new model-independent dynamic feedback technique, rotation rate tuning, for automatically and simultaneously tuning coupled components of uncertain, complex systems. The main advantages of the method are: 1) It has the ability to handle unknown, time-varying systems, 2) It gives known bounds on parameter update rates, 3) We give an analytic proof of its convergence and its stability, and 4) It has a simple digital implementation through a control system such as the Experimental Physics and Industrial Control System (EPICS). Because this technique is model independent it may be useful as a real-time, in-hardware, feedback-based optimization scheme formore » uncertain and time-varying systems. In particular, it is robust enough to handle uncertainty due to coupling, thermal cycling, misalignments, and manufacturing imperfections. As a result, it may be used as a fine-tuning supplement for existing accelerator tuning/control schemes. We present multi-particle simulation results demonstrating the scheme’s ability to simultaneously adaptively adjust the set points of twenty two quadrupole magnets and two RF buncher cavities in the Los Alamos Neutron Science Center Linear Accelerator’s transport region, while the beam properties and RF phase shift are continuously varying. The tuning is based only on beam current readings, without knowledge of particle dynamics. We also present an outline of how to implement this general scheme in software for optimization, and in hardware for feedback-based control/tuning, for a wide range of systems.« less
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