A fast orbit feedback system is designed at SSRF to suppress beam orbit disturbance within sub-micron in the bandwidth up to 100 Hz. The SVD (Singular value decomposition) algorithm is applied to calculate the inverse...A fast orbit feedback system is designed at SSRF to suppress beam orbit disturbance within sub-micron in the bandwidth up to 100 Hz. The SVD (Singular value decomposition) algorithm is applied to calculate the inverse response matrix in global orbit correction. The number of singular eigenvalues will influence orbit noise suppression and corrector strengths. The method to choose singular eigenvalue rejection threshold is studied in this paper, and the simulation and experiment results are also presented.展开更多
Details of the active ways to suppress Closed Orbit Distortion （COD）, including bending magnet sorting and survey and alignment of the magnets, are discussed based on the studies of affections to the COD by the bend...Details of the active ways to suppress Closed Orbit Distortion （COD）, including bending magnet sorting and survey and alignment of the magnets, are discussed based on the studies of affections to the COD by the bending magnet field error and the misalignment of quadrupoles. The closed orbit correction and the Slow Orbit Feed Back （SOFB） system for the SSRF storage ring are presented in this paper. With these available methods, better results were obtained during the commissioning period with 3 GeV beam energy.展开更多
Background:Long-term orbit stability is a key performance indicator in synchrotron radiation facilities and colliders nowa-days,in which the orbit correction and corresponding slow orbit feedback system are indispensa...Background:Long-term orbit stability is a key performance indicator in synchrotron radiation facilities and colliders nowa-days,in which the orbit correction and corresponding slow orbit feedback system are indispensable.Conventional method of orbit correction uses response matrix based on SVD algorithm,which becomes less effective after a long operation due to the fact that response matrix measurements cannot be taken during normal operation.Purpose:The purpose of this paper is to integrate machine learning model into the slow orbit feedback process and to automatically update the model online to better correct the orbit shifts.Methods:In this paper,we propose a method for slow orbit feedback of storage ring based on machine learning.Training the neural networks by using online data sets,which can establish the mapping relation between BPMs and correctors,and being updated automatically,without using extra time to remeasure the response matrix.Results:The experiments in this paper are all conducted and verified in the upgrading project of Beijing Electron-Positron Collider.By the way of learning automatically,the updated neutral network is closer to the real machine model,and the orbit after correction shows a smaller fluctuation relative to the golden orbit.Conclusion:Using the online data sets which reflect the response of orbit to correctors in real time to update the neural network can increase the orbit stability.展开更多
Background Most of the global orbit feedback algorithms in storage rings are based on response matrix(RM)singular value decomposition method.Commonly,the RM is the orbit distortion along the ring responding to the ste...Background Most of the global orbit feedback algorithms in storage rings are based on response matrix(RM)singular value decomposition method.Commonly,the RM is the orbit distortion along the ring responding to the steering magnet changes.For those methods RF frequency feedback is in a separated process.Methods and Results In this paper,the response matrix is expanded to the orbit distortion caused by the RF frequency variation.With this expanded RM,the orbit correction via steering magnet changes and RF frequency adjustment can be accomplished in one step.The commissioning results are carried out showing that the algorithm works stably.展开更多
In this paper a controller of pulse coupling feedback （PCF） is designed to control chaotic systems. Control principles and the technique to select the feedback coefficients are introduced. This controller is theoret...In this paper a controller of pulse coupling feedback （PCF） is designed to control chaotic systems. Control principles and the technique to select the feedback coefficients are introduced. This controller is theoretically studied with a three dimensional （3D） chaotic system. The artificial simulation results show that the chaotic system can be stabilized to different periodic orbits by using the PCF method, and the number of the periodic orbits are 2^n×3^m p （n and m are integers）. Therefore, this control method is effective and practical.展开更多
The problem of control of orbit for the dynamic system x ¨+x(1-x)(x-a)=0 is discussed. Any unbounded orbit of the dynamic system can be controlled to become a bounded periodic orbit by adding a periodic step ex...The problem of control of orbit for the dynamic system x ¨+x(1-x)(x-a)=0 is discussed. Any unbounded orbit of the dynamic system can be controlled to become a bounded periodic orbit by adding a periodic step excitation to the system. By using a nonlinear feedback control law presented in this paper the chaos of the dynamic system with excitation and damping is stabilized. This method is more effectual than the linear feedback control.展开更多
In this paper, we propose a semi-continuous dynamical system to study the cooperative system with feedback control. Based on geometrical analysis and the analogue of Poincare criterion, the existence and stability of ...In this paper, we propose a semi-continuous dynamical system to study the cooperative system with feedback control. Based on geometrical analysis and the analogue of Poincare criterion, the existence and stability of the positive order one periodic solutions are given. Numerical results are carried out to illustrate the feasibility of our main results.展开更多
文摘A fast orbit feedback system is designed at SSRF to suppress beam orbit disturbance within sub-micron in the bandwidth up to 100 Hz. The SVD (Singular value decomposition) algorithm is applied to calculate the inverse response matrix in global orbit correction. The number of singular eigenvalues will influence orbit noise suppression and corrector strengths. The method to choose singular eigenvalue rejection threshold is studied in this paper, and the simulation and experiment results are also presented.
文摘Details of the active ways to suppress Closed Orbit Distortion （COD）, including bending magnet sorting and survey and alignment of the magnets, are discussed based on the studies of affections to the COD by the bending magnet field error and the misalignment of quadrupoles. The closed orbit correction and the Slow Orbit Feed Back （SOFB） system for the SSRF storage ring are presented in this paper. With these available methods, better results were obtained during the commissioning period with 3 GeV beam energy.
文摘Background:Long-term orbit stability is a key performance indicator in synchrotron radiation facilities and colliders nowa-days,in which the orbit correction and corresponding slow orbit feedback system are indispensable.Conventional method of orbit correction uses response matrix based on SVD algorithm,which becomes less effective after a long operation due to the fact that response matrix measurements cannot be taken during normal operation.Purpose:The purpose of this paper is to integrate machine learning model into the slow orbit feedback process and to automatically update the model online to better correct the orbit shifts.Methods:In this paper,we propose a method for slow orbit feedback of storage ring based on machine learning.Training the neural networks by using online data sets,which can establish the mapping relation between BPMs and correctors,and being updated automatically,without using extra time to remeasure the response matrix.Results:The experiments in this paper are all conducted and verified in the upgrading project of Beijing Electron-Positron Collider.By the way of learning automatically,the updated neutral network is closer to the real machine model,and the orbit after correction shows a smaller fluctuation relative to the golden orbit.Conclusion:Using the online data sets which reflect the response of orbit to correctors in real time to update the neural network can increase the orbit stability.
基金supported by the National Natural Science Foundation of China(No.11975298).
文摘Background Most of the global orbit feedback algorithms in storage rings are based on response matrix(RM)singular value decomposition method.Commonly,the RM is the orbit distortion along the ring responding to the steering magnet changes.For those methods RF frequency feedback is in a separated process.Methods and Results In this paper,the response matrix is expanded to the orbit distortion caused by the RF frequency variation.With this expanded RM,the orbit correction via steering magnet changes and RF frequency adjustment can be accomplished in one step.The commissioning results are carried out showing that the algorithm works stably.
基金Project supported by the National Natural Science Foundation of China （Grant No 20373021） and Natural Science Foundation of Liaoning Province, China （Grant No 2050790）.
文摘In this paper a controller of pulse coupling feedback （PCF） is designed to control chaotic systems. Control principles and the technique to select the feedback coefficients are introduced. This controller is theoretically studied with a three dimensional （3D） chaotic system. The artificial simulation results show that the chaotic system can be stabilized to different periodic orbits by using the PCF method, and the number of the periodic orbits are 2^n×3^m p （n and m are integers）. Therefore, this control method is effective and practical.
文摘The problem of control of orbit for the dynamic system x ¨+x(1-x)(x-a)=0 is discussed. Any unbounded orbit of the dynamic system can be controlled to become a bounded periodic orbit by adding a periodic step excitation to the system. By using a nonlinear feedback control law presented in this paper the chaos of the dynamic system with excitation and damping is stabilized. This method is more effectual than the linear feedback control.
基金Supported by the National Natural Science Foundation of China(11671346,11501489,11371306,11301453)Supported by the Department of Education of Henan Province(14B110034)+1 种基金Supported by the Nanhu Scholars Program of XYNU,Foundation and Frontier Project of Henan(152300410019)Supported by the Youth Teacher Foundation of XYNU(2016GGJJ-14)
文摘In this paper, we propose a semi-continuous dynamical system to study the cooperative system with feedback control. Based on geometrical analysis and the analogue of Poincare criterion, the existence and stability of the positive order one periodic solutions are given. Numerical results are carried out to illustrate the feasibility of our main results.
