Publication Date


Document Type


First Advisor

Bobis, James P.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Electrical Engineering


Feedback control systems; Automatic control; Control theory


The Advanced Photon Source third generation synchrotron light source needs a stabilized particle beam position to produce high brightness and low emittance of the beam. Global orbit correction control is introduced which is utilized to achieve the demanding needs of the accelerator. This system consists of a digital communication system that collects beam position monitoring (BPM) data in digital form which is transmitted to the processor. The processor calculates the appropriate corrector strength from the data taken around the accelerator ring. This corrector strength is transmitted to the relevant corrector magnet to achieve beam repositioning. This thesis describes the procedure to determine an effective and optimal performing controller to meet the global orbit correction’s requirements. These conditions include frequency domain and time domain requirements consisting of vibrational noise attenuation, limiting of controller gains for stability, and improving the system time response. Theoretical analysis is discussed with different control schemes compared graphically to reveal the best control design. A range or set of control parameters are selected as acceptable to achieve the system’s performance requirements. Experimentation with an actual closed loop system comprised of a digital signal processor, power supply, accelerator corrector magnet, and Hall effect probe with gaussmeter is included to compare and contrast the theoretical and applied control. Plots of system time response, noise transfer function, and system transfer function frequency response of various designs are displayed. A summary of the effectiveness of this method to design controllers is provided describing its assets and disadvantages.


Includes bibliographical references (leaf [83])


x, 95 pages




Northern Illinois University

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