A model-based optimal control approach has been developed for the slow orbit feedback (SOFB) system to enhance orbit stability in the Siam Photon Source (SPS) storage ring. The control strategy utilizes a linear quadratic regulator (LQR) based on a multi-input, multi-output (MIMO) state-space model of the linear SPS storage ring, derived through system identification using MATLAB and SIMULINK. The necessary and sufficient conditions for controllability and boundedness of the dynamic system are established. Experimental simulations were conducted to assess the performance of the LQR controller in a practical SPS storage ring. The results demonstrate that the proposed control method effectively minimizes the quadratic cost function and error signals between setpoints and process variables for both horizontal and vertical orbit positions while ensuring system stability and robustness. The study also outlines the fundamental principles of optimal control theory, system identification, and future development directions.

This paper presents the enhancement of photon beam position stability at the Siam Photon Source (SPS) synchrotron through a real-time feedback control system incorporating a fault-tolerant control (FTC) algorithm. The system utilizes Photon Beam Position Monitor (pBPM) measurements within a global orbit feedback loop to minimize beam position fluctuations. The FTC algorithm plays a critical role in ensuring system reliability by detecting and compensating for disturbances, sensor errors, and actuator faults, maintaining stable beam conditions under varying operational scenarios. Experimental results demonstrate that the FTC-based feedback system significantly reduces photon orbit deviations, improving synchrotron radiation quality. By enhancing robustness and adaptability, the control system ensures precise beam positioning, making the SPS more reliable for scientific and industrial applications requiring high beam stability.