Motion protection framework for TPS insertion device control

The Taiwan Photon Source (TPS) is an advanced synchrotron radiation light source that provides high-brightness light for scientific research and industrial applications. The insertion device (ID) plays a critical role in controlling the electron beam trajectory to enhance synchrotron radiation intensity. However, due to radiation and signal interference in the operational environment, the motion control system of the ID faces challenges, especially when optical encoder anomalies occur, which can affect performance and may, under certain circumstances, lead to hardware damage. Traditional motion protection relies on software soft limits and hardware limit switches, but these mechanisms may not provide comprehensive and effective protection in the event of optical encoder failures. To address this, this paper proposes a multi-layered motion protection system. In addition to incorporating traditional protections, it also introduces an abnormality prediction mechanism based on the difference in optical encoder and potentiometer data. This mechanism can trigger an abort signal to the motor controller when an anomaly is detected to stop the abnormal motion. This architecture significantly improves the operational reliability of the TPS ID, ensuring long-term safe and stable performance.