LHC train control system for autonomous inspections and measurements

Intelligent robotic systems are becoming essential for inspection and measurements in harsh environments, such as the European Organization for Nuclear Research (CERN) accelerators complex. Aiming at increasing safety and machine availability, robots can help to perform repetitive or dangerous tasks, reducing the risk for the personnel as the exposure to radiation. The Large Hadron Collider (LHC) tunnel at CERN has been equipped with fail-safe trains on monorail able to perform autonomously different missions as radiation survey, civil infrastructures monitoring through photogrammetry, fire detection as well as survey measurements of accelerator devices. In this paper, the entire control architecture and the design of the low-level control to fulfil the requirements and the challenges of the LHC tunnel are described. The train low-level control is based on a PLC controller that communicates with the surface via 4G through VPN, where a user-friendly graphical user interface allows the operation of the robot. The low-level controller includes a PLC fail-safe program to ensure the safety of the system. The results of the commissioning in the LHC are presented.