Demonstration of an ITER relevant remote handling equipment for Tokamak close inspection

• Main Authors: Keller, D., Perrot, Y., Gargiulo, L., Friconneau, J.P., Bruno, V., Le, R., Soler, B., Itchah, M., Ponsort, D., Chambaud, P., Bonnemason, J., Lamy, S., Measson, Y.
• Format: Conference Proceeding
• Language: English
• Subjects: Electron tubes; Inspection; Joints; Prototypes; Remote handling equipment; Robots; Tokamaks
• ISSN: 2153-0858; 2153-0866
• DOI: 10.1109/IROS.2008.4650808

This work concerns the development of an ITER relevant advanced robotic systems for fusion reactor. The feasibility demonstration will be performed on the thermonuclear experimental Tokamak: Tore Supra, located in Cadarache facilities. The manipulator developed by the interactive robotics unit of CEA-LIST will be used for close inspection intervention tasks in a Tokamak. The robot must meet severe specifications: small diameter, long reach with a 9.5 m cantilever length, high dexterity to move in a Torus shape environment and able to carry a 10 kg payload on its end effector. As the robot must be introduced without breaking the machine conditioning, it has to cope with the vacuum and temperature constraints: Ultra High Vacuum (10 -6 Pa) and 120degC in use, 200degC during baking phase. This long reach multi-link carrier has 10 DOF (9 rotary joints and 1 prismatic joint). It is composed of 5 modules and a precise guiding and pushing system (the deployer) for a total weight of about 300 kg. The gravity effect in the manipulator is largely compensated by a special mechanical structure (the parallelogram) that helps reducing the size of the actuators. The severe operating conditions impose a selection of several vacuum and temperature technologies that have been tested, qualified or optimized to cope with the requirements.In September 2007, the Remote Handling Equipment deployment under atmospheric conditions in a real Tokamak environment (Tore Supra) enabled to qualify the entire prototype. The scenario has to be rehearsed under vacuum and temperature to achieve the complete feasibility demonstration of a Tokamak close inspection by means of a robotic equipment under real operating conditions. The demonstration is an important step in the project but further developments are or could be necessary to cope with 100% of the requirements toward a reliable industrial prototype. In particular, due to its size and weight, this large robot manipulator holds lots of elastic and geometric deformations. Thus its accuracy is a challenge. A mechanical model could be developed to take into consideration the flexibilities of the structure and by means of calibration, the model parameters could be identified and then integrated in a real time controller. Further advanced developments on the on line monitoring system are also necessary for operator assistance and fault detection.