Dynamic identification of the hydraulic Maestro manipulator-Relevance for monitoring

Maintenance tasks at ITER divertor level require the use of powerful force-reflective remote handling devices. CEA in collaboration with CYBERNETIX and IFREMER has developed the Maestro hydraulic manipulator (Modular Arm and Efficient System for TeleRObotics). For teleoperated tasks inside the ITER vacuum vessel, model-based monitoring of the robot can be used to warn the operator of possible failures, without additional sensors. In this paper, we present the experimentally identified dynamic model of the Maestro arm. Then, the use of this model to detect abnormal situations has been investigated. Even if close monitoring is limited to the case of moving axes, due to friction predominance at low velocities, the results help to draw up a detection strategy for unpredicted behaviour, such as collision of the robot with its environment.