Preliminary Concept Design of an Innovative Under-Actuated Gripper for the Remote Handling Operations in the RFX-Mod2 Fusion Machine

In the nuclear fusion framework the robots employed for inspection and maintenance tasks, are extremely afflicted by high amplitude oscillation due to the inertial loads that these robots must manage. To optimize space and weight of a robotic end-effector, remove components and not essential mechanism is the first step. However it’s crucial to ensure a satisfactory level of precision and performance in terms of grasping of the gripper. Therefore in remote handling all the design aspects have to face with the restricted volume allowed by the environment in which the robotic system has to be employed. The fusion machines, akin tokamaks, are characterized always by narrow access port or confined spaces; these aspects affect the design of the cross–section of the manipulators and of the end-effector. The objective of this work is to evaluate the implementation of an innovative compliant mechanism suitable for remote handling tasks. More specifically in this work an innovative gripper design that significantly reduces the need for complex internal mechanisms and transmissions is presented. This novel approach utilizes a kinematic system based on the deformation of the main body of the gripper itself. By leveraging the intrinsic flexibility and material properties of the structure of the end-effector; this design achieves the necessary motion and force transmission through its own deformation, simplifying the overall design, enhancing reliability and reducing the mass of the manipulator at the tip. The FACT (Freedom And Constraint Topology) is a topological method, employed to obtain a first conceptualization of the kinematic. Structural analysis has been done to verify deformation and stiffness rate of the gripper concept.