Conceptual Design of an In-Vessel Inspection Robotic Arm (InVIRA) for Tokamak Environment

Abstract

Content (Font 10) An in-vessel inspection robotic system has been conceptualized for operation inside a tokamak vessel. The robotic system is envisaged to comprise of a robotic arm, end-effector, microcontroller and wireless communication system. The end-effector is envisaged to be a special purpose camera for in-situ inspection between plasma shots. The three-link robotic arm, designed for ITER-like environment, has 4 revolute joints- 3 providing manipulation in poloidal plane and the fourth one providing limited movement in adjacent toroidal planes. This work provides the design of the system along with kinematic analysis of robotic arm. Solutions have been derived for forward and inverse kinematic models and the Jacobian matrix for the robotic arm linkage. Using Jacobian matrix, the relation between the end-effector velocity and the joint velocity of a manipulator is obtained i.e. given the individual joint velocity; the end-effector velocity is obtained. A CAD model has been generated to simulate the kinematic model and carry out computational stress analysis. Trajectory Planning is done using two techniques: Cubic Polynomial trajectoy and Blended trajectory for point-to-point motion without via points, without taking into account the dynamic part.