Modeling and simulation of EAST flexible in-vessel inspection robot based on absolute nodal coordinate formulation

In this paper, a flexible in-vessel inspection robot for inspecting the first wall inside the vacuum vessel of Experimental Advanced Superconducting Tokamak (EAST) is modeled using the absolute nodal coordinate formulation. The robot is a macro-micro robot including three curved telescopic booms. When the curved telescopic booms are extracted and retracted during the operation process, its overall length changes dynamically and then the vibration characteristics and deformation is time-varying. Since the location of the sliding contact point moves along the deformable axis of the flexible boom, it is difficult to derive the dynamic model of such robot. To model such robot, the spatial curved beam elements of the absolute nodal coordinate formulation for modeling the large rotation and deformation is used to model the flexible curved booms and the sliding joint constraint of the absolute nodal coordinate formulation is used to model the relative sliding motion between the flexible curved booms. Finally, the numerical simulation is used to demonstrate the effectiveness of the proposed model.