Solving nonlinear kinematics of a rail-guided inspection robot used for planning visual scans of reactor vessel internals

In this paper we present a robot for non-destructive visual scanning of an outside shell of the reactor vessel internals. The robot has a total of four degrees of freedom where one of the joints has nonlinear kinematics characteristics due to the construction of the rail-guided joint structure. The problem of solving the nonlinear kinematics of the robot has been addressed by taking the environmental and geometry constraints into account. Kinematics is used to calculate the scan path to cover a specified part of the reactor vessel internals. The described method has been implemented in an user-oriented visualization and control software tool called Fiona, which was tested on a real robot. We demonstrate the effectiveness of the presented method using Fiona in a simulated reactor vessel internals inspection environment.