In this paper, we present the innovative robotic tool design and modelling, validation of a new family of climbing robots that are capable of adhering to vertical surfaces through permanent magnetic wheels. The robotic system is composed of two modules, a sensing module, and magnetic wheel module which are arranged in a sandwich configuration, with the surface to climb interposed between them. To perform the inspection task, few magnetic wheeled climbing robots have been proposed for many industrial applications of ferromagnetic structures. To achieve a reliable system, good payload abilities, and minimize the power consumption of robot, the design of magnetic circuit and calculation of adhesion forces of magnetic wheel are drive factor to achieve all these. In this paper a four permanent wheeled robot is proposed to climb on the bridges and girders of the overhead cranes for health monitoring. An improved design of magnetic wheel is presented in this paper. Finite element method is performed on the wheel to get the magnetic flux distribution and calculate the attractive forces between the wheels and inspection area. By the simulation distribution of magnetic flux lines were compared on the plane inspection area and a curved concave and convex surface. By keeping the main objective of recognizing the fault into the ferromagnetic structures a wireless robotic system is proposed for the overhead cranes.