The modern situation that infrastructures are getting taller and massive makes the maintenance or inspection of large vertical structures more important; nevertheless, the lack of professional manpower, the high cost due to labor-intensive tasks, and high risk of the areas that are hard to reach are problems. There have been many attempts to solve the problems with a wall-climbing robot. As a result, various robots are researched and tested but most of the robots are not practical in the real field. In the previous study, the wall-climbing robots were classified into two types; an infrastructure-based wall-climbing robot and a non-infrastructure-based wall-climbing robot. The first one is not preferred by the architects due to the necessity of the infrastructures installed in a building and the size that is too huge to carry it to another building, even though it has high payload and safety. The second one needs no infrastructures, but most of the robots are laboratory level owing to a danger of falling or limited maneuverability. In the previous research, to supplement the weakness, a quadrotor-based wall-climbing robot mechanism was proposed, and the feasibility was verified through simple simulations and experiments. Through the quadrotor-based mechanism, the robot is not only possible to fly but also can stick on the vertical wall using just only four thrust forces. It makes the maneuverability of the wall-climbing robot extremely enhanced. In this paper, more advanced and additional researches are conducted. The dynamics of the robot is analyzed when it is in flying state or pose transformation state, and then the controllers are designed based on the dynamics. Especially, a pose transformation controller is designed to avoid the slipping and falling accidents when the robot transforms the pose from flying mode to stick mode. Similar to the previous work, the feasibility is verified through the simulations and tests. As a result, it is shown that the proposed robot can be used for the structural health monitoring with some additional equipment such as a camera.
doi: 10.12783/SHM2015/161