Quadrotor-Based Wall-Climbing Robot for Structural Health Monitoring

Abstract

As civil structures become massive and high, the inspection and maintenance become more important. However, most of the conventional inspection methods are labor-intensive and costly due to its high risk. To solve these problems, the need for wall-climbing inspection robots has been emerged. Infrastructure-based wall-climbing robots have been studied for a long time to inspect and maintain an outer wall of the building with high payload and safety. However, the infrastructure installed on the wall is not preferred because it hinders appearance of the building. Consequently, the architects don’t prefer the infrastructure-based wall-climbing robots. It’s one of the reasons why the wall-climbing robots that do not utilize additional infrastructure are gaining attention recently. In the conventional wall-climbing robots, they stick to the wall using adhesion mechanisms such as magnetics, vacuum system, or adhesion materials. The robots do not use the infrastructure for wall-climbing, but most of the technologies are in the laboratory level since the payload, safety, and maneuverability are not satisfactory. To overcome these problems, a quadrotor-based wall-climbing robot is proposed in this paper. The robot is designed for both wall-climbing and flying with four rotors and wheels coated with adhesive material. It can fly using the thrust forces generated by four rotors. Also, it can stick to the wall with the same thrust forces and then climb the wall with four wheels. The wall-climbing robot can stabilize its position even if it is suddenly detached from the wall by unexpected disturbances while climbing the wall by using the flying capability. The maneuverability and safety of the robot have been improved by using the four rotors and wheels coated with adhesive material. The feasibility of the main concept was verified through simulations and the prototype of the robot has been made. The mechanism of the proposed robot has been demonstrated on a wall of a building.