# Design and Development of a Climbing Robot for Wind Turbine Maintenance
## 1 Introduction
After reviewing previous research about climbing robot and considering many factors such as cost, material and time constraints, a modular mechanism with a compact design has been proposed to be implemented in the robot design. The problem statement is to design a climbing robot that reduces mechanical complexity, fulfill the stability against breaking or slipping, carrying load capacity and using a new approach of adhesion for the winding mechanism. Lastly, wheeled locomotion is always faster than legged locomotion and the use of rubber could provide a strong grip while minimizing the damage of the wind turbine tower surface. This study proposed a climbing model which adapts for a scaled-down 2 MW wind turbine tower. It is supported by a winding mechanism that utilizes a steel rope traction to optimize the force of the robot's driving wheel. The innovation of this climbing robot is that its method of adhesion uses a tension rope force to grip rather than conventional techniques such as magnetic adhesion, vacuum suction, electrostatic adhesion and propeller-type adhesion. The traction of the tension force needs to adapt the different diameter of the wind turbine tower, as it climbs through a circular truncated cone shape. The rope traction ensures a high degree of safety in the inspection and maintenance of the wind turbine, either onshore or offshore. The locomotion mechanism is a wheel-based mode for a faster and more robust climb. The four rubber wheels in contact with the wind turbine tower will provide sufficient friction as they roll on the tower surface and are prevented from slipping. This climbing robot can facilitate movement in a straight up-down motion with the wired \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Types of** & & & & & **Diameter of the** \\
**Climbing** & **Robot** & & & & & **Application (Pole, Tower, Tree, Pipelines)** \\ \hline “Ring”Climb & & Mechanical— & “Ring” robot in & Cylindrical & 3 kg & 100 mm \\ Robot [16] & & spring traction & triscretion Y-type design & tower & & \\ \hline \hline \multirow{2}{*}{Pobot V2 [17]} & \multirow{2}{*}{Wheel based} & Mechanical— & Rectangular body and & & & \\  & & self-locking & folded shape of arm & & & \\ \hline The UT-PCR [18; 19] & & & & & \\ \hline Tree Pruning [20; 21] & & & & & & \\ Robot [20; 21] & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Existing climbing robots. Figure 2: Design studies: (**a**) ”Ring” climb robot [16]; (**b**) Robot V2 [17]; (**c**) the UT-PCR [18; 19]; (**d**) Tree Pruning Robot [20; 21]; (**e**) the RETOV [22]; and (**f**) Multi-Robot [23]. DC power supply. Concerning the robot carrying load capability, it should be optimized to be strong and safe enough for carrying inspection or maintenance tools. With these goals, the approximate carrying payload is estimated at least 50% from the robot total weight against breaking or slipping. The mechanical design was analyzed and calculated as the most significant aspect, and the controller architecture of the climbing robot and the new approach of adhesion are shown in Section 2. It has been successfully tested to prove the stability of the innovative climbing design and experiment results are detailed in Section 3, and finally a conclusion is presented in Section 4.