## 2 Procedures in the Inspection and Maintenance of Power Lines
### Requirements and Functionalities  
In order to perform the installation of devices on the power line using aerial robotic manipulators, the following main system requirements have been identified: \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Device** & **Operation** & **Manipulator** & **Main Requirement** \\ \hline Clip-Type & Insertion/pushing & Linear actuator & High force (>100 N) \\ \hline Helical & Grasping and rolling & Dual arm & Dexterity, human-size \\ \hline Electrical spacer & Screwing & Screwdriver & Support screw/nut \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Procedure for the installation of the different devices. Installation of clip-type bird diverters, helical bird diverters, and electrical spacers. These are the target devices on which the solution design is focused. * Landing and takeoff from the power line. This allows an increment in the accuracy of the manipulation since the robot can operate with its base fixed on the cables. * Locomotion along power lines using the cables. In this way, the installation of several devices along a segment of the power line can be simplified, avoiding continuous landings and take-offs and improving energy efficiency. * Compatibility with the live-line operation. Cut-offs of the energy transmission during I&M tasks on power lines entail high costs due to the supply losses and should be planned to mitigate their effects. For this reason, these cut-offs should be avoided. * Autonomous installation of devices. The installation of devices, such as clip-type bird diverters, can become repetitive and relatively easy. Consequently, it should be automated to speed up the process and to reduce the operator workload. * Teleoperation capabilities for manipulation. In contrast to the previous requirement, the helical bird diverters require complex interaction with the power line that can be difficult to automate. In this case, teleoperation methods can be applied to achieve better performance by introducing the human in the loop. * Cognitive safe aerial manipulation. During the approaching phase to the power line and when operating around it, potential obstacles, such as trees, electric towers, or cables can be present and the associated collision and entrapment risks should be detected and mitigated. According to the previous requirements, the developed solution should incorporate the functionalities listed below:  
1. Task-oriented end effectors. The use of end effectors specially designed for the manipulation of a specific device leads to a more effective operation. 2. Dual-arm manipulation capabilities. Devices such as helical bird diverters are relatively large and difficult to manipulate due to their elasticity, so a dual-arm system is more adequate to perform their installation. 3. Manipulation with force interaction. The installation of devices involves the application of high forces to attach them in a reliable way to the power line. Since this can be critical, particularly if the robot is flying, the aerial manipulator and its control strategy need to be designed carefully. 4. Aerial manipulation with extended locomotion. The aerial manipulator can integrate a rolling base that allows movement along the power line once the robot has landed on it. In this way, flight segments can be substituted by rolling segments on the line, whose energy consumption is lower. 5. High-voltage-tolerant design. The electric and electromagnetic fields associated with the high voltage and current of the power line can disturb the robot electronics. Consequently, the robot design needs to deal with this difficulty. 6. Planning system for the installation of devices on power lines. The efficient installation of many devices in terms of time and energy requires the use of mission plans computed according to the particular characteristics of both the robot and the environment. 7. Autonomous navigation and manipulation.