## 4 Arms and End Effectors for Aerial Manipulation  
### Aerial Manipulation Platforms  
According to the requirements and functionalities identified in Section 2.3, four different aerial robotic manipulators are developed to perform the installation of the devices shown in Figure 1. These are the Main Local-Manipulation Platform (MLMP), the Deployable Manipulator with Carriage (DM-C), the Linear-Actuator Platform (LAP), and the Dual-Arm Platform (DAP). Figure 3 depicts these platforms.  
The MLMP platform is a multi-purpose aerial manipulator conceptually designed for the efficient installation of devices after landing on the power line and moving along it, using a rolling system inspired by [26]. This approach combines the benefits from rolling [20] and aerial solutions [22] into a compact system. To reach the stability required to operate on the cables, the mass is distributed in such a way that the center of mass is located below the cables. This aerial manipulator is endowed with a robotic arm with interchangeable end effectors that can be used for the teleoperated installation of clip-type bird diverters and electrical spacers. Nevertheless, opposite to other specialized solutions, such as [22], its multi-purpose design makes the MLMP platform suitable for other I&M tasks on power lines.  
The DM-C platform was conceived as an alternative to the MLMP. The main idea is to keep similar capabilities while allowing the decoupling of the aerial platform to the manipulator and the rolling system. Thus, the rolling manipulator can be deployed on the power line for the installation of devices. Simultaneously, the aerial platform can be used to provide devices from a supply point and to assist the rolling manipulator in aerial transitions between different segments of the power line. With this novel approach, the robot complexity increases but the installation of many devices can be addressed faster and with more efficient use of the whole system.  
The LAP platform is devoted to the fast and autonomous installation of clip-type bird diverters on flight. In contrast to the few state-of-the-art solutions available for the installation of bird diverters while flying, the LAP platform allows the application of high  
Figure 3: Aerial manipulation platforms: Main Local-Manipulation Platform (MLMP), Deployable Manipulator with Carriage (DM-C), Linear-Actuator Platform (LAP), and Dual-Arm Platform (DAP).  
forces during installation, without the need to use a heavy aerial vehicle. Hence, the installation mechanism consists of a high force (up to 90 kg) linear actuator that exerts a pushing force directly on the device, which is held by a clamp mechanism that transmits the reaction forces to the power line, isolating in this way the aerial platform. This manipulator is attached to an aerial platform on its bottom part through a passive spherical joint that avoids the propagation of wrench disturbances from the mechanism to the aerial platform during the realization of the operation on flight.  
The DAP platform is intended to install helical bird diverters for the first time on flight, using aerial robots. Due to the complexity in the manipulation of these large and flexible devices, this robot makes use of a teleoperated dual arm in the long-reach configuration [8; 27], replicating the dexterous manipulation capabilities of human operators. Similarly to the LAP platform, the long-reach manipulator is attached to the aerial platform through a passive revolute joint that reduces the disturbance transmission. Moreover, the long-reach feature offers two main advantages. Firstly, it increases the safety distance between the manipulation area and the robot propellers, which reduces collision risks. Secondly, it acts as an electrical insulator for the aerial platform because the link is made of PVC. Thus, after placing the main system electronics on the aerial platform, high-voltage physical interaction with the power line is possible.