Contact-Aware Control for Fully-Actuated Hexarotors equipped with Passive End-Effector

In recent years, the use of aerial robots, especially multi-rotor UAVs (Unmanned Aerial Vehicles), is becoming increasingly common in many different contexts ranging from outdoor and indoor applications, such as surveillance, monitoring, data collection, exploration and mapping. However, despite their growing occurence, UAVs are still underutilized for tasks that require direct interaction with the environment. This thesis focuses on the development of control strategies for Fully-Actuated Hexarotors equipped with passive EE in interaction with the surrouding environment. The control goal requires the regulation of the decoupled force and torque dynamics due to Hexarotor characterized by tilted-propellers, which entail the possibility to independently control the platform position and attitude, thus enhancing its interaction capabilities. More in detail, the analysis focuses on three phases of a generic Contact-Aware task: 1) navigation of the platform to a point of interest, 2) detection of contact between end-effector and wall/surface and 3) control of the actual interaction phase during which the end-effector must exert a desired force on wall/surface. First of all, in navigation phase the UAV is required to follow a 6D reference trajectory defined in terms of desired position and orientation. Different types of controllers (PID, Geometric, Flatness-Based and Hierarchical controllers) are analyzed and compared by testing different trajectories and accounting for various performance indexes. The goal is to establish the best controller among all those analyzed. Finally, the interaction control is analyzed accounting for the Hexarotor's EE exerting a force on a wall/surface: the EE's effect on the whole system's mass and on the inertia matrix are considered neglegible, so the interaction force can be applied to the Hexarotor's center of mass and oriented along the EE's axis.