Aerial Interaction Control in Outdoor Environments for a Micro Aerial Vehicle Equipped with a Robotic Arm

Physical contact with the surrounding environment is an essential and challenging task for unmanned aerial vehicles (UAV) to perform complex missions in the aerial manipulation field. Steady flight of an aerial manipulator is compromised due to the disturbances forces induced by the actuators of the manipulator, and the conditions of the indoor/outdoor environment. This paper focuses on the pose control performance of the aerial manipulator composed of an UAV and a 2-DOF arm for full contact of the system with a vertical surface in an outdoor scenario. The control technique is based on the Gain Scheduling (GS) approach incorporated into a proportional-integral-derivative (PID) algorithm to reduce the offset of the instability produced by the movement of the robotic arm, the wall effect and the external conditions like wind gusts. The visual simultaneous location and mapping (SLAM) method is implemented, exploiting the onboard sensing capabilities of the UAV without using another external caption motion method to estimate the pose of the system in the outdoor environment. The control design was implemented through extensive outdoor flight experiments to analyzed the behavior of the system in such conditions and obtained the gain value for the set of controllers. Experimental results of aerial contact with a surface show that the controller can suppress the disturbance mentioned above effectively, and make the system hover steadily with sufficient accuracy to complete aerial contact mission in an outdoor environment.