This paper presents the design, modeling and control of a fully actuated aerial robot for infrastructure contact inspection as well as its localization system. Health assessment of transport infrastructure involves measurements with sensors in contact with the bridge and tunnel surfaces and the installation of monitoring sensing devices at specific points. The design of the aerial robot presented in the paper includes a 3DoF lightweight arm with a sensorized passive joint which can measure the contact force to regulate the force applied with the sensor on the structure. The aerial platform has been designed with tilted propellers to be fully actuated, achieving independent attitude and position control. It also mounts a “docking gear” to establish full contact with the infrastructure during the inspection, minimizing the measurement errors derived from the motion of the aerial platform and allowing full contact with the surface regardless of its condition (smooth, rough, ...). The localization system of the aerial robot uses multi-sensor fusion of the measurements of a topographic laser sensor on the ground and a tracking camera and inertial sensors on-board the aerial robot, to be able to fly under the bridge deck or close to the bridge pillars where GNSS satellite signals are not available. The paper also presents the modeling and control of the aerial robot. Validation experiments of the localization system and the control system, and with the aerial robot inspecting a real bridge are also included.

In recent years, the fields of application of aerial manipulators have expanded, ranging from infrastructure inspection to physical interaction with flexible elements, such as branches and trees. This article presents the controlled shaking of a tree with an aerial manipulator. Our work aims at contributing to applications like the identification of tree parameters for environmental health monitoring or the collection of samples and fruits by vibration. To this end, we propose a control strategy for controlled shaking of flexible systems. We adopt a self-excited oscillation strategy that induces vibrations at the natural frequency of the system, at which the greatest amplification and therefore the greatest vibrations occur. Likewise, this work presents a simplified 1 degree of freedom (DoF) model based on the Rayleigh–Ritz method to analyze dynamic interaction between a tree and the aerial manipulator with the controlled shaking strategy. The proposed control strategy is evaluated through indoor experiments, where an aerial manipulator shakes an indoor tree made of bamboo canes. Experimental results show how the proposed model can estimate properly the amplitude of the vibration and the frequency of the vibration, depending on the grasping point and the control gain of the self-excited oscillation strategy.

This letter investigates the ground proximity effects of a fully-actuated multirotor unmanned aerial vehicle (UAV). Different configurations of tilted rotors and a wide range of UAV heights relative to the ground are considered. In order to characterize the effect, an extensive experimental study was conducted on a static test-bench. The experimental results display a behavior differing from that previously observed for multirotors with co-planar propellers and single-tilted rotors. We demonstrate that the ground effect increases with angle when the UAV is near the ground, while the opposite occurs for areas further away. Two new ground effect models are proposed, one for co-planar and another for fully-actuated configuration. In both cases, the models are dependent on the propeller radius, the distance between the rotors, the height of the UAV and the fountain effect. In addition, in the fully-actuated configuration, the model also depends on the inclination of the rotors. Finally, the proposed models are integrated into the UAV control architecture using the Aerodynamic Power Model Inversion (APMI) module, showing a significant improvement in flight accuracy when the ground effect is considered.

This paper presents the design, development, and validation in indoor scenario of an aerial delivery system intended to conduct the delivery of light parcels directly to the user through the window of his/her home, motivated by the convenience of facilitating the access to medicines to people with reduced mobility.The system consists of a fully-actuated multi-rotor (FAMR) equipped with a front basket where the parcel to be delivered is loaded by a lightweight and compliant anthropomorphic dual arm system (LiCAS) located at the supply point, using one of the arms to drop the parcel in the basket while the other arm holds its base to support the sudden moment exerted at the FAMR. The paper analyses four types of physical interactions raised during the operation on flight: (1) sudden changes in the mass distribution of the FAMR during the load/unload phase, affecting the multi-rotor position-attitude controllers, (2) impact and impulsive forces exerted by the human on the FAMR to demonstrate the reliability and robustness of conventional cascade controllers, (3) passive accommodation of the LiCAS while holding the FAMR during the parcel load, relying on the mechanical joint compliance, and (4) compliant human–FAMR interaction, interpreting the multi-rotor pose control error as a Cartesian/angular deflection to implement an admittance controller that allows the user guiding the platform. Experimental results allow the identification and characterization of these effects for different payload masses. The execution of the complete operation, involving the parcel load with the LiCAS and handover by the user through a window, is validated in a representative indoor scenario. Graphical

Logistics and service operations involving parcel preparation, delivery, and unpacking from a supply point to a user’s home could be carried out completely by robots in the near future, taking advantage of the capabilities of the different robot morphologies for the logistics, outdoor, and domestic environments. The use of robots for parcel delivery can contribute to the goals of sustainability and reduced emissions by exploiting their different locomotion modalities (wheeled, legged, and aerial). This article reports the development and results obtained from the first robotics hackathon celebrated as part of the European Robotics and Artificial Intelligence Network involving eight robotic platforms in three domains: 1) an industrial robotic arm for parcel preparation at the supply point, 2) a Centauro robot, a dual-arm aerial manipulator, and a wheeled-legged quadruped for parcel transportation, and 3) two humanoid robots and two commercial mobile manipulators for parcel delivery and unpacking in domestic scenarios. The article describes the joint operation and the evaluation scenario, the features and capabilities of the robots, particularly those involved in the realization of the tasks, and the lessons learned.

Aerial robots are transitioning from traditional surveillance and monitoring roles to more advanced tasks involving physical interaction. Despite this progress, physical Human-Aerial Robot Interaction remains largely underexplored due to the complexity and stability-related issues of such platforms. This paper introduces a novel control framework that enables an aerial platform to cooperatively transport an object with a human operator. The control approach is built on a nonlinear model predictive control (NMPC), integrating the dynamic models of the human, the aerial robot, and the transported object. To ensure safe and robust physical interaction, the NMPC is combined with a compliant controller. Additionally, our controller prioritizes forward motion over lateral movements to accommodate the human's natural direction of motion. We validate this framework through indoor flight experiments, demonstrating how a human operator and a fully actuated hexarotor can effectively collaborate to transport a bar. The results highlight the aerial robot's ability to assist the human during physical transportation tasks, enhancing efficiency and comfort.