This letter focuses on the problem of handling impacts by means of an aerial manipulator and proposes a solution that combines the control of the aerial manipulator's end-effector position with an innovative design approach of aerial manipulation systems, consisting of both active and passive joints. The approach aims at limiting the influence of impacts on the controlled attitude dynamics in order to allow the aerial manipulator to remain stable during and after impact. The developed concept is intended to convert kinetic energy into potential energy, which is permanently stored into elastic elements by means of directional locking mechanisms. The proposed approach has been tested on a 2 d.o.f. manipulator mounted on a quadrotor UAV. The manipulation system has one active rotational d.o.f. compensating for pitch movements of the UAV and one passive linear joint which is in charge of absorbing the impact energy. The device has been used to validate the method through experiments, in comparison with a rigid manipulator. The results show that the proposed approach and the developed mechanical system achieve stable impact absorption without bouncing away from the interacting environment. Our work has the ambition to propose a new direction towards aerial manipulators that are capable of performing highly dynamic physical interaction tasks.

A wide range of applications for which Unmanned Aerial Vehicles (UAVs) are ideally suited rely on the development of manipulators capable of exchanging forces with the environment. One such application is the installation and retrieval of intelligent sensors for monitoring wide-spread areas and locations that are difficult to access by any other means. Within this paper we report on both indoor and outdoor flights tests of a novel force controlled lightweight compliant manipulator which allows a UAV to carry out this type of task. Installation and retrieval are both demonstrated with different scenarios, indoors and outdoors. Key results include interaction forces up to 22 N exerted by a small-sized multirotor; placement and retrieval operations carried out on flat as well as cylindrical surfaces; and an analysis of the overall system. The results of multiple flight experiments clearly demonstrate the potential of this approach for the deployment of sensors and other force-related tasks.

On‐site inspection of large‐scale infrastructure often involves high risks for the operators and high insurance costs. Despite several safety measures already in place to avoid accidents, an increasing concern has brought the need to remotely monitor hard‐to‐reach locations, for which the use of aerial robots able to interact with the environment has arisen. In this paper a novel approach to aerial manipulation is presented, where a compact manipulator with a single degree‐of‐freedom is tailored for the placement and retrieval of sensors in the environment. The proposed design integrates on‐board sensing, a high‐performance force controller on the manipulator, and a thrust‐to‐force mapping on the flight controller. Experimental results demonstrate the high reliability achieved during both placement and retrieval tasks on flat surfaces (e.g., a bridge wall) and cylindrical surfaces (e.g., tree trunks). A total number of 89 flight experiments were carried out to demonstrate the robustness and potential of the compact, bespoke aerial design.

Mobile robots have revolutionized the public and private sectors for transportation, exploration, and search and rescue. Efficient energy consumption and robust environmental interaction needed for complex tasks can be achieved in aerial–terrestrial robots by combining advantages of each locomotion mode. This review surveys over two decades of development in multimodal robots that move on the ground and in air. Multimodality can be achieved by leveraging three main design approaches: adding morphological features, adapting forms for locomotion transitions, and integrating multiple vehicle platforms. Each classification is thoroughly examined and synthesized, encompassing both qualitative and quantitative aspects. The authors delved into the intricacies of these approaches and explored the challenges and opportunities that lie ahead in pursuit of the next generation of mobile robots. This review aims to advance future deployment of multimodal robots in the real world for challenging operations in dangerous, unstructured, contact‐prone, cluttered and subterranean environments.

Drones have been increasingly used in various domains, including ecological monitoring in forests. However, the endurance and noise of drones have limited their deployment to short flight missions above canopies. To address these limitations, we introduce ALBERO: a framework comprising a mechanical solution and an optimal planner to realise agile quadrotor perching on tree branches of steep incline. The gripper features an ultra-fast active mechanism inspired by birds' claws that enables quadrotors to perch swiftly on randomly-oriented tree branches. By perching, the drone can preserve energy for extended periods of time, while silently gathering forest data in the canopy. The intrinsic properties of the gripper allow for extra flexibility in size, surface roughness and shape imperfections of natural perches, such as those found in the wild. The gripper also has good scalability properties and can be easily matched to different drones' sizes and weights. The biggest advantage of this novel design lays in its ability to close reactively and ultra-fast (67 ms on the large gripper, 42 ms on the small gripper), enabling the quadrotor to perform agile perching manoeuvres from different angles and at different approach speeds. ALBERO's software module comprises of a trajectory planning algorithm adapted for branch perching, ensuring that the drone can perch on inclined cylindrical targets from any starting location in the proximity of the branch. These requirements translate in stringent positioning and orientation accuracy, but they enable the drone to land dynamically from a variety of positions within the forest.

With biodiversity loss escalating globally, a step change is needed in our capacity to accurately monitor species populations across ecosystems. Robotic and autonomous systems (RAS) offer technological solutions that may substantially advance terrestrial biodiversity monitoring, but this potential is yet to be considered systematically. We used a modified Delphi technique to synthesize knowledge from 98 biodiversity experts and 31 RAS experts, who identified the major methodological barriers that currently hinder monitoring, and explored the opportunities and challenges that RAS offer in overcoming these barriers. Biodiversity experts identified four barrier categories: site access, species and individual identification, data handling and storage, and power and network availability. Robotics experts highlighted technologies that could overcome these barriers and identified the developments needed to facilitate RAS-based autonomous biodiversity monitoring. Some existing RAS could be optimized relatively easily to survey species but would require development to be suitable for monitoring of more ‘difficult’ taxa and robust enough to work under uncontrolled conditions within ecosystems. Other nascent technologies (for instance, new sensors and biodegradable robots) need accelerated research. Overall, it was felt that RAS could lead to major progress in monitoring of terrestrial biodiversity by supplementing rather than supplanting existing methods. Transdisciplinarity needs to be fostered between biodiversity and RAS experts so that future ideas and technologies can be codeveloped effectively.