There are various desired capabilities to create aerial forest-traversing robots capable of monitoring both biological and abiotic data. The features range from multi-functionality, robustness, and adaptability. These robots have to weather turbulent winds and various obstacles such as forest flora and wildlife thus amplifying the complexity of operating in such uncertain environments. The key for successful data collection is the flexibility to intermittently move from tree-to-tree, in order to perch at vantage locations for elongated time. This effort to perch not only reduces the disturbance caused by multi-rotor systems during data collection, but also allows the system to rest and recharge for longer outdoor missions. Current systems feature the addition of perching modules that increase the aerial robots' weight and reduce the drone's overall endurance. Thus in our work, the key questions currently studied are: "How do we develop a single robot capable of metamorphosing its body for multi-modal flight and dynamic perching?", "How do we detect and land on perchable objects robustly and dynamically?", and "What important spatial-temporal data is important for us to collect?"

Perching with winged Unmanned Aerial Vehicles has often been solved by means of complex control or intricate appendages. Here, we present a simple yet novel method that relies on passive wing morphing for crash-landing on trees and other types of vertical poles. Inspired by the adaptability of animals' and bats' limbs in gripping and holding onto trees, we design dual-purpose wings that enable both aerial gliding and perching on poles. With an upturned nose design, the robot can passively reorient from horizontal flight to vertical upon a head-on crash with a pole, followed by hugging with its wings to perch. We characterize the performance of reorientation and perching in terms of impact speed and angle, pole material, and size. The robot robustly reorients at impact angles above 15{\deg} and speeds of 3 m/s to 9 m/s, and can hold onto various pole types larger than 28% of its wingspan in diameter. We demonstrate crash-perching on tree trunks with an overall success rate of 71%. The method opens up new possibilities for the use of aerial robots in applications such as inspection, maintenance, and biodiversity conservation.

Current UAVs capable of perching require added structure and mechanisms to accomplish this. These take the form of hooks, claws, needles, etc which add weight and usually drag. We propose in this paper the dual use of structures already on the vehicle to enable perching, thus reducing the weight and drag cost associated with perching UAVs. We propose a wing design capable of passively wrapping around a vertical pole to perch. We experimentally investigate the feasibility of the design, presenting results on minimum required perching speeds as well as the effect of weight distribution on the success rate of the wing wrapping. Finally, we comment on design requirements for holding onto the pole based on our findings.

Autonomous Nano Aerial Vehicles have been increasingly popular in surveillance and monitoring operations due to their efficiency and maneuverability. Once a target location has been reached, drones do not have to remain active during the mission. It is possible for the vehicle to perch and stop its motors in such situations to conserve energy, as well as maintain a static position in unfavorable flying conditions. In the perching target estimation phase, the steady and accuracy of a visual camera with markers is a significant challenge. It is rapidly detectable from afar when using a large marker, but when the drone approaches, it quickly disappears as out of camera view. In this paper, a vision-based target poses estimation method using multiple markers is proposed to deal with the above-mentioned problems. First, a perching target with a small marker inside a larger one is designed to improve detection capability at wide and close ranges. Second, the relative poses of the flying vehicle are calculated from detected markers using a monocular camera. Next, a Kalman filter is applied to provide a more stable and reliable pose estimation, especially when the measurement data is missing due to unexpected reasons. Finally, we introduced an algorithm for merging the poses data from multi markers. The poses are then sent to the position controller to align the drone and the marker's center and steer it to perch on the target. The experimental results demonstrated the effectiveness and feasibility of the adopted approach. The drone can perch successfully onto the center of the markers with the attached 25mm-diameter rounded magnet.

The device also could have valuable agricultural uses, "flying down in the plant canopy, looking for disease and measuring parameters like humidity, with much finer detail than is possible with overhead drones, enabling a new sort of'micro agriculture,' that could locally tailor the environment to optimize yields," Fuller says. Thus, he says releasing the bug from its leash "was really a necessary step to enable them to fly freely and perform the applications we envision." Perching -- staying aloft in the air with buzzing or flapping, landing and staying there -- is another goal. "Perching is something we're interested in because that's a very efficient way to operate for a long time, and it has already been demonstrated on the RoboBee, which still had a wire at that point," says Johannes James, a mechanical engineering doctoral student and member of the team. Robotic flies could alight on supports along a pipeline, or in a refining facility, for example, and perform long-term sensing along the length of the pipes, and then move elsewhere to collect more data, according to James.

This is a guest post. The views expressed here are solely those of the author and do not represent positions of IEEE Spectrum or the IEEE. The DARPA Robotics Challenge this past summer showcased how far humanoid robots have come--but also how far they have yet to go before they can tackle real-world practical applications. Even the best of the DRC behemoths stumbled and fell down, proving, as IEEE Spectrum noted at the time, that "not walking is a big advantage." There is, in fact, a new not-walking way for robots to perform many kinds of tasks better and faster: the dexterous drone.

This is a guest post. The views expressed here are solely those of the author and do not represent positions of IEEE Spectrum or the IEEE. The DARPA Robotics Challenge this past summer showcased how far humanoid robots have come--but also how far they have yet to go before they can tackle real-world practical applications. Even the best of the DRC behemoths stumbled and fell down, proving, as IEEE Spectrum noted at the time, that "not walking is a big advantage." There is, in fact, a new not-walking way for robots to perform many kinds of tasks better and faster: the dexterous drone.