A high payload aerial platform for infrastructure repair and manufacturing

The use of aerial robots in construction is an area of general interest in the robotics community. Autonomous aerial systems have the potential to improve safety, efficiency and sustainability of industrial construction and repair processes. Several solutions have been deployed in this domain focusing on problems in aerial manipulation and control using existing aerial platforms which are not specialised for the specific challenges in operating on a construction site. This paper presents a new compact, high thrust aerial platform that can act as a modular, application agnostic base for demonstrating a wide variety of capabilities. The platform has been built and tested flying both with manual controls and autonomously in a motion tracking arena while carrying a payload of up to 7.3 kg with a maximum flight time between 10–34 mins (payload dependent). In the future, this platform will be combined with vision based tracking sensors, manipulators and other hardware to operate in and interact with an outdoor environment. Future applications may include manipulation of heavy objects, deposition of material and navigating confined spaces

An aerial parallel manipulator with shared compliance

Accessing and interacting with difficult to reach surfaces at various orientations is of interest within a variety of industrial contexts. Thus far, the predominant robotic solution to such a problem has been to leverage the maneuverability of a fully actuated, omnidirectional aerial manipulator. Such an approach, however, requires a specialised system with a high relative degree of complexity, thus reducing platform endurance and real-world applicability. The work here presents a new aerial system composed of a parallel manipulator and conventional, underactuated multirotor flying base to demonstrate interaction with vertical and non-vertical surfaces. Our solution enables compliance to external disturbance on both subsystems, the manipulator and flying base, independently with a goal of improved overall system performance when interacting with surfaces. To achieve this behaviour, an admittance control strategy is implemented on various layers of the flying base's dynamics together with torque limits imposed on the manipulator actuators. Experimental evaluations show that the proposed system is compliant to external perturbations while allowing for differing interaction behaviours as compliance parameters of each subsystem are altered. Such capabilities enable an adjustable form of dexterity in completing sensor installation, inspection and aerial physical interaction tasks. A video of our system interacting with various surfaces can be found here: https://youtu.be/38neGb8-lXg

Evaluating immersive teleoperation interfaces: coordinating robot radiation monitoring tasks in nuclear facilities

We present a virtual reality (VR) teleoperation interface for a ground-based robot, featuring dense 3D environment reconstruction and a low latency video stream, with which operators can immersively explore remote environments. At the UK Atomic Energy Authority's (UKAEA) Remote Applications in Challenging Environments (RACE) facility, we applied the interface in a user study where trained robotics operators completed simulated nuclear monitoring and decommissioning style tasks to compare VR and traditional teleoperation interface designs. We found that operators in the VR condition took longer to complete the experiment, had reduced collisions, and rated the generated 3D map with higher importance when compared to non-VR operators. Additional physiological data suggested that VR operators had a lower objective cognitive workload during the experiment but also experienced increased physical demand. Overall the presented results show that VR interfaces may benefit work patterns in teleoperation tasks within the nuclear industry, but further work is needed to investigate how such interfaces can be integrated into real world decommissioning workflows

Learning tethered perching for aerial robots

Aerial robots have a wide range of applications, such as collecting data in hard-to-reach areas. This requires the longest possible operation time. However, because currently available commercial batteries have limited specific energy of roughly 300 W h kg -1 , a drone's flight time is a bottleneck for sustainable long-term data collection. Inspired by birds in nature, a possible approach to tackle this challenge is to perch drones on trees, and environmental or man-made structures, to save energy whilst in operation. In this paper, we propose an algorithm to automatically generate trajectories for a drone to perch on a tree branch, using the proposed tethered perching mechanism with a pendulum-like structure. This enables a drone to perform an energy-optimised, controlled 180° flip to safely disarm upside down. To fine-tune a set of reachable trajectories, a soft actor critic-based reinforcement algorithm is used. Our experimental results show the feasibility of the set of trajectories with successful perching. Our findings demonstrate that the proposed approach enables energy-efficient landing for long-term data collection tasks

Forest drones for environmental sensing and nature conservation

Protecting our nature and biodiversity is essential. For this purpose, remote sensing robotic platforms are increasingly explored to collect spatial and temporal data. However, there is still little attention on leveraging aerial robots to interact with trees for sample collection and targeted countermeasure deployment. In this study, we propose platforms and methodology that offer the use of aerial robots in the forests to conduct various tasks including leaf sample collection, visual sensing of forest topology and autonomous sensor placement. With the developed virtual reality (VR) interface, we show that remote environmental sensing, detection of plant pathogens, and sample collection are viable tasks that can be achieved by the proposed platforms. In this context, physical and visual sensing approaches as well as various aerial robots are introduced and discussed for forest applications

Human RSPO1/R-spondin1 Is Expressed during Early Ovary Development and Augments β-Catenin Signaling

Human testis development starts from around 42 days post conception with a transient wave of SRY expression followed by up-regulation of testis specific genes and a distinct set of morphological, paracrine and endocrine events. Although anatomical changes in the ovary are less marked, a distinct sub-set of ovary specific genes are also expressed during this time. The furin-domain containing peptide R-spondin1 (RSPO1) has recently emerged as an important regulator of ovary development through up-regulation of the WNT/β-catenin pathway to oppose testis formation. Here, we show that RSPO1 is upregulated in the ovary but not in the testis during critical early stages of gonad development in humans (between 6–9 weeks post conception), whereas the expression of the related genes WNT4 and CTNNB1 (encoding β catenin) is not significantly different between these tissues. Furthermore, reduced R-spondin1 function in the ovotestis of an individual (46,XX) with a RSPO1 mutation leads to reduced β-catenin protein and WNT4 mRNA levels, consistent with down regulation of ovarian pathways. Transfection of wild-type RSPO1 cDNA resulted in weak dose-dependent activation of a β-catenin responsive TOPFLASH reporter (1.8 fold maximum), whereas co-transfection of CTNNB1 (encoding β-catenin) with RSPO1 resulted in dose-dependent synergistic augmentation of this reporter (approximately 10 fold). Furthermore, R-spondin1 showed strong nuclear localization in several different cell lines. Taken together, these data show that R-spondin1 is upregulated during critical stages of early human ovary development and may function as a tissue-specific amplifier of β-catenin signaling to oppose testis determination

TiltDrone: a fully-actuated tilting quadrotor platform

Multi-directional aerial platforms can fly in almost any orientation and direction, often maneuvering in ways their under-actuated counterparts cannot match. A subset of multi-directional platforms are fully-actuated multirotors, where all six degrees of freedom are independently controlled without redundancies. Fully-actuated multirotors possess much greater freedom of movement than conventional multirotor drones, allowing them to perform complex sensing and manipulation tasks. While there has been comprehensive research on multi-directional multirotor control systems, the spectrum of hardware designs remain fragmented. This paper sets out the hardware design architecture of a fully-actuated quadrotor and its associated control framework. Following the novel platform design, a prototype was built to validate the control scheme and characterize the flight performance. The resulting quadrotor was shown in operation to be capable of holding a stationary hover at 30° incline, and track position commands by thrust vectoring

Optic flow based reactive collision prevention for MAVs using the fictitious obstacle hypothesis

Optical flow sensors and optical flow divergence (OFD) have offered partial solutions for obstacle avoidance, landing, and perching with micro aerial vehicles. Theoretically, OFD can indicate the risk of collision, providing that the sensors’ field of view is bounded within a single flat surface on the obstacle. However, in the real world, directly measuring the risk of collision with OFD generates false alarms due to rapidly changing speeds and irregular surroundings. In this letter, we present a new obstacle detection strategy based on an extended Kalman filter (EKF) combining the OFD with inertial sensing. The introduction of a fictitious obstacle hypothesis and the use of the EKF estimates enable us to differentiate the surrounding-generated OFD from the OFD caused by the actual obstacle. An embedded constant zero-OFD controller is then used for post-detection emergency deceleration. The ultra-light OFD estimation and control system, with a mass of 20 g , estimates OFD at 160 Hz . The system was validated on a 158 g mini quadrotor in both laboratory and field tests. Experimental results illustrate that the presented system can achieve accurate obstacle detection, near-obstacle distance estimation, and controlled deceleration to prevent collisions. 1 1 Video attachment: https://youtu.be/yIyYHYN0jOw

An intelligent aerial manipulator for wind turbine inspection and repair

This study proposes aerial robots utilizing repair operations at height for wind turbines. It is aimed to decrease the risks for human health for a repair operation in risky environments. We address the wind turbine repair problem by proposing a new aerial manipulator that can leverage online detection and decision making. Our proposed system can help to reduce the time and costs for infrastructure maintenance when autonomous aerial robots are deployed intelligently

Immersive view and interface design for teleoperated aerial manipulation

The recent momentum in aerial manipulation has led to an interest in developing virtual reality interfaces for aerial physical interaction tasks with simple, intuitive, and reliable control and perception. However, this requires the use of expensive subsystems and there is still a research gap between interface design, user evaluations and the effect on aerial manipulation tasks. Here, we present a methodology for low-cost available drone systems with a Unity-based interface for immersive FPV teleoperation. We applied our approach in a flight track where a cluttered environment is used to simulate a demanding aerial manipulation task inspired by forestry drones and canopy sampling. Through objective measures of teleoperation performance and subjective questionnaires, we found that operators performed worse using the FPV interface and had higher perceived levels of cognitive load when compared to traditional interface design. Additional analysis of physiological measures highlighted that objective stress levels and cognitive load were also influenced by task duration and perceived performance, providing an insight into what interfaces could target to support teleoperator requirements during aerial manipulation tasks