This paper presents a LiDAR-equipped unmanned aerial vehicle (UAV) performing semi-autonomous wind-turbine blade inspection which includes traversing to the blade tip and back, while keeping constant ...relative distance and heading to the blade plane. Plane detection is performed applying the RANSAC method on a subset of the gathered pointcloud. Utilizing the relative distance to the inferred plane as well as its normal vector, the UAV is able to maintain a constant distance and heading towards the plane while moving in parallel with it. The proposed procedure performs successful wind-turbine blade inspections with minimal operator involvement. Inspection results include high-resolution blade images as well as a 3D model of the wind-turbine structure. Finally, to show the feasibility of this approach, simulations are performed on a wind-turbine model and experimental results are presented for an outdoor single-blade inspection scenario both on a mock-up setup and a full-scale wind-turbine blade. It is worth noting that the system's adequacy has been fully validated in real conditions on an operational wind farm.
The DC current gain (β) of Si bipolar junction transistors (BJTs) reported so far decreases at cryogenic temperatures (CT), or shows a very limited improvement at best. For temperatures above 90 K, ...the Horizontal Current Bipolar Transistor (HCBT) behaves comparably to other published Si BJTs. However, cryogenic measurements of HCBT devices show a steep β increase at temperatures below 90 K. We report a current gain of 85 at 300 K, a minimum β of 31 at 90 K and an increase of β to 66 at 17 K. The collector-emitter breakdown voltage ( BV CEO ) measured around the peak β varies only within 0.2 V over the examined temperature range. Additionally, the Early voltage ( V A ) increases for temperatures below 50 K, improving the β V A product at 20 K by 2.2x as compared to 300 K, which makes the HCBT a potentially attractive technology for deep cryogenic applications. TCAD simulations of an equivalent Si BJT structure show that such considerable increase of β at CT can be attributed to the interplay between incomplete ionization (II) of acceptors in the base and bandgap narrowing (BGN) in the emitter in a specific range of HCBT doping profiles.
In this paper we address the problem of trajectory following in an unknown environment with an unmanned aerial vehicle (UAV). The main goal is to safely follow the planned trajectory by avoiding ...obstacles. The proposed approach is suitable for aerial vehicles equipped with 2D or 3D sensors, such as LiDARs. We present a novel algorithm based on the conventional Artificial Potential Field (APF) called Augmented Artificial Potential Field (AAPF) that corrects the planned path to avoid obstacles. Our proposed algorithm uses a combination of two attractive forces and both normal and rotational repulsive forces to avoid obstacles and handle local minima problems. The smooth trajectory following achieved with the MPC tracker allows us to quickly change and re-plan the UAV path. Comparative simulation experiments have shown that our approach solves local minima problems in trajectory following and generates more efficient paths to avoid potential collisions with static obstacles compared to our previously developed algorithm for obstacle avoidance. The laboratory experimental evaluation results indicate that the algorithm can be deployed on a real UAV with limited computational power and real-time processing requirements.
Periodic bridge inspections are required every several years to determine the state of a bridge. Most commonly, the inspection is performed using specialized trucks allowing human inspectors to ...review the conditions underneath the bridge, which requires a road closure. The aim of this paper was to use aerial manipulators to mount sensors on the bridge to collect the necessary data, thus eliminating the need for the road closure. To do so, a two-step approach is proposed: an unmanned aerial vehicle (UAV) equipped with a pressurized canister sprays the first glue component onto the target area; afterward, the aerial manipulator detects the precise location of the sprayed area, and mounts the required sensor coated with the second glue component. The visual detection is based on an Red Green Blue - Depth (RGB-D) sensor and provides the target position and orientation. A trajectory is then planned based on the detected contact point, and it is executed through the adaptive impedance control capable of achieving and maintaining a desired force reference. Such an approach allows for the two glue components to form a solid bond. The described pipeline is validated in a simulation environment while the visual detection is tested in an experimental environment.
Summary
Background
Osteoarthritis (OA) is a chronic degenerative disease of multiple joints with a rising prevalence. Pulsed electromagnetic field (PEMF) therapy may provide a cost-effective, ...noninvasive, and safe therapeutic modality with growing popularity and use in physical medicine and rehabilitation. The purpose of this study was to synthesize the current knowledge on the use of PEMF in OA.
Methods
A systematic review of systematic reviews was performed. The PubMed, Embase, PEDro and Web of Science databases were searched based on a predetermined protocol.
Results
Overall, 69 studies were identified. After removing the duplicates and then screening title, abstract and full text, 10 studies were included in the final analysis. All studies focused on knee OA, and four studies also reported on cervical, two on hand, and one on ankle OA. In terms of the level of evidence and bias, most studies were of low or medium quality. Most concurrence was observed for pain reduction, with other endpoints such as stiffness or physical function showing a greater variability in outcomes.
Conclusion
The PEMF therapy appears to be effective in the short term to relieve pain and improve function in patients with OA. The existing studies used very heterogeneous treatment schemes, mostly with low sample sizes and suboptimal study designs, from which no sufficient proof of efficacy can be derived. A catalogue of measures to improve the quality of future studies has been drawn up.
This paper presents a manipulator-equipped unmanned aerial vehicle (UAV) performing contact-based surface inspection. Using stereo camera information, a contact point is determined and an approach ...path is generated to ensure an autonomous workflow. The proposed inspection method uses an impedance controller to regulate the force applied by the end-effector to the contact surface. Due to the often adverse conditions in the real world, the aerial manipulator may fail to achieve contact after approaching the surface. Therefore, the impedance controller is coupled with an online stiffness estimation algorithm to increase the overall robustness of the inspection system and achieve stable surface contact. Finally, simulations in the Gazebo environment and experiments in the real world are performed to show the feasibility of this approach.
This paper presents the development of an algorithm using LabVIEW, a B2912B SMU, and a Model 22C Cryogenic temperature controller for automating the characterization of various semiconductor devices. ...The algorithm is carried out using LabVIEW. By removing human error and enhancing precision through temperature control, the research aims to streamline the measurement procedure. Users enter the desired temperature values into the LabVIEW program. The Cryocon 22C is then automatically turned on by the algorithm to use a PID control method to stabilize the temperature near the sample. Once the temperature has stabilized, the software performs automatic characterization of the sample, including Gummel plot and Gummel plot negative sweep. To accurately capture the temperature-dependent features of the sample, measurements are performed at various temperatures. The method has the potential to increase productivity in a variety of semiconductor characterization and research applications due to its success in achieving temperature stability and precise measurements.
Summary
Background
Post-COVID-19 fatigue is a frequent symptom in COVID-19 survivors, which substantially limits patients to achieve full recovery and potentially restrains return to work. The ...previous literature has not yet reported the use of pulsed electromagnetic fields in this indication.
Methods
Over the course of 5 weeks, 10 sessions of pulsed electromagnetic field treatment with a high magnetic flux density were applied to a patient suffering from post-COVID-19 fatigue syndrome. Fatigue, work ability, quality of life as well as anxiety, depression, stress level, and resilience were evaluated using validated patient-reported outcome measures.
Results
Fatigue, work ability, quality of life, and psychological well-being improved clearly over the course of the treatment and showed stable results 6 weeks later.
Conclusion
The use of pulsed electromagnetic field therapy with a device that allows sufficient penetration of the body tissue might be a promising physical modality to manage post-COVID-19 fatigue syndrome, which could reduce clinical and economic health consequences. Clinical sham-controlled studies are needed to evaluate the effect of pulsed electromagnetic fields in this indication.
This paper presents an Unmanned Aerial Vehicle (UAV) platform used for the competition held at the International Conference for Unmanned Aircraft Systems 2022 (ICUAS’22). The envisioned scenario in ...the competition is delivering an extinguishing ball to a fire with a UAV. Driven on that thought, the qualifying round of the competition is organized in a realistic simulation environment. The competitors are required to navigate through a cluttered environment into a free space, where they perform a search for the target and deliver the ball as close as possible to that target. The competition finals were organized as a part of the conference, with the same goal as in the simulation qualifiers. The UAVs used for the competition are prepared and provided by the organizers. A detailed description of the UAV software and hardware is outlined in the paper as a step towards standardizing aerial research platform.
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