Windy Environment Research Articles

Water-to-air unmanned aerial vehicle (UAV) based rolling shutter optical camera communication (OCC) system with gated recurrent unit neural network (GRU-NN)

Underwater sensors and autonomous underwater vehicles (AUVs) are widely adopted in oceanic research activities. As the number of underwater sensors and AUVs is growing quickly, the bandwidth requirements are increasing accordingly. In this work, we put forward and demonstrate a large field-of-view (FOV) water-to-air unmanned aerial vehicle (UAV) based optical camera communication (OCC) system with gated recurrent unit neural network (GRU-NN) for the first time to the best of our knowledge. As the UAVs are embedded with complementary-metal-oxide-semiconductor (CMOS) cameras, there is no need to install OCC receivers (Rxs), reducing the deployment cost. Moreover, the large photo-sensitive area of the CMOS camera can support a large FOV OCC transmission without the need for precise optical alignment. Here, by utilizing the column matrix identification during the rolling shutter pattern decoding in the CMOS image sensor, the scintillation caused by water turbulence can be reduced. Besides, in the outdoor and windy environment, the UAV will experience significant movement caused by the wind making it very difficult to capture stable OCC frames in the CMOS image sensor. Here, we propose and demonstrate utilizing GRU-NN, which is a special realization of the recurrent neural network (RNN) with memory cells capable of learning the time-domain dependent signals. It is shown that the GRU-NN can learn effectively from successive image frames in time-domain and produce correct prediction even under the windy and unstable UAV flying environment. Experimental results reveal that the proposed GRU-NN can outperform the previous pixel-per-symbol labeling neural network (PPS-NN), and also can significantly reduce the computation time when compared with long-short-term-memory-neural-network (LSTM-NN). The proposed system can decode 4-level pulse-amplitude-modulation (PAM4) rolling shutter OCC patterns at data rates of 5.4 kbit/s and 3.0 kbit/s under clear and cloudy water, respectively, fulfilling the pre-forward error correction bit-error rate (pre-FEC BER = 3.8 × 10−3). We also demonstrate that the UAV based OCC system can support data rates of 5.4 kbit/s, 4.2 kbit/s, and 3.0 kbit/s at distances of 2.2 m, 3.2 m, and 4.2 m, respectively, at outdoor and windy environments.

UAV Trajectory Tracking Using Proportional-Integral-Derivative-Type-2 Fuzzy Logic Controller with Genetic Algorithm Parameter Tuning.

Unmanned Aerial Vehicle (UAV)-type Quadrotors are highly nonlinear systems that are difficult to control and stabilize outdoors, especially in a windy environment. Many algorithms have been proposed to solve the problem of trajectory tracking using UAVs. However, current control systems face significant hurdles, such as parameter uncertainties, modeling errors, and challenges in windy environments. Sensitivity to parameter variations may lead to performance degradation or instability. Modeling errors arise from simplifications, causing disparities between assumed and actual behavior. Classical controls may lack adaptability to dynamic changes, necessitating adaptive strategies. Limited robustness in handling uncertainties can result in suboptimal performance. Windy environments introduce disturbances, impacting system dynamics and precision. The complexity of wind modeling demands advanced estimation and compensation strategies. Tuning challenges may necessitate frequent adjustments, posing practical limitations. Researchers have explored advanced control paradigms, including robust, adaptive, and predictive control, aiming to enhance system performance amidst uncertainties in a scientifically rigorous manner. Our approach does not require knowledge of UAVs and noise models. Furthermore, the use of the Type-2 controller makes our approach robust in the face of uncertainties. The effectiveness of the proposed approach is clear from the obtained results. In this paper, robust and optimal controllers are proposed, validated, and compared on a quadrotor navigating an outdoor environment. First, a Type-2 Fuzzy Logic Controller (FLC) combined with a PID is compared to a Type-1 FLC and Backstepping controller. Second, a Genetic Algorithm (GA) is proposed to provide the optimal PID-Type-2 FLC tuning. The Backstepping, PID-Type-1 FLC, and PID-Type-2 FLC with GA optimization are validated and evaluated with real scenarios in a windy environment. Deep robustness analysis, including error modeling, parameter uncertainties, and actuator faults, is considered. The obtained results clearly show the robustness of the optimal PID-Type-2 FLC compared to the Backstepping and PID-Type-1 FLC controllers. These results are confirmed by the numerical index of each controller compared to the PID-type-2 FLC, with 12% for the Backstepping controller and 51% for the PID-Type-1 FLC.

Design and stability performance optimization of a novel hybrid inspection robot walking device for smart grid applications

Inspecting in high-altitude windy environments requires maintaining a stable attitude to avoid significant oscillations, which is a crucial factor in advancing the use of hybrid power transmission line inspection robots (PTLIRs) in real-world scenarios for the electrical power and energy industry. We developed and optimized a novel walking device to improve the safety of hybrid PTLIRs operating in strong wind conditions. First, we investigate the operational conditions of transmission line inspection and design a walking device capable of transporting a flight device to be suspended under the line for inspection purposes. Second, a force equilibrium analysis is performed to explore the relationship between the key structural parameters of the walking device and the wind-induced deflection of the robot. A multiobjective optimization model is formulated to minimize the maximum deflection angle of the robot along three axes under wind loads. Finally, an optimization algorithm, using an improved non-dominated sorting particle swarm optimization (NSPSO) approach, is proposed to solve the model with good global search ability and fast convergence speed. A test platform is constructed to collect the wind deflection angle of a self-developed hybrid PTLIR under the transmission line. The test results demonstrate that the walking device can carry 30 kg to move along the transmission line. The average deflection angle of the robot around the Z axis is the highest under the influence of wind force level 7 (wind speed of 15.5 m/s) perpendicular to the windward surface of the robot. After optimization, the maximum deflection angle is limited to 10.38°, aligning within safety thresholds. The optimization algorithm effectively reduces the maximum deflection angles around the X, Z, and Y axes by 33.19 %, 39.21 %, and 13.23 %, with minimal average errors of 2.40 %, 3.87 %, and 2.13 %, respectively. The research in this paper can solve the bottleneck problem of robot practicality, which has important theoretical significance and practical application value for the safety, stability, and intelligent operation and maintenance management of power transmission lines.

Exploring GVS as a display modality: signal amplitude and polarity, in various environments, impacts on posture, and with dual-tasking.

Galvanic Vestibular Stimulation (GVS) has been proposed as an alternative display modality to relay information without increasing demands on the visual or auditory sensory modalities of the wearer or in environments where those modalities cannot be used (e.g., covert night operations). We further investigated this concept with four experiments designed to test: (1) thresholds at which subjects could distinguish between different GVS current amplitudes and polarities, (2) thresholds at which different bipolar (i.e., sinusoidal waveform with current oscillating between left and right directions) current frequencies were distinguishable among room temperature, hot, cold, and windy environments, (3) effects of unipolar (i.e., sinusoidal waveform with current occurring in only the left or right direction) currents on balance performance, and (4) dual-task performance among frequency and polarity modulated GVS conditions during a concordant visual search task. Subjects reliably distinguished between current amplitudes that varied from a pedestal of ± 0.6mA by a median of 0.03mA (range of 0.02-0.32mA) and between unipolar currents at a median amplitude of 0.55mA (range of 0.32-0.83mA). GVS frequency thresholds were robust to the environment conditions tested, with no statistical differences found. Sway and balance errors were increased with unipolar currents. GVS thresholds were not impacted by the dual-task paradigm, but the visual search scores were slightly elevated when congruently performing a polarity thresholding task. Overall findings continue to support GVS use as a display modality, but some limitations are noted, such as the use of unipolar currents under scenarios where postural control is important.

Exploring the influence of concave-convex surface modifications on piezoelectric wind energy harvesting: A numerical analysis

Wireless health monitoring sensors are significant for the safety of sea-crossing bridges, and their operation is dependent on a durable and reliable power source. Piezoelectric wind energy harvesters (PWEHs) can be effectively utilized in windy marine environments and provide a sustainable power supply for these sensors. This paper examines the influence of concave-convex surface modifications of a circular cylinder on the performance of the PWEH through numerical research to improve the output and operational bandwidth of traditional harvesters using cylindrical bluff bodies. An electromechanical model, coupled with computational fluid dynamics on low-Reynolds-number flows, was developed and different concave-convex configurations were proposed to explore the impact by numerical experiments. The results show that the configuration with two protrusions plus one groove is the optimal design. This configuration exhibits a much higher output with a maximum voltage of 19.5 V, representing a 464% increase compared to the cylindrical bluff body's 4.2 V, and a broader bandwidth with no upper limit across the wind speed range. This study provides insight into effective and ineffective efforts to enhance energy harvesting through concave-convex surface modifications and is advantageous to the advancement of self-powered marine sensing systems, particularly in the health monitoring of sea-crossing bridges.

Effect of Accumulated Dust Conductivity on Leakage Current of Photovoltaic Modules

Photovoltaic (PV) modules are often situated in hot and windy environments, such as deserts, where dust accumulation poses a significant problem. The build-up of dust can result in an increase in PV module leakage current, making the modules more vulnerable to potential-induced degradation (PID), ultimately leading to a reduction in the efficiency of PV power generation. In this study, we investigate the impact of dust accumulation on the surface of PV modules on leakage current. A dust model is developed based on the Arrhenius relation, taking into account the impact of temperature and density on dust conductivity. The equation for leakage current due to dust accumulation is derived based on the clean module leakage current equation. We undertake a simulation of natural conditions in a laboratory setting to analyze the impact of dust on the leakage current of photovoltaic modules. The results show the following: At high temperatures, the leakage current will significantly increase due to the elevated conductivity of the dust. The conductivity increased by 27.1%, 48.9%, 64.3%, and 118% for the four groups of dusty PV modules, respectively. Leakage current prediction has a better accuracy when dust is equated to series conductance. Dust can reduce the activation energy of PV modules by up to 3.48%.

Dynamic Deflection Measurement on Stiff Bridges with High Piers by Preloaded Spring Method

The deflection dynamic load allowance (DLA) of stiff bridges with high piers requires sub-millimeter accuracy. New technologies such as the vision-based optical method and GNSS are not yet recognized for use in DLA measurements due to their smaller SNR. Presently, the scaffolding method is widely utilized for dynamic deflection measurements in dynamic load tests owing to the reliability of employing rigid contact. When scaffolding is not available, engineers have to resort to a suspension hammer system. However, the mass eccentricity of the hammer, stretched-wire length, and wind will decrease the measurement accuracy. To overcome these drawbacks of the suspension hammer method (SHM), a preloaded spring method (PSM) and the related stretched-wire-spring system (SWSS) are proposed in this paper. The dynamic deflection of the coupled vehicle-bridge-SWSS was obtained by vehicle-bridge interaction (VBI) analysis. The sensitivity parameters of the PSM were analyzed and optimized to minimize the measurement error. Indoor experiments and field dynamic load tests were conducted to validate the feasibility and accuracy of the PSM. Additionally, the differences in dynamic deflection measurements between the PSM and SHM in windy environments were compared. The results show that, in a windless environment, the DLAs of the PSM are affected by the spring stiffness, stretched-wire length, and stretched-wire section stiffness, independently of the preload force. When the wind speed is less than or equal to 8 m/s and the pier height is less than 30 m, the maximum deflection measurement error of the PSM is −2.53%, while that of the SHM is −15.87%. Due to its low cost and high accuracy, the proposed method has broad application prospects in the dynamic deflection measurement of stiff bridges with high piers.

A conical shaped self-healing slippery film for enhanced fog harvesting in windy environment

Wind presents both advantages and disadvantages for water collection. It can bring an abundant fog resource to arid areas for water harvesting, however, some of the captured water droplets are inevitably blown away in a windy environment because of the easy-sliding property of the material surface. Herein, a conical-shaped, self-healing, liquid-infused film with tunable cone angles based on candle soot, thermoplastic poly (ethylene-co-vinyl acetate) (EVA), and hydrophobic silicone oil has been developed using a simple template method and traditional Chinese origami. Benefiting from the inward force induced by the conical structure, the condensed droplets prefer to gather toward the top of the conical structure in windy environments rather than splashing out, which usually occurs on a plane surface. This advantage can greatly ensure the high water collection efficiency of materials in windy regions. In addition, owing to the unique photothermal property and thermoplasticity of the designed conical structure, surface scratches during application can be quickly repaired under solar illumination without extra fossil energy consumption, and long-term stable application of the materials can be guaranteed. Therefore, this study finely synergized structure design and performance enhancement and established a new paradigm for effective and reliable fog harvesting applications.

UAV Trajectory Optimization for Maximum Soaring in Windy Environment

Optimal trajectory planning in a windy environment is a complex problem when airplane performance characteristics are considered. This paper introduces a novel form of Legendre pseudospectral optimization to solve boundary value problems in UAV trajectory planning. The proposed architecture applies Legendre–Gauss–Lobatto and Hamilton–Jacobi–Bellman equations to generate candidate pieces of trajectories with respect to the UAV dynamic constraints. Analytical performance-based solutions are also developed for sample cases to achieve an optimal criterion in trajectory planning. Moreover, the notion of wind soaring is exploited to use the beneficial effects of tailwind velocities in trajectory planning. Integral cost functions are handled by Gauss-type quadrature rules. Simulations demonstrate the efficiency of the pseudospectral method compared with other solvers, in eliminating the difficulties of boundary value problems by employing the boundary points in the interpolation equation. The effectiveness of the proposed approach is demonstrated through dynamic simulations.

Reducing Wall Shelf Product Defects Using the DMAIC Method in Furniture Industry Companies

The object of research is a place of business that produces household needs and wood-based industries. One of the products it produces is a minimalist wall shelf. In the period January –December 2021 minimalist wall shelf products are the products with the most defects. Manufacturing companies in this study have a product defect tolerance limit of 5% of the total production, but minimalist wall shelf products have a defect of 5.64%. This study aims to determine the types of defects that occur in wall shelf products, identify the causes of defects minimalist wall shelves and provide suggestions for improvements to reduce the number of future defects. In this research the method used is DMAIC. In the minimalist wall shelf production process, 4 types of defects were found. Based on the Pareto diagram, it was determined that the type of lacquer defect was not suitable to be the most dominant type of defect, namely 80.1%, it was also found that the DPMO value and sigma value on minimalist wall shelves were 14,100 and 3.69. Based on the analysis of the fishbone diagram method and Failure Mode and Effect Analysis (FMEA), it is known that the main root cause of product defects is a dirty, dusty and windy environment with an RPN (Risk Priority Number) value of 448. Analysis was carried out using the 5W + 1H approach to find improvements to overcome the problems that occur, obtained suggestions for improvements for the company, namely making work area picket schedules, making closed work areas, daily and monthly check sheetforms for maintenance of work tools, making varnish process work instructions, making training schedules for operators and submitting additional goods forms.

Investigation of characteristics and generating mechanism of wind noise on external microphone of mobile device

The multipurpose external microphone of mobile devices is exposed to the outside windy environment, which inevitably generates wind noise. The wind noise acts as noise in signal processing, like Active Noise Control and capturing voice, and damages the user's experience. This paper investigates the acoustic characteristics and generation mechanism of wind noise through experiments and numerical analysis for a commercial TWS earbuds model. The experimental results show that the wind noise has broadband characteristics with dominant low-frequency band noise (below 2500Hz), unlike general cavity flow. On the same model, the Lattice-Boltzmann method numerical analysis has been performed through powerFLOW software. The numerical result shows good agreement of +-3dB with experimental results in the 1/3 octave band spectrum for the wind noise band. Numerical results flow field investigation reveals that the disturbed flow field is induced by an interaction between the vortical structure of the inflow and separated flow field, which is governed by geometry configurations. The disturbances induce the complex pressure gradient on inflow into the microphone, measured as wind noise on the microphone. These results show that the wind noise measured by the microphone of mobile devices is a flow phenomenon caused by external excitation.

Clothing impact on post-exercise comfort: skin-clothing physiology in transient environment

Sportswear manufactured from hygroscopic fibres can absorb moisture during activity or intermittent exercise and may change the thermal management of clothing. This change in the thermal behaviour of the fabric can lead to buffer the post-exercise chill. During activity in a moderately cold environment clothing made of 100% wool fibre helps wearers to slow down evaporative and conductive cooling, which can provide more thermal and comfort sensation compared to 100% cotton, 100% viscose, and 100% polyester. Twelve males performed cycling in a controlled climate chamber of temperature: 15 ± 0.5 °C, and relative humidity (RH):50 ± 5% followed by a drying phase in a windy environment by wearing full-sleeve t-shirts. Wool shirt was observed to hold a greater torso skin temperature (p < 0.05) than the other fibre types. Participants were asked a range of comfort-related questions at varying intervals. The temperature sensation was found (p < 0.05) significant for wool clothing. Moreover, participants rated wool shirt significantly (p < 0.05) as more comfortable during the post-exercise phase.

Historical account and current knowledge of the southernmost Chiropterofauna in the world: the Magellanic/Fuegian bats

ABSTRACT A depauperate Chiropterofauna consisting of essentially three bat species (the year-round residents Histiotus magellanicus and Myotis chiloensis, and the apparently migratory Lasiurus varius), exists in the challenging cold and windy environment of the Magellanic/Fuegian region, which encompasses territories in Argentina and Chile, both continental and insular. Knowledge of that bat fauna benefitted from earlier explorers and naturalists visiting such southerly and isolated geographical confines, but still lacks a comprehensive scientific study, particularly in face of expected green-energy projects using aerogenerators known to cause bat fatalities elsewhere. Currently, there is a paucity of information on the fine-scale geographic distribution, local abundance, and migration patterns of those bats that needs to be remedied as soon as possible. Our review may aid orienting and focusing such a research program, which should hopefully be binational, on account of the artificial nature of the border between Argentina and Chile in Tierra del Fuego.

Which adjustment methods are suitable for the wind-induced errors of Geonor T-200BM3 precipitation weighing gauges in a periglacial site?

Single Alter shielded T-200BM3 weighing precipitation gauges are widely used in the measurement of all precipitation types (rainfall, snow and mixed precipitation) in unattended boreal or alpine regions, but their original datasets must be adjusted for undercatch errors caused by wind in snowy, windy and harsh environments. Therefore, previous researchers have developed many adjustment methods for all precipitation types on different time scales. However, which adjustment method is suitable for T-200BM3 weighing gauge wind-induced error adjustment in harsh alpine regions is unclear. Therefore, precipitation measurement intercomparison experiments were conducted in the Qilian Mountains from July 2018 to July 2021, and eight adjustment methods; were evaluated for wind-induced errors for daily, individual precipitation event, hourly, and half-hourly time scales. Z2004 outperformed the other adjustment methods in regard to the daily measurements of snow and mixed precipitation. Regarding individual snowfall events, M2007 reduced the absolute value of RMSE (bias) from 1.44 to 1.32 mm (0.77–0.24 mm) and could be recommended for snowfall event adjustment. K2017-1 attained a better performance than K2017-2 in regard to half-hourly snowfall and mixed sample adjustment and was more suitable for half-hourly snowfall sample adjustment. K2017-1 reduced the absolute value of bias from 0.07 to 0.00 mm for snowfall. Finally, Z2004, M2007, and K2017-1 yielded better adjustment results for the daily accumulation precipitation amount (>2 mm d−1), individual snowfall events (>2 mm per event), and half-hourly accumulation snowfall or mixed samples (>1 mm 30 min−1), respectively. However, further intercomparison in different climate regions is needed for trace precipitation samples.

Quadcopter neural controller for take-off and landing in windy environments

Quadcopter neural controller for take-off and landing in windy environments

Distributed observer-based finite-time control of moving target tracking for UAV formation

This paper disseminated two formation control strategies for multiple unmanned aerial vehicles (multi-UAV) system of moving target tracking in a windy environment. The communication among UAVs is modeled by a directed graph. The first control strategy proposes a distributed dynamic error observer and a guidance law to make the system global uniform asymptotic stability when the wind disturbance is a known constant. The second control strategy employs a distributed fixed-time observer and a finite-time stable guidance law to make the system globally finite-time stable with unknown wind disturbances. The stability of both formation control strategies is rigorous demonstrated mathematically. Finally, the excellent performance and reliability of the proposed guidance law for target tracking in a windy environment are verified through several simulation examples.

Fault-Tolerant Control of a Variable-Pitch Quadrotor under Actuator Loss of Effectiveness and Wind Perturbations

The actuator fault-tolerant control problem for a variable-pitch quadrotor is addressed under uncertain conditions. Following a model-based approach, the plant nonlinear dynamics are faced with a disturbance observer-based control and a sequential quadratic programming control allocation, where only kinematic data of the onboard inertial measurement unit are required for the fault-tolerant control, i.e., it does not require the measurement of the motor speed nor the current drawn by the actuators. In the case of almost horizontal wind, a single observer handles both faults and the external disturbance. The estimation of the wind is fed forward by the controller, while the actuator fault estimation is exploited in the control allocation layer, which copes with the variable-pitch nonlinear dynamics, thrust saturation, and rate limits. Numerical simulations in the presence of measurement noise show the capability of the scheme to handle multiple actuator faults in a windy environment.

Autonomous plume Near-Source search assisted by intermittent visible plume information using finite state Machine and YOLOv3-tiny

Since a plume’s visual characteristics have not been fully considered and utilized, the traditional plume near-source search methods lose a large amount of potentially available information, resulting in the low efficiency and reliability of near-source search. This paper proposes a novel plume near-source search approach assisted by the intermittent visible plume information using finite state machine and YOLOv3-tiny for a robot. A finite state machine is used to realize the autonomous behavioral decision-making of the robot according to the obtained visible plume information, olfactory information, and lidar information. In addition, the YOLOv3-tiny network is used to detect the intermittent visible plume information obtained by a depth camera to capture the color and texture of the plume. In order to improve the search reliability of the robot in the olfactory tracking behavior, a whale optimization algorithm is utilized to enable the robot to simulate the hunting behavior and the social mechanism of the whale group and conduct olfactory tracking of the plume. The experimental results show that this proposed plume near-source search approach achieves the success rates of 91.67% and 83.33% in windless and windy environments respectively, and the average total running time is 113.8 s and 159.6 s in the experimental environment with obstacles, respectively.

Wake dynamic characteristics of windproof structures in embankment–bridge sections along a high-speed railway under natural strong crosswinds

A recent trend in railway development around the world is the extension of high-speed railways to areas with harsh climatic environments. The aerodynamic performance of high-speed trains deteriorates when they run through embankment–bridge sections in a windy environment, posing potential safety risks. The present study aims to reveal the evolution mechanism of wake field in the transition section of the windbreak wall and wind barrier under natural strong crosswinds. First, the fluctuating characteristics of natural wind field collected by ultrasonic anemometers during a period of strong wind are captured. Next, the improved delayed detached eddy simulation scheme combined with the shear stress transfer k–w model is used to elucidate the difference of flow field modes on the leeward side of the windproof structure in the transition section under the conditions of constant and fluctuating crosswinds. Finally, the effects of model scale ratio (1:20, 1:10, and 1:1) on wind field simulation results on the leeward side of the windproof structure are revealed. Results show that the incoming flow with time-varying velocity evokes the instability of wake vortices of the windbreak wall in the embankment. The transient evolution results of the vortices obtained by the 1:10 model are in good agreement with those of the 1:1 model, whereas the results obtained by the 1:20 model have a large deviation.

Analysis of Wind Effect on Drone Relay Communications

In this study, we realized a relay network using drones and analyzed the impact of the sway angle of a drone’s attitude on communication in a windy flight environment. Drones in flight act as radio relay stations and communication among them is performed using radio equipment mounted on board. In a windy environment, a directional antenna is used for relay communication among them to avoid interference caused by the spread of radio waves in space and extend the relay distance. However, when wind occurs during flight, the flying attitude of the drone inclines, which causes the beam of the antenna to sway and the communication link to be disconnected, leading to a decrease in the transmission speed. In this study, we statistically evaluated the pitch, yaw, and roll axes of a drone through wind tunnel experiments. Furthermore, the pattern of the swing angle of the drone with respect to the wind speed was investigated using computer simulations to analyze the fluid dynamics and theoretically analyze the swing of the drone. Based on these results, the transmission speed when using a directional antenna was calculated. When the wind speed was 6.0 m/s, the pitch axis deflection angle of the drone was 13∘ at maximum, and the average transmission speed decreased by 33.3 Mbps. In this study, it was found that in communication between drones due to the wind, the transmission efficiency decreased depending on the sway angle of the aircraft.