Design and Experiment of an Aerial Electrostatic Spraying System for Unmanned Agricultural Aircraft Systems

2020 ◽  
Vol 36 (6) ◽  
pp. 955-962
Author(s):  
Shilin Wang ◽  
Xue Li ◽  
Hao Zhou ◽  
Xiaolan Lv ◽  
Weiguo Shen
Keyword(s):  
Droplet Size ◽  
Negative Electrode ◽  
Tree Canopy ◽  
List Type ◽  
Specific Charge ◽  
Chemical Application ◽  
Electrostatic Spraying ◽  
Aircraft Systems ◽  
Aircraft System ◽  
Pump Pressure

HighlightsA bipolar contact electrostatic spraying system is designed for an unmanned agricultural aircraft system.The electrostatic voltage does not affect the droplet size and relative span.The specific charge due to the negative electrode is higher than that due to the positive electrode.The droplets charged by the spraying system are more prone to be deposited on the underside of leaves.Abstract. Chemical application by unmanned agricultural aircraft systems (UAASs) has developed rapidly in China and other Asian countries due to their suitability to complex terrains, high working efficiency, and labor intensity reduction. To enhance spraying performance of unmanned aerial spraying systems (UASSs), an aerial electrostatic spraying system (AESS) was designed consisting of a lithium battery, electrostatic generator, positive and negative charging electrodes, tanks, pumps, and centrifugal atomizers. The AESS electrostatic voltage (EV) was adjusted from 15 to 35 kV, the atomizer rotation speed reached 9600 r/min, and the pump pressure ranged from 0.02 to 0.1 MPa. The AESS specific charge and droplet spectrum under water spraying was measured at different EVs. Results showed that the specific charge due to the negative electrostatic electrode was higher than that due to the positive electrostatic electrode. At a negative electrostatic electrode EV of 35 kV, its specific charge was 1.84 mC/kg. The negative and positive electrostatic electrode volume median diameters (VMDs) ranged from 81.39 to 84.04 µm and 86.8 to 88.80 µm, respectively, and no significant droplet size and relative span differences occurred between the different EVs for the same electrostatic electrode. The AESS was installed on single-rotor and multirotor UAASs for chemical application to pear trees. The results revealed that the electrostatic spray from the AESS has no effect on droplet deposition on the upper side of pear tree canopy leaves, while charged droplets can produce a wrap-around effect on the underside of the leaves, which promotes the adhesion of droplets on the underside of the leaves. The AESS is suitable for chemical application under aerial UAAS spraying. Keywords: Chemical application, Droplet spectrum, Deposition, Specific charge, Unmanned agricultural aircraft system.

scholarly journals Phenotyping Architecture Traits of Tree Species Using Remote Sensing Techniques

2021 ◽  
Vol 64 (5) ◽  
pp. 1611-1624
Author(s):  
Worasit Sangjan ◽  
Sindhuja Sankaran
Keyword(s):  
Remote Sensing ◽  
Structure From Motion ◽  
Tree Species ◽  
Tree Height ◽  
Tree Canopy ◽  
System Structure ◽  
List Type ◽  
Canopy Architecture ◽  
Chemical Application ◽  
Canopy Volume

HighlightsTree canopy architecture traits are associated with its productivity and management.Understanding these traits is important for both precision agriculture and phenomics applications.Remote sensing platforms (satellite, UAV, etc.) and multiple approaches (SfM, LiDAR) have been used to assess these traits.3D reconstruction of tree canopies allows the measurement of tree height, crown area, and canopy volume.Abstract. Tree canopy architecture is associated with light use efficiency and thus productivity. Given the modern training systems in orchard tree fruit systems, modification of tree architecture is becoming important for easier management of crops (e.g., pruning, thinning, chemical application, harvesting, etc.) while maintaining fruit quality and quantity. Similarly, in forest environments, architecture can influence the competitiveness and balance between tree species in the ecosystem. This article reviews the literature related to sensing approaches used for assessing architecture traits and the factors that influence such evaluation processes. Digital imagery integrated with structure from motion analysis and both terrestrial and aerial light detection and ranging (LiDAR) systems have been commonly used. In addition, satellite imagery and other techniques have been explored. Some of the major findings and some critical considerations for such measurement methods are summarized here. Keywords: Canopy volume, LiDAR system, Structure from motion, Tree height, UAV.

Assessment of Spray Deposition and Losses in an Apple Orchard with an Unmanned Agricultural Aircraft System in China

2020 ◽  
Vol 63 (3) ◽  
pp. 619-627
Author(s):  
Yang Liu ◽  
Longlong Li ◽  
Yajia Liu ◽  
Xiongkui He ◽  
Jianli Song ◽  
...  
Keyword(s):  
Pest Control ◽  
Plant Protection ◽  
Spray Deposition ◽  
Apple Orchard ◽  
Tree Canopy ◽  
List Type ◽  
Spray Drift ◽  
Reduced Pressure ◽  
External Contamination ◽  
Aircraft System

Highlights Field tests were performed in an orchard to evaluate spray performance of an unmanned agricultural aircraft system. A conventional air-assisted orchard sprayer was applied as a reference for comparing the feasibility of UAAS. The canopy deposition, airborne drift, loss to ground, and sprayer external contamination were tested. Field test results can provide a reference for the application of UAAS for pest control in orchards. Abstract. Unmanned agricultural aircraft system (UAAS) technology has developed rapidly in China in recent years. Due to their high application efficiency, all-terrain operation, and low-volume spraying, UAASs have been widely used for pest management in field crops, achieving good pest control and reduced pressure on farmers. In this study, the applicability of UAAS for orchard protection was tested in an apple orchard by spraying with a four-rotor UAAS and a conventional air-assisted orchard sprayer. The spray characteristics of both sprayers, including canopy deposition, drift in the air, loss to the ground, and external contamination on the sprayer, were measured and compared. The field results showed that the effective spray swath width of the UAAS was 2.23 m, and the maximum droplet density was 132 droplets cm -2 in the center of the flight line. The actual deposition in the tree canopy was lower with the UAAS than with the air-assisted sprayer, but the normalized deposition of the UAAS was equivalent to that of the air-assisted sprayer, and the coefficient of variation for deposition in all parts of the canopy was obviously higher for the UAAS than for the air-assisted sprayer. Due to the airflow produced by the high-speed rotors, the spray drift in the air was much higher with the UAAS than with the air-assisted sprayer, whereas the ground loss of the UAAS was 1/5 that of the air-assisted sprayer. Moreover, the rotor airflow of the UAAS caused a large amount of droplets to attach to the sprayer fuselage, causing the external contamination on the UAAS to be five times that of the air-assisted sprayer. Results showed that the use of a multirotor UAAS for plant protection in an orchard had considerable influence on the spray drift and external contamination of the spray equipment. Based on the results, the following recommendations can be made: (1) plant protection with a UAAS should be attained by spraying at a reasonable height to reduce the drift in the air, and (2) UAAS manufacturers should develop adequate spraying systems as well as appropriate UAAS designs for plant protection. Keywords: Air-assisted orchard sprayer, Apple orchard, Spray deposition, Spray loss, UAAS.

Coexistence Analysis of Civil Unmanned Aircraft Systems at Low Altitudes

Frequenz ◽  
2016 ◽  
Vol 70 (11-12) ◽  
Author(s):  
Yuzhe Zhou
Keyword(s):  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Rate Model ◽  
System Communication ◽  
Aircraft Systems ◽  
Communication Models ◽  
Ratio Criterion ◽  
Coverage Model ◽  
Aircraft System ◽  
Frequency Distance

AbstractThe requirement of unmanned aircraft systems in civil areas is growing. However, provisioning of flight efficiency and safety of unmanned aircraft has critical requirements on wireless communication spectrum resources. Current researches mainly focus on spectrum availability. In this paper, the unmanned aircraft system communication models, including the coverage model and data rate model, and two coexistence analysis procedures, i. e. the interference and noise ratio criterion and frequency-distance-direction criterion, are proposed to analyze spectrum requirements and interference results of the civil unmanned aircraft systems at low altitudes. In addition, explicit explanations are provided. The proposed coexistence analysis criteria are applied to assess unmanned aircraft systems’ uplink and downlink interference performances and to support corresponding spectrum planning. Numerical results demonstrate that the proposed assessments and analysis procedures satisfy requirements of flexible spectrum accessing and safe coexistence among multiple unmanned aircraft systems.

Minimizing Human Factors Mishaps in Unmanned Aircraft Systems

2013 ◽  
Vol 21 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Qaisar R. (“Raza”) Waraich ◽  
Thomas A. Mazzuchi ◽  
Shahram Sarkani ◽  
David F. Rico
Keyword(s):  
Human Factors ◽  
General Purpose ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Ground Control ◽  
Aircraft Systems ◽  
Engineering Standards ◽  
General Purpose Computer ◽  
Aircraft System ◽  
Purpose Computer

Unmanned aircraft system (UAS) mishaps attributable to lack of attention to human factors/ergonomics (HF/E) science in their ground control stations (GCSes) are alarmingly high, and UAS-specific HF/E engineering standards are years away from development. The ANSI/HFES 100-2007 human factors standard is proposed as a specification for the design of UASes because of the similarity between general-purpose computer workstations and GCSes. Data were collected from 20 UASes to determine the applicability of commercial standards to GCS designs. Analysis shows that general-purpose computer workstations and UAS GCSes are up to 98% similar. Therefore, our findings suggest that the application of commercial human factors standards may be a good solution for minimizing UAS mishaps.

scholarly journals Aircraft System State Recognition and Fault Prediction Based on a Test Diagnostic Model

2021 ◽  
Vol 1207 (1) ◽  
pp. 012025
Author(s):  
Yan Su ◽  
Hongcai Chen ◽  
Chenxuan Gu ◽  
Xiangyu Xing ◽  
Xuerui Liang
Keyword(s):  
Dynamic Testing ◽  
Complex Function ◽  
Modeling Method ◽  
Fault Prediction ◽  
Diagnostic Model ◽  
Prognostic Information ◽  
Skeleton Model ◽  
State Recognition ◽  
Aircraft Systems ◽  
Aircraft System

Abstract The existing testability models for fault prognosis of aircraft systems limit the implementation of prognosis and health management systems. This paper develops a test diagnosis modeling method and relevant algorithms to support dynamic testing and to evaluate fault prognostic ability during aircraft system design. According to the system principles and the complex function structure of aircraft systems, a test diagnostic model is established by integrating testing and prognostic information with a test diagnostic skeleton model using multi-signal flow. New test indexes are identified to assess the testability and prognostic ability of aircraft systems. Relevant state recognition and fault prediction algorithms are established by fusing the improved particle swarm optimization algorithm and Hidden Semi-Markov Model. The feasibility and validity of the test diagnostic modeling method and relevant algorithms are verified in an aircraft’s engine bleed air system. Training and test show that the model can support analysis and estimation, and the algorithms can ensure accurate results after training the HSMM using improved PSO algorithm.

scholarly journals Development and Prototype Testing of an Agricultural Nozzle Clog Detection Device

2021 ◽  
Vol 64 (1) ◽  
pp. 49-61
Author(s):  
Chin Nee Vong ◽  
Peter Ako Larbi
Keyword(s):  
Droplet Size ◽  
Detection System ◽  
New Technology ◽  
Quality Characteristics ◽  
List Type ◽  
Spray Application ◽  
Nozzle Clogging ◽  
Spray Pattern ◽  
Extended Range ◽  
Low Drift

HighlightsPrototypes of an agricultural nozzle clog detection system (for 18 nozzles) have been successfully developed.Spray quality characteristics (droplet size, pattern, and coverage) were not significantly affected when testing the device with extended-range nozzles (TeeJet XR8004).Most of the spray quality characteristics were significantly affected when testing the device with ultra low-drift nozzles (John Deere PSULDQ2004).Abstract. Agricultural nozzles are the main components that perform the spraying of agrochemicals, and their proper functionality is a key element for uniform spray application on crops. Because nozzles have small orifices, they can become clogged when there is debris from the agrochemical in the tank. Nozzle clogging during spray application results in poor pest and weed management and increased cost for re-spraying the affected crop row. Measures used to prevent nozzles from clogging include using screens or strainers to filter out debris before it reaches the nozzle tip, as well as performing regular checks on the nozzles. However, nozzle clogging still occurs during spraying despite the precautions taken. Thus, a device that can detect nozzle clogging during spraying is necessary to enable a quicker response that will ensure uniform application across each row of the crop. A novel, patented device for detecting clogged nozzles that is externally attachable to each nozzle on a sprayer boom was developed in the Precision Application Technology Lab at Arkansas State University. The main objective of this article is to present a general description of this prototype nozzle clog detection device and the nozzle clog detection system. Spray droplet size and pattern tests under controlled conditions and spray coverage tests under field conditions were conducted with and without the device to determine if there were significant differences in droplet size, spray pattern, or spray coverage between using and not using the device. The tests demonstrated that this new technology has potential for detecting clogged nozzles without significantly influencing spray quality for extended-range nozzles but not for ultra low-drift nozzles. To increase the reliability of the performance of this new technology, further improvements in the design need to be considered. Keywords: Clogged nozzle, Detection, Droplet size, Prototype device, Spray coverage, Spray pattern.

Performance Optimization of a Newly Designed Dynamic Fluidic Sprinkler

2021 ◽  
Vol 37 (1) ◽  
pp. 33-41
Author(s):  
Xingye Zhu ◽  
Alexander Fordjour ◽  
Shouqi Yuan ◽  
Frank Agyen Dwomoh ◽  
Zakaria Issaka
Keyword(s):  
Droplet Size ◽  
Performance Optimization ◽  
Structural Parameters ◽  
Direct Analysis ◽  
Low Pressure ◽  
Nozzle Diameter ◽  
Structural Parameter ◽  
List Type ◽  
Working Pressure ◽  
Coefficient Of Uniformity

HighlightsThe results confirmed that the optimal combination of structural parameters was achieved with the factor combination of 25 mm length of the tube, 150 kPa pressure, 3 mm diameter of the tube, and 5 mm nozzle diameter.The influencing factors in decreasing order of importance were: working pressure, length of the tube, and nozzle diameter for coefficient of uniformity, and nozzle diameter working pressure and diameter of the tube for range.Droplet velocities from test 7 ranged between 0 and 6.0 m/s, while that from test 2 was slightly larger, ranging from 0 to 6.7 m/s under low-pressure conditions.ABSTRACT: To select the appropriate combination of the factors for the dynamic fluidic sprinkler, hydraulic performance tests at low pressure were conducted. The main structural parameters in this study were the length of the tube (L), pressure (H), the diameter of the tube (M), nozzle diameter (N), they are represented by factors A, B, C, and D, respectively. An orthogonal array with four factors and three levels was selected, and the direct analysis technique was used to analyze the test data. The droplets and velocities data of the sprinkler were obtained by a Thies Clima Laser Precipitation Monitor. MATLAB R20014a software was used to calculate the simulated coefficient of uniformity (CU). The results showed that the optimum values of the structural parameters were: the length of the tube (25 mm), the working pressure (150 kPa), the diameter of the tube (3 mm), and the nozzle diameter (5 mm). The factors affecting coefficient of uniformity and range, in decreasing order of importance were nozzle diameter, pressure, length of the tube, and the diameter of the tube. The highest coefficient of uniformity obtained was 91% when the length of the tube was 25 mm. Droplet sizes decreased with the increase of pressure. Droplet size ranging from 0.1 to 4 mm was obtained under test 7 with a mean droplet size of 0.38 mm. The study can give a reference to the operation for saving water in sprinkler irrigated fields. Keywords: Droplet, Dynamic fluidic sprinkler, Orthogonal test, Structural parameter, Uniformity, Velocity.

Investigation of Branch Accessibility with a Robotic Pruner for Pruning Apple Trees

2021 ◽  
Vol 64 (5) ◽  
pp. 1459-1474
Author(s):  
Azlan Zahid ◽  
Long He ◽  
Daeun Choi ◽  
James Schupp ◽  
Paul Heinemann
Keyword(s):  
Path Planning ◽  
Free Path ◽  
Path Length ◽  
Computation Time ◽  
Tree Canopy ◽  
Random Tree ◽  
Target Point ◽  
List Type ◽  
Apple Trees ◽  
End Effector

HighlightsA branch accessibility simulation was performed for robotic pruning of apple trees.A virtual tree environment was established using a kinematic manipulator model and an obstacle model.Rapidly-exploring random tree (RRT) was combined with smoothing and optimization for improved path planning.Effects on RRT path planning of the approach angle of the end-effector and cutter orientation at the target were studied.Abstract. Robotic pruning is a potential solution to reduce orchard labor and associated costs. Collision-free path planning of the manipulator is essential for successful robotic pruning. This simulation study investigated the collision-free branch accessibility of a six rotational (6R) degrees of freedom (DoF) robotic manipulator with a shear cutter end-effector. A virtual environment with a simplified tall spindle tree canopy was established in MATLAB. An obstacle-avoidance algorithm, rapidly-exploring random tree (RRT), was implemented for establishing collision-free paths to reach the target pruning points. In addition, path smoothing and optimization algorithms were used to reduce the path length and calculate the optimized path. Two series of simulations were conducted: (1) performance and comparison of the RRT algorithm with and without smoothing and optimization, and (2) performance of collision-free path planning considering different approach poses of the end-effector relative to the target branch. The simulations showed that the RRT algorithm successfully avoided obstacles and allowed the manipulator to reach the target point with 23 s average path finding time. The RRT path length was reduced by about 28% with smoothing and by 25% with optimization. The RRT smoothing algorithm generated the shortest path lengths but required about 1 to 3 s of additional computation time. The lowest coefficient of variation and standard deviation values were found for the optimization method, which confirmed the repeatability of the method. Considering the different end-effector approach poses, the simulations suggested that successfully finding a collision-free path was possible for branches with no existing path using the ideal (perpendicular cutter) approach pose. This study provides a foundation for future work on the development of robotic pruning systems. Keywords: Agricultural robotics, Collision-free path, Manipulator, Path planning, Robotic pruning, Virtual tree environment.

PROSPECTIVE STRUCTURE AND FUNCTIONING OF THE CENTER FOR UNMANNED AIRCRAFT SYSTEMS OF EMERCOM OF RUSSIA

2021 ◽  
pp. 57-61
Author(s):  
Инесса Николаевна Исавнина ◽  
Юрий Николаевич Осипов ◽  
Владимир Иванович Ершов ◽  
Надежда Германовна Каменских
Keyword(s):  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Unmanned Aircraft System ◽  
Aircraft Systems ◽  
Departmental Level ◽  
Aircraft System ◽  
Operating Units

Развитие системы беспилотной авиации, независимо от ее предназначения и структурной принадлежности, предполагает согласованные усилия заинтересованных лиц (руководства, ученых и конструкторов, специалистов испытательных комплексов, преподавателей, инструкторов теоретического и практического обучения операторов управления летательными аппаратами и их полезными нагрузками) по совершенствованию технических характеристик и функционала беспилотных воздушных судов, а также по формированию соответствующих компетенций у персонала эксплуатирующих подразделений. Очевидным является тот факт, что все перечисленные мероприятия наиболее полно могут быть реализованы в рамках функционирования специальных центров развития беспилотных авиационных систем государственного или ведомственного уровня. The development of unmanned aircraft system, regardless of its purpose and structural affiliation, involves the concerted efforts of stakeholders (management, scientists and designers, specialists of test complexes, tutors, as well as theoretical and practical instructors for operators of aircraft and their payloads control) to improve the technical characteristics and functionality of unmanned aircraft, as well as to create appropriate competencies among the personnel of operating units. It is obvious that all these measures can be fully implemented within the framework of special centers for unmanned aircraft systems of state or departmental level.

Spray Characterization of Aerosol Delivery Systems for Use in Stored Product Facilities

2020 ◽  
Vol 63 (6) ◽  
pp. 1925-1937
Author(s):  
Fei Xyza B. Asuncion ◽  
Daniel L. Brabec ◽  
Mark E. Casada ◽  
Ronaldo G. Maghirang ◽  
Frank H. Arthur ◽  
...  
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Delivery Systems ◽  
Spray Angle ◽  
Insect Control ◽  
List Type ◽  
Aerosol Delivery ◽  
Spray Characteristics ◽  
Compressed Gas

HighlightsHandheld sprayers generated larger droplets and wider droplet size distributions than compressed gas sprayers.Sprayers with higher pressure and nozzles with wider spray angle produced smaller droplets.Droplet size distribution influenced spray coverage, mass concentration, deposition, and sprayer efficacy.The handheld sprayers had less spray coverage and efficiency than the compressed gas sprayers.The deposition at different locations was influenced by the volume of the space, aerosol dosage, and spray time.Abstract. Aerosol insecticides, including pyrethrins, can be used as methyl bromide replacements to control stored product insects inside flour mills and rice mills. The effectiveness of aerosol application for insect control requires knowing the spray characteristics of the equipment to be used and understanding factors that influence the effectiveness of insecticide application. The objectives of this study, as part of efforts to optimize aerosol applications, were to evaluate the characteristics of six aerosol delivery systems (two handheld sprayers and compressed gas sprayer systems fitted with two types of manifolds and two types of nozzles), estimate the dispersion and deposition of aerosol in a simulated stored product facility, and determine how the dispersion and deposition are affected by the characteristics of the sprayers. Results showed that the spray systems differed significantly in spray characteristics. The compressed gas sprayers generated significantly smaller droplets, more uniform droplet size distribution, and better spray coverage than the handheld sprayers. The ellipsoidal nozzle produced significantly smaller droplets than the circular nozzle. While the type of manifold had no significant effect on deposition, higher aerosol dosage and spray time resulted in significantly higher deposition. Results of this study will be used to improve spray techniques for stored product insect control, to validate computational fluid dynamics modeling of aerosol application, and to improve testing methods in large-scale spray testing inside commercial facilities. Keywords: APS spectrometer, Droplet size distribution, HELOS KR-Vario, Mass deposition, Spray characteristics, Spray nozzles.

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