Journal of Advances in Artificial Life Robotics
Vol. 4(1); June (2023), pp. 41–45
ON LINE ISSN 2435-8061; ISSN-L 2435-8061
https://alife-robotics.org/jallr.html

SUGISAKAMASANORI

Research Article

Analysis of Nozzle Effects on Droplet Adhesion in Rice
Cultivation Using A Hexacopter Unmanned Aerial Vehicle
Hazry Desa, Muhammad Azizi Azizan, Nurfadzillah Ishak, Tan Yew Tian

Centre of Excellence for Unmanned Aerial Systems (COE-UAS), Universiti Malaysia Perlis (UniMAP), Malaysia

ARTICLE INFO
Article History
Received 09 October 2022
Accepted 05 September 2023
Keywords
UAV
Spraying system
Nozzles
Droplet density
Average coverage

ABSTRACTThis study investigated the potential of a hexacopter unmanned aerial vehicle (UAV) spraying
system as one of the agricultural spraying methods in Malaysia. The altitude of the UAV heoperated at 1.5 meters and under a wind speed of 1.15 meters per second he tested three different
nozzles. The uniformity and spread of application in paddy field conditions were evaluated.
ImageJ software was used for evaluation. The results showed that using an electrostatic
centrifugal nozzle for droplet dispersion resulted in remarkable average droplet densities,
especially 134.03 deposits/cm2 in the upper region and 153.93 deposits/cm2 in the lower region.
Furthermore, in the electrostatic centrifugal nozzle, it was confirmed that 3478 droplets weredeposited in the upper region and 3255 droplets were deposited in the lower region.

© 2022 The Author. Published by Sugisaka Masanori at ALife Robotics Corporation Ltd.
This is an open access article distributed under the CC BY-NC 4.0 license(http://creativecommons.org/licenses/by-nc/4.0/).

address many challenges, the use of mechanized sprayers
and drones is increasing to optimize spray application
and reduce the burden of manual labor. Therefore,
modern agriculture is employing drone technology toreduce direct contact with fertilizers, pesticides, andother potentially harmful chemicals in an effort to keep
humans safe. [3].
Correspondingly, findings from [1] revealed significant
concerns among farmers, including breathing difficulties
during and after pesticide spraying (51.5%), itchiness andirritation (26%), and skin issues like rashes and peeling(13.7%). More severe instances involved farmers
collapsing, experiencing stomach discomfort, vomiting,and requiring hospitalization. Pesticide exposure waslinked to respiratory symptoms like coughing, wheezing,
and airway inflammation [4].
Presently, the adoption of UAV spraying systems isburgeoning within the agribusiness sector [2]. This trend
is particularly prevalent on farms as part of "Precision

1. Introduction
The Malaysian agricultural sector has received
significant investment from the government, primarily toimprove productivity, increase farmers' incomes andcreate jobs [1].
Traditional methods such as manual seed planting,composting, and pesticide spraying are popular among
farmers. Spraying pesticides and fertilizers is timeconsuming and less effective, so technological advances
are essential in the agricultural field [2]. The height of thecrop can make manual spraying operations very difficult.
As crops grow taller, uniform application of chemicals
becomes difficult and inefficient, which can reduceyields. Variation in crop height within a field can lead to
uneven application and taller crops can be physicallydemanding, costly and unsafe for workers. Sprayingsparsely can result in poor crop growth and quality, while
spraying too much can lead to wasted resources. To
Corresponding author’s E-mail: hazry@unimap.edu.my41

“Agriculture”, a movement aimed at agriculturalmodernization in developed countries [5]. The
introduction of his UAV spraying system for pesticide
application has brought enormous benefits. This
technology can reduce health and working conditions [6].
For effective pesticide spraying, selecting anappropriately sized nozzle is most important, but it is also
important to quantify the amount of spray, ensure
uniform spraying, It is essential to solve the problem ofnozzle function, such as minimizing the amount of spray.
The nozzle is important not only for breaking up theliquid into droplets, but also for establishing the spraypattern and ejecting the droplets accurately [7]. Given thearray of nozzle-related problems, this study aimed toaddress these challenges by investigating the applicationof his three different types of nozzles in paddy fields toimprove the spread of droplets throughout the paddy field
area. It is intended for analysis.
This study aims to address these issues by applying
three different types of nozzles in paddy fields andanalyzing the droplet spread over the entire paddy fieldarea.

Fig. 1. Arrangement of water sensitive paper

2.2. Specifications for the UAV AgriculturalSpraying System
This study examines the HSSB10L-606 hexacopter
sprayer drone, designated as the tested UAV spraying
system, as depicted in Fig. 2. The hexacopter sprayer
drone features six arms, six motors, and incorporates
three distinct types of spray nozzles for the purposes ofthis investigation. Fig. 3 contains the comprehensive
specifications of this system.
The drone's spraying tank could hold up to 10 liters ofliquid, and it had a maximum take-off payload capacityof 28 kg. In autonomous mode, the system exhibitedseamless take-offs and landings while maintaining aflying speed ranging from 0 to 12 m/s. The softwareinterface of this UAV spraying system was facilitated by
the IFLY application, which provided instructions forparameters such as flight height, spray span to ensure
proper overlap or precise spraying, flight speed, and turntime.

2. Experimental Approach
2.1. Testing approach and data acquisition
The research was conducted in an open field near theCenter for Unmanned Air Systems Research (COEUAS)
at Universiti Malaysia Perlis (UniMAP) in Malaysia.
Specifically, latitude: 6.43744 N, longitude: 100.18868 E
point. This study was conducted on his June 2022. The
UAV spray system was tested at a height of 1.5 meters
and a wind speed of 1.15 meters/second. The
environmental conditions were an average temperature of33°C and a humidity level of 84%. The total area of thefield is 140m x 70m. The test is for 2 weeks. Threedifferent nozzle types (flat fan, hollow cone, andelectrostatic centrifugation) were experimented, alloperated at 100% aperture ratio. A 7.6 cm x 2.6 cm watersensitive paper (WSP) was used to evaluate thedistribution of water droplets dispensed from the spraynozzle. Water-sensitive paper was placed at both the topand bottom of the rice field with a gap of 1 meter. Thisevaluation is shown in Fig. 1.
Water-sensitive papers were positioned within thepaddy plants, precisely between the upper and lower leaf
surfaces, with the intention of assessing the extent towhich the droplets could permeate.

42reached its peak at 3478 in the upper region and 3255 in
the lower region.
The penetration index registered the minimum value
across all nozzles, standing at 8%. This signifies thatdroplets could readily permeate through to the groundand lower surface of leaves, even accessing hard-to-reachregions. As indicated by Fig. 4, the electrostatic
centrifugal nozzle demonstrated exceptional uniformity
in droplet dispersion from the upper to the lower areas inpaddy plant applications. This can be attributed to its
finely dispersed mist. A previous study [8] suggested thatelectrostatic forces exert a more pronounced influence on
minute droplets compared to gravitational forces.
Consequently, the electrostatic charge carried by mist
droplets can result in enhanced deposition while
minimizing drift.
Subsequently, the examination of the flat fan nozzle
showcased diminished spray dispersion on the upper part,while exhibiting substantial droplet concentration on thelower region, measuring 1313.5 on the upper section and2629.8 on the lower portion. In comparison to the hollow
cone nozzle, this particular nozzle's performance can bedeemed subpar across all nozzle heights. Additionally,
the outcomes unveiled a notably elevated penetrationindex of 33% between the upper and lower areas,
underscoring that a greater number of droplets reachedthe lower section throughout the spraying procedure.
This procedure aligns with the findings from a study
mentioned in [9] where it was indicated that enhancing
the penetration of a flat fan nozzle into the crop canopy
was necessary, particularly when employing an 80degree nozzle angle.
Nonetheless, the hollow cone nozzle displayed anintermediate penetration percentage index between theupper and lower regions, measuring 26%. This

Fig. 2. HSSB10L-606 hexacopter sprayer drone
Hexacopter sprayer drone

Specification

Quantity of arms
Volume of the tank

6
10 Litres

Maximum take-off capacity

28 kg

Duration of flight

10-15 minutes

Flying height

0-30m

Flying speed

0-12 m/s

Spraying speed

0-8 m/sSpraying width>4-6m

Spraying flow

1-1.15 L/min

Sprayer drone size

2.0m*1.3m*0.45m

Fig. 3. Hexacopter sprayer drone system specification
3. Results and discussions
Various nozzles were assessed for their ability toachieve consistent and widespread spray distribution at a
uniform height. The dots created by the sprayed liquid onwater-sensitive paper were captured through scanningand subsequently processed using the DepositScan
software to calculate the mean droplet count within thesample data. The uniformity of spray dispersion at aheight of 1.5 meters was noted when using the nozzle atfull 100% opening. The outcomes of the analysis
regarding deposition for the flat fan nozzle, hollow conenozzle, and electrostatic centrifugal nozzle can be foundin Fig.4 and Fig. 5 presented below.
Referring to Fig. 4, it is evident that the electrostatic
centrifugal nozzle exhibited the most elevated average
droplet density on water-sensitive paper. Specifically,
this density measured 134.03 deposits/cm² at the upper
region and 153.93 deposits/cm² at the lower region.
Furthermore, the nozzle achieved an average coverage of
24.31% at the top and 21.91% at the bottom. The total
count of deposited droplets, which provides an overall
representation of droplet distribution in the targeted area,Fig. 4. Dispersion variation in hexacopter sprayer drone
system utilizing three distinct nozzles
corresponded with an average droplet density of 48.12
deposits/cm² at the top and 26.32 deposits/cm² at thebottom. The total deposit count, the smaller of the two
nozzle values, amounted to 816 at the top and 469.8 at
the bottom. This highlights that the droplet distribution
and penetration to the ground were hindered due to43

improper nozzle height. In line with this, [9] also
highlighted that the hollow cone nozzle is well-suited forspraying plants during their early growth stages, fromemergence until the tillering stage. This is attributed tothe plants' relatively lower height and medium density
during this period. However, beyond this stage, thehollow cone nozzle's suitability diminishes.

findings. Interestingly, when employing an electrostatic
centrifugal nozzle, the discrepancy in coverage wasminimal, with 24.31% for the upper region and 21.91%
for the lower region. This configuration notably exhibitedthe most substantial improvement in droplet distribution,
extending from the upper reaches of the rice canopy
down to the ground area.
3.
Utilizing an electrostatic centrifugal nozzle
resulted in the most significant total droplet deposition in
the designated region, amounting to 3478 in the upper
region and 3255 in the lower region. This outcome
underscores the successful distribution of improved
droplet dispersion within the target area, facilitated by thefiner mist produced by this nozzle.
The experiment illustrated that the size of droplets holds
significant importance in influencing the distribution anddrift of droplets during pesticide spraying. In the context
of enhancing the efficacy of UAV spraying systems, it isessential to minimize droplet drift and enhance droplet
distribution. This can be accomplished by strategicallysituating nozzles at an appropriate downwind height
relative to the spraying area, thus preventing potential
harm to plants due to pesticide drift. Additionally, theconfiguration of the nozzle's spray pattern profile iscontingent upon factors like nozzle type, capacity,pressure, height from the sprayed surfaces, andorientation angle. Investigating these variables is crucial
for achieving precise aerial spraying in future endeavors
related to agricultural precision.

Fig. 5. Distribution of droplet deposition

4. Conclusion
In this study, a comprehensive evaluation involving
three distinct spraying nozzle types was conducted withina paddy field, all operating at uniform heights and flow
rates. The research encompassed a comparative analysis
of various factors, including average droplet density,coverage, total deposition distribution, and droplet
penetration index across the target area. The ensuingconclusions are detailed below:
1.
The outcomes for both average droplet densityand penetration, concerning the dispersion of droplets
within the designated region, were notably influenced byvariables such as nozzle type, nozzle height, and flow
rate. Substantial variations in the rate of droplet
dispersion within the designated region were observed
across the three nozzle experiments. Notably, theemployment of an electrostatic centrifugal nozzle
resulted in a lower average droplet density, measuring134.03 deposits/cm² at the upper region and 153.93
deposits/cm² at the lower region. This configuration also
demonstrated exceptional droplet penetration, achieving
a rate of 8%. The application of an improved nozzle typeeffectively enhanced the droplet distribution rate fromthe upper to the lower portions of the rice canopy within
the designated region.
2.
The augmentation in droplet density did not
result in a corresponding escalation of total droplet
dispersion, as evidenced by the average coverage

References
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And Ecosystem”, Advances in Natural and AppliedSciences, 6(1), pp. 65–70, 2012.
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Khan, M. T., Kumar, N., Chauhan, A., & Soni, S. K.,”
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44

5. Debangshi, U., “Drone-Applications in Agriculture
Drones-Applications in Agriculture”, 2021.
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Dr. Nurfadzillah Binti Ishak
She received her PhD in Building
Engineering from the Universiti
Malaysia Perlis. She is currently aSenior Lecturer in the same
institution. She is Head of Built
Environment Intelligent (BELL) at
Centre of Ecellence for Unmanned
AerialSystem(COEUAS),
Universiti Malaysia Perlis.
Ms. Tan Yew TianAuthors Introduction
Prof. Dr. Hazry Desa

He received a Bachelor ofMechanical Engineering fromTokushima University, Japan. He
was also a senior design engineer at
R&D Sony Technology Malaysia,
and Tamura Electronics Malaysia
and as a researcher at Artificial Lifeand Robotics Laboratory, Oita
University, Japan. He was a Dean at
the Center for Communication
Skills and Entrepreneurship and the School of Business
Innovation and Technopreneurship and later, served as
Dean for the Faculty of Engineering Technology atUniversiti Malaysia Perlis. He is the director at the Centerof Excellence for Unmanned Aerial Systems (COE-UAS)
His research interests are in mobile robotics, unmannedsystems, and aerial robotics, resulting in notableachievements such as journal publications, patents, andprototype developments in Unmanned Aerial Systems(UAS). He is registered are professional Chartered
Engineer (CEng), Professional Engineer (Ir.), Professional
Technologist (Ts.), and also as senior memberships inIEEE and IET.
Dr. Muhammad Azizi Azizan
He received his PhD degree in Civil
EngineeringfromUniversiti
Malaysia Perlis and is currently
working as a Senior Lecturer at thesame institution. He is also cofounder and director of Haas
Solutions Sdn Bhd, a technology
startup company of Universiti
Malaysia Perlis

45

She received her Bachelor’s
Degreein
Mechatronic
Engineering in 2022 from theFaculty of Electrical Engineering
TechnologyfromUniversiti
Malaysia
Perlis(UniMAP),
Malaysia.