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© 2024 by the authors; licensee Asian Online Journal Publishing Group 
 

Agriculture and Food Sciences Research 
Vol. 11, No. 2, 110-115, 2024 

ISSN(E) 2411-6653/ ISSN(P) 2518-0193 
DOI: 10.20448/aesr.v11i2.6179 

© 2024 by the authors; licensee Asian Online Journal Publishing Group 

 
 

 
 
 
Design and experimentation of a pressure testing platform for tea tree canopy 

 
Pengfei Wang1   

Yongguang Hu2   
Decheng Liu3 
Qingmin Pan4 
Wenqiang Wu5 

 

 
( Corresponding Author) 

 
1,2,3,4,5Jiangsu Province, Zhenjiang, Jiangsu University, China. 
1Email: jsu.wpf@gmail.com  
2Email: deerhu@ujs.edu.cn  
3Email: 30116103@qq.com  
4Email: 2112116011@stmail.ujs.edu.cn  
5Email: dilanshengxue@126.com  

 
Abstract 

In the mechanized operations of tea gardens, components like cutting blades and suspension 
systems frequently interact with the tea tree canopy, resulting in complex push, squeeze, and 
pressure interactions. This makes it challenging to accurately measure the distribution 
characteristics of the forces involved. The uncertainty in these mechanical properties complicates 
mechanical design, posture adjustment, and positioning control. To address this, this study 
designed and developed a testing platform for pressure measurement in the tea tree canopy, 
aiming to systematically investigate the force characteristics and structural changes of the canopy 
under different penetration depths. The platform enabling high-precision recording of canopy 
responses under varying pressure conditions. The experimental results indicated significant 
differences in pressure values at different depths and locations. At a penetration depth of 1.0 cm, 
the minimum pressure value was 3.0 N, while the maximum pressure at a depth of 4.0 cm reached 
60.0 N. Moreover, the pressure exhibited a clear hierarchical distribution with changes in depth 
and position. The study observed a hierarchical structure within the tea tree canopy, comprise 
tender leaves, mature leaves, and branches. These findings provide important evidence and data 
support for the optimization of tea garden management and harvesting machinery design. 

 
Keywords: Pressure testing, Tea tree, Hilly region, Canopy structure of plants, Testing platform design, Field experiment. 

 
Citation | Wang, P., Hu, Y., Liu, D., Pan, Q., & Wu, W. (2024). 
Design and experimentation of a pressure testing platform for tea 
tree canopy. Agriculture and Food Sciences Research, 11(2), 110–115. 
10.20448/aesr.v11i2.6179 
History:  
Received: 24 October 2024 
Revised: 27 November 2024 
Accepted: 29 November 2024 
Published: 2 December 2024 
Licensed: This work is licensed under a Creative Commons 

Attribution 4.0 License  
Publisher:  Asian Online Journal Publishing Group 
 

Funding: This research is supported by the Regional Science Foundation 
projects (Grant number: 32460782) and Priority Academic Program 
Development of Jiangsu Higher Education Institutions (Grant number: 
PAPD-2023-87) 
Institutional Review Board Statement: The Ethical Committee of the 
Jiangsu University, China has granted approval for this study (Ref. No. 
20241115001). 
Transparency: The authors confirm that the manuscript is an honest, 
accurate, and transparent account of the study; that no vital features of the 
study have been omitted; and that any discrepancies from the study as 
planned have been explained. This study followed all ethical practices during 
writing. 
Competing Interests: The authors declare that they have no competing 
interests. 
Authors’ Contributions: All authors contributed equally to the conception 
and design of the study. All authors have read and agreed to the published 
version of the manuscript. 

 
Contents 
1. Introduction .................................................................................................................................................................................... 111 
2. Materials and Methods ................................................................................................................................................................. 111 
3. Result and Analysis ........................................................................................................................................................................ 113 
4. Conclusions ..................................................................................................................................................................................... 115 
References ............................................................................................................................................................................................ 115 

 
 
 
 

 

mailto:jsu.wpf@gmail.com
mailto:deerhu@ujs.edu.cn
mailto:30116103@qq.com
mailto:2112116011@stmail.ujs.edu.cn
mailto:dilanshengxue@126.com
https://creativecommons.org/licenses/by/4.0/
https://creativecommons.org/licenses/by/4.0/
https://www.doi.org/10.20448/aesr.v11i2.6179
https://orcid.org/0009-0009-5798-3478
https://orcid.org/0000-0002-3771-9380


Agriculture and Food Sciences Research, 2024, 11(2): 110-115 

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Contribution of this paper to the literature 
The article presents a device for testing the pressure of the tea canopy layer, which analogizes 
the pressure test of soil and has found physical stratification in the actual observation of the tea 
canopy layer. Currently, there is no research on measuring the pressure and stratification 
characteristics of the tea canopy layer. 

 

1. Introduction 
Tea tree (Camellia sinensis) is a globally significant economic crop, playing a crucial role in the agricultural 

and economic systems of countries such as China, Japan, and India [1]. As the scale of tea cultivation expands and 
labor costs rise, traditional manual management and harvesting methods can no longer meet the demands for 
efficiency and scale in modern tea production [2-4]. Consequently, the development and optimization of tea garden 
management and harvesting machinery have become key to advancing the tea industry towards modernization and 
automation. However, existing tea garden management and harvesting machinery often face a major challenge: the 
physical damage to the tea tree canopy structure during operation, which adversely affects the health of the trees 
and the quantity and quality of the tea leaves. Therefore, exploring the mechanical properties of the tea tree canopy 
under mechanical action and optimizing machinery design to minimize damage to the trees has become a core 
technical issue in the mechanization of the tea industry. The structure of the tea tree canopy not only influences 
photosynthesis, gas exchange, and moisture management but also directly affects the forces experienced during 
mechanical harvesting [3]. Different tea varieties and cultivation methods result in distinct canopy structures that 
exhibit varying mechanical properties under external pressure, raising design requirements for tea harvesting 
machines [5, 6]. During the harvesting process, the canopy experiences mechanical pressures such as compression 
and bending. Accurately designing the harvesting head to adapt to different canopy structures and reduce 
unnecessary physical damage directly impacts the efficiency and effectiveness of mechanized harvesting [7, 8]. 

With the advancement of sensor technology and mechanical analysis methods, studying the force response of 
the tea tree canopy under mechanical pressure has become increasingly feasible [9, 10]. Existing studies have 
shown significant differences in deformation, stress distribution, and physiological responses of plant canopies 
under varying external forces; particularly, external pressure significantly alters the physiological activities and 
morphological characteristics of the tea tree canopy. Although there are various tea canopy shot detection models 
available [11, 12]. Research on the pressure characteristics of tea tree canopies remains limited, and there is a lack 
of systematic experimental platforms to dynamically monitor the behavior of tea trees under stress conditions [13, 
14]. This study aims to design an experimental platform to simulate the force conditions of the tea tree canopy 
under different pressure levels, providing a scientific basis for the design of tea harvesting machines. The platform 
can precisely apply different pressure levels and monitor the stress distribution, morphological deformation, and 
physiological responses of the canopy in real time. It integrates stress sensors and data acquisition and analysis 
modules to record the stress and strain conditions of the canopy under mechanical action. This experimental 
platform not only offers new methods for understanding the pressure characteristics of tea tree canopies but also 
provides a theoretical foundation for the design and optimization of harvesting machinery. Through a systematic 
study of the response mechanisms of tea tree canopies under various pressure levels, this research will help enhance 
the operational efficiency of harvesting machines while reducing negative impacts on tea tree growth, thereby 
promoting the sustainable development of tea industry mechanization and achieving efficient tea garden 
management and harvesting. 
 

2. Materials and Methods 
2.1. Design Principle of Test Platform 

The dense foliage of the tea tree canopy can be approximated as a compact solid when a large panel is pressed 
down upon it, resembling compressible soil [15]. This allows for the study of the tea canopy using principles 
similar to those applied in soil mechanics. The Bekker settlement theory is based on statistical analysis of extensive 
experimental data and incorporates classical theories of soil mechanics. Bekker identified essential differences in the 
settlement processes between off-road vehicles and structures like foundations. Structures typically apply static and 
heavy loads, resulting in slow settlement rates and minimal displacement, while off-road vehicles exert dynamic 
and lighter loads, causing rapid and significant settlement. The state of the tea tree canopy structure under 
pressure aligns with Bekker's settlement theory. Therefore, applying this theory to the pressure characteristics 
testing of the tea tree canopy aims to analyze the deformation, compression, and mechanical responses of the 
canopy when subjected to external pressures (such as those from tea harvesting machines or other mechanical 
operations). This analysis will provide insights into the growth environment of tea and optimize the equipment 
used, offering foundational theoretical support for the design of the pressure characteristics testing platform for tea 
tree canopies. A model of soil settlement under pressure is illustrated in Figure 1. 

 
Figure 1. Schematic diagram of soil pressure subsidence. 

Note: 1. soil 2. platen. 



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2.2. The Overall Design and Function Realization of The Test Platform 
To meet the agronomic requirements of standardized tea planting models, the main functions and technical 

parameters of this testing platform are detailed in Table 1. The platform is designed with a gantry structure, as 
shown in Figure 2. It is driven by a stepper motor system allowing for three-axis movement: the Y-axis for lateral 
motion mounted on a moving frame; the Z-axis installed above the Y-axis for vertical movement; and the X-axis, 
which is fixed between two parallel Y-axes to achieve forward and backward movement. The coordinated motion of 
the three axes ensures precise control of speed and position for the platform. 

The control system utilizes a PLC (Programmable Logic Controller) to send pulse signals to the stepper motor 
drivers, converting these signals into angular displacement signals that drive each stepper motor for accurate 
motion control. In the platform design, the Z-axis must support equipment weighing up to 30.0 kg, while the X-
axis must carry the weights of the Y and Z axes, along with associated motors and testing equipment. To 
accommodate the complex terrain of the fields, the platform is equipped with a wheeled moving frame that allows 
for height adjustments in four directions, ensuring compatibility with uneven tea garden surfaces. The height of 
the moving frame is set at 1.2 meters to allow the platform to traverse tea ridges during operation. 

For the canopy compression tests, a membrane-type pressure sensor is chosen to accurately measure the 
mechanical responses of the tea tree canopy, as shown in Figure 3. This sensor offers high precision, sensitivity, 
and a wide measurement range (0-100 kg), making it suitable for measuring the pressure characteristics of the 
canopy. Its circular membrane design, which can be either of variable cross-section or flat type, provides excellent 
resistance to lateral loads, ensuring the stability and accuracy of the measurement data. The compact size of the 
sensor allows for easy miniaturization, making it suitable for installation within the limited space of the canopy 
testing platform. By providing continuous and stable mechanical parameters, this sensor offers a scientific basis for 
analyzing the mechanical characteristics of the tea tree canopy, optimizing its structure, and enhancing both the 
yield and quality of tea leaves. 

  
Figure 2. Side view of the test bench 

Note: 1 Z-axis dynamometer, 2 pressure sensors, 3 pressure plates, 4 racks. 
  

 
Figure 3. Bellows type tension pressure sensor (0-100kg/M8). 

 

2.3. Design and Implementation of Field Experiment on Test Platform 
The testing platform is illustrated in Figure 4, with dimensions of 1.5 m in height, 0.4 m in length, and 1.8 m in 

width. During the testing process, the measurement depth is first calibrated on the force gauge of the Z-axis, after 



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which the pressure rod is gradually lowered to the specified depths. The collected data is transmitted in real time to 
a computer for recording. Once measurements at each point are completed, the platform is manually moved to the 
next position for further measurements. 

To effectively simulate the impact of harvesting machinery on the tea tree canopy, a square wooden board 
measuring 20 cm × 20 cm is chosen for the pressure application. This size is determined by several considerations. 
First, it ensures that the pressure coverage area is moderate, effectively simulating the localized force of harvesting 
machines without interfering with or damaging the natural structure of the canopy due to excessive area. Second, 
the 20 cm × 20 cm board provides high operational convenience and accuracy for positioning, securing, and 
collecting pressure data. Additionally, this size is consistent with commonly used pressure plate dimensions in soil 
mechanics, enhancing the scientific validity and comparability of the test data. This choice not only meets the 
experimental design requirements but also provides a solid basis for subsequent analysis of canopy stress and 
optimization of equipment. 

To obtain representative pressure data, adult tea trees covering all canopy levels are selected for testing. As 
shown in Figure 5, the platform integrates pressure sensors, a data processing unit, and a recording system, 
allowing precise capture of pressure changes at different depths. Measurements are taken at 12 points across the 
canopy cross-section to analyze the distribution and patterns of data at varying depths of application. 

The zero point is established at the position where the sensor first contacts the canopy, resulting in zero 
pressure. Comparative data indicates that the sensor's readings are unstable at depths less than 10.0 mm, while 
depths exceeding 70.0 mm lead to canopy collapse, which is detrimental to cutting operations. Therefore, the final 
set pressure depths are established at 10.0 mm, 20.0 mm, 30.0 mm, and 40.0 mm to analyze their effects on the 
pressure characteristics of the Zhongcha 108 canopy. 

 

 
Figure 4. Test bench and test area. 

 

 
Figure 5. Location diagram of 12 collection points. 

 

3. Result and Analysis 
Using the testing platform shown in Figure 4, pressure measurements of the tea tree canopy were conducted at 

various compression depths, with results summarized in Table 1. Analysis of the pressure data at different depths 
(1.0 cm, 2.0 cm, 3.0 cm, and 4.0 cm) for each measurement point (illustrated in Figure 6) revealed a consistent 
pattern in pressure changes with respect to location and depth, exhibiting significant differences at varying depths. 
As the compression depth increased, the overall pressure values showed an upward trend, particularly at depths of 
3.0 cm and 4.0 cm, where pressure changes were more pronounced. Specifically, at a depth of 1.0 cm, the pressure 



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curve was relatively flat, with small differences in pressure between measurement points, indicating that the upper 
structure of the canopy was sparse. At a depth of 2.0 cm, pressure gradually increased, especially around 
measurement points 6 to 8, where a noticeable rise in pressure suggested an increase in canopy density in that 
region. At depths of 3.0 cm and 4.0 cm, the pressure curve exhibited peaks at measurement points 6 to 8, with 
values significantly higher than at other points, reflecting a dense middle layer structure in the tea tree canopy. 

Additionally, the pressure peaks concentrated at measurement points 6 to 8, particularly at depths of 3.0 cm 
and 4.0 cm, where the pressure sharply increased to its maximum. This indicates that the density of the canopy in 
this area is significantly greater than in other regions, likely corresponding to the distribution of the main leaves 
and branches of the tea tree. This phenomenon highlights the layered characteristics of the tea tree canopy: the 
upper layer (1.0 cm and 2.0 cm) is sparse, while the middle layer (3.0 cm and 4.0 cm) has increased density. At 
measurement points 9 to 12, the pressure gradually decreased with position, especially at deeper measurement 
points, indicating that the device had penetrated through the denser parts of the canopy into the sparser lower 
region. Overall, the trends in pressure changes with depth and position suggest that the tea tree canopy can be 
roughly divided into a sparse outer layer, a dense middle layer, and a sparse lower layer, exhibiting significant 
stratification. In future research, accumulating more pressure data will facilitate a quantitative assessment of the 
tea tree canopy structure and the establishment of a canopy pressure model. In agricultural machinery operations, 
real-time monitoring of compression depth and pressure changes can assist in precisely locating equipment within 
the canopy, supporting accurate pruning and harvesting of tea trees while enhancing operational precision and 
efficiency. This finding provides essential theoretical and practical support for the application of smart agricultural 
equipment in tea tree management. The layered structure of the tea tree canopy is distinctly illustrated in Figure 7. 
From top to bottom, the canopy can be divided into layers of tender leaves, mature leaves, fine branches, and old 
branches, with differences in physiological function and growth state across layers. This stratification is a result of 
the tea tree’s natural growth characteristics and pruning management, reflecting the process by which tea farmers 
optimize harvesting efficiency and improve tea quality. The successful design of the pressure testing platform for 
the tea tree canopy lays a solid foundation for future large-scale experiments. Upcoming work can involve 
accumulating pressure data across broader tests to refine the canopy pressure model, providing precise design 
guidelines for intelligent harvesting equipment. Furthermore, the analysis method based on pressure data 
demonstrates good versatility, making it applicable to various tea tree varieties and growth environments, thus 
offering data support for mechanized harvesting under diverse conditions. 
 
Table 1. Corresponding table of pressure/depth of tea canopy. 

Depth/cm 
Pressure/N 

1 2 3 4 5 6 7 8 9 10 11 12 

1.0 3.0 3.0 3.0 7.0 5.0 10.0 3.0 6.0 10.0 10.0 4.0 4.0 
2.0 9.0 8.0 14.0 17.0 18.0 22.0 24.0 15.0 18.0 16.0 10.0 8.0 
3.0 13.0 13.0 16.0 21.0 25.0 31.0 35.0 30.0 21.0 24.0 14.0 15.0 
4.0 17.0 26.0 21.0 27.0 30.0 43.0 60.0 40.0 30.0 28.0 25.0 18.0 

 

 
Figure 6. Measurement results of tea canopy pressure at the same pressure depth. 

 



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Figure 7. Schematic diagram of longitudinal section of tea row. 

Note: 1 Tender layer、2 Old leaf layer、3 Twig layer、4 Old branch layer、5 Ground、6 Twelve 
pressure sensor and its position. 

 

4. Conclusions 
The pressure collection system designed in this study demonstrates stable performance and effectively gathers 

pressure data from the tea tree canopy at various compression depths. Data analysis reveals the pressure 
distribution characteristics of the canopy structure at different locations and depths, confirming the non-uniformity 
of canopy density. Notably, localized areas exhibit peak pressure values, indicating a dense structure within the 
canopy. These findings provide critical references for understanding canopy characteristics and optimizing the 
design of tea harvesting equipment. The pressure data analysis enables a more accurate assessment of the specific 
location of machinery within the tea tree canopy, enhancing operational effectiveness. Pressure feedback allows the 
machinery to adjust operations in real time, facilitating more precise execution of harvesting tasks while 
minimizing disruption to the deeper canopy structure, thus improving positioning efficiency and protecting the 
healthy growth of the tea trees. This study deepens the understanding of the tea tree canopy structure and provides 
a scientific basis for the optimized design of intelligent tea harvesting equipment. By analyzing how pressure varies 
with depth, harvesting machinery can execute tasks more efficiently and intelligently, significantly contributing to 
the modernization, intelligent transformation, and sustainable development of the tea industry. 
 

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