Research

Open AccessArticle

V-Shaped Toothed Roller Cotton Stalk Puller: Numerical Modeling and Field-Test Validation

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Agriculture 2023, 13(6), 1157; https://doi.org/10.3390/agriculture13061157 - 30 May 2023

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Abstract

The V-shaped toothed roller cotton stalk puller has a low removal ratio and weak pulling effect. Hence, we constructed a simplified mathematical model of the V-shaped tooth roller stalk puller based on elastic collision theory and simple beam theory and conducted a mechanical [...] Read more.

The V-shaped toothed roller cotton stalk puller has a low removal ratio and weak pulling effect. Hence, we constructed a simplified mathematical model of the V-shaped tooth roller stalk puller based on elastic collision theory and simple beam theory and conducted a mechanical analysis based on this model to explore the causes of pulling errors and fractures. Specifically, the V-shaped tooth plates of the machine were optimized in an orthogonal experiment with the rotational speed, cogging angle, and ground clearance as the influencing factors, and the removal ratio as the evaluation index. This experiment was designed to enable analysis of the physical characteristics of cotton stalks, and the forces applied during the pulling process. Additionally, a V-shaped toothed roller-type stalk-pulling test bench was constructed. The results revealed that, unlike the cogging angle, the ground clearance significantly affected the removal ratio. Furthermore, the highest removal ratio (i.e., 97%) was achieved when the ground clearance was −20 mm, the rotational speed was 300 rpm, and the cogging angle was 32.5°. An L₉ (3⁴) orthogonal field experiment was also conducted with the rotational speed, cogging angle, and ground clearance as the influencing factors to investigate their respective influences on the stalk removal ratio. The results revealed that the ground clearance most significantly influenced the ratio, followed by the rotational speed, and cogging angle. The ground clearance and rotational speed of the V-shaped toothed roller were each found to significantly influence the ratio. Furthermore, a ground clearance of −20 mm, rotational speed of 300 r/min, and cogging angle of 25° yielded an average removal ratio of 98.27%. Through this research, the mechanism of toothed roller stalk pulling is further deepened and the toothed series stalk pulling technology provides theoretical support. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Calibration of Ramie Stalk Contact Parameters Based on the Discrete Element Method

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Agriculture 2023, 13(5), 1070; https://doi.org/10.3390/agriculture13051070 - 17 May 2023

Viewed by 315

Abstract

To obtain the physical parameters and contact parameters of ramie stalk decorticating simulation, the structural dimensions, density, moisture content, elastic modulus, and contact parameters of the ramie stalk were measured in this study based on the phloem and xylem of the ramie stalk. [...] Read more.

To obtain the physical parameters and contact parameters of ramie stalk decorticating simulation, the structural dimensions, density, moisture content, elastic modulus, and contact parameters of the ramie stalk were measured in this study based on the phloem and xylem of the ramie stalk. The physical stacking angles of the phloem and xylem were measured by the cylinder lift method and the extraction of the partition method, respectively. The contact parameters between the xylem and phloem of the ramie stalk were directly calibrated. Additionally, the contact parameters of the phloem–phloem, phloem–Q235A steel, xylem–xylem, and xylem–Q235A steel were used as calibration objects, and the simulated stacking angle was used as the evaluation index. Then, the Plackett–Burman test was designed to screen for the parameters which were significantly affecting the simulated stacking angle. Furthermore, the steepest ascent test determined the optimal range of values for two significant parameters of the phloem and three significant parameters of the xylem. Based on the central composite design, the second-order regression equations between the significant parameters of the phloem and xylem and the stacking angle were established, respectively. The physical stacking angles of 37.93° for phloem and 27.17° for xylem were the target values to obtain the optimal parameter group. The results showed that the restitution, static, and rolling friction coefficients between the xylem and phloem were 0.60, 0.53, and 0.021, respectively. The static and rolling friction coefficients between the phloem and phloem were 0.41 and 0.056, respectively. The rolling friction coefficient between the xylem and Q235A steel was 0.033, and the static and rolling friction coefficients between the xylem and xylem were 0.44 and 0.016, respectively. The verification test showed that the relative error values were less than 2.11%, which further indicated that the modeling method and parameter calibration of the ramie stalk phloem and xylem models were accurate and reliable. They can be used for the subsequent calibration simulation tests of ramie stalk bonding parameters and ramie stalk decorticating simulations. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Design of a Spring-Finger Potato Picker and an Experimental Study of Its Picking Performance

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Agriculture 2023, 13(5), 945; https://doi.org/10.3390/agriculture13050945 - 25 Apr 2023

Viewed by 602

Abstract

To address the problems of low pickup rates and high rates of wounds in the mechanised harvesting of potatoes under sectional harvesting conditions, a spring-finger potato picker was designed and its overall structure and working principles were described. The kinematic principle of the [...] Read more.

To address the problems of low pickup rates and high rates of wounds in the mechanised harvesting of potatoes under sectional harvesting conditions, a spring-finger potato picker was designed and its overall structure and working principles were described. The kinematic principle of the spring-finger was analysed based on the picking constraints, and the kinematic parameters of the picker were determined. A response surface Box–Behnken Design test design was used to carry out a quadratic orthogonal rotational test, with the speed of the spring-finger, the forward speed of the machine, and the embedded depth as test factors, and the loss rate and the wounded potato rate as evaluation indicators. The test results were optimised and analysed. When the spring-finger speed was 19.57 r/min, the forward speed was 0.61 m/s and the embedded depth was 71.31 mm, the loss rate was 1.18%, and the wounded potato rate was 5.71%. The optimised data were verified, and the results showed that the loss rate of the spring-finger potato picker was 1.48% and the wounded potato rate was 4.98%, meeting the potato picking and harvesting requirements. The research can provide a theoretical basis and design reference for the development and application of sectional potato harvesting machinery. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Design and Testing of a Self-Propelled Dandelion Seed Harvester

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Agriculture 2023, 13(4), 917; https://doi.org/10.3390/agriculture13040917 - 21 Apr 2023

Viewed by 771

Abstract

At present, there are few harvesters for dandelion (Taraxacum mongolicum) seeds, which limits the large-area planting of dandelion. Furthermore, manual harvesting is characterized by huge labor intensity, low efficiency, and high costs. Combining the material characteristics of dandelion plants and seeds [...] Read more.

At present, there are few harvesters for dandelion (Taraxacum mongolicum) seeds, which limits the large-area planting of dandelion. Furthermore, manual harvesting is characterized by huge labor intensity, low efficiency, and high costs. Combining the material characteristics of dandelion plants and seeds with agronomic requirements for harvesting dandelion seeds, a self-propelled dandelion seed harvester was designed. The harvester is mainly composed of collection devices, separation devices, transmission devices, and a rack. It can facilitate seed collection from plants, seed transportation, and seed–pappus separation in one operation. The collection and separation processes of dandelion seeds were studied to ascertain the main factors that affect the collection rate. Then, the collection and separation devices were designed, and their parameters were analyzed. Taking the forward speed, wind velocity of blowers, and rate of rotation of the drum as test factors and the collection rate as the evaluation index, quadratic regression orthogonal rotating field tests were performed. In this way, the optimal combination of operation parameters was determined: the collection rate is optimal when the forward speed is 0.8 m·s⁻¹, the air velocity from the blowers is 1.63 m·s⁻¹, and the rate of rotation of the drum is 419 rpm. Field test results showed that a favorable harvesting effect was achieved after operation of the harvester, and only small amounts of dandelion seeds remained unharvested. Under the optimal parameter combination, the collection rate reached 89.1%, which could meet requirements for practical field harvesting of dandelion seeds. The test results satisfy the design requirement. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Simulation and Experiment of Compression Molding Behavior of Substate Block Suitable for Mechanical Transplanting Based on Discrete Element Method (DEM)

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Agriculture 2023, 13(4), 883; https://doi.org/10.3390/agriculture13040883 - 17 Apr 2023

Viewed by 436

Abstract

The compression molding performance of a substrate block has a significant effect on the quality and stability of mechanical transplanting. The physical experiment and DEM simulation were combined to evaluate the compression molding behavior of substrate block in this study. A calibration procedure [...] Read more.

The compression molding performance of a substrate block has a significant effect on the quality and stability of mechanical transplanting. The physical experiment and DEM simulation were combined to evaluate the compression molding behavior of substrate block in this study. A calibration procedure of DEM parameters of peat particles was proposed at first. Then, the above parameters were brought into the contact model of the compression system–particles, and the effect of the loading speed on the compression behavior of the peat substrate block was investigated. The compressive force–displacement curves of the simulated and measured tests were all contained in the initial linear stage and non-linear stiffing stage. The particle number of central sections was higher than side section, and the variable coefficient was greater at higher loading speed. The substrate blocks all expanded after demolding. The higher the loading speed, the greater the expansion in the height’s direction, and the easier it was for cracks to be generated near the bottom. This study will provide a reference for the design of substrate block forming machines. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Design and Experiment of an Underactuated Broccoli-Picking Manipulator

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Agriculture 2023, 13(4), 848; https://doi.org/10.3390/agriculture13040848 - 11 Apr 2023

Viewed by 686

Abstract

Mature broccoli has large flower balls and thick stems. Therefore, manual broccoli picking is laborious and energy-consuming. However, the big spheroid vegetable-picking manipulator has a complex structure and poor enveloping effect and easily causes mechanical damage. Therefore, a broccoli flower ball-picking manipulator with [...] Read more.

Mature broccoli has large flower balls and thick stems. Therefore, manual broccoli picking is laborious and energy-consuming. However, the big spheroid vegetable-picking manipulator has a complex structure and poor enveloping effect and easily causes mechanical damage. Therefore, a broccoli flower ball-picking manipulator with a compact structure and simple control system was designed. The manipulator was smart in structure and stable in configuration when enveloped in flower balls. First, a physical damage test was carried out on broccoli according to the underactuated manipulator’s design scheme. The maximum surface pressure of the flower ball was 30 N, and the maximum cutting force of the stem was 35 N. Then, kinematic analysis was completed, and the statical model of the underactuated mechanism was established. The dimension of the underactuated mechanism for each connecting rod was determined based on the damage test results and design requirements. The sizes of each connecting rod were 50 cm, 90 cm, 50 cm, 90 cm, 50 cm, 60 cm, and 65 cm. The statical model calculated the required thrust of the underactuated mechanism as 598.66–702.88 N. Then, the manipulator was simulated to verify its reliability of the manipulator. Finally, the manipulator’s motion track, speed, and motor speed were determined in advance in the laboratory environment. One-hundred picking tests were carried out on mature broccoli with a 135–185 mm diameter. Results showed that the manipulator had an 84% success rate in picking and a 100% lossless rate. The fastest single harvest time in the test stand was 11.37 s when the speed of the robot arm was 3.4 m/s, and the speed of the stepper motor was 60 r/min. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Experimental Research for Digging and Inverting of Upright Peanuts by Digger-Inverter

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Agriculture 2023, 13(4), 847; https://doi.org/10.3390/agriculture13040847 - 10 Apr 2023

Viewed by 598

Abstract

In order to quickly dry the peanut pods and effectively reduce the mildew on peanut pods in rainy weather, this paper analyzed the research status of peanut digging and inverting technology in China and abroad, combined with the peanut two-stage harvesting mode. The [...] Read more.

In order to quickly dry the peanut pods and effectively reduce the mildew on peanut pods in rainy weather, this paper analyzed the research status of peanut digging and inverting technology in China and abroad, combined with the peanut two-stage harvesting mode. The orthogonal experiment was carried out by using the peanut digger-inverter to study the different forms of upright type, taking the rate of vines inverting, the rate of buried pods, and the rate of fallen pods as the evaluation indexes, and taking the traveling speed of the tractor A, the line speed of the conveyor chain B, and the line speed of the inverting roller C as the experimental factors. The results showed that, in the states of unpressed vines and pressed vines, the order of influence of the peanut digger-inverter on the evaluation indices was A > C > B. The optimal horizontal combination of unpressed vines was A₂C₃B₂, when the traveling speed of the tractor is 1.06 m/s, the line speed of the inverting roller is 2.12 m/s, and the line speed of the conveyor chain is 1.02 m/s; the rate of vines inverting was 71.07%, the rate of buried pods was 0.2%, and the rate of fallen pods was 0.22%. Under the condition of vines pressing, the best horizontal combination is A₂C₂B₂, when the travelling speed of the tractor is 1.01 m/s, the line speed of the inverting roller is 1.88 m/s, and the line speed of the conveyor chain is 1.02 m/s; the rate of vines inverting was 74.29%, the rate of buried pods was 0.14%, and the rate of fallen pods was 0.33%. The paired t-test was carried out by the peanut digger-inverter under the state of pressed and unpressed vines. There was little difference in the influence of each factor on the rate of fallen pods and the rate of buried pods, but there was a significant difference in the influence on the rate of vines inverting. The rate of inversion of vines under the state of pressed vines was higher than that under the state of unpressed vines. The research results will provide certain technical support for the late optimization of the peanut digger-inverter and create a hardware foundation for the intelligence and information harvesting of peanuts. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

An Application of Artificial Neural Network for Predicting Threshing Performance in a Flexible Threshing Device

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Agriculture 2023, 13(4), 788; https://doi.org/10.3390/agriculture13040788 - 29 Mar 2023

Viewed by 550

Abstract

Rice is a widely cultivated food crop worldwide, and threshing is one of the most important operations of combine harvesters in grain production. It is a complex, nonlinear, multi-parameter physical process. The flexible threshing device has unique advantages in reducing the grain damage [...] Read more.

Rice is a widely cultivated food crop worldwide, and threshing is one of the most important operations of combine harvesters in grain production. It is a complex, nonlinear, multi-parameter physical process. The flexible threshing device has unique advantages in reducing the grain damage rate and has already been one of the major concerns in engineering design. Using the measured test database of the flexible threshing test bench, the rotation speed of the threshing cylinder (RS), threshing clearance of the concave sieve (TC), separation clearance of the concave sieve (SC), and feeding quantity (FQ) are used as the input layer. In contrast, the crushing rate (Y_P), impurity rate of the threshed material (Y_Z), and loss rate (Y_S) are used in the output layer. A 4-5-3-3 artificial neural network (ANN) model, with a backpropagation learning algorithm, was developed to predict the threshing performance of the flexible threshing device. Next, we explored the degree to which the inputs affect the outputs. The results showed that the R of the threshing performance model validation set in the hidden layer reached 0.980, and the root mean square error (

R M S E

) and the average absolute error (

M A E

) were less than 0.139 and 0.153, respectively. The built neural network model predicted the performance of the flexible threshing device, and the regression determination coefficient R² between the prediction data and the experimental data was 0.953. The results showed revealed that the data combined with the ANN method is an effective approach for predicting the threshing performance of the flexible threshing device in rice. Moreover, the sensitivity analysis showed that RS, TC, and SC were crucial factors influencing the performance of the flexible threshing device, with an average relative importance of 15.00%, 14.89%, and 14.32%, respectively. FQ had the least effect on threshing performance, with an average threshing relative importance of 11.65%. Our findings can be leveraged to optimize the threshing performance of future flexible threshing devices. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessFeature PaperArticle

Research on Fault Diagnosis of HMCVT Shift Hydraulic System Based on Optimized BPNN and CNN

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Agriculture 2023, 13(2), 461; https://doi.org/10.3390/agriculture13020461 - 15 Feb 2023

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Abstract

There are some problems in the shifting process of hydraulic CVT, such as irregularity, low stability and high failure rate. In this paper, the BP neural network and convolutional neural network are used for fault diagnosis of the HMCVT hydraulic system. Firstly, through [...] Read more.

There are some problems in the shifting process of hydraulic CVT, such as irregularity, low stability and high failure rate. In this paper, the BP neural network and convolutional neural network are used for fault diagnosis of the HMCVT hydraulic system. Firstly, through experiments, 120 groups of pressure and flow data under normal and four typical fault modes were obtained and preprocessed; they were divided into 80 groups of training samples and 40 groups of test samples via random extraction, using the BP neural network model and convolutional neural network model for fault classification. The results show that compared with BP, PSO-BP and other models, the fault diagnosis rate of the BAS-BP neural network model can reach 92.5%, and the average diagnosis accuracy rate of the convolutional neural network can reach 97.5%, which can be effectively applied to the fault diagnosis of the HMCVT hydraulic system and provide some reference for the shifting reliability of hydraulic CVT. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Numerical Simulation of the Picking Process of Supernormal Jujube Branches

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Agriculture 2023, 13(2), 408; https://doi.org/10.3390/agriculture13020408 - 09 Feb 2023

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Abstract

This paper elaborates on a digital simulation study on supernormal particle flow used to investigate and analyze the process of picking up jujube branches, which was a meaningful attempt to search for accurate and effective advanced numerical analogy methods in the agricultural field. [...] Read more.

This paper elaborates on a digital simulation study on supernormal particle flow used to investigate and analyze the process of picking up jujube branches, which was a meaningful attempt to search for accurate and effective advanced numerical analogy methods in the agricultural field. In this paper, the meshless technology based on the element-free Galerkin method was used for the first time to present the effects of particle size, particle number and particle acting force on the movement of irregular particles, and the influence of the gear rotation speed, the feeding amount, and the jujube branch size on the movement behavior as well as the picking rate. It can describe not only the particles’ dynamic movement in the process of picking up jujube twigs, such as feeding, collision, throwing and rolling, but also the effect of the quality and shape caused by the particle size, which in turn affects the surface force of particles and interparticle acting force, thereby affecting the weight function in the analytical solution, the total feeding amount and the effect of the acting force resulting from the particles’ contact, roll and collision caused by gear rotation. The findings reveal that the digital simulation, based on the meshless Galerkin technology and Rocky software, is effective in dealing with issues related to supernormal particle flow. By eliminating the influence of geometric shapes on calculations, the method boasts an effective solution to the movement problems of irregularly shaped particles, which would be further applied in the agriculture field. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Research on the Measurement Method of Feeding Rate in Silage Harvester Based on Components Power Data

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Agriculture 2023, 13(2), 391; https://doi.org/10.3390/agriculture13020391 - 07 Feb 2023

Viewed by 734

Abstract

For existing problems, such as the complex interactions between a crop and a machine, the measuring difficulty and the limited measurement precision of the feeding quantity within the corn silage harvester, a method of feeding rate measurement based on key conditions data, working [...] Read more.

For existing problems, such as the complex interactions between a crop and a machine, the measuring difficulty and the limited measurement precision of the feeding quantity within the corn silage harvester, a method of feeding rate measurement based on key conditions data, working data cleaning, and multiple variate regression is proposed. Non-destructive rotation speed, rotation torque, and power consumption sensors are designed for the key mechanical components. The data conditions, such as rotating speed, rotating torque, power consumption, hydraulic pressure, and hydraulic flow for the key operation of parts including cutting, feeding, shredding, and throwing are monitored and collected in real-time during field harvesting. The working data are screened and preprocessed, and the Mann-Kendall boundary extraction algorithm is applied, as is multiple component time lag correction analysis, and the Grubbs exception detection method. Based on a Pearson correlation analysis results, one-factor and multiple-factor regression models are respectively developed to achieve an accurate measurement of the corn feeding rate. The field validation tests show that the working data boundary extraction results among the load-stabilizing components such as shredding roller and throwing blower are highly reliable, with a correct rate of 100%. The power monitoring data of the shredding roller and throwing blowers are significantly correlated with the crop feeding rate, with a max correlation coefficient of 0.97. The determination coefficient of the single-factor feeding rate model based on the shredding roller reaches 0.94, and the maximum absolute error of the multi-factor feeding rate model is 0.58 kg/s. The maximum relative error is ±5.84%, providing technical and data support for the automatic measuring and intelligent tuning of the feeding quantity in a silage harvester. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

A Method of Modern Standardized Apple Orchard Flowering Monitoring Based on S-YOLO

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Agriculture 2023, 13(2), 380; https://doi.org/10.3390/agriculture13020380 - 04 Feb 2023

Viewed by 1028

Abstract

Monitoring fruit tree flowering information in the open world is more crucial than in the research-oriented environment for managing agricultural production to increase yield and quality. This work presents a transformer-based flowering period monitoring approach in an open world in order to better [...] Read more.

Monitoring fruit tree flowering information in the open world is more crucial than in the research-oriented environment for managing agricultural production to increase yield and quality. This work presents a transformer-based flowering period monitoring approach in an open world in order to better monitor the whole blooming time of modern standardized orchards utilizing IoT technologies. This study takes images of flowering apple trees captured at a distance in the open world as the research object, extends the dataset by introducing the Slicing Aided Hyper Inference (SAHI) algorithm, and establishes an S-YOLO apple flower detection model by substituting the YOLOX backbone network with Swin Transformer-tiny. The experimental results show that S-YOLO outperformed YOLOX-s in the detection accuracy of the four blooming states by 7.94%, 8.05%, 3.49%, and 6.96%. It also outperformed YOLOX-s by 10.00%, 9.10%, 13.10%, and 7.20% for mAP_ALL, mAP_S, mAP_M, and mAP_L, respectively. By increasing the width and depth of the network model, the accuracy of the larger S-YOLO was 88.18%, 88.95%, 89.50%, and 91.95% for each flowering state and 39.00%, 32.10%, 50.60%, and 64.30% for each type of mAP, respectively. The results show that the transformer-based method of monitoring the apple flower growth stage utilized S-YOLO to achieve the apple flower count, percentage analysis, peak flowering time determination, and flowering intensity quantification. The method can be applied to remotely monitor flowering information and estimate flowering intensity in modern standard orchards based on IoT technology, which is important for developing fruit digital production management technology and equipment and guiding orchard production management. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Intelligent Algorithm Optimization of Liquid Manure Spreading Control

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Agriculture 2023, 13(2), 278; https://doi.org/10.3390/agriculture13020278 - 23 Jan 2023

Viewed by 821

Abstract

The growth of field crops needs appropriate soil nutrients. As a basic fertilizer, liquid manure provides biological nutrients for crop growth and increases the content of organic matter in crops. However, improper spraying not only reduces soil fertility but also destroys soil structure. [...] Read more.

The growth of field crops needs appropriate soil nutrients. As a basic fertilizer, liquid manure provides biological nutrients for crop growth and increases the content of organic matter in crops. However, improper spraying not only reduces soil fertility but also destroys soil structure. Therefore, the precise control of the amount of liquid manure is of great significance for agricultural production and weight loss. In this study, we first built the model of spraying control, then optimized the BP neural network algorithm through a genetic algorithm. The stability and efficiency of the optimized controller were compared with PID, fuzzy PID and BPNN-PID control. The simulation results show that the optimized algorithm has the shortest response time and lowest relative error. Finally, platform experiments were designed to verify the four control algorithms at four different vehicle speeds. The results show that, compared with other control algorithms, the control algorithm described here has good stability, short response time, small overshoot, and can achieve an accurate fertilizer application effect, providing an optimization scheme for research on the precise application of liquid manure. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Simulation Analysis and Experiments for Blade-Soil-Straw Interaction under Deep Ploughing Based on the Discrete Element Method

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Agriculture 2023, 13(1), 136; https://doi.org/10.3390/agriculture13010136 - 05 Jan 2023

Cited by 1 | Viewed by 1190

Abstract

The desirable sowing period for winter wheat is very short in the rice-wheat rotation areas. There are also lots of straw left in harvested land. Deep rotary tillage can cover rice straw under the surface to increase soil organic matter. Clarifying the effect [...] Read more.

The desirable sowing period for winter wheat is very short in the rice-wheat rotation areas. There are also lots of straw left in harvested land. Deep rotary tillage can cover rice straw under the surface to increase soil organic matter. Clarifying the effect of the rotary tillage blade on the soil and straw, as well as analyzing the movement patterns and forces on the straw and soil, are essential to investigate the deep rotary tillage process in order to solve the problems of energy consumption and poor straw burial effect of deep tillage and deep burial machinery. In this study, we built the interaction model of rotary blade-soil-straw through the discrete element method to conduct simulation and identified the factors that affect the power consumption and operation quality of the rotary blade. The simulation process reflects the law of rotary blade-soil-straw interaction, and the accuracy of the simulation model has been verified by field trials. The simulation test results show that the optimized structural parameters of the rotary tillage blade were 210 mm, 45 mm, 37° and 115° (R, H, α and β) designed based on this theoretical model can cultivate to a depth of 200 mm. The operating parameters were 8π rad/s for rotational speed and 0. 56 m/s for forward speed, respectively; the simulated and field comparison tests were conducted under the optimal combination of parameters, and the power, soil breaking rate, and straw burial rate were 1.73 kW, 71.34%, and 18.89%, respectively; the numerical error rates of simulated and field test values were 6.36%, 5.42%, and 8.89%, respectively. The accuracy of the secondary model was verified. The simulation model had good accuracy at all factor levels. The model constructed in this study can provide a theoretical basis and technical reference for the interaction mechanism between rotary tillage and soil straw, the optimization of machine geometry, and the selection of operating parameters. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Research on Flexible End-Effectors with Humanoid Grasp Function for Small Spherical Fruit Picking

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Agriculture 2023, 13(1), 123; https://doi.org/10.3390/agriculture13010123 - 02 Jan 2023

Cited by 1 | Viewed by 1026

Abstract

The rapid, stable, and undamaged picking of small-sized spherical fruits are one of the key technologies to improve the level of intelligent picking robots and reduce grading operations. Cherry tomatoes were selected as the research object in this work. Picking strategies of two-stage [...] Read more.

The rapid, stable, and undamaged picking of small-sized spherical fruits are one of the key technologies to improve the level of intelligent picking robots and reduce grading operations. Cherry tomatoes were selected as the research object in this work. Picking strategies of two-stage “Holding-Rotating” and finger-end grasping were determined. The end-effector was designed to separate the fruit from the stalk based on the linear motion of the constraint part and the rotating gripper. This work first studied the human hand-grasping of cherry tomatoes and designed the fingers with sinusoidal characteristics. The mathematical model of a single finger of the gripper was established. The structural parameters of the gripper were determined to meet the requirements of the grabbing range from 0 to 61.6 mm. Based on the simulation model, the constraint part was set to 6 speeds, and the fruit sizes were set to 20 mm, 30 mm, and 40 mm, respectively. When the speed was 0.08m/s, the results showed that the grabbing time was 0.5381 s, 0.387 s, and 0.2761 s, respectively, and the maximum grabbing force was 0.9717 N, 3.5077 N, and 4.0003 N now of clamping, respectively. It met the picking requirements of high speed and low loss. The criterions of two-index stability and undamaged were proposed, including the grasping index of the fixed value and the slip detection of variance to mean ratio. Therefore, the control strategy and algorithm based on two-stage and two-index for rapid, stable, and non-destructive harvesting of small fruit were proposed. The results of the picking experiment for seventy-two cherry tomatoes showed that the picking success rate was 95.82%, the average picking time was 4.86 s, the picking damage rate was 2.90%, the browning rate was 2.90% in 72 h, and the wrinkling rate was 1.49% in 72 h, which can meet the actual small spherical fruit picking requirements. The research will provide an idea for the flexible end-effectors with humanoid grasp function and provides a theoretical reference for small spherical fruit picking. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Parameter Optimization of Reciprocating Cutter for Chinese Little Greens Based on Finite Element Simulation and Experiment

by

Wei Wang

,

Xiaolan Lv

and

Zhongyi Yi

Agriculture 2022, 12(12), 2131; https://doi.org/10.3390/agriculture12122131 - 12 Dec 2022

Viewed by 707

Abstract

Optimizing the working performance of the cutting device for harvesting Chinese little greens is crucial to reducing energy consumption in cutting and improving cutting quality. To explore the mechanical characteristics of leafy vegetables in cutting, the dynamic process of cutting Chinese little greens [...] Read more.

Optimizing the working performance of the cutting device for harvesting Chinese little greens is crucial to reducing energy consumption in cutting and improving cutting quality. To explore the mechanical characteristics of leafy vegetables in cutting, the dynamic process of cutting Chinese little greens with a cutter was simulated numerically by using the finite element method based on theoretical analysis. In the numerical simulation, the response-surface methodology (RSM) and central composite rotatable design (CCD) were used to describe the influence rule of sliding–cutting angle (X₁), oblique angle (X₂), and the average cutting speed (X₃) on cutting stress. Then, the stress distribution pattern produced by the cutting blade and the stalks were evaluated by using different working parameters. Subsequently, taking the minimum cutting stress as the target value, the best combination of cutter structure and working parameters were obtained: the sliding–cutting angle was 29°, the oblique angle was 38°, and the average cutting speed was 500 mm/s. At the condition of optimal parameter combinations, the ultimate cutting stress of the upper cutting blade was 0.95 Mpa and that of the bottom cutting blade was 0.77 Mpa. A cutting test was carried out by using a bench test of the cutting performance, and the mechanical properties of cutting at different cutting speeds were studied. Test results showed that at the optimal cutting speed of 500 mm/s, the cutting stress on the cutter was relatively small and the cutting effect reached the best value. The finite element simulation of cutting the little greens reduced the test cost and provided a reference for the development of a cutting device with low power consumption. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Research and Experiments of Hazelnut Harvesting Machine Based on CFD-DEM Analysis

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,

,

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,

,

,

and

Agriculture 2022, 12(12), 2115; https://doi.org/10.3390/agriculture12122115 - 09 Dec 2022

Cited by 2 | Viewed by 819

Abstract

To solve the problem of difficult hazelnut harvesting in mountainous areas of Liaoning, China, a small pneumatic hazelnut harvesting machine was designed, which can realize negative pressure when picking up hazelnut mixtures and positive pressure when cleaning impurities. The key structure and parameters [...] Read more.

To solve the problem of difficult hazelnut harvesting in mountainous areas of Liaoning, China, a small pneumatic hazelnut harvesting machine was designed, which can realize negative pressure when picking up hazelnut mixtures and positive pressure when cleaning impurities. The key structure and parameters of the harvesting machine were determined by constructing a mechanical model of the whole machine and combining theoretical analysis and operational requirements. To explore the harvesting machine scavenging performance, Liaoning hazelnut No. 3 with a moisture content of 7.47% was used as the experimental object. Firstly, the terminal velocity of hazelnuts and fallen leaves was measured using a material suspension velocity test bench. Secondly, the gas–solid two-phase flow theory was applied comprehensively, and the motion state, particle distribution, and air flow field distribution of hazelnuts from the inlet to the outlet of the pneumatic conveying device were simulated and analyzed using the coupling of computational flow fluid dynamics method (CFD) and discrete element method (DEM) to evaluate the cleaning performance from the perspective of the net fruit rate of hazelnuts in the cleaning box. Finally, a Box–Behnken design experiment was conducted with the sieve plate angle, the distance of the sieve plate, and the air flow velocity as factors and the net fruit rate of hazelnuts as indicators to explore the influence of the three factors on the net fruit rate of hazelnuts. The parameter optimization module of Design-Expert software was used to obtain the optimal combination of parameters for the factors. The experimental results show that the test factors affecting the test index are the following: the air flow rate, the angle of the screen plate, and the distance of the screen plate. The best combination of parameters was an air flow velocity of 14.1 m∙s⁻¹, a sieve plate angle of 55.7°, and a distance of the sieve plate of 33.2 mm. The net fruit rate of hazelnuts was 95.12%. The clearing performance was stable and can guarantee the requirements of hazelnut harvester operation, which provides a certain theoretical basis for the design of a nut harvester. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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Open AccessArticle

Design and Multi-Parameter Optimization of a Combined Chinese Milk Vetch (Astragalus sinicus L.) Seed Harvester

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,

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,

and

Agriculture 2022, 12(12), 2074; https://doi.org/10.3390/agriculture12122074 - 02 Dec 2022

Viewed by 713

Abstract

In order to solve problems such as poor applicability of headers, weak separation ability of threshing mechanisms and poor impurity-removal ability of cleaning devices in the existing seed harvest methods of Chinese milk vetch (Astragalus sinicus L.), a combined Chinese milk vetch [...] Read more.

In order to solve problems such as poor applicability of headers, weak separation ability of threshing mechanisms and poor impurity-removal ability of cleaning devices in the existing seed harvest methods of Chinese milk vetch (Astragalus sinicus L.), a combined Chinese milk vetch seed harvester was designed in this paper. The parameters of the key components, such as the flexible anti pod-dropping seedling-lifting header, the longitudinal rod-teeth-type threshing device and the air-sieve-type layered impurity-controlled cleaning device, were designed and optimized. Aiming at reducing seed loss rate, breakage rate and impurity rate of Chinese milk vetch during the mechanical harvesting process, through multi-parameter optimization, the best combination of working parameters was obtained: machine forward speed was 3 km·h⁻¹, rotation speed of the threshing drum was 550 r·min⁻¹, rotation speed of the cleaning fan was 990 r·min⁻¹ and the scale sieve’s opening was 35 mm. Field tests were performed under these parameters, and the results showed that the seed loss rate of Chinese milk vetch was 2.35%, the breakage rate was 0.22% and the impurity rate was 0.51%, which were better than the technical requirements of loss rate and breakage rate less than 5% and impurity rate less than 3% specified in relevant standards. The research results can solve the shortage problem of efficient seed harvest equipment in large-scale planting areas of Chinese milk vetch, and will further help to carry out seed harvest experiments on different varieties of Chinese milk vetch and other green manure varieties in paddy fields. Full article

(This article belongs to the Special Issue 'Eyes', 'Brain', 'Feet' and 'Hands' of Efficient Harvesting Machinery)

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