INMATEH - Agricultural Engineering

22-32

Authors: Wusong XIAO, Po NIU, Pan WANG, Yingjie XIE, Fei XIA

Mini-tiller is an indispensable agricultural machinery in hilly and mountainous areas of China. Rotary blade is an important working part of mini-tiller, which directly affects the operation quality and power consumption of mini-tiller. In order to reduce the cutting resistance and power consumption of the rotary blade of mini-tiller, the cutting process of the rotary blade was analyzed by numerical simulation, and the tangential bending radius (R), bending angle (β) and edge thickness (c) of the rotary blade were selected as factors to optimize it. After comparing the cutting resistance and cutting power consumption of the rotary blade before and after optimization, the results show that the cutting force of the optimized rotary blade is smaller than that of the rotary blade before optimization. The cutting power consumption of the optimized rotary blade is 2.4% lower than that of the unoptimized rotary blade, which achieves the purpose of drag reduction and consumption reduction.

45-56

Authors: Zhenkun ZHI, Haifeng LUO

In order to solve the problem of complicated processes, low efficiency and high cost of economic tree trunks girdling, inspired by cam mechanism this study developed a new type of automatic half-ring girdling device, which can automatically complete a series of operations, including the tree trunk profile scanning, girdling trajectory calculating and automatic bark cutting. A pair of laser rangefinders and guide screws were symmetrically arranged on a half-ring rotating rail, which could rotate around the tree trunk, and two chainsaws assembled above the guide screws were controlled to move radially. The laptop was used as upper computer, and a 4-axis motion control card was used as the lower computer, which constituted the control system of precise movement. The programs of the tree trunk profile scanning, the xylem profile curve fitting and the chainsaw centre trajectory calculation were designed in LabVIEW. The scanning tests and girdling experiments were carried out on the different sections of the tree trunks in the laboratory. The feasibility of the automatic girdling device for economic tree trunks was verified with one complete and automatic girdling operation finished by this device, which took 150 seconds, and the error range of automatic girdling was within ±2mm. This device improves the automation degree of girdling operation and provides a support for the development of economic forestry.

77-86

Authors: Huhu YANG, Junlin HE, Jiaxuan LU, Tao WANG, Yuehua WANG, Yanxi GUO

This paper addresses the problem of the lack of intrinsic and contact parameters when applying the discrete element method to simulate and analyze the key aspects of white kidney bean seed sowing, harvesting and clearing. The experiment took white kidney bean seeds as the research object, measured the intrinsic parameters of white kidney bean seeds by using the universal testing machine, and measured the collision recovery coefficient of 0.445, static friction coefficient of 0.452 and rolling friction coefficient of 0.091 between white kidney bean seeds and Q235 steel plate by physical test and EDEM discrete element simulation parameter calibration. The stacking experiment was carried out by the cylinder lifting method, numerical processing was performed with MATLAB, and the actual stacking angle of white kidney bean seeds was 31.28°. The steepest climbing test was designed with the interspecific contact parameters as factors and the relative error between the actual and simulated stacking angles as indicators. The optimal combination of the interspecific contact parameters of white kidney bean was determined by response surface optimization analysis, and the interspecific collision recovery coefficient of white kidney bean was obtained as 0.39, static friction coefficient was 0.53, rolling friction coefficient was 0.092. Using the optimal parameters for the simulation test, the relative error between the actual stacking angle of white kidney bean seeds and the simulated stacking angle was 1.63%, indicating that the calibrated simulated contact parameters were reliable and could provide reference for the discrete element simulation of white kidney bean seeds.

96-105

Authors: Jinglong REN, Huili ZHANG, Guangyuan WANG, Chenlong DAI, Fei TENG, Moxian LI

This research is dedicated to enhancing the accuracy and processing speed of grape disease recognition. As a result, a real-time grape disease detection model named MSCI-YOLOv8s, based on an improved YOLOv8s framework is proposed. The primary innovation of this model lies in replacing the backbone network of the original YOLOv8s with the more efficient MobileNetV3. This alteration not only strengthens the ability of the model to capture features of various disease manifestations in grape leaf images but also improves its generalization capabilities and stability. Additionally, the model incorporates the SPPFCSPC pyramid pooling structure, which maintains the stability of the receptive field while significantly enhancing processing speed. The integration of the CBAM attention mechanism further accentuates the ability of the model to identify key features, substantially increasing the accuracy of disease detection. Moreover, the model employs Inner-SIoU as the loss function, optimizing the precision of bounding box regression and accelerating model convergence, thereby further enhancing detection efficiency. Rigorous testing has shown that the MSCI-YOLOv8s model achieves an impressive average precision (mAP) of 97.7%, with an inference time of just 37.2 milliseconds and a memory footprint of 39.3 MB. These advancements render the MSCI-YOLOv8s not only highly efficient but also extremely practical for real-time grape disease detection, meeting the actual demands of grape orchard disease identification and demonstrating significant potential for application.

117-128

Authors: Moxian LI, Xueliang CHANG, Xiaoning HE, Ning ZHANG, Wei LIU, Zhixin LIU, Tongtong DONG, Shuqi SHANG, Dongwei WANG, Maomao ZOU, Yunkang LI, Zhenjia MA

Aiming at the traditional peanut planter seed and fertilizer sowing depth inconsistency caused by seed burning and injury, fertilizer waste and low seed emergence rate, the design of a peanut planter with high-speed operation and controllable seed and fertilizer sowing depth was performed. The laser sensor is added to detect the height of the ridge and the furrow opener position feedback, and the speed sensor detects the operating speed of the peanut planter. The mechanical analysis of the four-link rod clarifies the control principle, improves the PID algorithm of the integral term, designs the control strategy based on the operating speed of the planter, controls the electro-hydraulic system, and realizes the sowing and fertilizing depth adjustment of the furrow opener. Through the design of three-factor three-level orthogonal simulation test, it is concluded that the vehicle speed and height deviation value are significant factors affecting the sowing and application depth, and under the verification of the field test, it is obtained that when the sowing depth is 50 mm under the speed of 3 km/h, the dynamic sowing depth qualification rate is 96.26%, and the maximum coefficient of variation of the sowing depth is 2.58%, which improves the effect of the existing control of the sowing depth of the peanut by 6.05%, and reduces the variation of the sowing depth by 2.85%. The research has demonstrated superior performance compared to traditional mechanical adjustment in regulating the planting depth of peanuts, thereby achieving the intended design objective.

138-147

Authors: Zhixin LIU, Shuqi SHANG, Shikuan MA, Yaxiu HOU, Tongtong DONG, Xiaoning HE

Aiming at the potato soil separation device of potato harvester, which generally has the problem of potato high damage in potato-soil separation, a three-stage potato soil low-loss separation device was developed, and orthogonal experiments were designed with the help of RecurDyn-EDEM coupled simulation method. A field bench was built for verification tests. The test proved that: when the lift transport chain speed was 1.40 m/s, travel speed was 0.60 m/s, amplitude was 32.0 mm, the impurity rate was 1.49% and the average force on potato was 1.801 N. The potato damage rate was 2.7%, indicating that the design of the three-stage potato soil low-loss separator device worked well.

162-172

Authors: Fengli LI, Jianghui CHEN, Keyi LIU, Jia ZHANG, Yaou ZHANG, Junchi YIN, Fei LIU, Manquan ZHAO

In order to solve the problems of easy seed shedding and poor seed population mobility during sowing, a precision seed metering tray for edible sunflowers with seed guide strips was designed in this paper. This article aims to adjust the adsorption posture of sunflower seeds by designing three types of structures: triangular seed guide strip, rectangular seed guide strip, and diamond seed guide strip. Seed population motion simulation and seeding performance experiments were conducted on the seeder. The experimental results show that adding a triangular seed guide strip to the seeding tray has the best disturbance effect on the seed population, with the highest proportion of seeds in the first adsorption stance seed (the seed centroid was adsorbed) and the highest qualification index. The working parameters for the best seed metering performance were obtained: the rotating speed of the seed metering disc was 8.41 r/min, and the vacuum degree was 3.5 kPa.

183-192

Authors: Yongpeng CHEN, Yi NIU, Weidong CHENG, Laining ZHENG, Dongchao SUN

To improve the accuracy of apple fruit recognition, enhance the efficiency of automatic picking robots in orchards, and provide effective visual guidance for the picking robot, a target recognition network model based on improved YOLOv5 is proposed. Firstly, the original apple images collected and the data images obtained by different data enhancement methods are used to establish a dataset of 1,879 images, and the dataset is divided into the training set and the test set under 8:2; then for the problem of low detection accuracy of apple fruits in the natural environment due to the mutual obstruction of apple fruits, this paper modifies the backbone network of YOLOv5 by adding the attention mechanism of the Transformer module, the Neck structure is changed from the original PAFPN to BiFPN that can perform two-way weighted fusion, and the Head structure adds the P2 module for shallow down sampling; finally, the recognition test is performed on the dataset, and a comparative analysis is performed according to different evaluation indexes to verify the superiority of the proposed model. The experimental results show that: compared with other existing models and the single-structure improved YOLOv5 model, the comprehensive improved model proposed in this paper has higher detection accuracy, resulting in an increase of 3.7% in accuracy.

203-213

Authors: Yupeng JIANG, Aiping SHI, Feng LIANG, Jun YANG

With the rapid urbanization in China, there has been a gradual increase in the production of kitchen waste, which poses significant environmental challenges. High-temperature aerobic fermentation is an effective method for recycling kitchen waste. This study focuses on utilizing kitchen waste, wood chips, and compound microbial agents as the main raw materials for fermentation. Various parameters such as temperature, moisture content, and amount of compound microbial agent were selected to conduct experiments on the high-temperature stage of the aerobic fermentation process for kitchen waste. Through response surface optimization experiments, it was determined that the optimal conditions for achieving fast high-temperature fermentation of kitchen waste are as follows: temperature at 60℃, moisture content at 60%, and amount of compound microbial agent at 10%. The order of influence on the reduction rate of kitchen waste is found to be temperature followed by the amount of compound microbial agent and moisture content. These findings provide valuable insights into resource utilization strategies for managing kitchen waste.

224-234

Authors: Hexia CHU, Hongxing LIU

Both cruising ability and safety should be considered in the 3D inspection path planning of agricultural unmanned aerial vehicles (UAVs). Specific to a complex working environment, the 3D inspection environment of agricultural UAVs was simulated through terrain modeling and threat modeling. First, the dynamic constraints of flight approaching rate and response time were added to the threat cost, and the 3D mission space model and flight path cost function were constructed considering the influence of UAVs’ turning performance. Second, the offset estimation strategy, variable spiral search strategy, quasi-reverse learning strategy and dimension-by-dimension mutation strategy were introduced into the dung beetle optimizer (DBO) algorithm to improve the global optimization ability and convergence rate of the algorithm. By establishing a three-dimensional trajectory planning model for unmanned aerial vehicles, the trajectory planning is transformed into a multi-objective function optimization problem, and an improved algorithm is used to solve the three-dimensional trajectory planning of unmanned aerial vehicles. The fitness is evaluated by considering the objective function of trajectory cost, terrain cost, and danger level, and the trajectory planning is iteratively optimized. The results indicate that the proposed improved dung beetle algorithm for trajectory planning has lower overall cost and stability in adapting to different complex terrain environments.

245-254

Authors: Ioan Aurel CHERECHES, Ferenc GASPAR, Ioan Alin DANCI

Soil moisture monitoring and control are essential aspects for precision agriculture. The paper presents the designing and calibration of a low-cost soil moisture monitoring system. The system includes 28 capacitive sensors, connected to an Arduino based data acquisition system, allowing simultaneous multi-point measurements. The calibration process was conducted on six reference points within the moisture content range of 0–25%. The calibration results indicate a non-linear variation and reveal a significant deviation between the sensors leading to the determination of individual variation curves for each sensor.

265-279

Authors: Nadiia SHMYGOL, Władysława ŁUCZKA, Nataliia GAVKALOVA, Zhanna HARBAR, Viktor KOVAL, Lucian-Ionel CIOCA

The study analyses trends in domestic markets and international trade in organic products in some Eastern European countries based on a multifactorial comparative analysis in the regional context and estimates of yield losses about traditional agricultural land processing technologies. Prospects for the development of organic farming by region and in general are determined based on unused reserves of agricultural land suitable for this. The study assessed the organic production development in different regions of Poland and Ukraine: the annual growth rate of transitional and organic lands should be at least +13.3% to meet the strategic goal of reaching 3% of the total agricultural land by 2030.

291-298

Authors: Bin WANG, Lili LI

Soluble solid content (SSC) is one of the important evaluation indexes of the internal quality and taste of fresh jujube. In order to realize the online nondestructive detection of SSC of fresh jujube, this paper took Huping jujube as the research object, adopted self-constructed nondestructive online testing system to collect the spectral information of jujubes (350~2500 nm), and studied the influence of the rotational speed of 4 r/min on the online prediction model of SSC of jujube. Kennard-Stone (KS) algorithm was used to divide the sample into correction set and prediction set. Six commonly used preprocessing methods such as SG smoothing (S-G), multiplicative scatter correction (MSC), standard normal variate (SNV), orthogonal signal correction (OSC), first derivative (FD), and second derivative (SD) were applied to the spectral data, and the regression coefficient (RC) algorithm and the successive projections algorithm (SPA) were utilized to select informative wavelengths, and a quantitative prediction model for the SSC of Huping jujube was established using partial least squares regression (PLSR). The results indicate that the PLSR prediction model established by preprocessing the original spectrum with OSC and combining it with RC algorithm to select characteristic wavelengths was optimal. Therefore, when predicting the SSC of Huping jujube, the optimal model was OSC-RC-PLSR, and the correlation coefficients of the correction set and prediction set were 0.846 and 0.782, respectively, and the corrected root mean square error (RMSEC) and predicted root mean square error (RMSEP) were 1.962 and 2.247, respectively. The results show that non-destructive detection of soluble solid content of jujube can be achieved by combining visible-near-infrared spectroscopy and appropriate regression model, which provides an innovative way for online sorting and identifying fresh jujube.

313-323

Authors: Wenqi GUO, Wenyi ZHANG, Yunxia WANG, Youqiang DING, Bin QI

In order to study the effect of population disturbance on the filling performance of the seed metering device, this paper uses the pneumatic precision seed metering device as the model, and uses EDEM software to simulate the population movement of three different seed metering devices. The bench test was carried out at different pressures at 12 km/h and at different speeds at 3.5 kPa. The results show that the designed seed disk with grooves has the most intense disturbance and the highest qualified rate. In order to verify the performance of the disk, full factor tests are carried out on the air pressure and speed, The test results show that when the operating speed is 10~12 km/h and the positive pressure is 3~3.5 kPa, the leakage rate is no higher than 5.42%, the replay rate is no higher than 0.42%, and the qualified rate is no lower than 94.58%. When the operating speed is 14 ~ 16 km/h and the positive pressure is 3.5~4 kPa, the leakage rate is not higher than 6.7%, the replay rate is not higher than 1.04%, and the pass rate is not lower than 93.12%. All the indicators are better than the national standard.

339-351

Authors: Yong DING, Jian ZHANG, Zhiguo PAN, Weijing WANG, LIU Qi, Shuai WANG, Zhenjia MA, Xiaokang WANG

The analysis of the clearing process of the cutting deck of a small plot wheat combine harvester requires the use of discrete element simulation methods. However, the current simulation test lacks the contact parameters such as wheat stalk and stalk-seed. In this paper, the wheat stalks and seeds at harvest time were taken as the research objects, and the calibration study of the discrete element simulation model parameters of stalks and stalk-seeds was carried out by means of mechanical test determination and EDEM software simulation. The stiffness coefficients of wheat stalks were determined by mechanical tests; the average values of wheat stalk stacking angle of 39.22° and wheat stalk-seed stacking angle of 44.41° were obtained by stacking angle tests. By the steepest climb test and binary regression test, the stalk normal stiffness coefficient was determined to be 5e+08N/m2 and tangential stiffness was determined to be 6.35e+08N/m2; the stalk-stalk collision recovery coefficient was obtained to be 0.551, static friction coefficient was obtained to be 0.797, and rolling friction coefficient was obtained to be 0.079 by the two-level analytical factorization test, the steepest climb test, and the three-factor response surface test. Based on this, the average value of wheat stalk-seed stacking angle was obtained to be 39.22° and the average value of wheat stalk-seed stacking angle was obtained to be 44.41° by the stacking angle test. On this basis, the coefficient of recovery of stalk-stalk collision was 0.434, the coefficient of static friction was 0.884, and the coefficient of rolling friction was 0.339 obtained by the three-factor response surface test. Three validation experiments were carried out by substituting the obtained parameters into the simulation test, and the error values were close to the error value %0.255 in the model, which proved that the experimental data were reliable.

363-374

Authors: Fan JIN, Dejiang LIU, Chengyi ZHONG, Keheng YAO, Jian TONG, Zhibing JIANG

In view of the lack of accurate contact parameters and the difficulty of measuring contact parameters in the discrete element simulation of mechanized harvesting of highland barley, this study took the wax-ripening highland barley as the object, carried out the discrete element simulation of highland barley stem based on EDEM, and calibrated the discrete element simulation parameters of highland barley stem by response surface optimization. In this paper, Plackett-Burman test was used to screen 8 initial parameters. It was found that the static friction coefficient between highland barley stems, the rolling friction coefficient between highland barley stems, and the rolling friction coefficient between highland barley stems and steel plates have significant effects on the particle angle of repose. Based on the optimal value range of significant factors determined by the steepest ascent test, a second-order regression model of the angle of repose and significant parameters was established and optimized based on the results of Box-Behnken test. The optimal parameter combination of significant parameters was obtained as follows: static friction coefficient between highland barley stems is 0.27, rolling friction coefficient between highland barley stems is 0.07, and rolling friction coefficient between highland barley stems and steel is 0.26. Finally, the simulation results under the optimal parameter combination are compared with the actual test angle of repose. The relative error is 0.52 %. That indicates that the parameters of the simulation calibration are credible, which can provide a reference for the future research on the cleaning device in the mechanized harvesting of highland barley.

402-413

Authors: Binxuan GENG, Guowei DAI, Huan ZHANG, Shengchun QI, Christine DEWI

Accurate potato sprout detection is the key to automatic seed potato cutting, which is important for potato quality and yield. In this paper, a lightweight DAS-YOLOv8 model is proposed for the potato sprout detection task. By embedding DAS deformable attention in the feature extraction network and the feature fusion network, the global feature context can be efficiently represented and the attention increased to the relevant pixel image region; then, the C2f_Atten module fusing Shuffle attention is designed based on the C2f module to satisfy the attention to the key feature information of the high-level abstract semantics of the feature extraction network. At the same time, the ghost convolution is introduced to improve the C2f module and convolutional module to realize the decomposition of the redundant features to extract the key features. Verified on the collected potato sprout image data set, the average accuracy of the proposed DAS-YOLOv8 model is 94.25%, and the calculation amount is only 7.66 G. Compared with the YOLOv8n model, the accuracy is 2.13% higher, and the average accuracy is 1.55% higher. In comparison to advanced state-of-the-art (SOTA) target detection algorithms, the method in this paper offers a better balance between comprehensive performance and lightweight model design. The improved and optimized DAS-YOLOv8 model can realize the effective detection of potato sprouts, meet the requirements of real-time processing, and can provide theoretical support for the non-destructive detection of sprouts in automatic seed potato cutting.

429-443

Authors: Jun YANG, Aiping SHI, Yupeng JIANG, Bochuan DING

At present, electric tractors experience significant battery energy loss during operation, resulting in a short continuous running time. Therefore, in order to reduce the power consumption of the tractor drive system, minimize battery energy loss, and extend the operating time under various conditions, this paper presents a method for driving an electric tractor based on dual-motor coupling. Based on the characteristics of the transmission structure, an online torque distribution strategy for dual-motor coupling-driven electric tractors using a fuzzy control approach is proposed. First, an enhanced genetic algorithm is utilized to optimize the fuzzy rule table. Simultaneously, it is compared with the offline optimization strategy of dynamic programming. Subsequently, a method that integrates test data models and theoretical models is employed to establish an efficiency model of key components of the electric tractor drive system and a longitudinal dynamics model of the entire machine. The performance of the entire vehicle was simulated and analyzed under plowing conditions. Finally, on the experimental bench, conduct steady-state load tests and dynamic performance tests on the dual-motor coupled drive system. The results show that the State of Charge (SOC) change trends of the fuzzy control strategy based on the improved genetic algorithm and the dynamic programming strategy are similar. The SOC change values are close, which enhances the adaptability of the electric tractor in various operating conditions. Compared with the fuzzy control strategy, the improved strategy reduced average power consumption by 8.8%, demonstrating that the fuzzy control energy management strategy based on the enhanced genetic algorithm is both economical and superior. The bench experiment demonstrated that the dual-motor drive system can adapt to load changes to achieve power distribution between the two motors, meeting the required workload while reducing power consumption.

466-479

Authors: Jingqiong WU, Xuke WU, Jiabo HUANG

As a bridge connecting agricultural production and consumption, the circulation of agricultural products has the function of connecting supply and demand, guiding production and promoting consumption. However, the development of rural logistics in China is slow, and most logistics centers still rely on experience to plan the pick-up vehicle routings, resulting in long transport time and high cost. In order to improve the efficiency of pick-up and reduce transportation costs, a joint optimization model of cold-chain pick-up vehicle routing and cargo allocation for fresh agricultural products was proposed in this study. Soft time window constraint and three-dimensional loading constraints were considered, and the lowest pick-up cost was used as optimization goals in this model. In addition, adaptive large neighborhood search algorithm (ALNS) and heuristic depth-first search algorithm (HDFS) were combined to solve the model. A case study of Kunming International Flower Auction Center was conducted to compare the schemes of pick-up vehicle routing before and after optimization. Results demonstrate that the pick-up cost after optimization decreases by 9.6 %, the number of vehicles decreases by one, the total volume utilization rate of vehicles increases by 23 %, and the total load utilization rate of vehicles increases by 15 %. This study provides a model reference and solution method for enterprise operators to formulate schemes of pick-up vehicle routing quickly and reasonably.

492-500

Authors: Yang LI, Yanmin TAO, Yulong CHEN, Yiteng LEI

The mechanical properties of lavender are the basis for design and study of mechanized equipment for planting and harvesting of lavender. This paper determines and studies the natural width and height of plant and spike length of three kinds of lavender widely planted in the Yili region and obtains the distribution rules of parameters of the basic physical properties of lavender. Meanwhile, the test of the mechanical properties of lavender was done at the moisture content in the harvest period and different moisture contents. The results indicated that the maximum separation force of the flower of three kinds of lavender (111.3N) was much smaller than the minimum breaking force of the stem (201.5N); and the moisture content significantly affected the mechanical properties of lavender, which could provide corresponding design parameters and important theoretical basis for the design of a new lavender harvester based on separation technology.

514-524

Authors: Jiahao LAN, Yunjie MA

To solve the problem that the moving trajectory and operating trajectory are relatively independent and time-consuming when robots transfer agricultural products from harvesting fields to warehouses or transport vehicles, a type of agricultural materials handling robot was designed, the optimal trajectory planning method for the collaborative operating time of agricultural materials handling robots was proposed, and the time optimal trajectory under the collaborative operation of robot operating system and traveling system was acquired. Specifically, the kinematic model and dynamic model for the collaborative operation of robots were established to perform time optimal trajectory planning for materials handling robots, the Beta distribution was then applied to the Whale Optimization Algorithm (WOA) for population initialization, and a nonlinear convergence factor was introduced to prevent local optimum in the later stage of iterations. Finally, WOA was improved combining the variable neighborhood algorithm to enhance the diversity of the neighborhood structure, and this improved algorithm was applied to model solving. The results reveal that the proposed trajectory planning method can facilitate robots to obtain a smooth and time optical moving trajectory in collaborative operations of materials grabbing and discharging and obstacle avoidance. The displacement, speed, acceleration, and force/torque curves of each joint of the robots change gently, and the double-crawler traction can meet the requirements of the robots and rapidly stabilize and track the time optical trajectory.

535-546

Authors: Dangqin XUE, Zhouming GAO, Jiaxi ZHANG

In this paper, a new horizontal-shaft roller-type cotton stalk puller was designed to address the problems of weak research on cotton stalk pulling and harvesting machines, poor agronomic adaptability, and insufficient research. First, the physical and mechanical properties of cotton stalk were experimentally studied, and the cotton stalk pulling force test was conducted. and it was positively correlated with the cotton stalk diameter. Then, the moisture content and the bending characteristics of cotton stalk were evaluated. The test results showed the bending characteristics were positively correlated with the moisture content but were not evidently influenced by the diameter. Second, with the missed pulling rate and pull-off rate as the evaluation indexes and three independent variables, namely, forward speed, linear speed of stalk pulling rod, and rotation speed of stalk pulling roller, as the influencing factors, a 3D response surface model was established. On this basis, the lack-of-fit term P (p = 0.3650) > 0.05 of the evaluation index—missed pulling rate P1—was acquired, and the P value of pull-off rate P2 was always smaller than 0.0001. Finally, the results demonstrated that the influence of various factors on the missed pulling rate of cotton stalk is significant and followed the order forward speed > linear speed of stalk pulling rod > rotation speed of stalk pulling roller; the significance level regarding the influence on the pull-off rate followed the order rotation speed of stalk pulling roller > linear speed of stalk pulling rod > forward speed. Through the parameter optimization analysis, the optimal parameter combination was obtained which coincide with the model optimization and prediction result. The proposed method provides a basis and experimental reference for studying cotton stalk harvesting machineries.

557-568

Authors: Junming HOU, Yachen YU, Ziyuan TANG, Liang ZHANG, Jiuyu JIN, Wei WANG

The mechanized harvesting of mulberry is important for its production. In the process of harvesting, it is considered not only the mechanical damage of mulberry fruit but also its harvesting efficiency. It is very important to improve the vibration harvesting efficiency of mulberry. In this study, modal analysis of mulberry trees and harmonic response analysis of branches were carried out to determine the harvesting frequency of the branch's vibration and other parameters. The effects of excitation frequency and vibration position on the triaxial acceleration of the mulberry branch at different positions were analyzed by vibration test. Then the triaxial acceleration of branches at different positions was analyzed. The conditions of the mulberry fruit shedding were obtained through theoretical analysis. Through the 20-order modal analysis of mulberry, it is concluded that a better vibration effect can be achieved when the vibration frequency is controlled at 4-16 Hz. According to the harmonic response analysis, the best excitation frequencies are 5-6 Hz, 10-13 Hz, and 14-16 Hz. The harmonic response analysis of fruit branches was carried out, and the stress of fruit stalks at 5 Hz, 10 Hz, and 15 Hz were analyzed. The result shows that the maximum stress is 2.9252×107 Pa, the excitation position is the first-order branch, and the excitation frequency is 15 Hz. The frequencies obtained from modal analysis and harmonious response analysis were used to conduct experiments. When the excitation frequency was 15 Hz, the triaxial accelerations aX, aY, and aZ were 2.12 g, 4.16 g, and 3.99 g, respectively, which were more conducive to the shedding of mulberry fruits.