Quadratic Orthogonal Rotation Combination Research Articles

Study on the Impact of Cutting Platform Vibration on Stalk Cutting Quality in Industrial Hemp

In response to the unclear impact of header vibration on cutting performance (stalk cutting quality and cutting energy consumption) during field operations of industrial hemp harvesters, this study utilized a vibration recorder to collect information on header vibration during the operation of industrial hemp harvesters. Through data processing, the dominant range for the resonant frequency and amplitude of the cutting platform is primarily concentrated between 5–45 Hz and 0–35 mm, respectively. Using numerical simulation techniques, a quadratic orthogonal rotation combination experiment was conducted with vibration frequency and amplitude as experimental factors and stalk cutting quality and cutting energy consumption as indicators. Regression equations were established to reveal the relationships between indicators and factors, elucidating the influence of each factor and its interactions on the indicators. Specifically, for the crack length indicator, the amplitude has a highly significant influence on the model, and there is a significant interaction effect between vibration frequency and amplitude on the model. As for the cutting energy consumption indicator, frequency and the interaction between frequency and amplitude significantly affect the model, while amplitude has an extremely significant impact on the model. Through comprehensive fuzzy evaluation, the optimal vibration parameter combination satisfying comprehensive cutting performance indicators was determined as a vibration frequency of 37.86 Hz and an amplitude of 5.34 mm. Furthermore, the reliability of the model has been further validated. This research can provide a reference for improving the field performance of industrial hemp harvesters.

Development and Experimentation of Intra-Row Weeding Device for Organic Rice

Weeds in paddy fields can seriously reduce rice yield. An intra-row weeding device with double-layer elastic rods was designed, considering the differences in mechanical properties between rice and weeds, which can press weeds into the soil and avoid damaging rice. The elastic force of the elastic rods can be adjusted by changing the position of the regulating mechanism to adapt to different weeding conditions. A measurement experiment was conducted to determine the variation rule of elastic force. The quadratic orthogonal rotation combination discrete element simulation experiment, which used weeding depth and weeding speed as experimental factors, and the amount of soil disturbance and the force of the inner and outer elastic rod in the horizontal and vertical directions as experimental indicators, was conducted to study the interaction between the weeding device and the soil. The optimal weeding parameters were obtained: the weeding depth was 15 mm, the weeding speed was 0.9 m/s. The field experiment, which used the various parameters of the weeding device as experimental factors and the weeding rate and damaging seedling rate as experimental indicators, was conducted to determine the weeding effect. The experimental results showed that the optimal position of the regulating mechanism was 270 mm, with a weeding rate of 80.65% and a damaging seedling rate of 3.36%. The weeding rate can be increased by at least 11.18% by adjusting the regulating mechanism to a suitable position under the same weeding conditions. This study can provide a reference for research on weeding machinery for organic rice.

Design and Experiment of an Electric Control Spiral-Pushing Feed Mechanism for Field Fertilizer Applicator

Due to the unique structural characteristics of the traditional spiral fertilizer applicator, the instantaneous filling coefficient cannot be determined, which is not conducive to achieving precise control of the fertilizer discharge rate. Therefore, a spiral-pushing fertilizer applicator has been designed. By using a structure of variable diameter and variable spiral pitch to squeeze fertilizer gradually, precise control of the fertilizer discharge is achieved. The study analyzes the effects of screw pitch, screw diameter, and rotational speed on the filling coefficient; it uses spiral pitch elongation percentage, spiral diameter elongation percentage, and rotational speed as experimental factors, and filling coefficient and particle axial velocity coefficient as experimental indicators. Through quadratic orthogonal rotation combination design experiments, the fertilizer discharge performance of the spiral-pushing fertilizer applicator was optimized. The experimental results indicate that for the filling coefficient, x1x2 has an extremely significant impact, while for the axial velocity coefficient of particles, x1 and x3 have an extremely significant impact. When the rotational speed x3 is 30 r/min, the optimized spiral pitch elongation percentage x1 is 189.82–200%, the spiral diameter elongation percentage x2 is 102.75–106.76, the filling coefficient is greater than 95%, and the particle axial velocity coefficient is less than 10%, achieving the best fertilizer discharge performance. An electrically controlled fertilizer discharge system was also designed, and bench tests were conducted on it. The results show that the average deviation between the fertilizer discharge performance of the spiral-pushing fertilizer applicator driven by the electrically controlled fertilizer discharge system and the preset value is 2.14%. This proves that, when the fertilizer demand changes, the fertilizer discharge flow can be adjusted through the electrically controlled fertilizer discharge system to achieve precise fertilization. This study provides a reference for the design of spiral fertilizer applicators.

Theoretical analysis and experiment of seed-picking mechanism of belt high-speed seed-guiding device for corn

Under the condition of high-speed sowing (12-16 km/h), due to the high rotational speeds of the seed disk, the seeds leave the disk at an excessively high speed, which challenges the seed-picking capacity of the belt-type high-speed seed guide device. In this paper, the theory of seed-picking mech-anism is analyzed, and performance optimization tests are completed to further improve the operation effect of the seeder. The mechanical model of seed picking was established through the force analysis of seeds. The influence of vacuum degree, feeder wheel rotation speed, and seed picking angle on seed picking quality and the parameter range of each factor were obtained by single factor test. A three-factor five-level quadratic orthogonal rotation combination test was performed, and the test re-sults were refined and evaluated. The test factors used were vacuum degree, feeder wheel rotation speed, and seed picking angle. The test indexes used were the seed picking rate, re- picking rate, and miss- picking rate. According to the results, the seed picking rate was 99.89%, the re-picking rate was 0, and the miss-picking rate was 0.11% when the vacuum degree was 6.89KPa, the feeder wheel rota-tion speed was 568.95rpm, and the seed picking angle was 7.6°.

Design and optimisation of seed-metering plate of air-suction vegetable seed-metering device based on DEM-CFD

The common problem of missed seeding during high-frequency sowing with air-suction seed-metering devices was investigated. A device was optimised and fitted with an auxiliary seed-supporting mechanism using pelletised Chinese flowering cabbage seeds as a typical example. Seed-metering was examined at the micro scale and the critical points were drag force and seed velocity. Suction hole capture duration, migration resistance and collision limit speed were defined as performance evaluation indices for seed filling and seed cleaning, respectively. Modelling by coupled discrete element method and computational fluid dynamics was adopted to simulate the gas–solid two-phase working process of the air-suction seed-metering device. The relationship between seed velocity and drag force was analysed to determine the characteristics of seed flow as well as airflow. At the macro scale, the evaluation indexes of filling and cleaning performance were defined, and experiments designed using quadratic orthogonal rotation combination were performed with maximum single seed rate as the final optimisation goal. The optimal parameter combination for the seed-metering plate was a seed spoon thickness of 1.2 mm, a spoon arc length of 3.2 mm, and a seed cleaning knife inclination of 61.2°. Bench comparison tests were applied to compare optimised seed-metering plate with the original seed-metering plate and the other two control groups at different operating speeds. Results showed that the optimised seed-metering plate had a seedless rate of 1.24%, which was lower than 4.26% obtained by the non-optimised seed-metering plate, indicating that the optimise device had excellent performance.

Identification of optimal irrigation and fertilizer rates to balance yield, water and fertilizer productivity, and fruit quality in greenhouse tomatoes using TOPSIS

The precise management of water and fertilizer is necessary to maximize greenhouse tomato production. Irrigation quantity and fertilizer application rate were experimentally varied to determine their effects on tomato yield, water and fertilizer productivity, and nutritional and flavor quality over four consecutive growing seasons in two cities, Yangling and Baoji. The experiment was designed as a quadratic orthogonal rotation combination with two factors at five levels and a total of 16 treatments. TOPSIS (technique for order preference by similarity to an ideal solution) models were created to predict the effects of drip irrigation water quantity and fertilizer application rate on indicators of tomato water and fertilizer productivity, yield and quality. The tomato indicators showed a downward opening quadratic relationship with irrigation quantity and a similar relationship with fertilizer application rate. The composite indicators exhibited a downward opening paraboloid relationship with irrigation and fertilizer rates. Tomato pan coefficient (Kcp) values in the range 0.74–0.78 and the fertilization coefficient (Kf) values in the range 1.13–1.27 produced optimal tomato growth in all experimental plots. To ensure the results of this study are of practical use, over 95% of the highest composite indicators were used to identify the optimal range of Kcp as 0.68–0.83 and the optimal range of Kf as 0.98–1.34 in spring, with corresponding ranges in fall being 0.68–0.82 and 1.06–1.41. This study proposes a method for analyzing tomato growth and provides guidance for precise irrigation and fertilizer management in greenhouse tomato production in Northwest China.

Optimal Design and Analysis of Cavitating Law for Well-Cellar Cavitating Mechanism Based on MBD-DEM Bidirectional Coupling Model

A variable velocity parallel four-bar cavitating mechanism for well-cellar can form the well-cellar cavitation which suits for well-cellar transplanting under a continuous operation. In order to improve the cavitating quality, this paper analyzed the structural composition and working principle of the cavitating mechanism and established the bidirectional coupling model of multi-body dynamics and the discrete element between the cavitating mechanism and soil through Recurdyn and EDEM software. Based on the model, a three-factor, five-level quadratic orthogonal rotational combination design test was conducted with the parameters of the cavitating mechanism as the experimental factors and the parameters of the cavitation as the response index to obtain the optimal parameter combination, and a virtual simulation test was conducted for the optimal parameter combination in order to study the cavitating law of the cavitating mechanism and soil. The test results showed that the depth of the cavitation was 188.6 mm, the vertical angle of the cavitation was 90.4°, the maximum diameter of the cavitation was 76.1 mm, the minimum diameter of the cavitation was 68.5 mm, and the variance in the diameters for the cavitation was 5.42 mm2. The cavitating mechanism with optimal parameters based on the Recurdyn–EDEM bidirectional coupling mode could further improve the cavitating quality.

Optimization and Experiment on Key Parameters of Harvester for Auricularia auricula

The Auricularia auricula harvester has low harvesting productivity, low qualification rate, and high breakage rate, and the lack of research on key operating parameters has become a bottleneck restricting the large-scale development industry. In view of the difficulty of industrialization and promotion of Auricularia auricula harvesting equipment, this paper combines the research on the physical properties of Auricularia auricula, adopts a quadratic orthogonal rotation combination design test and response surface analysis method to carry out the optimization and test of the key parameters of the harvesting equipment of Auricularia auricula, including the speed of the tray fungus stick (A), the frequency of the harvesting knife (B), and the distance of the harvesting knife (C). Design-Expert software was used to analyse the data and investigate the influence of each parameter and its interaction on the harvesting productivity, qualified rate, and breakage rate. The test results show that the factors affecting the harvesting productivity are in order: (A) > (B) > (C); the factors affecting the harvest qualification rate are in order: (C) > (B) > (A); and the factors affecting the harvesting damage rate are in order: (C) > (B) > (A). The multi-objective optimization results show that the optimal parameter combination of the key parameters of the Auricularia auricula harvesting equipment operation is that the tray speed is 308.17 r/min, the harvesting knife frequency is 10.78 Hz, the spacing between the harvesting knives is 84.67 mm, the productivity is 363 bags/h, the pass rate is 94.26%, and the breakage rate is 2.40%. The field production application under this optimized parameter combination shows that the productivity of the Auricularia auricula mechanized harvester is 346 bars/h, the qualified rate is 91.43%, and the breakage rate is 3.19%. This study can provide a reference for improving the quality of Auricularia auricula harvesting equipment.

Sustainable Soilless Cultivation Mode: Cultivation Study on Droplet Settlement of Plant Roots under Ultrasonic Aeroponic Cultivation

In order to solve the effects of environmental factors on the droplet settlement of a nutrient solution on plant roots when planting plants with ultrasonic aeroponic cultivation, this study aimed to obtain a suitable wind speed range and atomization time through a nutrient solution atomization experiment, to obtain the best control scheme through a multi-environmental parameter combination cultivation experiment. Taking an ultrasonic aeroponic cultivation device as the research object, and lettuce as the test material, experiments were carried out on two factors affecting the wind speed of an axial fan and the atomization time of the nutrient amount of ultrasonic aeroponic cultivation plants; the suitable wind speed range was 1.0–2.5 m/s. The temperatures of the lettuce root zones in the upper, middle, and lower layers of the ultrasonic aeroponic cultivation device at different time periods were obtained by atomizing the nutrient solution. When the optimum temperature for the root growth of lettuce was 15–20 °C and the wind speed was 1.0–2.5 m/s, the continuous atomization time of the nutrient solution was 66–184 min. Using a quadratic orthogonal rotation combination design method, three main factors, namely wind speed, ambient temperature, and atomization time, were selected to test droplet settlement in the lettuce roots. The droplet settlement in the lettuce root system was measured. The droplet settlement regression equation in the lettuce root system was established. The reliability of the regression model was tested according to the significance condition, and a simplified quadratic orthogonal regression equation was obtained. The main effect analysis, single factor analysis, and interaction effect analysis were used to analyze the model, and the model was further verified. The verification results showed that the relative error between the predicted value and the actual value of the average root droplet sedimentation was 5.8%. The optimum wind speed was 2.5 m/s, the ambient temperature was 16 °C, and the atomization time was 184 min when the ultrasonic aeroponic cultivation device designed in this study was used to cultivate lettuce. It could provide a theoretical reference and an experimental basis for the control of the related growth environment parameters of plants cultivated using ultrasonic aeroponic cultivation.

横轴流联合收获机脱分选装置创新设计与性能试验

Aiming at the problems of high grain entrainment loss rate and impurity rate of traditional horizontal axial-flow combine harvesters, a horizontal axial-flow threshing-separating device with coaxial differential threshing drum, conical cleaning fan, double-layer vibrating screen and spiral plate-tooth re-thresher is designed. Meanwhile, a test-bed with a feeding rate of 2 kg/s is designed to improve the device performance. The test through quadratic orthogonal rotation combination design method is used to inspect the effects of the differential drumspeed combination, conical fan blade taper, and length ratio of the high and low speed sections of the differential drum on the loss rate, crushing rate , impurity rate and threshing power consumption. The regression mathematical models of the loss rate, crushing rate, impurity content and threshing power consumption are established, and the multi-objective optimization calculation of the regression mathematical model is carried out by using MATLAB optimization toolbox. The results show that the order of the three factors affecting the loss rate and impurity content of the horizontal axial-flow threshing-separating device is the differential drumspeed combination, the conical fan bladetaper, and the length ratio of high and low speed sections of the differential drum. The field test results show that the performance index of the horizontal axial-flow separation device is better than the requirements of the national standard.

伸缩杆齿-纹杆式荞麦脱粒装置设计与试验

Aiming at the problems of high moisture content of stems during buckwheat harvesting and easy clogging of grid concave plates, a telescopic rod tooth-ribbed rod roller type threshing device was designed. The device is mainly composed of a ribbed rod roller and telescopic rod teeth. When the ribbed rod roller type rotates, the telescopic rod teeth do reciprocating telescopic motion. When the rod teeth rotate to the minimum threshing gap, the outstretch length is the smallest. When the rod teeth rotate to the top, the outstretch length maximum. The device solves the problems of poor material flow between threshing devices and clogging of grid concave plates. This threshing device was attached to the threshing performance test bench, and the buckwheat threshing test was performed. Through the single factor test, the threshing parameter range under the condition of low loss rate and damage rate of the threshing device was obtained: the speed of the threshing roller is 350~450 r/min, the feeding amount is 0.8~1.2 kg/s, and the threshing gap is 9~11 mm. Through the quadratic orthogonal rotation combination test, the results were fitted by multiple linear regression, and the regression equations of the loss rate and the broken rate were obtained, and the significance test was carried out. The response surface analysis of the main influencing factors was carried out to explore the influence of threshing parameters on the loss rate and damage rate. Through parameter optimization, the threshing parameter combination with the lowest loss rate and damage rate of the threshing device was obtained. The speed of the threshing roller is 405.47 r/min, the feed amount is 1.06 kg/s, and the threshing gap is 10.49 mm. Under these conditions, the loss rate is 0.05%, and the damage rate is 4.05%. The overall performance of the threshing device is good, which provides a theoretical basis for the research and development of buckwheat mechanized harvesting equipment.

Optimizing irrigation and fertilization frequency for greenhouse cucumber grown at different air temperatures using a comprehensive evaluation model

The strategy for irrigation and application of fertilizer is essential for the intensive production of greenhouse cucumber. In order to determine the optimal irrigation amount (IA) and fertilization frequency (FF) to promote the integrated growth of cucumber under global climate change in the future, we explored the comprehensive effects of air temperature (AT), IA, and FF on the growth, yield, fruit quality, water and fertilizer use efficiency of cucumber. A five-level quadratic orthogonal rotation combination design with three experimental factors (AT, IA, and FF) was applied for 23 coupling treatments over three growing seasons during spring (2020S) and fall (2020F and 2021F). The technique for order preference by similarity to ideal solution of combining weights based on game theory was applied to construct cucumber comprehensive growth evaluation model. Single and two experimental factors analysis showed that single factor and the coupling of AT−IA, AT−FF and IA−FF both had significant effects on the integrated growth of cucumber for three seasons. For the AT−IA−FF combination in 2020 S, levels of − 0.09 for AT (26.5/16.5, day/night, °C), − 0.21 for IA {97 % crop evapotranspiration (ETc)}, and − 0.13 for FF (time/6 days) were the optimal parameters for comprehensive cucumber growth. The corresponding combinations for 2020F and 2021F were determined as 0.15 and − 0.21 for AT (27.8/17.8 and 25.9/15.9, day/night, °C), − 0.09 and 0.05 for IA (99 % and 101 % ETc), and − 0.08 and − 0.07 for FF (both time/6 days). Furthermore, when the AT ranges were 18/8 − 21.7/11.7, 21.7/11.7 − 27/17, 27/17 − 32.4/22.4, and 32.4/22.4 − 36/26 (day/night, °C), the corresponding to IA and FF intervals that maximized cucumber integrated growth were: 87 %− 91 % ETc and time/6 − 7 days, 94 %99 % ETc and time/5 − 6 days, 99 %− 104 % ETc and time/4 − 5 days, 107 %− 114 % ETc and time/3 − 4 days, respectively. These results suggest for the future global climate change, comprehensively understanding the growth of cucumber could save resources and potentially enhance cucumber production.

Establishment of millet threshing and separating model and optimization of harvester parameters

Aiming at the problems of low threshing rate and high loss rate in threshing and separating device of millet combine harvester, an axial-flow threshing and separating device with front-end rasp bar and rear-end nail tooth structure was designed. The difference of threshing performance and separating performance between rasp bar and the nail tooth was obtained, based on the mathematical model of threshing and separating performance. The threshing and separating performance of the rotary roller of full stripe bar, full nail tooth, and combined-stripe bar and nail tooth were compared by model analysis. The earhead model was established by using Hertz-Mindlin with bonding model. The Discrete Element Method (DEM) simulation test was carried out, and its results combined with that of model analysis to optimize the rotary roller structure parameters. The simulation single factor tests were carried out to obtain the influence rules of rotary roller speed, threshing clearance and concave grid spacing on the operation performance. Finally, a three-factor five-level quadratic orthogonal rotation combination test was carried out. Using the method of variance analysis and multi-objective optimization, it was calculated the best operating parameters and optimal performance indicators of the device. The verification test of the optimization results shows that they are basically consistent with the optimization results, which shows that the rasp bar and nail tooth rotary roller can meet the requirements of millet threshing and separation operations. Mathematical model analysis and DEM can provide reference for the optimization design of millet threshing and separation device.

Stability characteristics and experiment of hydraulic drive four-wheel chassis

PurposeThis study aims to improve the maneuverability and stability of four-wheel chassis in a small paddy field; a front axle swing steering four-wheel chassis with optimal steering is designed.Design/methodology/approachWhen turning, the front inner wheel stops and the rear inner wheel is in the following state. The hydraulic drive system of the walking wheel adopts a driving mode in which two front-wheel motors are connected in series and two rear wheel motors in parallel. The chassis uses a combination of a gasoline engine with a water cooling system, a CVT continuously variable transmission and a hydraulic drive system to increase the control capability. The front axle rotary chassis adopts a step-less variable speed engine and a hydraulic control system to solve the hydraulic stability of the chassis in uphill and downhill conditions so as to effectively control the over-speed of the wheel-side drive motors. Through the quadratic orthogonal rotation combination design test, the mathematical models of uphill and downhill front-wheel pressures and test factors are established.FindingsThe results show that the chassis stability is optimal when the back pressure is 0.5 MPa, and the rotating slope is 4°. The uphill and downhill pressures of the front wheels are 2.38 MPa and 1.5 MPa, respectively.Originality/valueThe influence of external changes on the pressure of hydraulic motors is studied through experiments, which lays the foundation for further research.

Parameter optimization of waste coal briquetting and particulate matter emissions test during combustion: A case study

The abundant coal powder generated as a waste by-product during the lignite upgrading process is harmful to the environment. Lignite briquetting offers a practical solution for lignite usage. Altering the process parameters of briquetting can significantly improve briquette quality. In this paper, the characteristics of lignite briquettes, including drop strength and compressive strength were investigated. A combination of quadratic orthogonal rotation combination designs and regression equations established the best process parameters to be 40% weight of #2 upgraded coal, 20% weight of briquetting moisture, 25 MPa of briquetting pressure, and 12 h of drying time. The low error variance of the drop strength and compressive strength, at 0.01% and 1.83% respectively, verified the feasibility of the model. The analysis by scanning electron microscope (SEM) showed that the surface morphology of briquette was denser than that of raw coal. Finally, the combustion test of briquettes revealed that the particulate matter emission (PM2.5) of briquette was 16.7% lower than that of raw coal. In summary, these data provide a theoretical reference for realizing the reasonable utilization potential of waste products derived from industrial processes.

Analysis of the Mechanism and Performance Optimization of Burying Weeding with a Self-Propelled Inter Row Weeder for Paddy Field Environments

To solve the problems of poor quality mechanical weeding and no obvious plowing effect in complex paddy field environments, the burying weeding operation mode was proposed. The height and force acting on the weeds were the main factors that altered the effectiveness of burying. The structure of the rake teeth weeding wheel was designed and matched with appropriate power, and the rake teeth weeding device was optimized. To verify the rationality of the designed device, the forward speed of the machine, rotating speed of the weeding wheels and weeding depth were selected as the experimental factors, and the inter row weeding rate was selected as the experimental index. A quadratic orthogonal rotation combination experiment with three factors and five levels was designed and optimized. The results showed that when the forward speed was 0.64 m/s, the rotational speed of the weeding wheel was 140 r/min, the weeding depth was 56.8 mm, the inter row weeding rate predicted by the model was 88.43%, and the inter row weeding rate was determined by a confirmatory experiment to be 87.06%, which met the weeding requirements for modern agronomy. To intuitively analyze how the soil was disturbed by the weeding wheel, the explicit dynamic analysis software LS-DYNA was used to build a fluid–solid coupling simulation model of the weeding wheel and water soil. The soil density and coupling stress were used to analyze the plowing state of paddy soil when the weeding wheel was operated. This study provides references for the design and development of paddy field weeding components and for mechanical and soil coupling simulation in paddy fields.

穴施肥装置充肥性能研究及肥腔优化

Hole fertilization is an effective method to improve the utilization rate of chemical fertilizer. In order to improve the accuracy and stability of the amount of fertilizer discharging for the hole fertilization device, this paper proposed the method of rotary filling by notched disk, designed a hole fertilization device with notched disk, and completed the structure design of the device and cavity. Through the dynamic analysis of fertilizer particles in the process of fertilizer filling, this study found that the interface span of fertilizer cavity, the rotational speed of fertilizer disk, and the amount of fertilizer applied in each hole are the main factors affecting the performance of filling. Then, this study carried out the three-factor quadratic orthogonal rotation combination simulation test to optimize the structure of the cavity. The test used the discrete element method with interface span of fertilizer cavity, the rotational speed of fertilizer disk, and the amount of fertilizer applied in each hole as test factors and the accuracy and variation coefficient of filling amount as evaluation indexes. Results showed that the optimal performance was obtained when the cross section span of the cavity was 13.58°, the opening width was 29.56 mm, and the depth was 22.08 mm. The field validation showed that the average accuracy of filling amount per hole was 97.67%, and the average variation coefficient was 1.90%. The performance of fertilizer discharge satisfied the design requirements, and agreed with the law of the simulation results. The research results could provide a theoretical basis for the design of hole fertilization device and the improvement of filling performance.

Design Evaluation and Performance Analysis of the Inside-Filling Air-Assisted High-Speed Precision Maize Seed-Metering Device

In view of the problems of a poor seed-filling state and poor seed-cleaning effect of a precision metering device under high-speed working conditions, an inside-filling air-assisted high-speed precision maize seed-metering device was designed, fabricated, and evaluated. The overall structure and working principles of the seed-metering device are explained. Theoretical analysis and parametric design of the key parts, such as the horizontal stirring notch seed-metering plate and the wheel seed-cleaning mechanism, were carried out. The main factors that produce multiple seeding problems were studied. The forward speed (FS) and working pressure (WP) of the seed-metering device are determined as the main factors affecting the seeding performance. A quadratic orthogonal rotation combination experiment was designed. The relationship between influencing factors and performance indexes was constructed using the Design-Expert 10.0.7 software. The response surface method was used to optimize the experimental results. The results of the bench validation experiments showed that the seeding performance of the seed-metering device was excellent when the FS of the seed-metering device was 13.10 km/h and the WP of the seed-metering device was 4.75 kPa. The results of the bench comparison showed that the seeding performance of the designed seed-metering device was better than that of the conventional air-suction precision seed-metering device. This study provides theoretical and practical references for the optimized design of a pneumatic precision seed-metering device and the sustainable development of grain.

Calibration and Experimental Validation of Contact Parameters for Oat Seeds for Discrete Element Method Simulations

Highlights The static friction coefficient and rolling friction coefficient of oat seeds were calibrated by the discrete element method. Two representative oat varieties were selected. The hollow cylinder method and sidewall collapse method were used together to reduce the test error. Abstract . Hulless and shelled oat are two types of oat with major differences in physical appearance. To study the contact parameters between the two different oat seed types, these parameters were delineated with the discrete element method and graphic image processing technology. Using plexiglass as the contact material, the experiments used two different angle of repose measurement methods—hollow cylinder and collapse sidewall devices, to perform bench and simulation experiments on the two different oats. Under different measurement methods, bench experiments measured the angles of repose of the two oat seed types at 33.19°, 33.82° and 22.45°, 23.57°; the static friction coefficient and rolling friction coefficient were the experimental factors, and the angle of repose was the experimental indicator in the simulation. The steepest climbing experiment determined the optimal range of the experimental factor, and the regression equation between the static friction coefficient, rolling friction coefficient and angle of repose was established by a quadratic orthogonal rotation combination experiment. Finally, the angles of repose measured by the bench experiment with the two different measurement methods were treated as target values, the coefficient of static friction and the coefficient of rolling friction were solved; the coefficient of static friction between hulless oats was 0.36, and the coefficient of rolling friction between hulless oats was 0.052; the coefficient of static friction between shelled oats was 0.24, and the coefficient of rolling friction between shelled oats was 0.036. The obtained contact parameters between seeds were input into EDEM, the simulation and bench experiment results were verified. The difference between the simulation results and the actual values was within 3%. The angle of repose of oats after calibration was close to the actual situation, and the calibration results had high reliability and provided a referencefor the measurement of contact parameters between other agricultural crop seeds. Keywords: Calibration, Contact parameters, Discrete element method, Oat.

Design and Testing of a Shearing and Breaking Device for Mulch Film and Cotton Stalk Mixtures

HighlightsThis article presents a shearing and breaking device for mulch film and stalk mixtures after mechanized recovery.The focus is on a curved V-shaped mechanism with three-dimensional precompression and shearing functions.The device can efficiently and continuously perform film crushing, stalk crushing, and entanglement breaking.The crushed film and stalk mixture is conducive to material separation, further treatment, and recycling.Abstract. Because the mixture of mulch film and stalks collected in harvested cotton fields in Xinjiang, China, cannot be separated mechanically, a technical solution for shearing and breaking is proposed. This study designed a shearing and breaking device for film and stalk mixtures that can continuously perform film crushing, stalk crushing, and entanglement breaking. The design focuses on a curved V-shaped shearing mechanism, which provides three-dimensional shearing and improves the crushing of film and stalks. The linear speed of the conveying rollers (x1), the working angle of the shearer (x2), and the speed of the shearer spindle (x3) were selected as influencing factors, and the crushed film rate (Ph), crushed stalk rate (Gh), and broken entanglement rate (Kh) were used as evaluation indexes in quadratic orthogonal rotation combination tests. The test results were analyzed with Design-Expert software, and a regression model between each factor and the evaluation indexes was established to analyze the significance of each factor’s influence. The results showed that the influences of the three factors on Ph in descending order were x3, x2, and x1. The order of influence on Gh and Kh was x3, x1, and x2. The optimization module in the software was used for parameter optimization, and the optimal combination of working parameters of the device was x1 = 0.98 m s-1, x2 = 153°, and x3 = 753 r min-1. The optimized parameter combination was tested and verified, and the results were Ph = 77.28%, Gh = 87.78%, and Kh = 85.30%. The test results are basically consistent with the predicted values, and the optimized working parameters are reliable and can meet the requirements for the shear fracture of film and stalk mixtures. This research provides a technical reference for the cutting and crushing of complex mixed solid materials. Keywords: Agricultural machinery, Curved V-shaped moving knife, Design, Film and stalk mixture, Parameter optimization.