Search Results (17)

In the cotton fields in Xinjiang, residual film is present in the soil for a long period of time, leading to a decrease in the tensile strength of the residual film and increasing the difficulty of recycling. Existing technologies for residual film recovery focus on mechanical properties and ignore the dragging and tearing of residual film by cotton stubble. The effect of cotton straw–root stubble on residual film recovery can only be better determined by appropriate machine operating parameters, which are essential to improving residual film recovery. Through analyses of the pickup device, key parameters were identified, and a model was built by combining the FEM and SPH algorithms to simulate the interaction of nail teeth, residual film, soil and root stubble. The simulation revealed the force change law of residual film in root stubble-containing soil and the influence of root stubble. By simulating the changes in the characteristics of the residual film during the process, the optimum operating parameters for the nail teeth were determined: a forward speed of 1849.57 mm/s, a rotational speed of 5.5 r/s and a soil penetration angle of 30°. Under these optimized conditions, the maximum shear strain, pickup height (maximum deformation) and average peak stress of the residual film were 1293, 363.81 mm and 3.42 MPa, respectively. Subsequently, field trials were conducted to verify the change in the impact of the nail teeth at the optimized speed on the recovery of residual film in plots containing root stubble. The results demonstrated that when the root stubble height was 5–8 cm, the residual film averaged a recovery rate of 89.59%, with a dragging rate of only 4.10% at crossings. In contrast, 8–14 cm stubble plots showed an 82.86% average recovery and an 11.91% dragging rate. In plots with a root stubble height of 5–8 cm, compared with plots with a root stubble height of 8–14 cm, the recovery rate increased by 6.73%, and the dragging rate of residual film on root stubble decreased by 7.81%. The percentage of entangled residual film out of the total unrecovered film was 30.10% lower in the 5–8 cm stubble plots than in the 8–14 cm stubble plots. It was confirmed that the effect of cotton root stubble on residual film recovery could be reduced under appropriate machine operating parameters. This provides strong support and a theoretical and practical basis for future research on the correlation between root stubble and residual film and how to improve the residual film recovery rate. Full article

To address the negative impacts in recovering large areas of residual plastic film from corn stubble in the Hexi irrigation area—such as the residual film containing substantial amounts of soil, corn stubble, and corn straw, and high power consumption during the operation process—in this study, a combined operation machine was designed for corn straw crushing and residual film recovery. The machine consisted of a double-wing, single-blade shovel for lifting the film and cutting corn stubble, a corn straw-crushing and returning device for reducing the residual film impurity rate, an eccentric teeth shifting cylinder for picking up residual film, a device for shifting residual film, and a collection device for bundling residual film. The key components of the combined operation machine were designed based on an agronomic model for corn planting and the mechanized operation requirements in the Hexi irrigation area. The optimal combination of operating parameters was devised based on theoretical calculations and single- and multifactor simulation tests. The results showed that when the angle of entry of the film-lifting shovel was 25.14°, the rotational speed of the eccentric teeth shifting cylinder was 80.96 rpm, and the forward velocity of the machine was 4.03 km/h, while the rate of recovery of residual film was 92.56%. The field test showed that the residual film contained 16.65% impurities, and the qualified rate of corn straw crushing was 88.51%, with a relative error of 0.65% from the optimized value. The experimental results provide theoretical support and a design reference for research on the mechanized recycling of residual film in large areas of corn stubble. Full article

To improve the film-picking performance of toothed chain tillage residual film recycling machines, the working parameters of a film-picking device were optimized using a Box–Behnken design, with the film-picking rate as the response parameter. The effectiveness of the film-picking device, along with soil compaction, torque, and stress on the picking teeth during the process, was evaluated through DEM-MBD coupling simulations and experiments. The optimized working parameters for the film-lifting device were found to be forward speed $\mathrm{v}=1.94 \mathrm{m}·{\mathrm{s}}^{-1}$, picking tooth speed $\mathrm{n}=10.47 \mathrm{r}\mathrm{a}\mathrm{d}·{\mathrm{s}}^{-1}$, and penetration depth $h=125 \mathrm{m}\mathrm{m}$. Under these conditions, the film-picking rate for the single-tooth and multi-tooth devices were 88% and 90%, respectively, with a 2% error. The simulation and experimental values for soil compaction, torque, and stress during the film-picking process were 800 Pa, 2.72 $\mathrm{N}·\mathrm{m}$, and 6.4 N, respectively. The corresponding simulation values were 870 Pa, 2.53 $\mathrm{N}·\mathrm{m}$, and 6.5 N, with errors of 8%, 7%, and 2%. This study provides valuable insights for optimizing the design of residual film recycling machines and predicting soil compaction, tooth torque, and stress. Full article

The operating parameters and operating effect of a residual film recycling device can be predicted, and the key parameters can be determined based on the DEM–MBD coupling simulation. The parameters obtained from the parameter calibration are the basis of the simulation. This study calibrates DEM parameters for the soil-touching components of a tillage residual film recycling machine. A film-picking model for elastic tooth–soil–residual film interactions was established. The reliability of the contact parameters was verified by comparing the simulation and experimental angle of repose for soil–soil (43.6° vs. 42.42°, error was 2.7%) and residual film–residual film (43° vs. 43.7°, error was 1.6%) using the funnel and bucket methods. A DEM model for film–soil detachment was developed, with a force analysis showing an 8.1% error between the simulation (0.34 N) and experiment (0.37 N). Additionally, a DEM–MBD coupling model was used to analyze the recovery rate of residual film under elastic teeth, yielding a 2% error between simulation (90%) and experiment (92%). This study provides a basis for DEM parameter optimization in soil-touching components. Full article

The interaction law between soil and tillage components is the basis for designing and selecting soil tillage components. This paper uses the discrete element method to explore the soil penetration performance of the comb teeth of a pneumatic film-stripping tillage residual film recycler under different structural and working state parameters. The soil particle contact model is set up, the virtual prototype of the comb roller is established, and EDEM (Version 2018, DEM Solutions Company, Edinburgh, UK) discrete element software is applied to simulate the interaction between the comb roller and the soil particles during the residual film recycler’s operation. Simulation and test results show that using a spiral arrangement of tooth comb knives (Alar, 843300, China, Zhongyuan Stainless Steel Bending Manufacturing Co.) can reduce the impact load on the machine, improving the soil disturbance and facilitating the penetration of soil mulch. The composite force on the combing roller increases with comb depth in the soil for a combing roller depth of 6–18 cm. Moreover, the rotational speed varies within the range of 60–120 r/min. The forward speed of the recycling machine significantly affects the soil penetration performance of the comb roller; the power it consumes increases with forward speed. This study can provide a reference for the structural design and optimization of working parameters of future deep tillage machines. Full article

Plastic film mulching technology occupies a prominent position in China’s agricultural production and plays an important role in improving crop yields, which can increase farmers’ income and ensure national food security. As the current residual film recycling mechanism is incomplete, the accumulation of residual film in the soil has gradually increased, and the problem of residual film pollution has posed a serious threat to agricultural production and the natural environment. Ridge mulching cultivation is one of the main planting patterns for grain and oil crops, such as peanuts, potatoes, and maize, in China. In this paper, the planting patterns, mulching conditions, characteristics, and distribution of residual film of the typical ridge mulching crops, such as peanut and potato, were analyzed. The merits and demerits of various kinds of residual film recycling machines and the application status and operation quality of peanut and potato residual film recycling machines are summarized. Problems and suggestions for the mechanized recycling of residual film were raised. This study may provide ideas for the development of residual film mechanization recycling of ridge mulching crops. The aim of this study is to propose practical solutions by analyzing the current status and existing problems of mechanized residual film recovery in order to reduce residual film pollution, protect the environment, and achieve sustainable agricultural development. Full article

The existing residual film-recycling machines struggle to efficiently recover and separate film stubble in a single operation. With roller-type film-rolling device unloading difficulties and other problems, in order to improve the recovery efficiency of film stubble and the separation effect while reducing human labor and to improve work efficiency, we designed an automatic hydraulic unloading film stubble-recycling integrated residual film-recycling machine. The angle of the membrane lifting device was determined by theoretical calculations using the method of coupled simulation of EDEM and ANSYS Workbench. We analyzed the amount of resistance as well as the maximum stress and deformation during the working process of the membrane-lifting device and focused on the design of the membrane–soil separating device and membrane-rolling device. The depth of the film shovel, the forward speed of the machine, and the rotational speed of the driving wheel of the jogging chain were selected as the test factors, and the residual film recovery rate was taken as the evaluation index. A three-factor, three-level test was designed by applying the principles of the Box–Behnken experimental design. The results show that when the forward speed is 1.36 m/s, the soil depth is 147.16 mm, and the rotational speed of the driving wheel of the shaking chain is 77.89 r/min, the recovery rate of the residual film is 87.56%, and the relative error between the experimental value and the optimized value is 2.73%. The experimental results can provide a theoretical basis for the design of the residual film-recycling machine. Full article

Plastic film mulching technology can effectively enhance crop yield and quality, and the use of mulch has been increasing in recent years; however, the problem of mulch residue is worsening due to the large amount of recycling work and slow natural degradation. In this study, a potato seedling killing and residual film recycling machine is designed to provide good working conditions for potato harvesters before harvesting in response to the problems of difficult separation of film tangles, the low net rate of recycling due to the mixing of residual film with soil, and the high soil content in residual film recycling operations in northwest China. The machine is based on the potato monoculture and double row planting mode in Gansu area. This paper puts forward the overall design scheme and carries out the theoretical analysis and parameter determination of the key components, such as the seedling killing device, the film surface cleaning device, the film unloading device, and so on. Using EDEM software to carry out the virtual simulation test and Design-Expert13 to analyze the test results, we determined the optimal working scheme for the machine, with a forward speed of 0.8 m/s, a film gap of 125 mm, and a spiral stirrer speed of 600 r/min. Based on a field test for verification, the test results show that the machine’s residual film recovery rate was 83.3%, the impurity rate was 3.8%, and the rate of injury to the potatoes was 1.4%. The machine meets the requirements of national and industry standards, and it can simultaneously realize straw crushing, film surface cleaning, residual film recycling, and hydraulic film unloading operations, with better operating results and while reaching the expected results. It can also provide a reference for the design and testing of a seeding and residual film recycling machine. Full article

In view of the large difference in moisture content of cotton stalk in autumn in Xinjiang, the existing process of obtaining discrete element simulation parameters of cotton stalk is low in accuracy and complicated in operation, leading to the problems of poor universality and low accuracy in regard to the discrete element simulation parameter-calibration method in the process of mechanized transportation, throwing and returning to the field. Therefore, the experimental study on cotton stalk with different moisture content was carried out with the accumulation angle as the response value, so as to construct a parameter model that can quickly and accurately calibrate cotton stalk with different levels of moisture content. The model has high applicability and flexibility, and it can be widely used in the simulation test of various cotton field-operation machinery, such as a residual film-recycling machine, cotton picker, crushing and returning machine and other equipment. The water content–accumulation angle model was established by the cylinder-lifting method, and the correlation coefficient of the model was 0.9993. Based on EDEM 2020 software, the Hertz–Mindlin model was used to simulate the stacking angle of cotton stalk, and the rolling friction coefficient, static friction coefficient and collision recovery coefficient between cotton stalk and cotton stalk–steel were obtained. Through the Plackett–Burman test, climbing test and Box–Behnken test, three significant parameters, namely the rolling friction coefficient, static friction coefficient and static friction coefficient between cotton stalk and steel, were selected from discrete element simulation parameters to characterize the moisture content of cotton stalk, and the accumulation angle–discrete element parameter model was established. The p-value of the model was less than 0.0001, and the relative error was only 2.67%. Based on the moisture content–stacking angle model and the stacking angle–discrete element parameter model, the moisture content–discrete element parameter model was constructed. The model was verified by the cylinder-lifting method and the plate-drawing method, and the relative error was only 2.79%. Finally, the model was further verified by comparing the effect of the throwing uniformity between the mechanical simulation test and field test, and the relative error was only 4.75%. The test proves that the moisture content–discrete element parameter model is accurate and reliable, not only providing the design basis and support for the mechanization research of cotton stalk conveying and returning to the field in Xinjiang but also providing ideas for the calibration of discrete element simulation parameters of other crop straws. Full article

This paper takes the frame as the research object and explores the vibration characteristics of the frame to address the vibration problem of a 1-MSD straw-crushing and residual film recycling machine in the field operation process, and an accurate identification of the modal parameters of the frame is carried out to solve the resonance problem of the machine, which can achieve cost reduction and increase income to a certain extent. The first six natural frequencies of the frame are extracted by finite element modal identification and modal tests, respectively. The rationality of the modal test results is verified using the comprehensive modal and frequency response confidences. The maximum frequency error of modal frequency results of the two methods is only 6.61%, which provides a theoretical basis for the optimal design of the frame. In order to further analyze the resonance problem of the machine, the external excitation frequency of the machine during normal operation in the field is solved and compared with the first six natural frequencies of the frame. The results show that the first natural frequency of the frame (18.89 Hz) is close to the external excitation generated by the stripping roller (16.67 Hz). The first natural frequency and the volume of the frame are set as the optimization objectives, and the optimal optimization scheme is obtained by using the Optistruct solver, sensitivity method, and grey correlation method. The results indicate the first-order natural frequency of the optimized frame is 21.89 Hz, an increase of 15.882%, which is much higher than the excitation frequency of 16.67 Hz, and resonance can be avoided. The corresponding frame volume is 9.975 × 10⁷ mm³, and the volume reduction is 3.46%; the optimized frame has good dynamic performance, which avoids the resonance of the machine and conforms to the lightweight design criteria of agricultural machinery structures. The research results can provide some theoretical reference for this kind of machine in solving the resonance problem and carrying out related vibration characteristics research. Full article

The extended duration of mulching in Xinjiang cotton fields leads to a significant decline in the tensile strength of plastic film. When recycling is in operation, the soil and the spring teeth of the machinery used can easily cause secondary damage and fracture the residual film. Establishing appropriate working parameters for recycling is essential to enhance the overall quality of collection efforts. By analyzing the motion process of a chain-tooth residual film pickup device, we identified key working parameters that significantly impact the efficiency of recycling. Employing the finite element method (FEM) and a coupled algorithm incorporating smooth particle hydrodynamics (SPH), we developed a coupled finite element model representing the interaction among spring teeth, soil, and residual film. Through simulation and analysis of the process of inserting the spring teeth into the soil to collect film, we derived the governing rules for residual film stress and deformation changes. Utilizing forward speed, rotational angular velocity, and angle of entry into the soil of the spring teeth as test factors and selecting the residual film stress and the residual film deformation as test indices, we conducted a multi-factor simulation test. We established a mathematical model correlating test factors with test indices, and the influence of each factor on the test index was analyzed. Subsequently, we optimized the working parameters of the spring teeth. The results indicated that the optimal working parameters are forward speed of 1111.11 mm/s, rotational angular velocity of 25 rad/s, and angle of entry into the soil of 30°. At these values, the average peak stress of residual film was 4.51 MPa and the height of residual film pickup was 84.48 mm. To validate the optimized the spring teeth impact on performance, field experiments were conducted with recovery rate and winding rate as test indices. The results demonstrated a 92.1% recovery rate and a 1.1% winding rate under the optimal combination of working parameters. The finite element model presented in this paper serves as a reference for designing and analyzing key components of residual film recycling machines. Full article

For the residual film recycling machine work, after the recovery of residual film, cotton stalks, crushed soil, and other impurities are not easy to separate; it is challenging to realize the secondary use of the problem. A waste film and impurity wind selection device were designed to recognize waste film recycling and separate soil film rods. The overall structure and working principles of the machine are described. A three-dimensional computational fluid dynamics model of a film rod separation device was developed. The flow field within the film rod separation unit was analyzed by numerical simulation using 2023 R1 ANSYS Fluent software. Based on the differences of impurities such as residual film, soil, and cotton stalks in terms of density, suspension velocity, and their characteristics, the pressure distribution and velocity distribution of the internal flow field of soil, residual film, and cotton stalks at the site were investigated. The air inlet velocity, screen cylinder rotation, and main shaft rotation velocity were changed. Experiments were conducted to obtain wind selection parameters for suitable soil, residual film, and cotton stalk separators. Analysis of orthogonal experiments, polar variance of analysis, and analysis of variance yielded a better combination of working parameters: when the drum sieve velocity is 25 r/min, the spindle velocity is 35 r/min, and inlet wind velocity is 14 m/s, after the separation of residual film impurity rate of 8.9%. The results of the study can provide a theoretical basis for the development of film separation equipment. Full article

After the residual film recycling machine recovers the film, some small pieces of the film will remain on the surface of the field. To solve the problem of collecting small pieces of film, it is necessary to develop a piece of intelligent picking equipment. The detection of small pieces of film is the first problem to be solved. This study proposes a method of an object detection algorithm fusing multi-scale features (MFFM Faster R-CNN) based on improved Faster R-CNN. Based on the Faster R-CNN model, the feature pyramid network is added to solve the problem of multiscale change of residual film. The convolution block attention module is introduced to enhance the feature extraction ability of the model. The Soft-NMS algorithm is used instead of the NMS algorithm to improve the detection accuracy of the model in the RPN network. The experimental results show that the model is able to effectively detect surface residual film in complex environments, with an AP of 83.45%, F_1-score of 0.89, and average detection time of 248.36 ms. The model is compared with SSD and YOLOv5 under the same experimental environment and parameters, and it is found that the model not only ensures high-precision detection but also ensures real-time detection. This lays the theoretical foundation for the subsequent development of field surface residual film intelligent picking equipment. Full article

The residual agricultural plastic film in China is not easily recovered due to the thinness and poor mechanical properties of domestic films, and a large amount of plastic film remaining in farmland soil poses a great threat to soil quality and crop production. A spring-tooth residual plastic film collector (SRPFC) is widely used in domestic residual plastic film (RPF) recycling operations. However, there are two major problems in the current SRPFC: the low recovery rate of the residual film (RRRF) caused by the difficulty of film-stripping and the high impurity rate in the film (IRF). In this paper, a stripping and impurity removal device (SIRD) is designed to address the existing problems of SRPFC, which is mainly composed of film-stripping tooth plates (FTP), two wind-collecting hoods, and two centrifugal fans. The motion and force analysis of the RPF in the film-stripping process was carried out, and the arc FTP was determined to be used for film-stripping. The size parameters of the FTP were obtained by establishing the coordinate system to solve the differential equation. By comparing and analyzing the force of RPF in the airflow field of the test bench for suspension speed and the airflow field of the wind-collecting hood, the RPF equivalent particle was established. The discrete phase model (DPM) in Fluent software was used to simulate the movement of the RPF equivalent particle, and the calculated air volume range of the centrifugal fan was 5501.88~6829.92 m³/h. The effects of forward speed, rotating speed of film conveying chain harrow (FCCH), and rotating speed of the centrifugal fan on RRRF and IRF were studied by orthogonal rotary combination experiment. The test results showed that the best combination of machine operation parameters was when the forward speed was 5 km/h, the rotating speed of the FCCH was 235 r/min, and the rotating speed of the centrifugal fan was 1978 r/min. Under these conditions, the RRRF was 92.53%, and the IRF was 9.31%. Field experiments were carried out with the rounded parameters, and the average RRRF was 92.07%, and the average IRF was 9.56% under the parameter combination, indicating that the optimization scheme of the device was feasible. Full article

Given the problem of the low tensile performance of the plastic film used in China, which brings about difficulties in curl-up film collecting, in this study, a contrast test was carried out on the tensile property of high-performance film for full recycling and the ordinary polyethylene film (PE film) that is used extensively in China. Test results showed that, within the service period, the elongation at break and tensile yield stress of the high-performance film were higher than those of ordinary polyethylene film, and, within the film-laying period of 0~30 days, the reduction scale of the elongation at break and tensile yield stress was higher than that within the film-laying period of 30~180 days. In this study, in order to obtain the lowest tensile performance of the film by curl-up film collecting, the operation principles of the curl-up film collectors were analyzed. The test on the force of curling up the film in the process of overcoming the force between the film and soil was analyzed. Test and analysis results showed that, for different sampling positions, film pick-up angles, and film types, the tensile stress on the film while pulling it up was within a range of 15.97~21.86 MPa. In order to verify the curling up effect of differently structured film collectors on different types of film with different thicknesses, a field test on film curl-up collecting was designed. A contrast test was carried out on two types of curl-up film collectors, 1JRM-2000 and 11SM-1.2, and the test results showed that the film recycling rate and working performance on the film laid in the same year by the film collector with a fixed film pick-up angle were higher than those for varying film pick-up angles. The curl-up film collector fixed with an automatic film-guiding mechanism is not affected by the velocity difference between the linear velocity of the film curl-up mechanism and the advancing velocity of the machine. The film recycling rate and working performance on the film laid in the same year by the 11SM-1.2 curl-up film collector can meet the operational requirements for collecting high-performance film with thicknesses of 0.008 mm and 0.01 mm. This research can provide a reference for simplifying the structure of residual plastic film collectors, increasing the film recycling rate, and reducing the cost. Full article