The technology of plastic film mulching is widely applied in Xinjiang, but it also brings about serious issues of residual film pollution. Currently, the 1MSF-2.0 residual film recovery machine can effectively address the problem. However, it faces challenges such as high overall machine weight and noticeable frame vibrations, which affect the stability of the entire machine operation. The frame, as the installation foundation, needs to bear loads and impact. Therefore, the reliability of the frame is crucial for the stability of the entire machine. Improving the frame’s vibration is of great importance. In response to the significant vibration issues during the operation of the 1MSF-2.0 residual film recovery machine, this paper utilized Workbench 2020 R2 to establish a finite element model of the machine frame and conducted static analysis to obtain strength information, thereby initially understanding the optimization space of the frame. Building upon this, Mechanical was employed to solve the first 14 natural frequencies and mode shapes of the frame, and the accuracy of the theoretical analysis was verified through modal testing. After analyzing the frequency characteristics of external excitation forces, it was found that the fourth-order natural frequency of the frame fell within the frequency range of the excitation force of the shaft of the straw grinder, causing resonance in the frame and necessitating structural optimization. The optimal results indicated that the optimized frame increased in mass by 4.41%, reduced the maximum stress value by 2.56 MPa, and increased the fourth-order natural frequency to 22.7 Hz, avoiding the frequency range of the excitation force of the shaft of the straw grinder, thus improving the resonance issue. This paper provides a reference for optimizing the design of the frame of the residual film recovery machine.

In order to reduce ground drop loss during mechanical pepper picking and improve the net recovery rate, a drum snap finger picking device was designed. The picking device is mainly composed of a picking drum and auxiliary picking components; the picking finger arrangement was designed biomimetically and its structure and operating parameters were optimized by the DEM (discrete element method). According to the physical and mechanical characteristics of the pepper and the simplified three-dimensional model of the picking device, a virtual simulation model of the pepper-picking device was established using the EDEM software. Through simulation analysis and using the orthogonal test method, the main factors which affect the ground drop loss rate of pepper and their optimal parameter combination values were determined. The simulation results were verified by a pepper-picking field experiment. Orthogonal tests show that, when the picking drum speed ($V^{\prime }$) is 210 rpm, the pepper-feeding speed ($V^{″}$) is 1100 $\mathrm{m}\mathrm{m}·{\mathrm{s}}^{-1}$, the bending angle of each picking spring tooth (C) is 162°, and each group of circumferential fingers has rows, the picking device has a good picking effect. At this time, the ground drop loss rates in both the simulation and field test were 7.50% and 7.85%, respectively, and the drop error was only 4.46%, which was within the allowable range. The design form and parameter optimization simulation method in this paper provide an important reference for the design and optimization of pepper-harvesting machinery.

The discrete elemental parameters of pod pepper seeds were calibrated for future numerical optimization of the pod pepper seed cleaning device. The study concentrates on calibrating the intrinsic and contact parameters of pod pepper seeds utilizing the discrete element method. Compression tests were performed to ascertain intrinsic parameters such as Poisson’s ratio and the seeds’ elastic modulus. The static friction coefficient and collision restitution coefficient between the seeds and steel plates were identified through incline and free-fall tests. Plackett–Burman, steepest ascent, and Box–Behnken experiments were performed to establish a second-order regression model correlating significant parameters with the angle of repose. The optimal parameter combination, based on the measured angle of repose (32.45°), yielded static friction coefficients between seeds, rolling friction coefficients between seeds, and static friction coefficients between seeds and steel plates of 0.608, 0.018, and 0.787, respectively. The two-sample t-test of the physical and simulated repose angles yielded p > 0.05, and the relative error of the physical and simulated repose angles was 0.68%, which confirmed the reliability of the calibration parameters. The findings indicate that the calibration method for pod pepper seeds effectively informs the calibration of parameters for other irregular crops.

The optimization of film-unloading and film–soil separation components can effectively improve the residual film unloading rate and reduce impurity content. So, the DEM models of soil and residual film were established and the suspension and flow characteristics under fluid action were analyzed based on the CFD—DEM coupling simulation in this article. The matching parameters of the film-unloading and film-lifting device were optimized with the Box–Behnken test. When the wind velocity was between 1.65 and 10.54 $\mathrm{m}·{\mathrm{s}}^{-1}$, the film–soil separation effect was the best, with a film–impurity separation rate of 96.6%. The optimized parameter combination of the film-unloading device and film-lifting device is A = 9°, B = 40 mm, and C = 40 mm (A, B, and C represent the angle between the teeth and the normal of the air inlet, the minimum distance between the teeth and the air inlet, and the width of the air inlet, respectively). With the optimized parameter, the best film unloading effect is achieved, the minimum wind velocity of film unloading is 2.6 $\mathrm{m}·{\mathrm{s}}^{-1}$. This article provides theoretical and simulation methods for assessing the flow characteristics of flexible particles and parameter optimization of air suction devices, which is conducive to the high-purity recovery of residual film.

Nowadays, many scholars at home and abroad have studied the vibration of agricultural machinery, especially harvesting machinery. However, this research has lacked the analysis of vibration characteristics of harvesters under the condition of multi-vibration excitation in field work. Therefore, by taking the chassis frame and main vibration sources of a 4JZ-1700 crawler pepper harvester as the research object, this paper aims to investigate the vibration characteristics of the pepper harvester under different working conditions, and the impact of the excitation of various working parts on the chassis frame. Firstly, a modal simulation was carried out with the modal module of ANSYS Workbench to study the natural frequency of the chassis frame. The results demonstrated that the natural frequency of the chassis frame was within 23–76 Hz. A DH5902 dynamic signal acquisition instrument was used to collect vibration signals from seven measuring points under different working conditions of the whole machine, and the collected time domain signals were extracted by Fourier transform. According to the time domain signal, the amplitude at the engine support was the largest under the static no-load condition, and the transmission of engine vibration was attenuated to a certain extent, which imposes a significant effect on the vibration isolation and vibration reduction of the harvester frame. Under the field walking condition, the amplitudes of the left front of the chassis frame and the driving shaft of the cleaning separation device were abnormal, which was mainly attributed to the unequal road surface and the high center of gravity of the cleaning separation device. Through frequency domain analysis, it can be found that the main vibration frequency of most measuring points of the harvester was close to the vibration frequency of the engine under the static no-load condition, and the excitation frequency of most measuring points approximated to the working frequency of the picking drum and the cleaning separation device under the field walking condition. In addition, there were plenty of phenomena in which the main frequency of vibration was detected in the high frequency region above 200 Hz, with messy frequency values. This is due to the poor lubrication of the bearing part of the harvester, causing intense friction between the rotating shaft and the bearing, which also drives the high frequency vibration of the chassis frame. In general, this study can provide a method reference for vibration analysis of agricultural machinery and propose effective measures to reduce vibration based on the conclusions.

The discrete element method can be used to analyze the interaction between tools and soil. It can be used to guide the optimal design of tools, but the appropriate simulation and test method selected is important to achieve the goal. This paper mainly introduces the disturbance of soil by tillage tools. The disturbance of the soil by tools include soil loosening, soil movement, and soil mixing. The disturbance contour is used to visually display the disturbance results, and the cross-sectional area, lateral soil throwing amount, ditch ridge height, ditch width, and ditch backfill are used to characterize the cross-sectional shape. Tracers are usually used to track soil particles to visually display the particle movement path during disturbance; this can be used to study the soil disturbance trend by the tools. When parameters and models are appropriate, the movement and contact of microscopic soil particles can be accurately simulated. By comparing the particle behavior of simulation and experiment, the contact model and contact parameters can be verified. The method introduced provides a reference for the optimal design of the tools and the research of disturbance by the tools.