Aiming at the existing single-motor agricultural tractors, which often have a mismatch between power and working conditions and a poor operation effect under different tillage modes, this paper designs a torque allocation strategy for agricultural electric tractors under different tillage modes. Firstly, the torque is divided into basic and compensating, and a calculation model is established. Then, the Particle Swarm Optimization algorithm is used to find the optimal demand torque position, and fuzzy control rules allocate the motor torque in combination with the battery SOC. Finally, the strategy’s effectiveness in different tillage modes is verified by MATLAB/Simulink simulation and bench test. The test results show that the strategy can distribute the motor torque stably according to the load torque change and pedal opening under three PTO transitions and the plowing and rotary tillage modes. The main and speed control motors respond in about 3 s with good real-time performance. The drive wheel torque can reach 1600 N·m during plowing and rotating operation. The PTO torque can reach 60 N·m during the rotating process. The maximum torque of the output shaft can reach 150 N·m with good plowing performance. During all operations, the SOC of the battery shows a steady linear decrease, and the battery discharge has stability.
During the harvesting of cut-stem vegetables, the structural parameters of cutters have an important influence on the harvesting effect. Structural parameters of stalks directly affect the cutting effect of the cutter. The thickness of the stalk xylem has a strong influence on the cutting stability and cutting surface effect of the cutter. In this paper, the effect of the broccoli stalk xylem on conventional toothless cutters was investigated using broccoli stalks as the cutting object. It was found that a thicker xylem leads to shear force fluctuations, which in turn affects the smooth operation of the cutting device. Taking locust mouthparts as the research object, a bionic multi-tooth cutting method is proposed in this paper to obtain the contour curve based on the locust upper jaw cutting tooth lobe. By establishing the regression equation, the contour curve of the cutting teeth is fitted accurately. The cutter edge is designed with the locust’s maxillary incisive lobe as the bionic object. ANSYS software was used to simulate the cutting of a double disc cutter and broccoli stalk. The effect of each factor was analyzed by response-surface regression to determine the optimal cutter speed, machine forward speed, cutting inclination, blade overlap, and optimal cutting position. The cutting test is verified via broccoli stalks and a cutting test bench to further determine the cutting device operating parameters. The optimal operating parameters of the cutting device were 0.239 m/s forward speed, 30.974-degree cutting edge angle, 10.066 mm blade overlap, and 467.511 rpm.
Sorghum is an important grain crop in many countries worldwide, yet it often suffers from high levels of fragmentation during harvest due to varying maturity. To this end, a study was conducted to investigate the crushing characteristics of sorghum grains subjected to compression and impact loading at different moisture contents. By configuring sorghum kernels with varying ranges of water and determining their physical parameters, such as length, width, etc., the geometric mean diameter of sorghum kernels was 3.105–3.550 mm, and the sphericity was above 75%. Compression tests were conducted on sorghum kernels in the triaxial direction. The compression energy was calculated to be 13.409–19.229 J on the X-axis, 16.313–21.409 J on the Y-axis, and 17.609–24.741 J on the Z-axis. In contrast, the apparent contact modulus of elasticity was calculated, with the maximum modulus of elasticity up to 72 MPa in the Z-axis direction, and the variations in the X-axis and Y-axis were approximate. Finally, mechanical impact tests were conducted to measure the critical angle of seed breakage, and a mathematical model was established to predict the impact of mechanical breakage force. The error between the predicted and experimental values was within 3%. This paper conducted compression and impact mechanics tests on sorghum seeds at different moisture contents to provide a design basis for sorghum harvesting and processing and other harvesting equipment.
As rice yield rises, the issue of broken axis windings in mature rice threshing drums is becoming increasingly severe. To disclose the winding characteristics and signal traits of the drums during the threshing process of mature rice, this paper undertakes an analysis of the winding characteristics and signals of the drums in rice with the assistance of a vibration test and analysis system. Since rice can lead to drum winding and shaft breakage, this paper alters the driving mode of the drums to exhibit the influence of rice on them. Firstly, the transfer characteristics of the frame need to be studied and analyzed, followed by subsequent research. The test results indicate that the horizontal displacement of the cylinder axial trajectory rises with the growth of the transmission chain, while the vertical displacement drops with the growth of the transmission chain. Additionally, to investigate the effect of mature rice on the threshing performance of horizontal axis II and horizontal axis III, a control variable method was employed. This approach allowed for the observation of how mature rice influences the threshing roller by systematically adjusting both the threshing gap and the rotational speed of the roller. It can be discerned from the test results that with the reduction of the threshing gap of affected mature rice, the unstripped rate gradually declines, while the entrainment loss rate gradually increases. As the rotational speed of horizontal shaft roller III increases, the rate of uncleared material gradually decreases, while the rate of entrainment loss progressively rises. The research findings can furnish a reference for the winding characteristics of rice on rollers and the enhancement of vehicle driving comfort.