The garlic combine harvester has essentially realized the mechanized harvesting of garlic. However，its intelligence level is relatively low. During the operation，problems such as yaw，overflow and blockage are prone to occur，which affect the operation quality and harvesting efficiency of the whole machine. To address these issues，this paper presents an STM32-Based real-time monitoring system for garlic combine harvesters，which can monitor the yawing，overflow，and blockage failure problems in real-time with high accuracy，and can also provide voice broadcast reminders . The system comprised a row assist modules，a yield monitoring module，a fault diagnosis module and an STM32 microcontroller. The row assist modules utilized an MPU6050 gyroscope to ascertain the direction of the harvester，which was then compared with the set direction angle warning and alarm threshold to determine whether the harvester had deviated from the normal operational route. The yield monitoring module multiplied the weight of a single garlic by the total number of garlic counts to calculate the total weight of the harvested garlic，and compared it with the set threshold of the full bin to ascertain whether the collection bin was indeed full. Fault diagnosis was performed by the Hall sensor，which collected the rotational speed of the follower wheel of the clamping and conveying mechanism and compared it with the set threshold to judge whether a blockage occurrs. The maximum error value of the row assist module，as determined through indoor commissioning，was 1.3°. The minimum error value was 0.2°. The yield detection module monitoring count accuracy was 96.7%. The fault diagnosis module identified the average error value of rotational speed as 0.8 r/min，with an error rate of 0.4%. This enabled the module to accurately monitor the follower wheel rotational speed changes when the clamping device was blocked. The results of the field test demonstrate that the designed monitoring system is feasible，accurate and stable. The findings of this study indicate that the proposed monitoring system can operate reliably over an extended period，issuing timely alerts when the garlic harvester is exhibiting signs of yawing，overflowing，and blocking issues. This could markedly enhance the operational quality and efficiency of traditional garlic harvesters.

Improving the precision of mechanized seeding is the key breakthrough in vegetable planting, which can save cost and increase the efficiency of seeding. In order to improve the seeding performance of seed metering device, the computational fluid dynamics and discrete element method (CFD-DEM) coupling simulation technology was adopted to simulate the single factor performance of the seed metering device. Also, the movement characteristics of seeds under different suction nozzle structure and operation parameters were analyzed. In order to explore the best combination of parameters, the central composite design (CCD) was carried out by factoring the cone angle of suction nozzle, the angular velocity of seed plate, and the negative pressure and considering their effect on the two responses of the qualified index and the miss index. The variance analysis of the experimental results showed that the negative pressure had the most impact on the qualified index and the miss index, followed by cone angle of suction nozzle, and angular velocity of the seed plate. A parameterized mathematical model was then established to determine the parameter optimization region. Parameter optimization indicated that the qualified index of seeding was greater than 95% and the miss index was less than 2.5% at a cone angle of 50°, negative pressure in the range of 4.87-5.64 kPa, and an angular velocity in the range of 1.67-1.95 rad/s. The bench verification experiment further verified the accuracy of the parameter optimization results. The results of simulation and parameter optimization in this paper can provide reference for the development of seed metering device in the future.

To investigate the movement characteristics and filling performance of seeds in the working process of seed metering device, the movement characteristics of seed A which successfully completed the seeding process and seed B that dropped in advance during the working process were studied based on computational fluid dynamics and discrete element method (CFD-DEM) coupling approach. The analysis of seed velocity, compressive force and position were found that the movement characteristics of the two types of seeds in the process of moving to the leftmost side of the seed plate were basically the same. During the movement from the leftmost side of the seed plate to the positive pressure zone, the velocity and compressive force of the seed change greatly. The process was relatively unstable, and seeds were prone to fall early. The effects of seed agitator's rotational speed and seed layer thickness on seed filling performance were studied by single factor simulation test. The results showed that the seed filling performance was better when the seed agitator's rotational speed and seed layer thickness were 3 rad/s and between 35 and 40 mm respectively. The research results provided a reference for improving the structure and seed filling performance of seed metering device.