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Plot breeding is a very important link of seed breeding, providing for the field experimental data and breeder seed or original seed. Seed harvested from the plot is commonly processed with manual tools or cleaned by simple machines. A batch seed cleaner is a piece of special equipment to meet the specific processing of germplasm materials in the experimental area. However, there are multiple operation procedures, high labor intensity, and low efficiency in seed batch processing. Manual operation with independent electric control systems has also caused uncontrollable clean-up quality, inefficient and time consuming. This study aims to develop a novel batch seed cleaner for the specific requirements of high efficiency, no residue and easy cleaning. An automatic control system was introduced to implement automatic operation using STM32 embed programming. A variety of functional modules were included, such as feeding margin detection, variable frequency vibration, high-frequency vibration cleaning, screen tilting adjustment, and terminal display with interactive interface and STM32 main control system. Hardware and software of the control system were designed for a sequence working flow, including the feeding, winnowing, and sieving. Three groups of photoelectric sensors were installed to monitor the location and status of the seed. Specifically, the No.1 photoelectric sensor was installed in the lower part of the hopper to monitor and control the feeding and air separation system. The No.2 and the No.3 photoelectric sensors were mounted on the two ends of the lower screen to control the screening device and vibration motor. An angle sensor was used to detect the angle of the screen. The key working parameters and functions were optimized, including the feeding speed, sieving vibration frequency, clean-up vibration, and tilt angle adjustment. The priority flag bit was used to optimize the sequential operation. An optimal control strategy was achieved for a stable and reliable system. A prototype performance test was carried out for high robustness of the automatic control system, thereby systematically investigating the influence on the quality and efficiency of seed batch cleaner. The cleaning test for corn seed showed that the coefficient of variation for the seed purity, the percentage of chosen seed, and working time were 0.15%, 0.26%, 2.2% and 2.19% respectively, under the set working conditions. An optimal combination was gained for the quality requirements of plot seeding, where the cleaning process was smooth, while the automatic control system operated normally, and the batch seed cleaner worked reliably. This finding can provide a sound reference for the automatic control system in the intelligent batch cleaner for seed or granular materials. [ABSTRACT FROM AUTHOR]

Plot breeding has become a key part for the selecting of seed and the preparation breeding program to date, providing for the evaluation data and breeder or original seeds. At present, preserving biodiversity and ecosystem functions have posed a great challenge on the seed mechanization of field experiment in rapidly increasing rural areas in China, particularly on the special agronomic and test requirement. Seed harvesting from the plot is still in manually processing with a simple assistant tool, or by commonly used machines to clean, such as screen separator and air-screen separator with the capacity about 50-100 kg/h. A special cleaning device is lacking for the plot seeds in the modern variety breeding. Technology and equipment of seed cleaning have been a focal issue to efficiently promote the production capacity or quality in a plot breeding. In the special need of seed processing, a novel cleaning treater was systematically designed in this study, thereby to improve the mechanization level of plot breeding. The seed cleaning device in batches consisted of the frame, feeding system, winnowing system, sorting unit, driving unit, and electronic control system. A combined screen with open frame and variant-frequency vibration was used in the device, further to enhance the working quality, such as batch cleaning efficiency and preventing seed mixing, as well as easy operation in screen cleaning. Other main components were also optimized in this study. Furthermore, A Box-Behnken test was conducted, where the seed purity, percentage of chosen seed, and working time were selected as test indexes, while the feeding rate, vibration frequency, amplitude, and screen inclination angle were selected as factors for design. The results showed that the amplitude, vibration frequency, and the interaction between them were significant factors, indicating a strong influence on the seed purity and percentage of chosen seed. The working time greatly depended on the feeding rate, vibration frequency, and amplitude. An optimum combination of selected factors was achieved, where the feeding rate of 0.072 kg/s, the vibration frequency of 6.25 Hz, the amplitude of 5 mm, and the screen inclination angle of 4.6°, to reach an optimal design with the seed purity of 98.8%, the percentage of chosen seed of 99.7%, and the working time of 50 s. A performance test was also carried out, indicating that the experimental data was basically consistent with that in the model prediction on condition of 3 kg per batch. The data demonstrated that the processing capacity of the device can be 10 batches per hour (15 kg per batch), where all the indexes can meet the design requirements. This finding can provide a sound reference for the optimal design of batch cleaning device for the seed or other granular materials. [ABSTRACT FROM AUTHOR]