Interaction between the scraper of the wine grape cleaning machine and the anti-cold soil

Abstract: Fully automatic soil cleaning and retaining operation in spring have been emerging in the wine grape-producing areas in northwest China. However, some challenges have still remained on the current single scraper soil cleaning components, such as the high power consumption of the whole machine during the operation, and the low soil cleaning efficiency. In this study, a novel double-scraper type soil cleaning machine was developed to explore the dynamic interaction with cold soil during operation in the grape-growing regions of Northwest China. The number and dimensions of the scrapers were also determined. Specifically, the overall dimensions of the machine were 2 000 mm×2 500 mm×1 600 mm (length×width×height), among which the height of the large scraper was 600 mm, the length was 1 400 mm, the height of the small scraper was 300 mm, the length was 600 mm, and the single-side soil cleaning depth of the whole machine was 300-500 mm. After that, a theoretical analysis was made to determine the force of the large scraper and its influencing factors of working resistance. An EDEM software was utilized to simulate the interaction between the discrete soil particle groups and the mechanical properties in the different scrapers with various curved surfaces, cutting angles, and inclination angles. As such, a relationship was obtained for the back soil condition of the scraper and the flow law of the soil particle groups. Then, a three-factor and three-level orthogonal test was designed to obtain the best working parameters of the scraper with the amount of back soil as the evaluation index. A single-factor analysis and a bench test were also conducted to verify the simulation. The results showed that the primary and secondary factors were the scraper surface profile, the cutting and inclination angle, in terms of the amount of back soil of the scraper. Furthermore, the best scraping performance was achieved, where the scraper curved surface was in the parabolic profile, the cutting angle was 55°, and the inclination angle was 60°, and the least amount backed soil was 43.2 kg, indicating a better consistence with the simulation. A double-scraper physical prototype was also fabricated. A comparison test was then performed on the traditional single-scraper soil cleaning and retaining machine. The test results showed that the soil removal rate of the double-scraper soil cleaning rattan lifter was 75.03 %, which was 27.2 percentage points higher than the traditional single-scraper cleaning machine (47.83 %). In response to the requirements of soil cleaning operations in Northwest China, the back soil volume of the newly developed scraper was 91.42 kg, which was 38.74 % lower than that of the traditional one in the field. The findings can provide a strong theoretical reference for the subsequent development of a scraper-type soil cleaning machine.