Discontinuous totalizing automatic quantitative feeding technology for granular agricultural products

Granular agricultural products can often be packaged quantitatively before sales. The speed and accuracy of material feeding are important indicators to evaluate quantitative feeding in quantitative packaging production lines. However, it is difficult to accurately and efficiently feed the granular agricultural products, due to the irregular appearance, uneven volume, and easy dispersion. In this study, discontinuous totalizing quantitative feeding was proposed, according to the volumetric and gravity (static weighing). A closed-loop control system was constructed with iterative learning. A dynamic quantitative feeding equipment was also developed for the granular agricultural products. The feeding mechanism of the equipment was composed of several measuring cups with variable volume under accurate control by the shaft. The reinspection mechanism of the equipment was composed of a reinspection weighing scale, removal, and unloading device, in order to inspect the actual quality of the feeding. The working procedure of the equipment was as follows. Firstly, the packaging target was evenly divided into several parts. And then one part of the target quality was quantitatively fed with each measuring cup during feeding. Finally, the actual quality of all measuring cups was totalized to obtain the packaging target. Furthermore, a gravity (static weighing) quantitative feeding was used to inspect the actual quality of the previous one before feeding to the next measuring cup in each group. The inspected error was used to adjust the volume of the next measuring cup in the same group. Since the packaging target quality was obtained by totalizing the feeding of several measuring cups, the volume of the following measuring cups was continuously corrected to make the totalizing feeding actual quality of the group of measuring cups in a group of feeding, regardless of whether there was an error in the first few measuring cups. This discontinuous totalizing feeding was integrated to improve the quantitative accuracy of the equipment. Taking 600 g of soybeans, red beans, or mung beans as examples, a series of quantitative feeds were carried out on the equipment. The experimental results showed that the feeding quality error was controlled within 0.2% when the number of measuring cups was 5 and the equipment rotational speed was 2 r/min. The error was effectively reduced during dynamic quantitative feeding. Particularly, the quantitative accuracy was much higher than that in the national standard requirement. The finding can provide a feasible technical solution to the high-accuracy quantitative feeding of granular agricultural products, such as traditional Chinese medicine pill packaging, quantitative sowing and fertilization, and quantitative feeding of granular fertilizers.