Design and experiments of pickup device of peanut harvester after cutting peanut straws

Abstract: Peanut straw is excellent feed for animals. In order to realize the animal feed utilization of peanut straw planted with plastic film, a "three-step" harvesting method (cutting-digging-picking and harvesting) was put forward Specifically, peanut straws is cutted before digging to shorten the peanut plant, reduce the transverse size and increase the pod-straw ratio, which is conducive to the harvest operation. At present, there is no suitable pickup device for peanut harvest after cutting straws. Based on the existing peanut combine harvesting techniques, an elastic-tooth pickup device was designed in this paper. As an important part of peanut combine harvester, the elastic-tooth pickup device was mainly composed of pickup elastic tooth, conveying plate, support plate, installation base of pickup elastic tooth, installating tube, main shaft, etc. The transverse sizes of the post-cutting peanut plants were analyzed by using SPSS software, and the separation distance of the neighboring elastic teeth was determined as 7 cm. Based on the theoretical analysis of the conditions of peanut plants picking and throwing, radius of gyration and rotating speed of the elastic tooth determined as 21 cm and 60 r/min, respectively. Through the analysis of the stress situation during the peanut plant picking, the bending angle of the pickup elastic tooth and the length of the bending part were determined to be 102° and 4 cm, respectively. Through analysis of the movement trajectory of the pickup elastic tooth tips by using Matlab software, the movement trajectory of different rows of elastic tooth tips was calculated, the row number of elastic tooth was determined to be 6. Finally, field experiments of the peanut pickup device were carried out. The results showed that the pickup rate was 98.07%, and the drop rate caused by the pickup device was 1.23%, the operation performance of the pickup device met the requirements of peanut pickup harvest after cutting straws. During operation, there were two main reasons for missing picking, firstly, a small amount of peanut plants after cutting were too short and dropped to the ground from the elastic teeth gap; secondly, during the digging operation, some shallow ditches were formed when the tractor tires rolled on the ground, the peanut plants falling in the shallow ditches could not be picked up, resulting in missing picking. There were three main reasons for the pod drop, firstly, some peanut straws decayed and straws strength decreased; secondly, the peanut pod after straws cutting lost the "protection" of peanut vine, which increased the probability of the elastic teeth hitting the pod directly; thirdly, because a small number of peanut plants could not be picked up at one time, and need to be picked up for 2-3 times continuously, multiple picking and beating increased the drop of pod. This study can provide a basis and reference for the development and improvement of the pickup harvest technique for peanut and other short crops.