Longitudinal Axial Flow Rice Thresher Feeding Rate Monitoring Based On Force Sensing Resistors
Abstract The threshing unit is the main working unit of the combine harvester and plays an essential role in rice threshing efficiency, seed loss, and seed damage. Every thresher has its limitation for feeding quantity, and when the feeding quantity exceeds the maximum rated amount, the thresher gets blocked, which results in higher losses, low threshing efficiency, more power consumption, and combine overloading, then combine shutting down at the end. In this study, a longitudinal axial flow rice threshing platform has been constructed, and a stress monitoring system for the top cover of the threshing drum was designed using force sensing resistors. The sensors were installed on the thresher top cover inner surface to detect the impact and extrusion forces caused by the threshing process and detect the feeding rate when it exceeds the suitable feeding of the combine. Three feeding rates (0.8, 1.1, and 1.4 kg/s) and three thresher speeds (1100, 1300, and 1500 rpm) were tested. The time of the testing process was calculated using high-speed photography. The obtained results revealed that the force signals collected by thin-film sensors significantly correlated with thresher rotating speed and feeding rate. This study provides a new method for threshing drum real-time feeding quantity monitoring and early warning of thresher blockage.