Effects of the blade disk vibration in axial and cutting parameters on the cutting quality of sugarcane harvesters

Abstract: Sugarcane Cutting Quality (SCQ) has been one of the most important limiting factors in a sugarcane harvester. The sugarcane ratoons can be broken to reduce the budding rate, thus leading to the sugarcane yield decrease in the subsequent year. It is an extremely serious threat to the sugarcane yield for cost-saving planting. This study aims to investigate the effects of axial blade disk vibration and cutting parameters on the cutting quality of sugarcane harvesters. A series of cutting tests were performed on a self-developed test platform of a sugarcane harvester. The SCQ evaluating indexes were selected as the number of sugarcane cracks, the crack thickness, the crack depth, and the number of sugarcanes with broken ratoons. Then, the Comprehensive sugarcane Cutting Quality Evaluating Value (CCQEV) was calculated with the four parameters through the improved entropy as the test index. A regressive equation was established using single-factor tests, the orthogonal test, and the quadratic regressive orthogonal rotary combination test. The axial blade disk vibration was characterized by the vibration amplitude, frequency, and rotation velocity of the blade disk, together with the moving velocity of the sugarcane harvester, the blade installing angle, and their interactions on the SCQ. The results showed that there were strong linear negative relationships between the SCQ and the axial blade disk vibration amplitude, the SCQ and the axial blade disk vibration frequency. The significance coefficients of the axial blade disk vibration amplitude and frequency were 0.002 and 0.035, respectively. There were significant effects on the SCQ. By contrast, the significance coefficients of the sugarcane harvester moving velocity, the blade disk rotation velocity, and the blade disk installing angle were greater than 0.05, indicating no significant effect on the SCQ. The significance coefficients were 0.045 and 0.036 for the interaction of the axial blade disk vibration amplitude and frequency, as well as that of the axial blade disk vibration amplitude and the blade disk rotation velocity, respectively, indicating the significant effects on the SCQ. The significance coefficients of other interactions were greater than 0.05, indicating no significant effect on the SCQ. The significance levels were ranked in the descending order of the axial blade disk vibration amplitude > frequency > the sugarcane harvester moving velocity > the blade disk rotation velocity > the blade disk installing angle. There was a specific interaction between the axial blade disk vibration amplitude and frequency and that between the axial blade disk vibration amplitude and the blade disk rotation velocity. The greater the axial blade disk vibration amplitude and frequency were, the greater the CCQEV was, and the worse the SCQ was. The greater the axial blade disk vibration amplitude and the blade disk rotation velocity were, the greater the CCQEV was, and the worse the SCQ was. Moreover, a high-speed camera was used to capture the sugarcane-cutting process. Several times of cutting rather than one time were implemented in the sugarcane harvester, due to the axial blade disk vibration. There was an outstanding height difference between the cut-in points. The significance levels of the axial blade disk vibration amplitude and frequency were higher than those of the rest. There was also some effect of the interaction between the axial blade disk vibration amplitude and frequency on the SCQ. Therefore, an analysis was made to clarify the influencing mechanisms of the axial blade disk vibration amplitude and frequency as well as their interaction with the SCQ from the angle of the multi-cutting process. The vibration amplitude of sugarcane harvesters decreased to improve the natural frequencies of the body frame, whereas, the cutting system of sugarcane harvesters increased to avoid the resonance phenomenon. This finding can provide a strong reference for the higher SCQ in sugarcane harvesters.