Optimized design and experiment of the tassel gathering mechanism for 4BL-1 type white radish combine harvester

White radish has been one of the most popular root vegetables in recent years. The mechanized production of white radish often includes the ploughing, planting, managing, cleaning, and post-processing of mature products. Among them, the harvesting has been the weakest degree of mechanization in the production. The "Picking type" harvesting can serve as the joint harvesting for the white radish. The tassel can also be operated to realize the clamping, conveying, and tassel-cutting processes. Therefore, the gathering quality of the tassel can directly determine the overall harvesting. However, only a few reports focused on the tassel gathering of white radish. In this study, a tassel-gathering mechanism was designed for the white radish, according to the tassel's physical properties and fracture mechanics. The complete gathering of tassels was achieved in the highly qualified rate of cutting head with the low loss and damage rate in the process of machine harvesting. The gathering of white radish tassels into bundles was realized from the natural "semi-prostrate" state in the field, particularly for the operation of the subsequent links. A kinematic model of tassel gathering mechanism was constructed to propose the concept of "tassel-gathering speed ratio". The optimal range was learned during mathematical modeling; The mathematical model was constructed to explore the influence of structural and key motion parameters (such as the forward speed, tassel gathering speed ratio, and the installation angle of the tassel gathering mechanism) on the tassel performance. The mathematical model was then used to determine the performance of tassel gathering. The optimal structure and motion parameters of the tasseled gathering mechanism were solved to consider the complexity of the field environment and the unfavorable control of variables in the test. An indoor bench test was carried out to combine with the theoretical analysis. The influenced factors were taken as the forward speed, tassel gathering speed ratio, and installation angle of the tassel gathering mechanism of the white radish combine harvester. The success and breakage rate of tassel gathering were taken as the evaluation indexes. The three-factor and three-level response surface test was carried out using Design-Expert software. The regression mathematical model was established between the influenced factors and the indexes. The parameters of the model were optimized at the same time. The test results showed that the significance of the success rate of tassel gathering was ranked in the descending order of the forward speed, the tassel gathering speed ratio, and the installation angle of the tassel gathering mechanism; The significance of the breakage rate of tassel gathering was ranked in the descending order of the tassel gathering speed ratio, installation angle of tassel gathering mechanism, and forward speed. The optimal combination of parameters was the forward speed of 0.4 m/s, tassel gathering speed ratio of 3.9, and the installation angle of the tassel gathering mechanism of 86.3°. The success and breakage rate of tassel gathering were predicted as 94.56% and 10%, respectively. Experimental verification showed that the success and the breakage rate of tassel gathering were 92.04% and 8.81%, respectively, under the optimal combination of parameters. The evaluation indexes were close to the prediction, which fully met the demand of tassel gathering of picking-type combine harvester for the white radish. This finding can also provide a strong reference to optimize the white radish harvester machinery.