Design and Experiment of Profiling and Damping Device for Rapeseed Tooth-belt Pickup

Rapeseed is one of the most important oil crops in China. Obstruction exists in mechanized combine harvesting because of the biological characteristics of rapeseed. In recent years, the two stage-harvesting is widely adopted due to the advantages in well-adapted ability of rapeseed variety and high quality of the harvested rapeseed, but there are still some problems in the pick-up stage especially the low operation efficiency and quality due to the instability when working on the uneven terrain. Aiming at the problem of low operating stability of existing rapeseed pickers during the high-speed operation in complex fields, a profiling-damping device for articulated toothed-belt pickup was designed. By establishing the kinematic model of the profiling and vibration reduction system, the key structures and operating parameters that affected the stability of profiling were determined. And the specific parameters which could play important roles in the operation process were analyzed. The spring stiffness coefficient k, system damping ratio ξ and forward speed vf were selected as the test factors, and the variation coefficient of peak angle of hinged point was selected as the test index based on the response surface method of three factors and three levels Box-Benhnken combination test. The order of the factors affecting the average degree deviation was obtained from large to small as follows: damping ratio, stiffness coefficient and forward speed. The order of the factors affecting the stability of profiling was obtained from large to small as follows: forward speed, stiffness coefficient and damping ratio. The optimum parameter combination under the minimum average degree deviation and profiling stability variation coefficient was found as follows: stiffness coefficient of 9.7 N/mm, damping ratio of 0.38 and forward speed of 0.95 m/s. Field comparison tests were carried out using the approximate optimal parameters combination, the results showed that the average loss ratio of the pickup harvester with the profiling-damping device was 4.53% and the average impurity ratio was 3.22%. The loss and impurity ratio were 30.73% and 27.64% lower than the one that without the device respectively and the operation quality was significantly improved. The research results can provide references for improving the profiling and operation stability and quality. © 2020, Chinese Society of Agricultural Machinery. All right reserved.