To improve soil clod removal and reduce potato damage in potato combine harvesters, this study investigates the processes involved in soil clod removal and potato collisions within the bar-lift chain separation device of the harvester. It outlines the structure and working principles of the machine, theoretically analyzes the key dimensions of the digging device and potato-soil separation components, and derives specific structural parameters. A dynamic mathematical model of the bar-lift chain is established, from which the dynamic equations are formulated. The analysis identifies factors that influence the dynamic characteristics of the bar-lift chain. This study examines the working principles and separation performance of the potato-soil separation device, with a focus on the collision characteristics between potatoes and both the screen surface and the bars. Key factors such as the separation screen's line speed, the harvester's forward speed, and the tilt angle of the separation screen are considered. Simulations are performed using a coupling method based on the Discrete Element Method (DEM) and Multi-Body Dynamics (MBD). Through simulation experiments, the optimal parameter combinations for the potato-soil separation device are determined. The optimal working parameters are identified as a separation screen line speed of 1.25 m/s, a forward speed of 0.83 m/s, and a tilt angle of 25 degrees. Field harvesting experiments indicate a potato loss rate of 1.8%, a damage rate of 1.2%, an impurity rate of 1.9%, a skin breakage rate of 2.1%, and a yield of 0.15-0.21 ha/h. All results meet national and industry standards. The findings of this research provide valuable theoretical references for simulating potato-soil separation in combine harvesters and optimizing the parameters of these devices. Future potential research will consider the automatic regulation of the excavation volume of the potato-soil mixture, aiming to achieve intelligent control of the potato-soil separation operation.

A rotor vibration potato-soil separation device (RVPSD) is proposed in view of poor potato-soil separation and higher potato damage rate. Separation efficiency between potatoes and soil and the potato damage rate are selected as evaluation indicators, and a coupling simulation model of potato-soil separation based on Discrete Element Method (DEM) and Multibody Dynamics (MBD) is built up according to structure and working principle of the separation device. The optimal combination of working parameters of the RVPSD is obtained via simulation experiment. The results show that the optimal working parameters of vibration point position, conveying speed of potato-soil separation elevating chain, rotor amplitude and rotor vibration frequency are 646.5 mm, 1.08 m/s, 26.7 mm and 5.9 Hz respectively. The field validation experiment is carried out based on the optimal combination parameters. The results show that the potato-soil separation efficiency and potato damage rate of the RVPSD are 97.8 % and 1.16 % respectively, the field experiment results are basically consistent with the simulation results, which proves the correctness of the simulation model. It can provide theoretical reference for rotor vibration potato-soil separation process simulation and device parameter optimization.