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.

To investigate the influencing factors and intrinsic relationships between potato impact force and impact damage during potato soil separation, a testing system for potato impact force was established. The impact force test system is composed of a base, a height adjustment device, a simple separation screen, a soil storage tank, an impact force sensor, and so on. By allowing potatoes to fall freely to simulate the collision process, impact force data are collected, and a high-speed camera is used to locate the impact position and analyze the degree of damage. Through the response surface analysis method, the influencing factors and laws of the impact force and impact damage during the collision process between potatoes and rods under soil and no-soil conditions were studied. The results of the response surface analysis indicate that when the screen inclination is within the range of 14.12 degrees to 14.77 degrees, falling height ranges from 453.83 mm to 500 mm, screen rod spacing falls within 36.50 mm to 40 mm, and the screen rod material is rubber. Potatoes can still be at a relatively low damage level when enduring a large impact force. This study has significant implications for reducing potato impact damage during harvesting, enhancing economic benefits in the potato industry, and advancing the technical level of potato harvesting equipment. In the future, based on the results of this study, further exploration can be made to optimize the design of potato harvesting equipment so as to better reduce the damage to potatoes during harvesting and subsequent processing processes and promote the sustainable development of the potato industry.

Aiming at the problems of high skin-breaking rate and high impurity rate of sweet potato during harvesting operations, a low-damage fresh-eating sweet potato combine harvester based on a two-segment potato-soil separation device was designed by using a d-type elevator chain combined with a double-buffer clearing platform technology. The results show that the best working parameters of the harvester are a vibrating shaft frequency of 5.2 Hz, elevator chain speed of 0.37 m/s, and cleaning platform speed of 0.58 m/s, in which the sweet potato skin-breaking rate is 1.09% and the impurity rate is 1.90%, which is in line with the standard.

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.