Design and study of anti-blocking type potato stubble disc clamping and pulling device based on MBD-DEM coupled simulation

Aiming at the potato seedling killing machine low seedling removal rate and poor effect of stubble separation device which affects the harvest efficiency and quality, combined with the ridge planting mode and stubble distribution characteristics, based on the principle of flexible pulling to design a anti-blocking tpye potato stubble disc clamping and pulling device. On the basis of elaborating the overall structure and working principle of the device, the structural parameters and operating parameters were clarified, and the theoretical analysis of the stubble righting, clamping and pulling process was carried out.The main factors affecting the stubble pulling effect were the device forward velocity, the angular velocity of the stubble pulling disc(SPD) and the number of the pressure disc grilles. The MBD-DEM coupled simulation model was established, and the three-factor, threelevel orthogonal test was conducted with the machine forward velocity, the angular velocity of SPD, and the height of SPD from the ground as the test factors, and the rate of stubble bond breaking and root particles retention as the evaluation indexe. The optimal parameter combinations of the forward velocity of 559.2 mm/s, angular velocity of 4.92 rad/s, and the height of SPD from the ground of 30 mm were obtained through the response surface analysis of the experimental results and the optimization of the parameters. Potato stubble disc pulling test bench was built, and the one-way test was conducted to determine the optimal number of pressure disc grilles as 18, and the corresponding parameter combinations of the test bench were 124 r/min for stubble feeder drive, and 46/min for stubble pulling drive, and the validation test indicated that: fracture rate of stubble was 6 %, and missing rate of stubble was 4.8 %, which basically fit the results of the simulation test, and the device had a good stubble pulling effect, which met the design requirements of the high harvesting efficiency of potato harvester and low contamination.