Optimization and experiment of counter-rotating straw returning cultivator based on discrete element method

Abstract

This study is mainly about the optimization, simulation and experiment of a Counter-rotation Straw Returning Cultivator (CSRC), aiming at the problems that the existing CSRC has serious entanglement of grass, terrible jam of soil, large energy consumption, and poor straw coverage rate. Besides, an optimized Rotary Blade Roller (RBR) and a device to avoid the jam of soil were designed to optimize CSRC. A discrete element simulation model of straw-soil-RBR was established based on the EDEM software. The optimization simulation experiment of 4 factors and 3 levels, which took the single-blade operation width, bending angle, advance speed and rotation speed of RBR as factors, and used the straw coverage rate and power consumption as evaluation indicators, was carried out to optimize the structure parameters and working parameters of the RBR with the method of orthogonal experiment. The simulation experiment results showed that the optimal combination of parameters of the RBR at the tillage depth of 130 mm were 237.58 r/min of RBR rotation speed, 1.11m/s of forward speed, 35 mm of single-blade working width, and 134.09° of bending angle. Field tests showed that the straw coverage rate was 89.29%, the average torque was 517.25 N·m, the soil fragmentation rate was 83.21%, and the flatness of the surface after cultivation was less than 4 cm under the conditions of optimal parameters mentioned above. Therefore, the CSRC perfectly satisfied the industry standards, and meet the design requirements of machinery.