Design and test on double-roller sweet potato vine crushing and returning machine

ABSTRACT At present, all most sweet potato crushing machineries are improved based on potato seedling killer or straw crushing and returning machine, and adopt single-roller mulch type seedling killing structure, and there are problems such as low crushing qualification rate of ridge vines, easy entanglement of stalks and high damage rate. This not only requires manual further removal of the vines, but also the damaged sweet potato cannot be stored, which affects the yield. To solve the problems, a double-roller sweet potato vine crushing and returning machine with the structure of the front roller picking and the back roller crushing was designed. The Box-Behnken test design method was adopted to establish a quadratic regression model that took the picking roller speed, the cutter roller speed and the ground clearance as the test factors, and the vines breaking qualified rate, the stubble height, and the sweet potato damage rate as evaluating indicator.The analysis of the influence of interactive factors showed that the contribution rate of each factor to the vines breaking qualified rate was picking roller speed> cutter roller speed > ground clearance; the contribution rate of each factor to the stubble height was ground clearance> pickling roller speed > cutter roller speed; the contribution rate of various factors to the sweet potato damage rate was ground clearance> cutter roller speed > pickling roller speed. The optimization results showed that when the picking roller speed was 631 r/min, the cutter roller speed was 1906 r/min, and the ground clearance was 21 mm, the vines breaking qualified rate was 96.2%, the stubble height was 28.8 mm, and the sweet potato damage rate was 0.16%. The research results can provide new test schemes and complete design parameters for sweet potato vine crushing operations.