Computational model and adjustment system of header height of soybean harvesters based on soil-machine system

Abstract

With wide distribution and a large planting area, soybeans are an important cash crop in China. Due to the low position of soybean plants, improper control of the header height during harvesting is likely to cause poor harvesting and soil shoveling. To solve such problems, a soybean harvester header-height adjustment system is developed in this study. A profiling mechanism and hydraulic driving system were designed based on a current soybean harvester. The interaction between the soil and the harvester’s profiling mechanism was explored, the force and motion of the profiling mechanism were analyzed, and a relational model between the detection angle of the angular transducer and the rotational angle of the profiling mechanism was built. By analyzing the soil compactness of soybean growing plots, a linear fitting method was used to establish a mathematical model of soil compactness and compacting depth, a computational model of profiling the header height was determined, and an adaptive header-height adjustment system was designed. Evaluation indicators of the soybean harvester header-height adjustment system were constructed and a field harvesting experiment was conducted, whose results show that the absolute error between the average stubble height and the profiling height set by an industrial personal computer (IPC) before the tests was less than 2 mm. The variation coefficients of stubble height in the four groups of tests were 9.3%, 11.6%, 8.5%, and 6.5%, with respective profiling control accuracy of 88%, 86%, 90%, and 92%, ground flatness and soil compactness have little effect on the overall control effect of the control system.