土下切根聚拢式菠菜有序收获机设计与试验

Design and Experiment of Spinach Harvester with Root Cutting and Gathering under Soil

摘要:

针对现有菠菜收获机作业时存在的有序性差、茎叶损伤大等问题，设计了一种土下切根聚拢式菠菜有序收获机，可将4行菠菜土下切根后聚拢为2行横向有序收集，缩小横向收集尺寸。对根切铲机构和夹持输送装置进行了设计与分析，对夹持切割瞬时和聚拢输送过程中植株姿态变化进行了理论分析，获得了影响菠菜植株姿态变化以及不发生掉落和不产生茎秆损伤的关键参数。运用Box-Behnken试验设计方法进行了台架试验，以机器前进速度、夹持轨道倾角、夹持带输送速度为因素进行三因素三水平正交试验，建立以收获损失率和菠菜伤茎率为响应指标的二次回归模型。通过响应曲面法分析各因素对响应指标的影响，验证试验结果表明：机器前进速度为1.1km/h，夹持轨道倾角为18°，夹持带输送速度为0.45m/s时，收获损失率为2.47％，伤茎率为3.05％，各项性能满足菠菜机械化收获要求。

Abstract:

Spinach, as a typical stem and leaf vegetable, has relatively high economic and nutritional value. To solve the problems such as poor orderliness and large damage to stems and leaves existing in the mechanical harvesting operation of spinach, a spinach ordered harvester with root cutting and gathering under the soil was designed. The collection scheme of cutting the roots of four rows of spinach under the soil and gathering them into two rows for orderly conveying was adopted, reducing the size of the lateral collection frame. It can achieve the operation process of “clamping into the soil and cutting roots-orderly conveying-gathering and collecting-turning and spreading” at one time. The root cutting shovel mechanism and the clamping, conveying, gathering and collection device were designed and analyzed. The key parameters of the triangular root cutting shovel and the clamping gap of the clamping belt that prevented spinach from dropping and stem damage during clamping and conveying were determined. A theoretical analysis was conducted on the changes in plant posture during the instantaneous working process of clamping and cutting, and the main factors influencing the posture changes of spinach plants were obtained. A bench test was conducted by using the Box-Behnken experimental design method. A three-factor and three-level orthogonal test was carried out with the machine’s forward speed, the inclination angle of the clamping track, and the conveying speed of the clamping belt as factors, and a quadratic regression model was established with the harvest loss rate and the spinach stem injury rate as response indicators. The influence of each factor on the response index was analyzed by the response surface method. The verification test results showed that when the machine’s forward speed was 1.1km/h, the inclination angle of the clamping track was 18°, and the conveying speed of the clamping belt was 0.45m/s, the harvest loss rate was 2.47%, the stem damage rate was 3.05%, and all performances met the requirements of mechanized spinach harvesting.