茶园同轴螺旋开沟深松施肥一体机多目标优化与试验

Multi-objective Optimization and Experiment of Coaxial Spiral Trenching-Subsoiling-Fertilizing Integrated Machine in Tea Garden

摘要:

针对丘陵茶园坡地行间狭窄、地表残茬导致施肥机失稳、施肥不均、通过性差及开沟困难等问题，本文设计了一种同轴螺旋开沟深松施肥一体机，可同时实现深松、开沟、施肥和覆土作业。对开沟装置和排肥装置等关键部件进行了优化设计，建立了螺旋施肥土壤颗粒运动学与力学模型，确定了螺旋开沟刀具临界转速；提出了一种基于离散元法的土壤-机具互作模型，开展了单因素与 Box-Behnken 中心组合试验，建立了开沟性能参数的回归模型，采用多目标优化方法优化作业参数。优化结果为前进速度0.20 m/s、螺旋刀具转速193.23 r/min、刀具螺旋角30.12°。在优化组合参数下，仿真开沟深度稳定性系数为98.56%，沟底宽度一致性系数为97.32%，覆土率为83.14%，排肥稳定性系数为98.76%，排肥均匀性系数为98.05%。田间试验结果表明，开沟深度稳定性系数、沟底宽度一致性系数、排肥稳定性系数、施肥均匀性系数和覆土率平均值分别达到 95.01%、93.07%、97.73%、97.49%、81.67%，各指标满足茶园施肥农艺要求。研究结果为丘陵茶园机械化高效精准施肥提供了一种有效的技术装备参考。

Abstract:

In response to the problems such as narrow inter-row space on hilly tea gardens, unstable operation of fertilization machines due to surface residues, uneven fertilization, poor mobility and difficulty in trenching, a coaxial spiral trenching and deep loosening fertilization integrated machine was designed, which can simultaneously perform deep loosening, trenching, fertilization and soil covering operations. The key components such as the trenching device and the fertilizer discharge device were optimized. The kinematics and mechanics model of spiral fertilization of soil particles were established, and the critical rotational speed of the spiral trenching tool was determined. A soil-machine interaction model based on the discrete element method was proposed. Single-factor and Box-Behnken central combination experiments were carried out, and a regression model of trenching performance and parameters was established. The operation parameters were optimized by using multi-objective optimization methods. The optimization results were a forward speed of 0.20 m/s, a rotational speed of the spiral trenching tool of 193.23 r/min, and a spiral angle of the tool of 30.12°. Under the optimized combination parameters, the stability coefficient of trenching depth was 98.56%, the consistency coefficient of trench bottom width was 97.32%, the soil covering rate was 83.14%, the stability coefficient of fertilizer discharge was 98.76%, and the uniformity coefficient of fertilizer discharge was 98.05%. The field test showed that the average values of the stability coefficient of trenching depth, the consistency coefficient of trench bottom width, the stability coefficient of fertilizer discharge, the uniformity coefficient of fertilization and the soil covering rate were 95.01%, 93.07%, 97.73%, 97.49% and 81.67%, respectively. All the indicators met the agronomic requirements for fertilization in hilly tea gardens. The research results can provide an effective technical equipment reference for the mechanized, efficient and precise fertilization in hilly tea gardens.