双通道斜置式撒肥叶片单圆盘离心式变量撒肥机设计与试验

Design and Experiment of Single-disc Centrifugal Variable-rate Fertilizer Spreader with Double-channel Inclined Spreading Blades

摘要:

撒肥是农业生产的重要环节,提高撒肥均匀性在保证作物产量与品质的同时也减少对环境造成的污染。针对单通道直线式撒肥叶片撒出肥料分布均匀性差等问题,设计了一种双通道斜置式撒肥叶片的单圆盘离心式变量撒肥机,采用模糊PID算法开发双变量撒肥控制系统,可依据实时信息实现落肥量与撒肥幅宽的同时调节。通过分析肥料颗粒在叶片前端、后端和空气中的受力情况,构建肥料颗粒运动学模型,确定叶片最佳参数,以实现肥料均匀分布。基于离散元法建立撒肥仿真模型,分别进行单因素试验与正交试验并进行响应面分析。试验结果表明:在落肥口开度8°,叶片偏角0. 42°,叶片斜角16. 22°,圆盘转速450 r/ min,前进速度1. 1 m/ s 时,肥料分布状态达到最佳,此时肥料分布均匀性变异系数为18. 7% ,撒肥有效幅宽为10. 96 m。进行台架试验与田间试验,对仿真试验结果与双变量撒肥控制系统性能进行验证,结果表明:台架试验与仿真试验的肥料分布均匀性变异系数平均误差为0. 24% ,说明离散元法可准确模拟撒肥过程;肥料分布均匀性变异系数为24. 5% ,肥料施用控制精度为90. 7% ,总排肥量稳定性系数为94. 6% ,单位面积施肥量误差为19. 8% ,满足农艺要求。该研究结果为提高撒肥均匀性及精准变量施肥技术研究提供重要参考。

Abstract:

Fertilizer spreading is a crucial part of agricultural production. Improving spreading uniformity can ensure crop yield and quality while reducing environmental pollution. To address the poor uniformity of fertilizer distribution when spread by the single-channel linear type spreading blades, a single-disc centrifugal variable rate fertilizer spreader based on double-channel inclined spreading was designed. A double-variable fertilizer spreading control system was developed by using the fuzzy PID algorithm, which can adjust the fertilizer application rate and spread width simultaneously according to real time information. A complete kinematic model was constructed by analyzing the fertilizer particles at the front and rear of the blades and in the air, and optimum blade parameters were determined to achieve the most uniform fertilizer distribution. A fertilizer spreading simulation model was established based on the discrete element method, and single-factor tests, orthogonal tests, and response surface analysis were carried out. The test results showed that when the fertilizer outlet opening was 8°, the blade deflection angle was 0. 42°, the blade inclination angle was 16. 22°, the disc rotation speed was 450 r/ min, and the forward speed was 1. 1 m/ s, the fertilizer distribution reached the best state. At this time, the coefficient of variation of fertilizer distribution was 18. 7% , and the effective spreading width was 10. 96 m. Bench tests and field tests were conducted to verify the simulation test results and the performance of the double- variable fertilizer spreading control system. The results showed that the average error in the coefficient of variation for fertiliser distribution uniformity between the bench test and the simulation test was 0. 24% , indicating that the discrete element method can accurately simulate the fertilizer spreading process. The coefficient of variation of fertilizer distribution uniformity was 24. 5% , the fertilizer application control accuracy was 90. 7% , the total fertilizer discharge stability was 94. 6% , and the error of fertilizer application per unit area was 19. 8% , meeting the agronomic requirements. The research results can provide an important reference for improving fertilizer spreading uniformity and studying precise variable rate fertilization technology.