离心式变量撒肥机多轨迹重叠撒肥作业机理研究及机构优化

Accuracy, uniformity and consistency of multi-pass overlapping application using centrifugal fertilizer spreader are the technical problems that agricultural machinery researchers have been facing for a long time. Aiming at the problems of low application accuracy and poor distribution uniformity in the process of centrifugal fertilization, this project intends to apply the theory of mechanical system dynamics, sensing detection and control technology to build the dynamic coupling system discrete element simulation model. Organically integrated the virtual simulation technology, high-speed photography analysis and bench test methods, the kinematics and dynamics characteristics of spreading process were studied, the internal relation between application accuracy, particle distribution uniformity and structure parameters, motion parameters of spreader device were ascertained, the generation and influence mechanism of multi-pass overlapping spreading performance were uncovered, as well as the particle variation law in transverse and longitudinal distribution. By comprehensive application of multi- objective digital simulation, multi-factor response optimization, multi-data mining theory and other technical methods, the parametric model of simulation system and the prediction mathematical model of operation quality were established to obtain the optimization design scheme of fertilizer spreader device, and realize the optimal combination of structure and operation parameters. The research results will provide data reference for traditional empirical fertilization and technological innovation of centrifugal variable fertilization in China.

离心式变量施肥机多轨迹重叠撒肥准确性、均匀性、一致性是农机科研者长期面临的技术难题。针对离心变量撒肥作业过程中撒肥量准确性低和肥料分布均匀性差等问题，本项目拟运用机械系统动力学理论，结合传感检测与控制技术，组建颗粒-撒肥装置动力学耦合系统离散元仿真模型，将虚拟仿真技术、高速摄影分析与台架试验等手段有机融合，研究撒肥作业过程运动学和动力学特征，探明撒肥准确性、颗粒分布均匀性与撒肥装置结构和运动参数的内在联系，揭示多轨迹重叠撒肥作业质量产生机制和影响机理以及颗粒横向、纵向分布变异规律；综合应用多目标数字仿真、多因素响应面优化、多数据挖掘理论与田间试验验证等技术方法，建立仿真系统参数化模型与作业质量预测数学模型，获取撒肥装置综合优化设计方案，实现撒肥装置结构和作业参数最优化组合，为传统的经验式均衡施肥提供一定的数据参考，为我国离心式变量施肥技术创新和设备研发提供理论依据和新方法。

随着现代农业种植的规模化发展，施肥作业效率和肥料利用率越来越受到关注，离心式变量撒肥技术成为实施高效精确农业的核心技术之一。目前，有关离心式变量撒肥机构工作过程的认知尚未达到理论水平，对撒肥作业形成机理研究还很粗浅，机构综合优化方法欠缺，造成撒肥性能准确性低和肥料分布均匀性差的局限，严重制约了变量撒肥机构创新水平、降低了作业质量。本项目以我国长江中下游地江苏稻麦轮作区水稻种植常用颗粒肥料为研究对象，完成了颗粒肥料物理、力学特性参数测定，建立了基础数据库。改造试制了离心撒肥装置试验台架，分析了撒肥作业过程中肥料颗粒-撒肥机构之间相互作用关系，联合建立了典型肥料颗粒群多体模型、撒肥装置虚拟样机三维模型以及颗粒-机构动力学耦合系统离散元仿真模型。开展了不同结构参数、作业参数等工况条件下离心撒肥作业过程动态仿真试验分析，研究了叶片倾角、撒肥高度、排肥流量以及圆盘转速对离心撒肥颗粒横向分布变异规律的影响。研究了不同排肥流量、圆盘转速撒肥策略时肥料颗粒分布均匀性，及其对单位面积撒肥量和撒肥作业有效幅宽的影响，揭示了离心撒肥作业质量产生机制和影响机理；开展了系统变量作业横向、纵向耦合变化特征研究，建立了影响因素与响应值之间的相互关系拟合函数和撒肥量预测模型。设计了多因素、多指标性能数字化仿真综合试验，分析了结构参数对撒肥作业质量单因素效应和多因素交互作用，优化了撒肥装置关键结构参数，获取了机械化离心变量撒肥作业质量提升技术途径。最终，通过对比离心撒肥精度和撒肥量准确性，呈现出节肥减量功效；分析验证了变量撒肥后作物群体长势结构，改善了长势空间差异性、均衡土壤结构和养分、促进了作物产量发挥，从而评价离心式撒肥机变量撒肥性能。本研究一定程度上弥补了离心式变量撒肥作业机制基础理论研究的不足，为我国精准农业实施过程中离心变量撒施技术创新和装备研发提供了理论依据和方法。