Authors

Abstract

ABSTRACT In order to solve the problems of low correlation between variable fertilizer application system and soil nutrient content detection and insufficient real-time performance, a variable fertilizer application system based on real-time soil nutrient content detection was developed. This paper describes the structure, working principle and design of key components of the soil information acquisition and fertilizer application system. It includes the simulation and analysis of fertilizer application using the discrete element method and the selection of curved blade fertilizer application discs. The system uses STM32F429IGT6 microcontroller and ROS higher-level computer for decision making. The device detects soil nutrients in real time, adjusts the fertilizer motor speed accordingly, and runs autonomously along the planned path. The decision coefficient R^2 between the fertilizer application rate and the speed of the fertilizer application wheel is not less than 0.97, and the relative error between the actual fertilizer application rate and the theoretical fertilizer application rate is up to 5.91%, with the maximum value of the coefficient of variation (CV) of 10.18%. The indoor bench test shows that the relative error between the actual fertilizer application rate and the target fertilizer application rate within a single operating grid is up to 6.2%, with the maximum value of CV being 6.64%. The field test in the orchard showed that the maximum relative error between the actual fertilizer application and the target fertilizer application in a single operation grid was 6.3%, and the maximum value of CV was 12.34%, and the fertilizer application was completed in the operation grid, which demonstrated that the device was able to realize real-time and accurate variable fertilizer application according to the soil nutrient information.

Abstract in Chinese

针对变量施肥系统与土壤养分含量检测之间的关联性程度低，实时性不足的问题，开发了一种基于土壤养分实时检测的变量施肥系统。本文介绍了土壤信息采集与施肥系统的结构、工作原理和关键部件的设计。其中包括利用离散元法对撒肥进行仿真和分析，以及对弯曲形叶片撒肥盘的选择。系统采用 STM32F429IGT6 微控制器和 ROS 上位机进行决策。装置能实时检测土壤养分，相应地调整施肥电机转速，并沿着规划的路径自主运行。排肥量与排肥轮转速之间决定系数R^2不小于0.97，实际排肥量与理论排肥量相对误差最大为5.91%，变异系数最大值为10.18%，室内台架试验表明，单个作业栅格内的实际施肥量与目标施肥量的相对误差最大值为6.2%，变异系数最大值为6.64%。果园田间试验表明，单个作业栅格内的实际施肥量与目标施肥量的相对误差最大值为6.3%，变异系数最大值为12.34%，且施肥均在作业栅格中完成，试验表明，该装置能够根据土壤养分信息实现实时精准变量施肥。