Authors

Abstract

In order to solve the problems of low efficiency of fertilization and spraying in the hilly mountains of China, a vehicle-mounted fertilization and spraying machine was designed. The whole structure and working principle of the machine were described, and the key components of fertilization and spraying are designed. The kinetics and kinematics of fertilizer particles and droplets were modeled by theoretical analysis of their motion characteristics in the air. The fertilization and variable spraying control system based on the core controller MCU (Microcontroller Unit) was set up. And the system can adjust the rotational speed of the disc and can automatically change the spraying volume by real-time detection of forward speed to achieve a constant spraying volume per unit area. The test results showed that: when the disc speed was greater than 90 r/min, the uniformity coefficient of variation was less than 15%, which satisfied the operational requirements; the uniformity coefficient of variation reached the minimum value of 10.03% when the disc rotation speed was 180 r/min, and the best fertilization performance was achieved at this time. In the spraying system, the actual spraying volume increased with the increased forward speed, and the relative error between the theoretical flow rate and the actual flow rate was 6.25% at most, and the average error was 5.94%, which could achieve the purpose of variable spraying. The research results can provide technical reference for the design and development of fertilization and spraying machinery in hilly areas.

Abstract in English

针对西南丘陵山区施肥、喷雾效率低的问题，设计了一种车载式施肥喷雾一体机。介绍了该机的整机结构和工作原理，并对关键部件进行了设计。通过对肥料颗粒和液滴进行动力学分析，建立了运动模型。对以单片机为核心控制器的变速喷雾控制系统进行了设计，该系统可根据前进速度自动改变喷雾量，实现单位面积喷雾量恒定作业。通过设置不同参数进行施肥和喷雾性能试验，试验结果表明，当落肥口开度为0.6时，肥料均匀性变异系数最小，为9.01%，施肥性能最佳；不同落肥口开度下的平均施肥量范围为16.56~540.76g/min。当PWM(脉宽调制)占空比为100%时，喷雾变异系数最低(变异系数为0.0254)，喷雾稳定性最好，不同占空比下的平均喷雾量范围为74.94~345.41 ml/min。研究结果可为西南地区施肥与喷雾一体化设计提供参考。