果园自动变距精准施药系统设计与试验

针对我国北方果园施药设备自动化程度不高、农药利用率低、适应性差等问题，设计了基于冠层体积估算的果园自动变距精准施药系统。施药系统的喷施臂在控制系统的控制下可以在水平和垂直方向调整喷雾距离和喷施高度，以适应不同果园的果树特征。为实现精准喷施，利用红外测距传感器组成了传感器阵列，通过该阵列探测冠层，将测得的数据用数学方法构建了冠层体积估算模型，并设计了喷雾参数调整方案，使得喷雾距离与喷雾量可进行相应调整。为验证施药系统的性能，测试了喷施臂在接收到移动指令时的响应时间与运动实际耗时以及冠层体积估算模型的准确率，并选用仿真桃树进行了定距和变距两组自动对靶喷施试验。结果表明，喷施臂的移动可实现瞬间响应，运动实际耗时与理论耗时几乎一致，冠层体积估算模型的相对误差为11.27%；与定距对靶喷雾相比，自动变距对靶喷施的农药附着率提高了18.66%，节约了30.25%的药液。

Design and Experiment of Automatic Variable-distance Precison Spraying System in Orchard

Aiming at the problems of low automation, low pesticide utilization and poor adaptability of orchard spraying equipment in northern China, an orchard variable distance spraying equipment based on crown volume estimation was designed. The spraying arm of the equipment could adjust the spraying distance and height in horizontal and vertical directions under the control of the control system, so as to adapt to the characteristics of fruit trees in different orchards. In order to achieve precise spraying, a sensor array was constituted by infrared ranging sensor to detect the crown. The data measured by sensor array was used to build a tree crown volume estimation model by mathematical method, and the adjustment scheme of spray parameters was designed to make the spray distance and spray volume adjusted accordingly. In order to verify the performance of the spraying system, the actual movement time and the response time of the spraying arm when received the movement command and the accuracy of the crown volume estimation model were tested. Two groups of automatic target spraying tests of fixed distance and variable distance were carried out on simulated peach trees. The results showed that the movement of the spraying arm could achieve the instantaneous response and the actual movement time was almost consistent with the theory, and the relative error of the volume estimation model was 11.27%. Compared with the fixed distance target spraying, the variable distance automatic target spraying increased the pesticide attachment rate by 18.66%, and saved 30.25% of the liquid medicine.