基于无人机平台的气振式核桃采收机设计与试验

针对云南山地种植的深纹核桃树体高大造成现有机械难于采收，而人工爬树用竹竿击打采收成本高且伤亡大的问题，提出了搭载无人机的气振式核桃采收原理及方法，基于深纹核桃成熟果实的果柄连接强度的测试与分析结果，进行了核桃脱落的气振流动仿真分析，设计了搭载于六旋翼农业植保无人机上的气振式核桃采收机，分析了气振式核桃采收机在发射气振时的反冲稳定性，实施了气振式核桃采收机搭载无人机进行采收的试验验证，按效率优先和采净率优先两种采收模式，对气振式核桃采收机的采收效率和采净率做了预测分析。研究结果表明，核桃成熟度为80%、90%和100%时，使核桃果柄断裂实现落果的气振临界流速分别为77.5、69.0、58.5m/s；气舱容积为20L且气压为1MPa时,气振式核桃采收机的气动喷口至核桃挂果位置的最佳距离为0.5m，单次气振流动采收的最大有效面积的仿真值和试验值分别约为0.09m2和0.10m2，最大有效采收面积随着到气动喷口距离增大而减小。

Design and Validation of Pneumatic Vibration Walnut Picking Machine Carried by UAV

In response to the Yunnan mountainous areas planted deep-striped walnut trees are tall and large, which makes the existing fruit picking machinery difficult to reach the planting to harvest the fruit, as well as manually climbing walnut trees with bamboo poles to hit the picking fruit was high cost and casualties. For the first time, the principle and method of pneumatic vibration picking walnut with UAV were proposed. Based on the test and analysis results of the connection strength of the stalk of deep-grained walnuts, the pneumatic vibration flow simulation analysis of walnuts dislodged by pneumatic vibration was carried out. A walnut pneumatic vibration fruit picking machinery installed on a six-rotor agricultural plant protection UAV was designed. The stability of the pneumatic walnut picking machinery was analyzed when the machine was subjected to the recoil of the airflow during the launch of the air-vibration flow. The pneumatic vibration fruit picking machinery for walnuts mounted on a UAV was tested and validated. According to the two harvesting modes of efficiency priority and harvesting rate priority, the fruit picking efficiency and net picking rate of the pneumatic vibration walnut picking machinery were predicted and analyzed. The results showed that the critical flow velocities at which pneumatic vibration caused walnut stalk breakage were 77.5m/s, 69.0m/s and 58.5m/s when the ripeness of walnuts was 80%, 90% and 100%, respectively. The optimal distance from the pneumatic nozzle of the pneumatic vibration walnut picking machinery to the fruiting position was 0.5m for a pneumatic compartment with volume of 20L and pneumatic pressure of 1MPa. The simulated and experimental values for the maximum effective area of a single pneumatic vibration flow for fruit picking at this location were approximately 0.09m2 and 0.10m2, respectively. The maximum effective area for fruit picking in a single pass was decreased as the distance to the pneumatic nozzle increased.