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

GUO Guanzhu, YANG Liyang, LUO Ya’nan, XU Guangming


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.

Keywords: deep-grained walnut, UAV  pneumatic vibration flow, picking machinery, harvesting efficiency


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