Effect of Air Pressure and shaking Frequency on Fruit Damage in Mechanical Harvesting of Apples

Abstract. Low fruit quality is the most critical barrier for the success of mechanical harvesting of fresh market apples using mass harvesting methods. To address the fruit quality issues, reduce the damage rate, and expedite the commercialization of mechanical harvesting of fresh market apples, an innovative air suspension-based catching(ASC) mechanism were designed and fabricated to collect fruit detached by mechanical shaking device (apple tree limb shaker). The objective of this paper was to investigate the effect of air suspension and shaking frequency on fruit damage in mechanical harvesting of apples. Three apple varieties with different physical characteristics (‘Honeycrisp‘, ‘Pacific Rose‘, and ‘Pink lady‘) were used to conduct the field trials. The air pressure settings for the ASC mechanism played an important role in reducing the risk of apple damage and improve the fruit quality. The effect of shaking frequency of apple tree limb shaker on fruit quality was not significant. With the pressure increased from 0 to 1.03 MPa, the fruit quality had been greatly improved. Due to the limit of air compressor used in this study, the air suspension-based catching mechanism was only tested in limited pressure range. In future, the test pressure range may be expanded more to improve the catching performance in reducing fruit damage.