Citrus Fruit Movement Assessment Related to Fruit Damage during Harvesting with an Experimental Low-Frequency–High-Amplitude Device

Abstract

The profitability of fresh citrus crops outlines the possibility of using mechanical systems to reduce the high cost of the manual harvesting operation. In this line, an experimental light shaker with low frequency and high amplitude and a hydraulic arm was developed. This device had been successfully used for harvesting ornamental citrus trees. In previous studies, it was proven that the removal percentage was adequate, but the percentage of slightly damaged fruit increased compared to a traditional fruit trunk shaker. Visualizing the fruit movements in high-speed video recording images during harvesting, a higher impact level was observed due to the higher amplitude. The aim of this study was to analyze the fruit movement during the vibration with the experimental shaker compared to the movement when vibrating with an orchard tractor mounted trunk shaker related to the increase of slightly damaged fruit when using the experimental shaker. Fruit movement parameters (fruit distance, fruit displacement, speed and acceleration) when using the two harvesting systems (experimental shaker and trunk shaker) were compared analyzing the high-speed video recordings. Results showed that the higher vibration amplitude produced a maximum distance experienced by the fruits (maximum displacement of 0.135 m with the experimental shaker compared to 0.078 m with the trunk shaker) that could cause a higher damage level (74% of slightly damaged fruits using the experiemntal shaker compared to 14% using the trunk shaker).