Abstract:Aiming to meet the agronomic requirements of blueberry plantations in China, a domestically produced self-propelled integrated blueberry harvester was designed. The vibration mechanism for blueberry picking was analyzed, and the vibration equation of blueberry plants was established. The vibrational output response of the blueberry plant and the fruit detachment force under multiple excitation conditions were analyzed through the application of orthogonal transformation and canonical transformation of the equations. Based on the agronomic requirements of blueberry cultivation, the design requirements for the harvester were determined. The structural design was then conducted for the harvesting mechanism, fruit collection system, and fruit conveying system utilizing the self-developed prototype for harvesting experiments, along with data from preliminary and orthogonal tests, the regression equations for the machine harvesting evaluation indicators were established. It was found that the machine’s travel speed, the rotational speed of the harvesting unit’s hydraulic motor, and the finger-comb spacing had interactive effects on both the harvesting efficiency and the fruit quality. The machine’s travel speed was directly proportional to the harvesting efficiency, while inversely proportional to the fruit damage rate. The rotational speed of the harvesting unit’s hydraulic motor was directly proportional to both the fruit harvesting efficiency and the fruit recovery rate;conversely, the finger-comb spacing was inversely proportional to the rate of unripe fruit harvest. Based on the comprehensive analysis of the orthogonal experiment results, the optimal working parameters for the machine were identified as follows: a travel speed was 35m/min, a hydraulic motor rotational speed was 100r/min for the harvesting system, and the finger-comb spacing was 200mm. A human-machine comparative experiment conducted under the optimal parameters demonstrated that the machine achieved an unripe fruit rate of 8.4%, the fruit damage rate of 3.8%, the fruit recovery rate of 90.1%, and the harvesting efficiency of 1.37kg/min, which was 10.78 times higher than manual picking efficiency.
