Information to improve the design of the current machine harvesters for reduction of bruising damage to blueberry fruit destined for the fresh market

The majority of U.S. northern highbush blueberry (Vaccinium corymbosum) and southern highbush blueberry (V. corymbosum hybrids) for the fresh market is hand harvested because of the high bruising damage to the fruit caused by current machine harvesters. To reduce bruising, it is important to understand how the harvester?s machine parts interact with the fruit. A miniature instrumented sphere, hereafter referred to as Smart Berry, was developed to mimic a blueberry (Vaccinium species and hybrids) fruit and to quantitatively measure mechanical impacts experienced by a real blueberry fruit during mechanical harvesting. The Smart Berry sensor recorded impacts using three single-axis accelerometers with a maximum sampling frequency of 3 kHz and ?500 gn sensing range. Calibration tests showed that the maximum error of the measurement was 0.53% of the output span. The diameter of the sensor (1 inch) was only half of that for the current smallest instrumented sphere on the market. Used together with a close-up video, the fully calibrated sensors were used to identify and measure mechanical impacts occurring in a commercial rotary blueberry harvester. The data suggested that the catch pan created the largest single mechanical impacts. Thus, reducing the drop height or padding the surface could be effective measures to reduce bruising damage caused by the catch pans. The Smart Berry was also used to compare harvesters with two different detaching mechanisms. The rotary detaching mechanism created significantly fewer and lower-magnitude impacts than the slapper mechanism (P ? 0.05). Manual drop tests demonstrated that the impact data recorded by the Smart Berry can be correlated with bruising damage experienced by blueberry fruit. Taken together, the data can be used to improve the design of the current machine harvesters for reduction of bruising damage to blueberry fruit destined for the fresh market, and potentially lead to enhanced highbush blueberry production efficiency in the long run. Original title, full list of authors and sourcesA Miniature Instrumented Sphere to Understand Impacts Created by Mechanical Blueberry HarvestersChangying Li1,4, Pengcheng Yu1,Fumiomi Takeda2 andGerard Krewer31College of Engineering, 712F Boyd Graduate Studies, University of Georgia, Athens, GA 306022Appalachian Fruit Research Station, USDA-ARS, 2217 Wiltshire Road, Kearneysville, WV 254303Department of Horticulture, University of Georgia, Tifton, Tifton Campus, 2360 Rainwater Road, GA 31793. Current address: Krewer Consulting, LLC, 550 Mary's Drive, Woodbine, GA 31569. HortTechnology, 1 August 2013; Vol. 23, No. 4 The picture is by landscapedia.info