Combined impact sensing and data acquisition units for studies of bruising during handling of fruits and vegetables

Abstract

The transport and handling in the agricultural produce, packaging, and electronic components industries result in varying degrees of damage to the merchandise due to high accelerations and contact impacts. The objective of the research described here was to develop practical data acquisition designs to allow collection of impact data for identification of damaging impacts. Among the designs already developed and tested are a cubical and two spherical enclosed systems. The impact transfer characteristics for each of the three geometries has been developed. The 11.4 cm cubical case consisted of three physical sections which were filled with a material to solidify the total structure. The 14 cm diameter spherical case consisted of four sections also filled with a material to solidify the total structure. The non-symmetrical interfaces between the sections of the case, after assembly, resulted in insignificant variations in the outputs from the three axes of the tri-axial accelerometer. An 8.9 cm diameter spherical unit was constructed for smaller size and weight applications. This unit consisted of one circuit board sprayed with an electrical insulation material then sprayed with foam insulation to lighten the final cased unit. The insulated board assembly was put into a mould, potted with melted beeswax and coated with a soft, pliable plastic coating. The results of impact data calibration tests from the various geometrical configurations are discussed. The spherical units, when exposed to identical conditions as the product it simulates, and the cubical unit when used in transport and electronic components industry studies, provide excellent data replication of the impacts experienced.