2ND-GENERATION IMPACT FORCE RESPONSE FRUIT FIRMNESS SORTER

A probe-type sensor was developed to measure the impact response of fr uit conveyed on a packing line and predict firmness. The impact probe consisted of a machined aluminum mass connected to an air cylinder, wi th the fruit struck on the side from a Fred distance. Peak acceleratio n of the mass during impact was used to predict flesh firmness measure d by penetrometer. Static tests on commercially grown 'Bartlett' pears gave a correlation between peak acceleration and penetrometer firmnes s of 0.83. The prototype handling system consisted of a feed belt for singulation, an inclined chute for alignment a sensor belt for spacing and lateral stabilization prior to impact, and a pneumatically activa ted gate to separate the fruit into two firmness classes. Dynamic test s on pears loaded singly onto the feed belt showed a correlation of 0. 84 between peak acceleration and penetrometer firmness. Handling perfo rmance with pears continuously loaded onto the feed belt showed that 9 7% of the fruit were properly aligned at the time of sensing, 86% of t he fruit were singly spaced, and 98% were properly handled by the segr egation system after sensing. Firmness classification errors for remov ing soft fruit were 14% on soft fruit and 37% on firm and hard fruit. Similar tests for removing hard fruit gave errors of 13% on soft and f irm fruit and 51% on hard fruit.