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With computer technology, intelligent robots have been widely used in many fields, citrus harvesting robot at home and abroad have carried out research, but because of the special structure of citrus organization in the picking process vulnerable machine robot damage. Therefore, the study of the basic mechanical properties of citrus, you can design and citrus picking robot transport, storage and processing to provide a theoretical basis. By compressing test and puncture test study citrus in different directions (axial and radial) and different parts of the (cross-sectional and longitudinal section) on the mechanical differences. The results showed that: citrus compression resistance in different directions difference was not significant, approximately 105N, compression resistance and citrus fruit diameter, weight and pericarp thickness rupture correlation coefficient is small; citrus mechanical single fruit in cross section smaller differences In longitudinal section mechanical difference was significant, and at the bottom of the worst anti-destruction capability, therefore, in citrus picking machines should be avoided during grasping and bottom contact; Citrus Fruit significant difference between the mechanics. Statistical analysis of the whole fruit citrus compression resistance and the test probe to P2, the test rate of 1mm / s under the conditions of puncture hardness distribution and test conditions on the mechanical properties of citrus. Because differences between the larger citrus fruits, test the samples selected a wide range of sizes. The results showed that: when the whole citrus fruit when the pressure is less than 70N, citrus rupture rate of 0%, the pressure 80N ~ 120N, the citrus rupture was 90%; when subjected citrus puncture force of less than 3N, the citrus perforation rate is 0%, most of the hardness test samples puncture 4N ~ 8N; test rate (2mm / s, 4mm / s, 6mm / s, 8mm / s, 10mm / s) of the citrus compression resistance, puncture hardness, fracture displacement and puncture displacement was not significant; citrus puncture test probe test results significantly affected, hardness and puncture puncture displacement of the probe diameter increases. Through the puncture test and shear test all parts of citrus peel and flesh of the mechanical properties of hardness puncture, citrus peel derived upper, middle and lower puncture hardness difference was not significant, in 5N ~ 6N; different directions (horizontal and vertical ) peel obvious difference between the shear stress; outer rind of the shear stress greater than the internal, external peel upper, middle and lower average shear stress of 2794Pa, 2778Pa and 2431Pa, internal to 2073Pa, 1981Pa and 1607Pa; citrus pulp puncture smaller hardness of about 1N; citrus and stems tensile test, the citrus peel easily damaged, in order to prevent damage to the fruit, the tension should not exceed 17.5N. By compressing test and puncture test effects of different maturity and different varieties (origin) the mechanical properties of citrus trend, the test results show that: with the increasing maturity of citrus, compression resistance and puncture hardness declining, early rapid decline , the late slow; Zhejiang, Shanghai, Zhenjiang three citrus obvious difference of mechanical characteristics, the design of the machine may refer to the mechanical properties of Zhenjiang, citrus, oranges compression resistance and puncture maximum hardness, tangerine minimum. At room temperature, the natural state and refrigerated storage conditions of three kinds of citrus quality changes during storage, the test results showed that: mass loss rate increased with the increase of storage time; Vc content into a downward trend; soluble solids content first and then decreased; changes in mechanical properties of more complex: normal and natural state puncture hardness first increases and then decreases, while the frozen state of the mechanical properties of citrus small changes in the first 30 days, the latter is gradually increasing.
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