Engineering properties of colored capsicum crop for innovative robotic harvesting solutions in protected agriculture

Abstract: Capsicum annuum L., also known as bell or sweet pepper, is a globally significant horticultural crop in the Solanaceae family. India’s red and yellow colored capsicum holds 13^th rank in export. In India, color capsicum is a valuable crop, yielding 2.34 times more per square meter in protected cultivation comparing open field. Tamil Nadu contributes 16,689 tonnes on 284 hectares, comprising 5.13% of India’s total. Modern agriculture benefits from automation and robotics, especially in protected cultivation for selective, high-quality capsicum harvesting, reducing labor fatigue. In consideration to the issues like timely and repetitive harvestings and shortage of labour a study was focused to develop a robotic harvester. The study evaluated the engineering attributes of red and yellow capsicum during protected cultivation, classified into size categories A, B and C. Moisture content ranged from 83.6% to 87.12%. Capsicum dimensions spanned 57 mm to 110 mm in length, 52 mm to 98 mm in width, and 51 mm to 96 mm in thickness. Red capsicum had slightly larger arithmetic, geometric, square mean, and equivalent diameters, with sphericity ranging from 0.89 to 0.93. Surface area varied from 87 cm² to 316 cm², volume from 108 cm³ to 363 cm³, and mass from 67 g to 226 g, with red capsicum slightly larger. The highest static friction coefficient was with aluminum, at 0.61 to 0.66. Using the CIELAB model for color estimation, the significant color difference for red and yellow capsicum were 79.26 and 70.28 respectively. Moisture content was negatively correlated with aspect ratio and sphericity, and other attributes had positive correlations. This data is valuable for potential capsicum harvesting mechanization in robotics and protected cultivation.