Design of a Low-Cost Robotic Prototype for Fruit Harvest with Flexible Gripping Using 3D Printing

Abstract The accelerating demand for food production driven by economic, political, and social factors has highlighted the need for innovative solutions to increase harvesting efficiency. In response, this work presents the design and development of a prototype robotic arm for fruit harvesting, suitable for medium-sized fruits such as citrus, apples, and pears in semi-controlled environments like greenhouses and experimental orchards. The system integrates four Nema 17 stepper motors (17HS8401) and four 360-degree servomotors (MG996R), structured as a three-degree-of-freedom mechanism to balance simplicity and functionality, enabling easy replication. The arm components were fabricated using 3D printing technology, combining rigid polylactic acid filament for structural parts and flexible thermoplastic polyurethane filament for the adaptive gripper. The unique design eliminates the need for sensors, allowing adaptable and reliable fruit collection using cost-effective actuation while minimising damage to delicate produce. Experimental validation showed success rates of 87% for citrus fruits, 67% for apples, and 60% for pears, highlighting the system‘s adaptability to different fruit geometries and textures. Comprehensive force and torque calculations ensure the system‘s operational viability despite relying on low-cost electronic components. These findings demonstrate that the proposed robotic solution offers a practical, low-cost, and adaptable approach for agricultural automation, bridging the gap between laboratory prototypes and deployable systems for small- and medium-scale producers.