Pumpkin harvesting robotic end-effector

摘要

The development of an end-effector with a unique harvesting methodology based on the properties of pumpkin was presented in this paper. The components of the end-effector designed using Solidworks software; it dynamically simulated using SAM software; and after several modifications, the final components manufactured and assembled. This end-effector is a five-fingered anthropomorphic hand with electric drive and internal impactive gripping mode, designed to grasp and harvest heavyweight crops with a radius range of 76.2 to 265 mm by consideration of sustainable force distribution. The controlling unit of the system was a PLC system consists of a computer, a position board, an amplifier, a servo motor, switching units, and emergency switches. The coordinate of pumpkins enter the PC manually and after analysis using a controlling algorithm, the PC sends the related commands to the servo motor and switch unit via position board and optical cables. The controlling algorithm developed using the Denavit-Hartenberg (D-H) method. The maximum stress values of the final design were 6.2 x 10(7) and 7.8 x 10(7) N/m(2) in the opened and closed mode, respectively. The accuracy, repeatability, harvest possibility, and harvesting success rate were 8.78 mm, 8.32 mm, 92%, and 79%, respectively. The results proved that the fingers components have enough capability under the maximum payload of the system, and the designed end-effector can harvest the different varieties of pumpkin because the range of radius, volume and mass can cover the extracted physical parameter of pumpkins. The results indicated that the designed controlling unit and developed algorithm could control the system properly and do the desired function appropriately.