Review. Technologies for robot grippers in pick and place operations for fresh fruits and vegetables

摘要

Robotics has been introduced in industry to replace humans in arduous and repetitive tasks, to reduce labour costs and to ensure consistent quality control of the process. Nowadays robots are cheaper, can work in hostile and dirty environments and they are able to manipulate products at high speed. High speed and reliability and low robot gripper costs are necessary for a profitable pick and place (P&P) process. However, current grippers are not able to handle these products properly because they have uneven shapes, are flexible and irregular, have different textures and are very sensitive to being damaged. This review brings together the requirements and phases used in the process of manipulation, summarises and analyses of the existing, potential and emerging techniques and their possibilities for the manipulation of fresh horticultural products from a detailed study of their characteristics. It considers the difficulties and the lack of engineers to conceive of and implement solutions. Contact grippers with underactuated mechanism and suction cups could be a promising approach for the manipulation of fresh fruit and vegetables. Ongoing study is still necessary on the characteristics and handling requirements of fresh fruit and vegetables in order to design grippers which are suitable for correct manipulation, at high speed, in profitable P&P processes for industrial applications.