Study of the influence of robotic gripper parameters on apple fruit damage

Abstract

The article discusses the design of a robotic device intended for effective apple fruit harvesting with minimum damage. The research was conducted in the Federal Scientific Agroengineering Center VIM from 2020 to 2023. The developed device is equipped with specialized mechanisms and sensors designed to reduce the negative eff ects on apples during harvesting. The study aims to justify the parameters of the robotic device for apple fruit picking and to conduct laboratory experimental studies of the grip strength eff ect on fruit damage during robotic fruit harvesting. A classification of gripping devices was developed based on the analysis of their design parameters and types. A concentric three-fingered gripper tool with rotating and sliding elements added to the gripping device was selected as the prototype device. As a result of studying the size and weight parameters of apples of the ‘Jonathan’ and ‘Granny Smith’ cultivars, data were obtained that enable one to describe the characteristics of these fruits more fully. Th e grapho-analytical method was employed to select the optimal geometric parameters of the gripper claws. We designed a robotic gripper which has several components, including gripper claws and a movable base. A laboratory setup was developed to simulate the operation of the manipulator and conduct experiments. Th e setup makes it possible to create conditions close to the actual manipulator operation and study the processes of grasping and holding fruits. The three-factor experiment allowed us to analyze the impact of the grip strength of the gripper claws, as well as the distance from the fruit to the gripper on the damage to fruits. It has been determined that these parameters have a signifi cant eff ect on the process of grasping and holding fruits. Entirely optimal values of these parameters contribute to reliable holding of a fruit in the gripper claws with minimal damage. As a result of analyzing the size-mass parameters of fruits, we found the average size and weight of apples of the Jonathan and Granny Smith cultivars. Th e design parameters of the robotic device were justifi ed. A 3D robotic gripper model was developed. We also manufactured an experimental robotic gripper model which underwent laboratory tests. As a result, the parameters of the grip strength and the distance from the fruit to the gripper were identified.