Over-view of robotic grippers for physical manipulation with agricultural products

An overview of agro-grips used to control weeds and harvesting is presented. The relevance of the study is justified by the possibility of improving the quality of fresh fruit and vegetable products, reducing production costs, decreasing the labor shortage by developing and introducing agricultural robots. The classification of the grippers, which are installed on robotic agricultural machines for manipulating fruits, weeds and other objects, is compiled. There are 22 types of grip depending on 6 selected criteria: drive type, the presence of the drive in the grip, the number of fingers, the type of grip movement, the type of mechanism, the type of sensors. In this classification, we mainly consider the characteristics of the gripper, which is installed at the end of the manipulator and is responsible for physical contact with the object. Therefore, the main attention is paid to problems requiring direct capture of objects by the agro robot. The problems of direct spraying of weeds or pruning of branches and leaves, in which manipulators also participate, but the objects of influence are not captured by the robot are mentioned. Examples of existing agricultural research robots equipped with combined grippers according to the proposed classification, referring to different types: vacuum gripper with a video camera for capturing tomatoes, six-finger pneumatic gripper with a video camera, a two-fingered gripper with pressure and collision sensors for picking up an apple, three-fingered capture with a video camera for capturing citrus fruits and others are shown. Further work will be devoted to the study of the problems of physical interaction of agro robots with processed objects, differing in weight, density, geometry, surface roughness and other parameters. The issue of joint interaction of a group of heterogeneous terrestrial and airborne robots in the performance of the target agrarian task in an autonomous mission will also be investigated.