With the rapid development of robotics, robots gradually replace people to complete various tasks. Grasping is one of the most common tasks in industry and daily life. In addition to typical pick-and-place task, grasping a tool is the basis for performing other tasks, such as grabbing the key to open the door, grabbing a hammer to nail, etc. The robotic grippers are the manipulator in which the robot completes the grasp. Their performance characteristics have a significant impact on work efficiency because they are the parts interacting with the grasping objects directly. Therefore, this paper researches on robotic gripper and its related technology from the following aspects. First of all, the current robotic gripper type is analyzed in detail. Second, the research status of the most promising robotic gripper is reviewed widely. Third, the critical technology of robotic gripper is studied deeply. Finally, the analysis of robotic gripper development trend is performed prospectively.

As a non-destructive, real-time, fast, objective, and economical detection method, machine vision technology has been widely used in target recognition and positioning in various fields in recent years. Selective picking of tea buds is an important prerequisite for high-quality and efficient tea production. Autonomous picking of tea based on machine vision has become a research hotspot at home and abroad. At present, many scholars have studied the visual recognition and positioning methods in the process of intelligent tea picking, but the effect has not yet reached the actual picking requirements. In order to give everyone a comprehensive understanding of the existing research methods, this article systematically reviews the tea bud segmentation and bud picking point positioning methods based on machine vision technology, and prospects the application prospects and directions of machine vision technology in tea picking.

During the rotation, aero-engine impeller blades are subjected to the alternating load of high frequency, low stress and small strain, so it is effortless for the impeller blades to enter the stage of very-high-cycle fatigue (VHCF). The research on the VHCF performance of 2A60 aluminum alloy is of great engineering significance to verify the reliability of the impeller in service. In this paper, the VHCF performance of 2A60 aluminum alloy is studied by fatigue life curve and fracture morphology. The results show that the fatigue properties of 2A60 aluminum alloy under different cooling conditions are different, and the VHCF properties under ethanol cooling conditions are better than those under water cooling conditions. However, under either water-cooled or ethanol-cooled conditions, the fatigue fracture mode of 2A60 aluminum alloy is single, showing a surface crack initiation mode, and the S-N curve shows a continuous downward trend without the intermediate platform. The VHCF crack originated from the stress concentration on the sample surface and the cleavage fracture occurred in the grains near the crack source in the early stage of crack initiation. The VHCF process of the sample is also the relaxation process of its residual stress.

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