End-effector for robotic harvesting of a tomato fruit with calyx

Abstract. Current robotic prototypes mainly harvest fruit clusters by gripping and cutting the main rachis. However, severe cluster vibration and fruit falling may occur during speedy harvesting. Determining the characteristics of this vibration and falling is important to achieve optimal control in robotic harvesting. Therefore, a virtual grip-and-cut model of cluster picking was developed, and corresponding cluster vibration and fruit falling simulations were performed for robotic harvesting. Multi-property finite element modeling of the main rachis was based on measurements of the rachis compression, shearing, and bending properties. A simulation model of cluster vibration was then built and combined with an end-effector model to obtain a virtual model of grip-and-cut cluster picking. The 3D vibration simulation model of a fruit cluster coupled with the grip-and-cut end-effector model effectively characterized the complex vibration in multilevel and multicomponent fruit clusters with individual diversity of the components’ properties. With the virtual model for cluster picking, dynamic interactive simulation can be realized of the fruit cluster and the grip-and-cut end-effector. Experiments verified that the average deviation of the average swing angle and fruit falling ratio were 6.09% and 8.71%, respectively. Furthermore, the finger-rachis deviation and grip-and-cut speed had a significant influence on the swing angle and fruit falling ratio. The 3D vibration simulation model of a fruit cluster and the virtual model of cluster picking are useful tools for virtual analysis and design of robotic harvesters. Keywords: Falling, Fruit cluster, Harvesting, Robot, Simulation, Vibration.

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Development of a Robotic Harvesting Mechanism for Button Mushrooms

Transactions of the ASABE ◽

10.13031/trans.14194 ◽

2021 ◽

Vol 64 (2) ◽

pp. 565-575

Author(s):

Mingsen Huang ◽

Xiaohu Jiang ◽

Long He ◽

Daeun Choi ◽

John Pecchia ◽

...

Keyword(s):

Success Rate ◽

Air Pressure ◽

List Type ◽

Test Results ◽

End Effector ◽

Suction Cup ◽

System A ◽

Laboratory Test Results ◽

Target Locations ◽

Robotic Harvesting

HighlightsA robotic mushroom picking mechanism was developed, including positioning, picking, and stipe trimming.The picking end-effector was designed based on a bending motion around the stipe-substrate joint.The overall success rate of the developed picking mechanism reached 91.4%.Acting time and air pressure for the suction cup were studied in mushroom bruise level tests.Abstract. Button mushroom (Agaricus bisporus) harvesting mainly relies on costly manpower, which is time-consuming and labor-intensive. Robotic harvesting is an alternative method to address this challenge. In this study, a robotic mushroom picking mechanism was designed, including a picking end-effector based on a bending motion, a four degree-of-freedom (DoF) positioning end-effector for moving the picking end-effector, a mushroom stipe trimming end-effector, and an electro-pneumatic control system. A laboratory-scale prototype was fabricated to validate the performance of the mechanism. Bruise tests on the mushroom caps were also conducted to analyze the influence of air pressure and acting time of the suction cup on bruise level. The test results showed that the picking end-effector was successfully positioned to the target locations. The success rate of the picking end-effector was 90% at first pick and increased to 94.2% after second pick. The main reason for the failures was inclined growing condition of those mushrooms, resulting in difficulties in engaging the mushroom cap with the suction cup facing straight downward. The trimming end-effector achieved a success rate of 97% overall. The bruise tests indicated that the air pressure was the main factor affecting the bruise level, compared to the suction cup acting time, and an optimized suction cup may help to alleviate the bruise damage. The laboratory test results indicated that the developed picking mechanism has potential to be implemented in automatic mushroom harvesting. Keywords: Bruise test, End-effector, Mushroom, Robotic harvesting.

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Research on Key Technology of Truss Tomato Harvesting Robot in Greenhouse

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.442.480 ◽

2013 ◽

Vol 442 ◽

pp. 480-486 ◽

Cited By ~ 6

Author(s):

Chao Ji ◽

Jing Zhang ◽

Ting Yuan ◽

Wei Li

Keyword(s):

Success Rate ◽

Execution Time ◽

Tomato Fruit ◽

Color Difference ◽

Growth Characteristics ◽

Robot System ◽

End Effector ◽

Key Technology ◽

Key Technologies ◽

Harvesting Robot

In order to improve the automated vegetable-harvesting level, a robot system for truss tomato harvesting and two key technologies of picking-point recognition and end-effector design were proposed. An algorithm used the segmentation feature of the color difference 2r-g-b to recognize the truss tomato fruit and the assistant mark. According to the growth characteristics of the stem of tomato truss, the approximate fitting curve of stem and the contour of assistant mark were extracted to generate the optimal picking-point for location of tomato truss. The hardware structure of an end-effector based on flexible transmission was designed, and the function of cutting and grasping could be realized simultaneously by the end-effector. Experimental results show that the success rate for harvesting truss tomato was 88.6%, and the average execution time for picking a truss tomato was 37.2s.

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