Triz-Aided Design and Experiment of Kiwifruit Picking End-Effector

Aiming at the problems of high damage rate and loss rate of the existing safflower harvesting equipment, this study designed a rotary cutting safflower harvesting end effector by combining the growth characteristics and mechanical properties. Through force analysis of the cutting tool, the key factors, which affects the harvesting performance, were clarified to be the blade inclination and the knife shaft speed. The Fluent software was used to analyze the flow field of the harvesting chamber, which aims to determine the appropriate wind speed. To improve the working performance of the rotary cutting safflower harvesting end effector, a three-factor, three-level orthogonal test was carried out with the blade inclination, knife shaft speed and wind speed as the influencing factors, and with the recovery rate, damage rate and loss rate as the response indexes. A regression model for the three-factor interaction was developed and optimized based on the results of the Box-Behnken test. The optimal parameter combination is: the blade inclination is 15°, the knife shaft speed is 1570 r/min, and the wind speed is 6 m/s. A test of the optimization results showed that the recovery rate was 91.47%, the damage rate was 7.51%, and the loss rate was 4.67%. This study can provide theoretical basis and technical reference for the mechanized harvesting of safflower.

Design and Experimental Optimization of Rotary Cutting Safflower Harvesting End Effector

LI,

ZHANG,

ZHANG

et al. 2023

Design and Simulation of Three-Degree-of-Freedom Wrist Structure of Picking Manipulator

SUN,

GONG,

ZHANG

2023

In order to solve the problem of poor flexibility of existing picking manipulators, a picking manipulator with a wrist joint has been designed, the wrist is capable of rotating 45° forward and backward around the x and y axes. Firstly, ANSYS was used to simulate the performance of different hoses under different conditions, and finally a 4*6 mm PVC hose was selected to replace the internal cardan joint as the transmission component. Secondly, the wrist structure was optimised using genetic algorithm to reduce the tendon rope variation differences to 0.31 mm and 0.24 mm. Finally, the results of orchard picking experiments indicate that the end-effector rotation of 720° can ensure that the fruit stalks can be unscrewed, the time required to complete the picking is 1.6 s, and the overall picking success rate was 100%. After 9 days of placing the harvested fruit, both the flesh and skin are intact, indicating that the manipulators can complete the non-destructive picking operation.

Design and Experiment of Multi-Fruit Gripping

FU,

CAI,

GUO

et al. 2024

Self Cite

Kiwifruit picking robots can replace manual labor for mechanized kiwifruit harvesting. However, existing picking robots encounter issues such as low separation efficiency of fruit stalks, poor stability of fruit gripping, and inaccurate identification when picking kiwifruit clusters. In response, a multi-fruit picking end-effector was designed to pick clusters of kiwifruit efficiently based on their distribution characteristics. The gripping range of the gripping device was determined based on the parameters of the spatial distribution of the fruit clusters. A multi-fruit gripping mechanics model was constructed, and the gripping force was analyzed to ensure efficient and stable fruit picking. Critical parameters of the fruit stalk separation device were determined through kinematic trajectory analysis to improve the separation efficiency of fruit stalks. Additionally, a dual-sensor fusion recognition method was proposed to identify fruit cluster locations accurately. The results of the picking experiment demonstrate that the end-effector can pick fruits in an average time of 8.28 s per cluster, with a net fruit-picking rate of 87.5% and a fruit damage rate of 7.5%. The end-effector shows a positive picking effect on kiwifruit fruits distributed in clusters. This study can serve as a reference for the development of kiwifruit-picking robots.