Open Access

ARTICLE

Numerical Simulation of An Experienced Farmer Lifting Tubers of Cassava for Designing A Bionic Harvester

by Wang Yang¹, Juanjuan Li¹, Jian Yang¹, Lin Wei⁴

1 College of Mechanical Engineering, Guangxi University, Nanning 530004, China.
2 Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology, College of Mechanical Engineering, Guangxi University, Nanning 530004, China.
3 Corresponding author. E-mail: gxuyangjian@163.com; Tel: +86-13557014056
4 Department of Agricultural and Biosystems Engineering, South Dakota State University, Brookings 57007, USA.

Computer Modeling in Engineering & Sciences 2015, 104(6), 471-491. https://doi.org/10.3970/cmes.2015.104.471

Abstract

Harvesting is the most difficult and costly operation in cassava production. Currently, most cassava harvest still depends on manual tools. Effective mechanized harvesters are necessary to improve harvesting quality and reduce production cost. Therefore, it is very important to figure out key information for designing an effective tuber lifting system used in bionic “dig-pull” harvesters. A numerical simulation model of human-stem-tuber-soil system was developed to carry out numerical simulation of manually pulling tuber. Coupling algorithm of Lagrange and smoothed particle hydrodynamics (SPH) was used in the model. Lifting mechanism of experienced farmer was studied at a micro level. Influence of lifting velocities was discussed. The results show that when the soil volume was compressed by 5% in the lifting direction, a ring sheared surface of soil occurs. The soil is gradually sheared and fractured along with the surface during lifting. After that, the soil falls down on ground due to tuber jittering and completely detaches from the tuber. Large lifting velocity, resulting in high harvesting efficiency, but consumption of energy also increases. Before the height achieves 75 mm, higher velocity is beneficial for improving efficiency, but after that, lifting velocity should be appropriate to avoid tuber broken and lost.

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Keywords

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