Simulation of southern potato grader based on ADAMS.

Based on the analysis of existing grading methods, this study focuses on developing a new grading scheme for southern potato, which can automatically adjust the distance between two rolling bars. Using ADAMS software the dynamic simulation model of potato grader has been established, and the simulation results showed that the little potato P1, middle-sized potato P2 and big potato P3 were separated successively. It could strongly prove that this design is feasible. There was little motion when the potatoes were under grading, which indicated that the device worked smoothly. The analysis results of contact forces showed that as the weight of the potato increases, the force between it and the rolling bars enhances, especially for the force between the potato and the movable bars, as in the experiment the maximum value of the contact force between P4 and moving roll was 813.7N. The conclusions can provide the basic data to the optimum design of sample machine. 摘要 分析已有物料分级方法,设计出一种可自动调节辊杆间距的南方马铃薯机械化分级方案;应用 ADAMS 软件构建马铃薯分级机构动态仿真模型,仿真试验结果表明:小薯 P1、中薯 P2、大薯 P3 先后被分 离出来,机构设计方案可行,薯块在辊杆上跳动较小,机构运动较平稳;接触力分析结果表明:薯块与辊杆 接触力随薯块质量增大而变大,其中与动辊杆接触力变化最显著,试验中超大薯 P4 与动辊杆的极值接触力 达 813.7 N;该研究为样机制作提供了优化设计基础。 INTRODUCTION China is one of the main potato producing countries in the world. In 2013 its cultivated area reached up to 8421 acres and the yield was more than 19.18 million tons, which ranked first in the world (MOA Department of Plantation Management, 2014). In China, “The major production of potato is in the north, while the economic benefit is in the south ". It is because planting winter potato in the south can take full advantages of the idle paddies after rice harvest. Its planting time is short and can go into the market very soon, which can make up for the shortages of the season-restricted northern potato. With its high economic efficiency, the southern potato is popular with the market and the planting households. At present, potato planting in southern China has gradually transferred to the mechanized production not only in planting, but also in field management and harvesting. But the mechanization in potato grading progresses slowly, people still use manual grading method, which is labour-intensive and inefficient, and at the same time can’t respond quickly to market demands (PingYuan Xiong et al, 2011). Grading equipment imported from abroad are expensive and difficult to maintain, while the domestically developed grading equipment is still in trial stage and of low efficiency, especially when it is faced with the juicy and thin-skinned southern winter potato, they can help to make high injury rate. Grading method is the key of potato grading equipment, so this study focuses on designing a simple and efficient grading mechanism based on the physical properties of southern potato. By using the ADAMS software to make kinematics analysis, this study will verify the correctness of the device design scheme and make clear the kinematic parameters, which can provide designing basis for the prototype production. MATERIAL AND METHOD Existing grading methods There are several methods in fruits grading: mesh screen method, grid cylinder method, weight grading method, optical method and rolling-bars grading method (Blasco et al, 2009; LiangLong Hu, et al, 2007; LiuFang ShenTu et al, 2014; Mendoza et al, 2014; Riquelme et al, 2008; XiaoPing Yang et al, 2014;