Authors

Abstract

In order to solve the problems of lower seed-filling stability and wheat seed damage of mechanical shooting seed-metering device, the filling structure of shooting device was optimized. The effects of seed movement were obtained through analyzing the kinematics and dynamics of wheat seed through the seed distributor. The influence factors were the inner diameter of the seed distributor, the rotation speed of the seed distributor and the inclination angle of distributor window. Moreover, the structural parameters of the seed distributor were optimized. Inclination window of seed distributor was obtained to increase shooting speed and seed filling performance. The EDEM discrete element software was used to simulate the motion process to explore the different factors on the internal wheat seed movement in shooting device, which five seed distributors in different inclination parameters were designed. The coefficient of variation of shooting uniformity and shooting speed of wheat seed were selected as test indicators. The orthogonal test results showed the primary and secondary order of influencing factors for each test index. For the coefficient of variation of shooting uniformity, the order was rotation speed of seed distributor, inner diameter of seed distributor and inclination angle of distributor window. For the shooting speed, the order was rotation speed of seed distributor, inclination angle of distributor window and inner diameter of seed distributor. Furthermore, a verification experiment was evaluated in Conservation tillage research center of China Agricultural University, in 2020. Seed-metering device was manufactured by resin material by 3D printing, and high-speed camera was taken to obtain wheat seed movement and shooting speed. The verification test showed that the uniform variation coefficient of the seeding amount and average shooting depth was 8.6% and 32 mm, respectively, while the inner diameter of the seed distributor, inclination angle of the distributor window and rotation speed was 125 mm, 25° and 1,100 r/min, respectively. With a shooting speed of 34.7 m/s to meet shooting requirements in North China Plain (over 30 mm), this study provides a new solution for the optimization of mechanical shooting seed-metering device.

Abstract in Chinese

针对机械式小麦射播排种器充种效果较差，导致播种均匀度、排种稳定性不佳的问题，对排种器分种结构进行优化，通过对小麦种子经过分种装置时的运动学与动力学分析，得出影响种子运动状态的因素为分种轮内径，分种轮转速及分种轮开口倾斜角度，并对分种轮的结构参数进行优化，采用开口侧壁后倾形式以提升种子的运动速度，提高充种效果，并结合EDEM离散元软件对排种器的充种、排种过程进行仿真试验，探究不同因素对排种器内部种子运动的影响规律，并采用试验台试验对仿真优化结果进行验证。试验结果表明：在分种轮内径为125 mm，开口倾斜角度为25°，转速为1100 r/min时，其排种量均匀度变异系数为8.6%，排种速度为34.7 m/s，平均播种深度为32 mm，满足华北地区小麦播种作业要求，该文为机械式射播排种器的优化提供了一种新的解决方案。