预切种振动供种式木薯播种器勺链排种机构设计与试验

针对目前预切种式木薯精密播种器存在充种困难以及播种合格指数低等问题,在播种器中进一步设计勺链排种机构。阐述播种器工作原理以及设计勺链排种机构相关参数,基于最速降线理论对排种机构的捞种勺进行参数设计,并对机构作业的充种与投种过程中木薯种茎受力和运动状态进行理论分析,确定影响充种性能因素显著性主次顺序为捞种勺型式、捞种勺数量、输送链运动速度以及充种倾角。利用EDEM软件进行单因素仿真,得出不同试验因素对充种性能的影响规律;进行响应面BBD仿真试验,确定最优因素参数组合。研制播种器样机进行台架和田间试验,结果表明当充种倾角为37°、捞种勺数量为12个、输送链运动速度为0.63 m/s时,充种合格指数为93.8%,漏充指数为1.9%。田间试验表明预切种振动供种式木薯播种器勺链排种机构作业性能较优,满足木薯精密播种农艺要求。

Design and Experiment of Spoon Chain Seed Metering Mechanism of Precutting Vibration Seed Feeding Cassava Planter

In the earlier stage, a stepped vibrating seed sowing mechanism in the seed supply link of the precutting cassava seeder was designed. In order to further realize the precision seeding of cassava seed stems, a seed sowing mechanism was designed behind the stepped vibrating seed sowing mechanism to complete reliable seed filling and precision seeding. However, it was blind to take a single kind of stem from the cassava seed stem group that had been adjusted and sequenced through the seed metering mechanism scoop, which was easy to cause problems such as missing filling and reseeding. The spoon chain seed metering mechanism was further designed to solve the problems of seed filling difficulty and low seeding qualification index of the current precutting cassava precision seeder. The working principle of the seeder and the parameters related to the design of the spoon chain metering mechanism were described. Based on the theory of the fastest descent line, the parameters of the seed scoops of the metering mechanism were designed. The forces on the cassava seed stems and the motion state during the seed filling and seed feeding process of the mechanism were theoretically analyzed. It was determined that the significant factors affecting the seed filling performance were the type of seed scoops, the number of seed scoops, the motion speed of the conveyor chain, and the seed filling angle. Single factor simulation was carried out by using EDEM software, and the influence rules of different test factors on seed filling performance were obtained. The response surface BBD simulation test was carried out to determine the optimal factor parameter combination. The prototype seeder was developed for bench and field tests. The results showed that when the seed filling angle was 37°, the number of seed scoops was 12, and the moving speed of the conveyor chain was 0.63m/s, the qualified index of seed filling was 93.8%, and the missed filling index was 1.9%. The field experiment showed that the spoon chain seed metering mechanism of the precut seed vibrating seed feeding cassava seeder had better performance and it can meet the agronomic requirements of precision cassava sowing.