基质块苗移栽机挡销式自动送苗分苗装置设计与试验

Design and experiment of the automatic conveying and separating device for substrate block seedling transplanting machine

针对叶类蔬菜自动移栽送-分苗成功率低和伤苗率高的问题,该研究以甘蓝基质块苗为对象,设计了一种输送带+挡销组合式送-分苗装置,结合甘蓝基质块苗力学特性,开展送-分苗过程理论分析,确定装置稳定送-分苗条件和关键机构工作参数。搭建试验台进行单因素试验,确定关键因素参数范围,选取前输送带电机转速、后输送带电机转速和挡销频率为主要试验因素,以分苗成功率和基质块破损率为评价指标进行Box-Behnken中心组合试验,建立二阶回归模型,分析各影响因素对指标的影响关系并进行综合优化。试验结果表明:前输送带电机转速104 r/min、后输送带电机转速75 r/min、挡销频率1.85 s/次时送分苗效果较优,台架验证试验分苗成功率92.73%、基质块破损率4.09%,田间验证试验分苗成功率91.81%、基质块破损率4.62%,两指标的两次验证试验与优化结果相比误差值均小于2%,表明该装置具有较高的稳定性。该研究可为蔬菜自动移栽装备的设计提供参考。

Vegetables have been the second largest cultivated crop after grain in China,among which leaf vegetables account for 25%of the total planting area of vegetables.Among them,seedling transplanting is one of the most important steps during planting.Automatic transplanting can be expected as an effective way to fully meet the requirement of single-plant planting of leafy vegetables.However,it is still lacking in the automatic transplanting equipment of leaf vegetables,particularly on the reliability.Two challenges remain in the application of the automatic transplanter in leafy vegetables:first,the sending and dividing seedlings are suitable for long-stem seedlings of solanocarps with developed roots,rather than broad-leaved and short-stem leafy vegetables.Second,the high accuracy of sending and dividing seedlings can lead to the low reliability of the machine and the planting efficiency.Therefore,it is urgent to explore raising seedlings,conveying and separating suitable for the automatic transplanting of leafy vegetables,in order to improve the mechanical planting level of leafy vegetables.In this study,a combined conveying and separation device was designed with the conveyor belt and stop pin for the cabbage substrate block seedlings,particularly for the high success rate and low injury rate of automatic conveying and separating of leafy vegetables.Combined with the mechanical properties of cabbage substrate block seedlings,the theoretical analysis was carried out to determine the stable conveying and separating conditions of the conveying and separating device and the working parameters of the key mechanism.The test bench was built for the single-factor test to determine the range of key factor parameters.The front conveyor belt motor speed,rear conveyor belt motor speed,and frequency of the stop pin were selected as the main test factors.The Box-Behnken central composite test was carried out with the success rate of seedling separation and the substrate block breakage rate as the evaluation indexes.The second-order regression model was established to clarify the influence of various influencing factors on the indexes.The results showed that the better performance of conveying and separating was achieved,when the motor speed of the front conveyor belt was 104 r/min,the motor speed of the rear conveyor belt was 75 r/min,and the frequency of the stop pin was 1.85 s per time.The success rate of seedling separation was 92.73%,and the damage rate of the substrate block was 4.09%in the bench verification test.The success rate of seedling separation was 91.81%and the damage rate of the substrate block was 4.62%in the field verification test.The error values of the two verification tests and the optimization were less than 2 percental points,indicating the high stability.This finding can provide a strong reference for the design of automatic vegetable transplanting equipment.