基于排种频率实时反馈的油菜排种器设计与试验

Design and Experiment of Seed Metering Device for Rapeseed Based on Seeding Frequency Feedback

以电机转速作为控制目标的电控排种器,在复杂工况下存在实时播种量不稳定、难以达到农艺要求播量的问题,为此设计了一种可根据实时播量信息进行反馈控制的油菜排种器。油菜排种器由螺管排种机构、小粒径种子感知模块、检测及控制模块和驱动模块组成。为使种子有序通过小粒径种子感知模块传感区域,对导种管进行了结构设计,使其能够与传感器模组匹配,从而有效减少播量漏记。对排种器进行转速排种频率测定及播量准确率测试,基于测试结果构建了播量检测准确率补偿模型,从而降低播量检测误差。以小粒径种子感知模块中传感器模组获取的实时播量信息作为排种控制器控制输入,设计了排种器控制系统。台架试验表明,油菜排种器排种频率在10.1~60.4 Hz范围内,排种器播量检测准确率达到98.75%,不同转速下的排种量稳定性变异系数不超过1.16%。田间试验表明,在拖拉机不同前进速度下,播种量误差率不超过2.55%,排种量稳定性变异系数不超过0.98%。该油菜排种器可为小田块精量播种提供技术支撑。

The seed metering device for rapeseed was the core working part of rape mechanized seeding technology.The performance of seed metering device for rapeseed directly determined the quality of rape seeding.One of the trends to achieve intelligent sowing is to obtain sowing information through real-time detection of rape seed flow and control the sowing volume accordingly.The electronic control seed metering device that used motor speed as the control target had the problem of unstable seeding quantity in real time under complex working conditions.This problem has made it difficult for the seed metering device to achieve the agronomy requirements of sowing quantity.A seed metering device which can perform feedback control based on real-time sowing information was designed to solve this problem.The seed metering device for rapeseed consisted of a screw tube seed rowing mechanism,a detection and control module,a small grain size seed sensing module and a drive module.In order to orderly pass all seeds through the sensing area of the small grain size seed sensing module,the structure of the seed guide tube was designed.This seed guide tube can match the sensor module.It can effectively reduce loss sowing.The seed metering device for rapeseed was tested for rotation speed-seeding frequency measurement and seeding accuracy rate.A seeding quantity compensation model was constructed based on the result of test.This model reduced sowing detection errors.The seed metering device for rapeseed was tested for rotation speed-seeding quantity measurement and seeding accuracy rate.A seeding quantity compensation model was constructed based on the result of test.This model reduced sowing detection errors.A seed metering device control system was designed by using the small grain size seed sensing module to complete real-time seeding information detection,and it used the detected information as input to the control system.The control module calculated based on the set seeding information and the forward speed information measured by the hall speed measurement module.The control module converted the difference between the theoretical seeding frequency and the actual seeding frequency measured in real time by the small grain size seed sensing module into the speed difference as the controller input.The control module decided on the corresponding duty cycle.The bench test showed that the seeding quantity detection accuracy of the seed metering device for rapeseed detection was higher than 98.75%in the range of 10.1~60.4 Hz seeding frequency.The coefficient of variation of seeding quantity stability of seed metering device for rapeseed was less than 1.16%at different rotation speeds.The field test results showed that the error rate of sowing quantity was less than 2.55%and the coefficient of variation of seeding quantity stability of seed metering device for rapeseed was less than 0.98%at different forward speeds of the tractor.This seed metering device for rapeseed provided technical support for precision sowing in small plots.