马齿形玉米种子尖端激光定向与胚面识别装置研制

Development of tip orientation and embryo side recognition device for dent corn seeds

为了实现玉米种子的尖端定向与胚面识别,该文以现有尖端定向装置输出的马齿型玉米种子为对象,基于激光开关和测距原理,提出了一种尖端定向与胚面识别方法:依据马齿形玉米种子尖端窄大头宽的轮廓特征,利用激光开关传感器等部件对玉米种子的尖端朝向进行识别,并将大头朝前的玉米种子进行剔除;依据马齿形玉米种子胚面上有胚沟而反面较为平整的表面特征,利用激光测距传感器等部件对尖端朝前的玉米种子进行胚面识别。设计并搭建了玉米种子尖端定向与胚面识别装置,配合现有的尖端定向装置进行试验,结果表明:尖端定向与胚面识别装置的尖端定向成功率达到99.1%,相比现有的尖端定向装置提升了9.5个百分点,胚面识别准确率为96.4%。该方法基本可以实现玉米种子的尖端定向,同时保证胚面识别准确率达到较高水准。该文提出的玉米种子尖端定向与胚面识别方法可为后续玉米种子的自动化定向包装提供参考。

Automatic directional packaging of corn seeds is the precondition for realizing mechanical directional sowing of corn.The key technology is tip orientation and embryo side facing recognition.Combined with the actual demand of directional packaging,tip orientation for dent corn seeds needs that the tip orientation success rate reaches 100%(i.e.the tip is completely directed),and the embryo side facing recognition accuracy rate is required to achieve a high level at the same time.In addition,combining the actual demand of agricultural production and popularization,the method and its dependent device used to realize the tip orientation and embryo side recognition method for corn seeds should have low requirements for the working environment and the operation cost should be reduced as far as possible.The existing methods of tip orientation and embryo recognition are difficult to fulfil practical requirement.On the basis of the available research results of the research team,taking dent corn seeds with horizontal posture and tip orientation incomplete exported by existing tip orientation device as research object,a tip orientation and embryo side recognition method for dent corn seeds based on laser switch and range theory was proposed and the tip orientation and embryo side recognition device was designed in this paper.According to the shape characteristics of the corn seeds,the corn seeds large head facing forward was removed by using the laser sensors and other components first to get the seeds tip orientation done,and then the embryo side facing direction of each corn seed was identified one by one and outputed.There were 2 main characteristics of the corn seed shape:shape characteristic and surface characteristic.The shape characteristic was that the outline of corn seed was similar to"V"shape with narrow tip and wide large head,the surface characteristic was that there was a germinal groove extending from tip to large head on the embryo side,and the germinal groove shape was approximately elliptical,and its long axis coincided with the symmetric axis of the embryo side,the reverse side was smooth.The tip orientation method was proposed based on the shape characteristics of corn seed and laser switch sensor.Referring to the shape characteristics of the corn seed,a"V"shape slot was designed,the corn seeds with tip facing forward could enter into the slot,while the corn seeds with large head facing forward could not enter the slot as the large head of seed would block the entrance,based on this difference,by means of a normally open laser switch sensor,a specific straight track and a push rod,the tip orientation of each corn seed could be identified and the corn seeds with large head facing forward were removed.When the seed’s tip was oriented,it would be stayed in the slot with tip facing forward,and then the direction of embryo side would be recognized based on the surface characteristic and laser range sensor.With the combined of designed device and existing tip orientation device,a practical test bench was built and the orientation test for dent corn seeds was carried out to verify the actual effect of tip orientation and embryo side recognition method.The result showed that:the tip orientation success rate of existing tip orientation device was 89.6%,the embryo side recognition accuracy rate of designed device was 96.4%and the tip orientation success rate of designed device was 99.1%,which increased by 9.5 percentage points comparing with the existing tip oriented devices.The orientation method proposed in this study could basically realize the tip orientation of the corn seeds,and at the same time,the embryo side recognition accuracy rate could be reached to a high level.Generally,the tip orientation and embryo side recognition method and the device proposed in this paper have low requirements for working environment and low operation cost,which could provide a reference for automatic directional packaging and mechanically directional sowing of corn.