| In China,manual operation is mainly used for seedling transplantation in the facility,and the manual production efficiency is low and the operation quality is unstable.Therefore,with the large-scale production of seedlings in the facility,the mechanized transplantation demand for seedlings in China is more and more urgent.For improving the hydroponic leafy vegetables seedling production efficiency and solve the plug seedling transplant operations in engraftment period filling the gaps with seedlings,leaves covered each other for using coco-peat as the main cultivation substrate of hydroponic leafy vegetables seedling.We put forward a kind of insert and contraction type seedling transplant manipulator device and on the basis of high pressure air blowing seedlings,and connecting with the computer three-dimensional modeling technology,fluid mechanics simulation,mathematical modeling and experiment method to transplant manipulator and blowing leaves device are studied,the main contents are as follows:1.In this study,the physical characteristics of seedlings were determined and analyzed by means of machine vision measurement and mechanical property test platform,aiming at the parameters of the operation required for designing of the transplantation manipulator with coco-peat as the main cultivation substrate.The plant height,crown width,leaf stem diameter,root distribution ratio,lateral projection area of leaves and initial coverage of leaves to plug hole were obtained.In terms of the mechanical characteristics of seedlings,the pulling force of seedlings and the bending force of middle stem were obtained.2.A 4 expansion needle transplantation manipulator with a diameter of 2.5 mm and an insert angle of 76°was designed for 50 plug seedlings with coco-peat as the main cultivation substrate.In the process of transplanting,it is difficult to explain the influence of transplanting parts on seedling root system by only relying on the mass percentage of substrate scattering.And the distance between the telescopic needles was determined to be36 mm under the condition that the telescopic needles were kept intact during the transplantation of coco-peat.Transplant operation performance test showed that leaf vegetables seedling root state impact on the success rate of transplantation is the largest;manipulator operation acceleration also has certain influence.The test results also show that for normal growing coco-peat cultivating kale seedlings roots,the root system distribution rate is more than 80%,the vertical acceleration is 0.3 m/s~2,horizontal acceleration is 1.5m/s~2 and substrate block under the moisture content of 81%,kale seedlings transplant success rate can reach 100%,and the operating efficiency can reach 1500 plants/hour.3.The production of hydroponic leafy vegetable plug-seedlings uses coco-peat as culture substrate in South China.Coco-peat has lowered density than peat-moss,and the friction between substrate block and pickup tool is small.So,it is hard to pick up in mechanism transplantation.In order to increase the friction,the existing transplanting manipulator had relatively complex structures.To simplify the structure of transplanting manipulator and improve the stability of picking up substrate block,four stainless steel fingers with rectangular cross-section were used in this research.A vertical driving was used to realize the coupling effect that could insert and shrink at the same time,by applying different combination of constraints to the steel fingers.This could increase friction between the steel fingers and the substrate block,and then enhance the stability of the substrate block.Different combinations of constraints were applied to the rectangular stainless steel fingers(3 mm×0.8 mm).The working videos of steel fingers were taken by high-speed photography.High-speed motioned analysis software was used to acquire and analyze traces of steel fingers movements.When the length which top end of the steel fingers moved outward(X)is equal to 1.5 mm,the length which guiding part widened(Y)is equal to 1 mm,the shrinking distance of steel fingers is 4.2 mm.In this research,16-day hydroponic leafy vegetable plug-seedlings were used for performance,which cultivated by coco-peat substrate with the moisture in the substrate at 81%.The transplanting manipulator was attached to a Denso robotic arm to conduct transplanting performance test.When the shrinking distance of steel fingers increased from 0 mm to 3.2 mm and the inserting angle decreased from 80°to 77°,the lifting force of substrate block increased by118%from 1.45 N to 3.16 N.However,excessive shrinkage stirred the substrate block,which would reduce the friction between the substrate block and pickup parts and lowered the lifting force of pickup part in the substrate block.The experimental results also demonstrated that when the shrinking distance of the steel fingers reached 3.2 mm and the root distribution rate reached 46%,the success rate of transplantation was 80%.When the leafy vegetable plug-seedlings root distribution rate reached 92%,the success rate of transplantation was 96.67%.The degree of root distribution rate was positively correlated with the transplantation success rate.Therefore,in order to ensure an acceptable success rate of transplantation,the root distribution rate of leafy vegetable plug-seedlings should be at least 90%.This study provides a technical reference for developing simplified transplanting manipulator that can be used to transplant the hydroponic leafy vegetable plug-seedlings with coco-peat as the culture substrate.The experiment was carried out with the transplant prototype,and the operation efficiency can reach 2000 plants/hour under the condition that the success rate of transplanting is more than 90%.4.In the big plug seedlings mechanized filling process,the leaves of adjacent seedlings will extend to the tray vacancy to be filled,so that the transplanting manipulator will injure the adjacent seedlings when filled seedlings.In this paper,a seedling blowing device contained high pressure and jet pipe is designed for plug tray vacancy filling.The inner diameter of the jet pipe is 5 mm,the jet hole number is 8 and the punched diameter is1 mm.Aiming at seedlings of Spathiphyllum,Anthurium,Guangfu no.1 flowering cabbage,Lvbao kale,Chinese pakchoi and Italy elite lettuce seedlings,the jet pipe property experiment on blowing plug seedlings shown that the pressure of jet pipe has largest effect on the coverage rate after blowing the seedling leaves,and the breed of plug seedlings has largest effect on the success rate of filling for plug seedlings.The ratio of the cross section area of the air inlet and the cross section area of the air outlet which named proportional coefficient of inlet and outlet section also has effect on the coverage rate after blowing the seedling leaves,and has effect on the success rate of filling for plug seedlings too.For the Spathiphyllum seedlings,when the pressure of the jet pipe is 0.22 Mpa,the success rate of filling for plug seedlings can reach 91.1%,for the Anthurium seedlings,when the pressure of the jet pipe is 0.28 Mpa,the success rate of filling for plug seedlings can reach 84.5%,for the Guangfu no.1 flowering cabbage,Lvbao kale,Chinese pakchoi and Italy elite lettuce seedlings,when the pressure of the jet pipe is 0.16 Mpa,the success rate of filling for plug seedlings can reach 87.3%.This study can provide technical reference for the development of non-destructive filling seedling equipment for the big plug seedlings. |
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