| The potato planting area and production of China have ranked first in the world.The mechanical sowing percentage was 23%.Spoon-chain metering is the most widely used metering device in small and medium-sized potato planter at present because of its high reliability,low cost,and adjustable plant spacing.Its performance is closely related with the planting quality.However,spoon-chain metering still encounters loss sowing problem,which can be reduced by optimizing structure and parameters of metering device.Nevertheless,the rate of loss sowing is still around 7%.Artificial assistance metering can resolve these problems effectively but with increased labor intensity and hidden danger.Ground wheel slipping is mainly the result of lacking driving capacity,which can be caused by huge load torque or ground drive failed attached to the soil/residue surface.To solve this problem,a motor was employed to drive the metering device instead of the ground wheel.Working speed was measured by transducer.The mechanical system is an improvement of the potato planter type 1220 produced by Menoble Company.A metering control system was developed to control the metering speed according to the ground wheel speed.A regression experiment was conducted with three factors(chain speed,chain tightening distance and cup tilting)and two indicators(missing-seeding rate and double-seeding rate).Based on the results of regression experiment,a numerical regression model was built and a multi-objective optimization method was used to get an optimal solution.Subsequently,the optimized device was tested in the field.The device design presents a tilting seed cup with a guard plate and an electric control system.The laboratory test showed that the missing-seeding rate increased with the chain speed.It initially decreases and then increases with the chain tightening distance and cup tilting angle.The double-seeding rate declines with the chain speed.It increases initially and declines afterward with the chain tightening distance.The optimization resulted in a missing-seeding rate of 4.4%and a double-seeding rate of 8.8%under the parameters of 0.32 m/s seeding speed,0.94 mm tightening distance,and 12.5° cup tilting angle.The field test demonstrated that electric control instead of ground wheel-driven chain enables fast seeding and precise intra-row seeding distance.A loss sowing detection method based on capacitance value precision measurement technology was proposed in this paper,and an automatic reseeding system was designed which was mainly composed of control system,capacitance sensor and reseed-metering device.In order to test performance of the automatic compensation system,a performance test is carried out using self-made device.Spoon-chain is driven by a servo motor and its speed is adjusted by servo driver.Reseeding-chain is driven by a servo motor and its speed is controlled by PLC controller.Micro potatoes are used in main metering system and reseeding system.The metering speed is set as 0.3,0.4,0.5,0.6 and 0.7 m/s,and the number of theoretical seed metering is 600 at different speeds.By mounting a laser sensor on seed discharge hole,the number of normal seeding and reseeding are recorded by PLC automatically.The automatic reseeding system of designed can solve the problem of miss-seeding in the process of seeding very well. |
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