| In recent years, with the development of precision seeder seeding technology, precision seeding has become the main development direction of modern seeding, which has many advantages such as saving seeds, reducing cost, increasing yield etc. In this paper, the related research is based on a new high-yield technology "double fine-seeding", compared with "single fine-seeding", seeding quantity of double fine-seeding does not raise doubly and plant spacing is sparse, which can make wheat root grow strongly and plants have strong lodging resistance. Twin-row precision sowing ensures the conditions of aeration and photopenetration which has solved many problems such as congestion, shading and intercepting mare light between the lines ect. and thus achieve the purpose of increasing wheat prodution. Combined with requirements of twin-row precision sowing technology and mechanical structure features of seeding device, double precision seeder for wheat was produced on the previous research.Most of existing seeders use ground wheel to drive mechanical seed-metering device. However, in the field, After crops are harvested, the soil doesn’t be ploughed, the soil surface has30%stubble to overlay at least, together with the the ground unevenness which make the wheel so declined adhesive strength and slippery that the uniformity of seeding can’t be ensured. Otherwise, mechanical methods that replace the transmission ratio by speed change mechanism ars used for changing the seeding quantity in the precise sowing-machine, However, these methods are not exact enough and transmission mechanism is easy to go wrong, difficult to achieve the requirements of precision seeding. Therefore, this paper based on present situation of seeder seeding system designed a kind of automatic control system for wheat double precision sowing machine on the later research.The system used stepping motor as actuator for driving the metering-device, in which way the metering drive device has been improved. In order to realize control seeding, rotary encoder was used for speed measurement of the precision seeder which made the speed of seeding and the forward speed of sowing machine keep consistent. The slip rate of tractor wheel is much smaller than of ground wheel, so the rotary encoder is installed on the tractor wheel directly. Setting seed spacing could be operated by keying input. With microprocessor (CPU) judging the speed, together with setting the seeding space (or sowing rate), this system regulated the stepping motor speed, so as to drive the device to sow as needed. In addition, because of distance between the tractor driver and seed metering device, control devices have to use the tedious wire connection. This system realized the data transmission successfully between velocity measurement and driving device by using bluetooth module, so that the system could save the wire and control devices were easy to install and dismantle. In addition, the system can realize some auxiliary functions such as lcd display, alarm and so on.The control system of Twin-row precision sowing was designed with a brand new concept, and the system who mixed together advanced sensor technology, wireless transmission technology and automatic control technology could improve the performance of the system and realize automation and intellectuality of precise seeder. |
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