| The seeding is an important step for factory tray nursing seedlings of rice. The tray nursing seedlings seeder matching with rice seedling thrower and transplanter should be developed, which is an important guarantee to realize rice planting mechanization.The rice nursing seedlings seeders have been research since the 1970s. With the development of the nursing seedlings technology, technique and automation level of the rice nursing seedlings pipeline gradually improve at home and abroad. From seeding accuracy, traditional mechanical seeder with great sowing rate is used for early conventional rice. Although this machine has many advantages such as simple structure and high efficiency, it has some damage for the seed. For hybrid rice, the vibration seeder and the vibration combined with pneumatic type seeder is adopted to realize precision seeding. At present, this kind of seeder has many disadvantages such as uneven seed, high cavities ratio and low sowing accuracy.With the constant development of new rice varieties and planting technology, original conventional rice and hybrid rice were replaced by super rice having excellent quality and high yield. Characteristics of planting technique of this rice is precision seeding, cultivating strong seedlings, wide space planting, quantitative controlling seedlings, aerobic irrigation, precision fertilization and integrated control. After having analyzing equipments for rice precision seeding of tray nursing seedlings at home and abroad, it can be conclude that available seeder is not suitable to the super rice. So technology of the rice nursing seedlings seeders must be improved.According to the main technical difficulties and some key technologies, the main contents and conclusions of the paper are following:1) By research and analysis on work principle and seeding technology about rice precision seeder at home and abroad, some key technologies in the tray nursing seedlings of super rice such as precision seeding, accuracy of throwing seeding, reducing empty hole and high efficiency need use the advanced seeding technology, control method and detection means, which can obtain better seeding property and high working reliability and improve the comprehensive technical level of the tray nursing seedlings of rice.2) Based on the vibration principle, the vibration combined with pneumatic type seeder is designed in detail, then basic theory and working performance about electromagnetic vibration supplying seed device and pneumatic vibration tray system are researched and analyzed. Prediction model of quantitative supplying seed based on the back-propagation neural networks is established and relative error of testing sample is less than 5%. The quantitative supplying seed model established is simulated, which provide the basis for choosing the working parameters of quantitative supplying seed device. The preferable parameters combination of pneumatic vibration tray system is obtained by using orthogonal test. Working performance of pneumatic vibration tray system is detected by the adjustment of pressure valve. Two motion types of rice seed in pneumatic vibration tray, namely downslide and jump, are presented based on the theoretical analysis of motion conditions. By the dropping seed speed optimization test , the effect rules of seed flow on seeding uniformity are presented and it can be concluded that ideal sowing condition could not be achieved in manner of single seed flowing. The optimum dropping seed speed should be chosen within the range of 1/1.50~1/1.40 times of single seed flowing, and then input gas pressure of air-style vibrator is obtained according to Fig. 2.25 and Fig. 2.26, which can ensure sowing qualified rate more than 85% and cavities ratio less than 3%. By theoretical analysis and experimental study on vibration precision seeder, precision seeding technology of super rice is solved in two aspects of the quantitative supplying seed and uniform seeding. The vibration precision seeder is developed, and it can satisfy various technical requirements.3) Using the magnetic directional valve and cylinder, a kind of the synchronous matching system of continuous transport tray cave and cylinder-seeder sucking hole used for the pneumatic double-drum precision seeder is developed for the first time, which achieve the cave of tray matching the hole of pneumatic cylinder-seeder in precision. Through synchrodrive calculation, synchronization transmission process between the cave of tray and the suction holes of pneumatic cylinder-seeder are finished by chain drive. Two-layer supply mechanism and synchronous matching mechanism can minimize laboring effectively and make the cave of tray match the hole of pneumatic cylinder-seeder in precision. The test results show that the qualification rate of synchronous matching mechanism is 98.2% when the productivity is 450 trays per hour. The device of continuous transport tray and cave-hole synchronous matching was developed. So a technical problem of super rice precision seeding is well solved. This system has many advantages such as simple structure, high efficiency, low cost and good working performance.4) To improve the seedlings survival rate of super rice precision seeding, seeding cavity detection in tray nursing seedlings of super rice based on computer vision technology and reseeding is put forward. The programmer is written and utilized on virtual LabVIEW software platform by using computer vision technology, and a series of functions such as acquisition and processing of sensor signal, acquisition and processing of tray image and data storage are finished. The mask images consistent with the tray seeding cavities and binary images of seeds are synthesized by using the image processing functions provided by vision module under red light R component plot. The binary mask images of seeds are established and seed gray average in mask image are obtained, which can be the base of identifying cavity. This tray detection system are set behind the seeding process and made application test. The test results show that cavity detection accuracy is more than 75% and these cavity data provide foundation for reseeding.5) The improvement-type pneumatic double-drum precision seeder used for tray nursing seedlings of rice is developed, which are configured the synchronous matching system and the seeding cavity detection technology for the first time. This machine is complete-functions, advanced technology and high seeding accuracy, but complex structure and high technologies, so it is applicable for the high precision tray nursing seedlings of super rice.6) The popular type (2CYL-450) rice nursing seedlings seeding pipeline is developed in this paper. This machine has advantages of simple structure, strong currency and easy adjustment, which is applicable when the tray hole is close to the drill. The test results show that at 2±1 seeds per hole, the sowing qualified rate is 90% and cavities ratio is 1.4% when the productivity is 450 trays per hour, which come up to the technical index of super rice nursing seedlings seeding. For the conventional rice, variation coefficient of supplying seed is less than 5%, which come up to the precision seeding at 5~8 seeds per hole, too. In a word, field application tests were conducted by the prototype in Pinghu city of Zhejiang province and state farms of Heilongjiang province. Tests result show that this prototype can satisfy the rice nursing seedlings seeding with a variety of trays and rice.
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