| Nowadays, for most of the precision seeder we used in our country, its seed-metering device is driven by land wheel. The driving way leads ground wheel slipping seriously and bad seedling uniformity when the surface of the farmland is complicated or covered by stubble. The traditional mechanical sowing equipment adjusts the plant spacing by regulating gear manually to change the transmission ratio, which can only achieve fixed proportion regulation but not meet the step-less regulation. Besides, because the sowing process of the precision seeder has the characteristic of relatively closed, it is difficult to observe the specific seed-metering condition only by using our eyes. The crop yield will be influenced greatly once miss-seeding happened in the sowing process. Therefore, based on the series of existing problems of the precision seeder, the intelligent control system for corn precision seeder is developed in this subject with the method of combining advanced sensor technology, wireless transmission technology and automatic control technology.The control system uses the single chip computer as the controlling center, stepper motor to drive the rotating shaft metering device. It can achieve the aim that making use of the speed of the tractor controls the rotating speed of the rotating shaft metering device to step-less regulating plant spacing according to the mathematical model between tractor’s speed, the plant spacing and the rotating speed of the stepper motor. The laser sensor is used to monitor the sowing condition, once the sowing fault occurs, the alarming system that controlled by the SCM gives an alarm in time. DWIN screen is used to display the information of sowing parameter to let driver know sowing condition in time. In addition, because tractor’s cab is far away from seed-metering device and the field environment is severe, wire transmission is complicated. Therefore, wireless transmission chips are used to transfer signal.The following researches were mainly carried out in this subject:(1) Complete the two and three dimensional design of sowing unit and manufacture the sowing unit.(2) To set up hardware part of the control system. The selection of hardware components are confirmed in the control system, based on consulting a large number of relevant literature and understanding the principle, merit, demerit, applicable occasion of the related electronic components, and the design of related circuit also are accomplished.(3) To design software part of the control system. Controlling system’s modular software is designed with C language, mainly including the main program, information collection subprogram, wireless transmission subprogram, alarm subprogram, display subprogram and stepper-motor driving subprogram, etc.(4) The designed control system is installed on the precision seeder unit to process various experiments. Analyze the obtained test data to reach conclusions and then make improvements for shortcomings.Experimental results show that the control system can adjust the rotating speed of seed-metering device on the basis of tractor’s speed and realize uniform seeding. The performance indicators of the control system are up to the national requirements, and the reliable ratio of alarm system is high. |
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