Design And Experiment Of Liquid Fertilizer Control System

At present,Chinese wheat and corn crop planting area mainly depends on the use of solid fertilizer to improve the production of crops,but solid granular fertilizer utilization efficiency was low and easy to cause environmental pollution and other issues.Compared with the solid fertilizer,liquid fertilizer has obvious advantages,such as high efficiency,convenient use,low manufacturing cost and low environment pollution.Instead of the solid granular fertilizer,liquid fertilizer was an inevitable trend,but the liquid fertilizer technology in our country was not very mature.Mainly embodied in two aspects,the first was the development of liquid fertilizer machinery technology was backward,and the second was the liquid fertilizer control technology development lags behind.The NERCITA designed the 3ZF-150 type liquid fertilizer injection point machine.To improve the level of Chinese fertilizer liquid injection machine and its control system,designed the liquid fertilizer variable fertilizer injection control system on the basic of this machine.This design can effectively improve the utilization rate of liquid fertilizer,and can be the important measures of fertilizer application promotion.The main contents of this paper are as follows:(1)The liquid fertilizer variable fertilizer injection control system design requirements and designed the overall scheme was analyzed.The mechanical structure of liquid fertilizer injection point machine was introduced;In the existing fertilizer injection machine mechanical structure,analyzed the requirement of control system,and the key factors affecting the fertilizer injection precision was analyzed.This paper proposed the design scheme of the control system;To carry out the design of liquid fertilizer variable fertilizer injection control system,the control system from two aspects of the main control computer and slave computer monitoring system design.(2)The main control computer equipment of control system was designed.The selection of the master device human-computer interaction module and communication module were completed.The process of establishing the human-computer interaction module software development environment and engineering were introduced.This chapter introduced the software development environment and the construction process ofhuman-computer interaction module.The interface design of human-computer interaction module was completed.This chapter introduced the program example of man-machine interactive equipment.On the basis of this,the communication program between the master control equipment and the lower computer monitor equipment were designed.(3)This chapter completed the hardware design of monitoring equipment of the control system.According to the system requirements,the design scheme of hardware equipment for monitoring equipment was planned.(4)The software design of lower machine control equipment was completed.According to the system requirements,the software design of the monitoring system of the lower computer was planned.The PID algorithm involved in the control system was summarized,and the characteristics of the different implementation modes of PID algorithm were analyzed,and the optimal control algorithm was selected.The software design of pressure control unit and flow control unit in the monitoring system of the lower computer was completed.The PID parameters of pressure and flow PID control algorithm were optimized by simulation software.(5)According to the overall design requirements of the control system,the control system and the whole machine were tested and verified.The calibration test of flow sensor meter coefficient was carried out,and the control precision of the injection was improved.The results showed that the system can have a good response speed and control accuracy to the pressure control,and the average error of the pressure control test was 2.86%.The experiment results show that the relative error of the static injection test was about 1%,and the control accuracy was good.Performance of the control system and prototype field verification test,the test data show that fertilizer consumption to maintain maximum relative error under 10%,the average relative error was 5%,that machine and control system had good operation performance.