Design Of Water-Fertilizer Integrated Variable Mixed Fertilizer Control System

Precise fertilizer distribution is a key issue in the current research on the integration of water and fertilizer.It can achieve the supply of crop nutrients on demand,while also improving fertilizer utilization,saving water and increasing efficiency,and reducing pollution.This paper designs a water and fertilizer integrated nutrient liquid control system based on STM32 single-chip microcomputer and Android mobile phone platform through research on the characteristics of fertilizer pump,structure of fertilizer blender,simplified dimensionality reduction algorithm,control algorithm and software and hardware design.This system uses the Android platform mobile phone APP to complete the following functions:users can view the water supply and fertilizer supply at any time;according to the needs of different crops,manually modify the water and fertilizer ratio and nutrient solution concentration value to achieve online monitoring of irrigation and fertilization information;at the same time,for the user Provide contact information and online query function of agronomy experts.In order to achieve precise fertilizer distribution,the characteristics of the fertilization pump were first analyzed.The characteristics of the GQS submersible screw pump were measured.The relationship model between the three variables of flow,pressure and voltage was established,and it was carried out by the side folding algorithm.Dimension reduction is simplified.The test results show that,compared with the original model,after using the simplified algorithm to simplify the model,the average error remains within 3%,and the single-chip operation time is reduced by 86.8%,and the algorithm is simplified without affecting the accuracy of the fertilizer,quick control,the purpose of improving fertilizer efficiency.Design the structure of the fertilizer blender,add a throttle end inside the pipeline,weld four fertilizer inlets above the pipeline,shorten the overall length of the device,set up a calibrated pipeline,and perform linear regression on the flow values of the two pipelines to get R2 it is 0.999,and the actual flow rate of the fertilizer mixer is obtained through calculation,so as to make hardware preparation for achieving the accurate ratio of water and fertilizer.Through software program design,the flow rate and pressure value of the fertilizer mixer are collected and transmitted,and the system operation status is monitored in real time,so that the user can connect the Wi-Fi module to modify the water and fertilizer ratio parameters through the mobile phone.Through the experiment,the linear relationship between the PWM duty cycle and the motor voltage is obtained.The correlation coefficient R2 is equal to 0.9987.The PWM duty cycle is changed to adjust the speed of the fertilizer pump.The control algorithm in this paper uses segmented proportional parameters to achieve nutrient solution regulation.After actual verification,the overshoot is about 3%.The system can run stably and can meet the design requirements of the control system.