Research And Development Of Mixed Equipment And Control System Of Integration Of Water And Fertilizer For Solid Fertilizer

With the development of water and fertilizer integration technology,water and fertilizer integration equipment has developed rapidly,but most of them apply liquid fertilizer or dissolve solid fertilizer into liquid fertilizer in advance,lacking of water and fertilizer integration equipment that directly applies solid fertilizer.This paper designs a mixed equipment and control system of integration of water and fertilizer for solid fertilizer,which can realize the simultaneous addition,dissolution and application of solid fertilizer.Through the detection and feedback of fertilizer concentration,speed of adding fertilizer and flow of water supply are changed to realize the uniform and adjustable of the concentration of fertilizer solution at the outlet of the mixed equipment.The fuzzy PID control algorithm is adopted in the control system for closed-loop control,which can quickly respond to and stably adjust the concentration of fertilizer solution and improve the fertilization performance.The main research work and results are as follows:(1)Design of mixed equipment of integration of water and fertilizer for solid fertilizerA kind of mixed equipment of integration of water and fertilizer for solid fertilizer is designed,which can irrigate and fertilize on demand,and realize the simultaneous addition,dissolution and application of solid fertilizer.The mixed equipment is mainly composed of fertilizer adding mechanism,water supply mechanism,fertilizer mixing mechanism,output mechanism and energy supply system.The fertilizer adding mechanism adopts the way that motor drives screw to rotate and feed fertilizer.The water supply mechanism adopts the DC pump to draw water source directly.Fertilizer mixing mechanism can accelerate the dissolution of solid fertilizer,and fertilizer solution is applied to field by the output mechanism finally.The mixed equipment is powered by battery and can be supplemented by solar panel.The appropriate structural parameters are selected according to the actual needs and tests.The structure design of the equipment is completed,and the performance parameters of fertilization are determined.The overall fertilization uniformity coefficient is about 46.29%.(2)Design of mixed fertilization control system of integration of water and fertilizerThe mixed fertilization control system of integration of water and fertilizer was constructed,including fertilizer adding module,water supply module and fertilizer concentration detection module.The fertilizing module is controlled by pulse number and frequency,which realizes the precise adjustment of the speed of adding fertilizer.The water supply module is controlled by pulse width,which realizes the precise regulation of water supply flow.Through the detection and feedback of fertilizer concentration,the real-time change of fertilizer adding speed and water supply flow can realize the uniform and adjustable of fertilizer concentration at the outlet of mixed fertilizer equipment.The fuzzy PID control algorithm and the establishment of mixed fertilizer model are used to optimize the control system of the mixed fertilizer equipment and form a closed-loop feedback control,which can quickly respond to and stably adjust the concentration of fertilizer solution and improve the fertilization performance.Human-computer interaction module is designed,which can display and adjust the parameters such as the speed of adding fertilizer,the flow of water supply,the concentration of fertilizer solution on the control panel,and has interfaces such as mode selection,manual/automatic control,monitoring screen,parameter curve,etc.(3)Experimental study on mixed fertilization of integration of water and fertilizerThe test bench of mixed equipment of integration of water and fertilizer is set up.Through the calibration of fertilizer concentration,fertilizer adding speed,water supply flow and liquid level,the functional relationships between fertilizer concentration and control quantity are established.Through the test of the energy supply system,it is determined that the continuous working time of the equipment is 7 hours,and the equipment can work for a long time with solar power supply.According to the experiment of the fertilizer adding mechanism and water supplying mechanism,the error of the control accuracy of the fertilizer adding and water supplying mechanism is less than 5%.The uniformity coefficient of fertilizer application increased by 22.87% and the highest reached 74.58% in the whole experiment of the equipment.The influence of the speed of adding fertilizer and the flow rate of supplying water on the concentration of fertilizer solution was obtained by using the control variable method.When the water supply flow is fixed,the concentration of fertilizer solution increases with the increase of fertilizer adding speed,and when the fertilizer adding speed is fixed,the concentration of fertilizer solution increases with the decrease of water supply flow.By setting the target concentration of fertilizer solution at the outlet of the mixed fertilizer barrel and measuring the actual concentration of fertilizer solution,the change curve of the concentration of fertilizer solution is obtained.The response time is about 10 min,and the fluctuation range of fertilizer liquid is within 1g/L.After adjustment,the adjustment time is about 20 min,and the steady-state error is about 0.55g/L.The experiment shows that the control system of water fertilizer integrated solid fertilizer automatic mixing equipment has good stability,rapidity and accuracy.