Automatic control system of water and fertilizer based on fuzzy control algorithm and simulation

摘要

In order to improve the precision of mixing fertilizer, this paper has improved its structure on the basis of pulse width modulation of the VENTURI variable fertilization device, and realizes the concentration of liquid fertilizer by pH and EC sensor to make it a closed-loop control Mixed fertilizer device. The device adopts the control strategy of the thickness level 2 adjustment. First, the corresponding duty relation is called according to the measured inlet pressure, and the duty ratio of the solenoid valve PWM control is automatically adjusted. And the fuzzy control algorithm is used to further fine-tune the duty cycle of PWM so that the concentration of the mixture is as close as possible to the target concentration. Finally, the fuzzy control and PID control of the flow control valve are simulated. The results show that fuzzy control is better than PID control in response speed and overshoot, and both steady - state errors are within ± 3.0%.