Design and Experiment of Multi-reflux Variable Spraying Control System

Abstract

In order to solve the problems of unreasonable pesticide application methods and relatively simple control methods in the spraying process of large-scale wide-width spraying machine, a multi reflux variable spraying control system was designed based on the 3WP-1200 spraying rod spraying machine with 22m spraying width. The control system could adjust the proportional control valve according to the running speed of the sprayer, which realized the variable spraying by changing the spray flow rate caused by the opening of return port. The control system was divided into five paths to control all sprinklers, and each path could be controlled separately. When one or more routes were disconnected, the corresponding return port could be opened, so that the spraying quantity of the other sprinklers would not change without changing the flow rate of the system. At the same time, its multi-reflux control method made the system pressure more stable and control precision higher. Moreover, the hardware and software of the system were designed, and the liquid level calibration and spray accuracy test of the control system were carried out. In the liquid level calibration test, the liquid volume corresponding to different liquid levels was calibrated, and the determination coefficient R2 of the calibration model was 0.994. In the flow control accuracy test, the target flow rate of a single sprinkler had little difference from the actual flow rate, and the relative error was not more than 4.1%. In the spraying control test, the spraying flux could vary with the speed, but the actual spraying flux was almost the same as that of the set spraying flux, and the relative error was within 6%. These experimental results showed that the system could achieve variable spraying with high control accuracy.

Keywords: wide-width sprayer, variable rate spraying, multi-reflux, control system