Study On Spray Uniformity Automation Test System

Pesticide product leads to agricultural ecological environment pollution and food safety problem because of superfluous application. The out-date instruments and techniques are the main reason for that. AS the key component of the chemical pesticide spray, the performance of the nozzle decides the pesticide product efficiency. Spray uniformity is one of important indicators of the nozzle performance. Therefore, the research of the spray distribution uniformity has great significance.Compared with advanced countries, the nozzle performance test instrument is deficient, great error in the measurement and low automation degree because of lack of the investment in agricultural scientific research and component. In our country distribution bench for spray nozzle is mostly "V" collecting tank, measuring data by cylinder and weighting sensor. This bench has simple structure, short precision but easy to operation, which can measure one-dimensional spray uniformity of the nozzle. It is fit for fan nozzle rather than cone nozzle. To solve above problems, an automatic test system based on ultrasonic distance sensor is designed. This system which can accuracy control spray pressure and realize data acquisition by microprocessor can collect liquids sump and realize the measurement of two dimensional spray uniformity by ultrasonic distance sensor driven by step motor accurate motion. The computer software can set spray pressure and finish the data display, storage and graphical display.The main content includes:1、Analyzed current domestic and overseas development status and main research methods of spray distribution, discussed the importance and significance of spray uniformity then;2、Designed test system proposal of two-dimensional spray uniformity and introduced the main component of the system;3、Designed the hardware parts. This system includes the following modules:MSP430f149microprocessor as the core of the control system, pressure control module, data acquisition module, power module, serial communication module;4、Designed easy-to-use interface, identified the motion schemes of stepper motor, adopted the complete coverage movement locus of head-to-tail in sequence, finished data display, storage and graphical display;5、Analysis of the error of this system, designed the three factors and three levels orthogonal experiment, and studied the influence of the nozzle type, spray pressure, nozzle height on the distribution coefficient of variation.