A DSP-Based Control System for Precision Variable Rate Fertilization

Abstract

A real-time control system with TMS320F2812 DSP microprocessor as a control core for precision variable rate fertilization was designed, which were composed of the power system, DSP microprocessor controller, executive mechanism for variable rate fertilization, data storage module, speed test module and human-computer interaction module. A human-computer interaction interface system based on data storage and graphics was developed and the main control program was programmed. When the control system is working, the fertilizer rate is firstly entered by human-computer interaction interface, nextly the fertilizer rate and speed information are read into the DSP controller, and then the speed information is transmitted to monitor, finally the output pulses needed by motors are calculated, so the fertilizer rate can be controlled accurately. An experiment was conducted in the laboratory environment. The results showed that the error of fertilization rate of each fertilizer element was nitrogen (N: 0.05%), phosphorus (P:0.73%) and potassium (K:1.16%) respectly, and the consistency variability coefficient of fertilization rate of each fertilizer was nitrogen (N: 0.31%), phosphorus (P: 0.32%) and potassium (K: 0.15%) respectly. The control system for precision variable rate fertilization has high precision, good reliability and stability.