Dynamic performance test of auger-type metering device for Variable Rate Fertilizer Applicator (VRFA)

Abstract

The auger-type metering device for variable rate fertilizer applicator (VRFA) was designed and considered to have a better performance compared to other types of metering device. Static performance testing has been done with very good performance results. The system can follow each dose instruction given both step response and stair-step response testing. The objectives of this study were to do dynamic performance tests and analysis of the auger-type metering device which was controlled using a proportional-integral-derivative (PID) controller. In this test, the variable rate fertilizer was mounted to a transplanter machine. A DC motor rotated the auger, and the motor speed was controlled using a PID controller. The step response test was conducted to get a dynamic calibration equation by measuring the fertilizer discharge at a particular set-point of DC motor speed. The results obtained showed that fertilizer discharge has a linear relationship with the motor speed (R2 = 0.984). Fertilizer distribution testing was conducted using a stair-step response. These test results showed that the fertilizer was uniformly distributed to the track. Similarly, the increase in the DC motor speed is correlated with the amount of fertilizer was distributed to the track.