Performance Evaluation of Variable Rate Spraying System under Simulated Conditions

Precise canopy measurement is the key to success for a variable rate spraying system. In this study, a variable rate spraying system was developed and its performance was evaluated under simulated laboratory conditions. The calibration and testing of individual components of the system were performed before integration into a system. Linear relationship was observed between distance and voltage (R2= 0.995) during calibration of the ultrasonic sensor. The detection range of ultrasonic sensor in real working conditions was found in the range of 0.20 to 7.5 m. It was maximum with flat surface board as compared to the artificial plant. Performance of the system was also tested under simulated dynamic conditions with plants. The mean absolute percentage error (MAPE) in canopy depth and specific spray volume was observed between 10.12% to 11.85% and 11.03% to 12.44%, respectively. The results also demonstrated that MAPE of canopy depth and specific spray volume was higher with plants grown in pots than that of with reference flat surface board, and this could be attributed to variation in canopy size, shape etc. However, the developed variable rate spraying system performed satisfactorily in executing the variable rate spray delivery under simulated conditions.