Nozzle height control with tubular type linear synchronous motor in agricultural spraying

SUMMARY Keywords: Agricultural spraying, nozzle height control, permanent magnet tubular linear synchronous motor In agricultural spraying, keeping the height of the spraying at the correct value reduces pesticide drift and provides uniformly distributed pesticide accumulation on the target plant. In this study, an agricultural nozzle height control test system was developed that can adjust the spraying height between spraying nozzle and the plant using a permanent magnet tubular linear synchronous motor (PMTLSM), which has the triangle motion profile. In the test bench, the nozzle height adjustment is performed by the PMTLSM, depending on the height data from the ultrasonic distance sensor. Ultrasonic sensor has been located in two different position. In the first construction, it has been located before the PMTLSM and in the second construction, it has been located on the rotor of the PMTLSM. The developed system was experimentally tested in the laboratory environment and under field conditions. Laboratory experiments were carried out without the use of chemical fluids in the conveyor belt system with artificial plants. In the experiments, the nozzle height coefficient of variation (CV) and the PMTLSM RMS current value were calculated for six different acceleration values (2.5, 5, 10, 20, 40, 60 m/s2) of PMTLSM and four different speeds (1, 2, 3, 4 km/h) of conveyor belt. In the field tests, the active nozzle was used and the CV value for the three different tractor speed (4, 8, 12), percentage wetted area and the uniformity of distribution in the forward direction was calculated. In the laboratory experiments, the optimum acceleration value according to minimum CV and minimum RMS current criterion was found as 20 m/s2. According to the experimental results, when nozzle height control was applied, the CV value decreased from 16.77% to 5.17%, while the uniformity of distribution in the forward direction increased from 56.57% to 86.11% at 12 km/h under field conditions. Under the test conditions, the developed system has kept the distance between the different sized plants and the nozzle with the minimum error at the set value and also increased the uniformity of distribution in the forward direction.