Automatic Control System of Boom Height and Spray Test

摘要

The oblique boom caused by the undulating terrain of field altered the spraying height along the spray boom, which had a bad effect on the spray deposition uniformity. In order to maintain suitable spraying height between the spray boom and crop canopy, an automatic control system of boom height was designed and applied to improve the spray deposition uniformity in this work. Three ultrasonic sensors installed on the three-section booms were used to detect the boom height of each section in real time, respectively. The movement direction (up or down) and speed of each boom were controlled by the hydraulic system which adjusted the boom height according to the set boom height and the actual boom height. The structure of boom sprayer and the adjustingprinciple'of three-section booms including the software and hardware of the control system were described. Ground tests were carried out to compare the spray deposition characteristics between the off-adjustment boom pattern and auto-adjustment boom pattern. The results showed that the spray deposition coefficient of variation was about 30% when the boom tilted around 3 degrees passing the step track with the off-adjustment boom pattern, while the auto-adjustment boom pattern was only about 10%. The automatic control system of boom height could keep the tilted boom at an appropriate spraying height, which could make a contribution to improve the spray deposition uniformity and the spray effect of boom sprayer.