1992 Volume 54 Issue 2 Pages 31-39
The present study aims to develop an automatic control device of spraying height for a boom sprayer. This paper discusses the sensibility of a 40kHz ultrasonic sensor on various kinds of target plants. The sound reflectances were in the range from 0.82 to 0.96, and the sensor sufficiently received the reflected waves from leaf surfaces. The sensor was able to detect the sensor to target height when the rate of leaf surface diameter to the height was larger than 0.05. The results obtained showed that the sensor detected the height within 6cm bias error in the case of broad leaves such as potatoes, kidney beans and sugar beets. As for linear leaves such as wheat, the sensor could not detect the height correctly because of the decrease of reflected echo.
From these results, it was considered that the ultrasonic sensor could be utilized as a control device for spraying height with corrections suitable for kinds and growth stages of crops.
