Sprayer boom height measurement in wheat field using ultrasonic sensor: An exploratory study

Area of Science:

• Agricultural Engineering
• Sensor Technology
• Robotics

Background:

• Accurate crop canopy height measurement is crucial for precision agriculture.
• Ultrasonic sensors offer a potential solution for non-contact height detection.
• Understanding influencing factors like speed and terrain is vital for reliable data.

Purpose of the Study:

• To investigate the influencing factors and laws of ultrasonic sensor detection for wheat canopy height.
• To design and test an adjustable-speed ultrasonic sensor platform.
• To propose a canopy height calculation method using K-mean clustering.

Main Methods:

• Developed a test platform with an adjustable-speed ultrasonic sensor.
• Conducted tests on step surfaces, bare soil slopes, and wheat canopies with varying densities.
• Applied K-mean clustering for canopy height calculation and analyzed detection characteristics.

Main Results:

• Ultrasonic sensor exhibited an average detection error of 1.35% on step surfaces, with a maximum offset of 10.4cm.
• Relative error for bare soil detection was 1.4% under quasi-static conditions; dynamic detection was affected by terrain and speed.
• Wheat canopy detection showed larger distances than manual measurements, with smaller canopy density increasing error (average deviation 0.14m, max variance 0.07cm²).

Conclusions:

• The ultrasonic sensor platform provides valuable data on influencing factors for crop canopy height detection.
• The K-mean clustering method offers a viable approach for calculating canopy height.
• Findings support the technical application of ultrasonic sensors for bare soil and sparse crop detection in agricultural fields.