|NOGUCHI, NOBORU - Hokkaido University|
|ISHII, KAZUNOBU - Hokkaido University|
|MATSUO, YOUSUKE - Institute Of Agricultural Machinery|
Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2011
Publication Date: 5/1/2011
Citation: Mizushima, A., Noguchi, N., Ishii, K., Matsuo, Y., Lu, R. 2011. Development of a low-cost attitude sensor for agricultural vehicles. Computers and Electronics in Agriculture. 76(2):198-204.
Interpretive Summary: Attitude (roll, pitch and heading) sensor is important for advanced agricultural vehicle applications such as autonomous guidance systems and precision farming. Accurate vehicle orientation can improve the accuracy of autonomous guidance compared to the guidance system for vehicle position only. Attitude sensor is also useful for computer vision-based precision farming. It can convert the captured image coordinate (pixel) to the GPS coordinate system (latitude, longitude) to generate field maps for providing information to make better management decisions. Currently, expensive sensors such as three-axis fiber optical gyroscope are still the mainstream technology in vehicle attitude sensing research. In this research, a low-cost attitude sensor was developed using two inclinometers and three vibratory gyroscopes. The accuracy of the attitude sensor was evaluated for various field conditions, i.e., flat field, sloping field and bumpy road. The results showed that the attitude sensor is suitable for use with agricultural vehicles in terms of accuracy and cost. The proposed technology used in the attitude sensor will help to develop advanced agricultural applications.
Technical Abstract: The objective of this research was to develop a low-cost attitude sensor for agricultural vehicles. The attitude sensor was composed of three vibratory gyroscopes and two inclinometers. A sensor fusion algorithm was developed to estimate tilt angles (roll and pitch) by least-squares method. In the algorithm, the drift error of the gyroscopes was estimated using the inclinometers. In addition to tilt angles, the attitude sensor also estimated the absolute heading angle and position with inclination error correction by integrating a GPS. Tests were conducted on a flat field, sloping ground and bumpy road. Results showed that the attitude sensor was able to estimate the roll angle with the maximum root mean square error of 0.43 deg, the pitch angle with 0.61 deg and the heading angle with 0.64 deg. Moreover, the attitude sensor dramatically improved the positioning accuracy from 25.9 cm to 3.0 cm in the sloping ground test and from 8.4 cm to 3.7 cm in the bumpy road test. The proposed technology used in the attitude sensor will help to develop advanced agricultural applications.