Abstract
An assessment was made of the attitude calculation accuracy of hydraulic excavators used for the computerized construction of forest work roads. An inertial measurement unit (IMU) was mounted on the four parts (upper revolving structure, boom, arm, and bucket) that determine the posture of the excavator. The toe position of the bucket was calculated from the various posture angles, and the accuracy was verified using TS. The results revealed an average height error of 1.03 cm, which is compliant with the specified standard of a maximum error of 5.0 cm set by the Ministry of Land, Infrastructure, Transport, and Tourism. However, the error in the three-dimensional direction was as large as 7.05 cm. A close examination of the cause of this error revealed an error in the IMU azimuth measurement of 0.7° on average and as large as 6.0°. As a different way, the azimuth angle was calculated using the coordinate values of the rear prism surveyed by TS, and it was found that doing so reduced the average error in the three-dimensional direction to 1.75 cm.
