Abstract
Functions of self-diagnosis and abnormality alarming were added to the Tilling Robot employing the XNAV navigation system to assure the reliability and the safety of unmanned operation. The self-diagnosis function confirms the normality of the navigation data acquisition and the robot's setting and actions before unmanned operation. The abnormality alarming function checks the states of the navigation data acquisition and the robot's operation during unmanned operation. When the self-diagnosis or the abnormality alarming function detects any abnormalities, correction and recovery to normal states are accomplished with man-robot communications. These functions were confirmed to operate as designed by the test with abnormal states.
