Patent attributes
The invention provides a posture detecting device, which comprises a tilt detecting unit as rotatably supported around two shafts perpendicular each other to an outer frame and for detecting a tilting from the horizontal, encoders provided on each of the shafts, motors provided so as to rotate each shaft, and a first arithmetic processing unit for driving/controlling the motor based on a detection result from the tilt detecting unit, wherein the first arithmetic processing unit drives the motors so that the tilt detecting unit detects the horizontal based on a signal from the tilt detecting unit when the outer frame is tilted and calculates a posture of the outer frame based on outputs of the encoders when the tilt detecting unit detects the horizontal.