A robot apparatus which may be turned to a sound source direction by a spontaneous
whole-body concerted operation. With the possible range of rotation of the neck
unit of a robot apparatus 1 of Y and with the relative angle
of the direction of a sound source S to the front side of the robot apparatus 1
of X, the entire body trunk unit of the robot apparatus 1 is rotated
through (X-Y), using the leg units, while the neck joint yaw axis of the
robot apparatus is rotated through Y to the direction of the sound source
S, so that the robot apparatus is turned to the direction of the sound source S.
If the robot apparatus 1 has found the face of a person already known to
the robot apparatus through previous learning and has verified that the person
has accosted the apparatus, the body trunk unit is rotated through Y, at
the same time as the neck joint yaw axis is rotated through -Y to eliminate
neck distortion as the apparatus is gazing at the object, so that the apparatus
may face the sound source S aright by a spontaneous operation.
