Method of teaching robot and robot

A method of teaching a robot, the robot including:

• a robot arm freely movable at least in two axial directions that are directions in an X-axis and a Y-axis;
• a hand mounted to a distal end of the robot arm and including two branching distal end portions that are a first distal end portion and a second distal end portion;
• a mapping sensor configured such that a sensor beam travels straight through space between the first and second distal end portions, the mapping sensor detecting whether or not a target has blocked the sensor beam;
• and a controller configured to control an operation of the robot arm,
• the method comprising:
• a placing step of placing the target at a taught position;
• a first specifying step of causing the hand to advance straight from a predetermined position and specifying a position of the target in a forward-rearward direction in a reference coordinate system of the robot when the target has blocked the sensor beam;
• a swinging step of causing the hand to swing about a predetermined pivot, which is on an axis perpendicular to an optical axis of the sensor beam, to scan the target in a horizontal direction by means of the sensor beam;
• a determining step of determining whether or not the target has coincided with a position along a central axis of the hand in its longitudinal direction based on a detection signal of the mapping sensor, the detection signal of the mapping sensor having changed due to the swinging of the hand;
• a shifting step of, if it is determined in the determining step that the target has not coincided with the position, calculating an offset amount of the hand based on the detection signal of the mapping sensor, the detection signal of the mapping sensor having changed due to the swinging of the hand, and causing the hand to shift to either right or left along the optical axis of the sensor beam in accordance with the calculated offset amount;
• a second specifying step of, if it is determined in the determining step that the target has coincided with the position, specifying a position of the target in a right-left direction in the reference coordinate system of the robot;
• and
• a teaching step of teaching the robot a position of the hand, the position corresponding to the taught position, based on the positions of the target specified in the forward-rearward direction and the right-left direction.