Method of correcting shift of working position in robot manipulation system

A method of correcting a shift of a position of a working tool in a robot manipulation system, comprising:

• moving the working tool in one direction from a first position toward a contact detecting member until the working tool abuts the contact detecting member to detect a first contact position where the working tool contacts the contact detecting member;
• rotating the working tool around a tool longitudinal axis serving as a rotational axis on a robot coordinate system by a predetermined angle to change a posture of the working tool to a second position;
• moving the working tool in the one direction from the second position toward the contact detecting member until the working tool abuts the contact detecting member to detect a second contact position where the working tool contacts the contact detecting member;
• calculating the first position based on the first and second contact positions and the predetermined angle;
• obtaining a difference as a shift amount between the first position and a theoretical tool working position which is previously obtained as a control reference point by a robot control program;
• and
• storing the obtained shift amount to correct a position of the working tool in a subsequent robot manipulating operation.