Teaching system, teaching method and robot system

A teaching system comprising:

• a display unit;
• an image generating unit configured to generate a virtual image of a robot, a workpiece as a work target of the robot and a positioner for holding the workpiece;
• a display control unit configured to control the display unit to display the virtual image generated by the image generating unit;
• a work line generating unit configured to, upon receiving an operator's operation of selecting a ridgeline of the workpiece of the virtual image, extract individual teaching target points of the ridgeline and generate a work line as a set of line segments each interconnecting the target points adjoining each other;
• a calculation unit configured to calculate teaching values for positions and postures of the positioner on a point-by-point basis so that a vector direction of the work line at each of the target points becomes substantially parallel to a horizontal direction;
• and
• a teaching program generating unit configured to generate a teaching program for operating the positioner based on the teaching values calculated by the calculation unit.