Method of controlling robot, method of teaching robot, and robot system

A method of teaching a robot, comprising:

• measuring a measured coordinate value of a feature point through a measurement using a vision sensor supported by the robot;
• computing a converted amount of positional difference, the converted amount of positional difference being obtained by converting an amount of positional difference between the measured coordinate value and a predetermined target coordinate value of the feature point, to an amount of positional difference of a determination point different from the feature point,
• comparing at least the converted amount of positional difference with a first threshold, and correcting a posture of the robot depending on the amount of positional difference if the amount of positional difference exceeds the first threshold, and
• repeating the measuring, the computing, and the correcting, and setting, as a teach point, a posture of the robot obtained in a state where the converted amount of positional difference is equal to or smaller than the first threshold.

A robot system comprising:

• a robot;
• a vision sensor supported by the robot;
• and
• a controller configured to control the robot and the vision sensor,
• wherein the controller is configured to
• calculate a transformation parameter which indicates an amount of positional difference between a measured coordinate value of a feature point obtained by using the vision sensor and a predetermined target coordinate value of the feature point, and
• correct a posture of the robot so that a converted amount of positional difference is equal to or smaller than a predetermined threshold, wherein the converted amount of positional difference is calculated by applying the transformation parameter to coordinates of a determination point positioned at a position different from the feature point.

A robot system comprising:

• a robot;
• a vision sensor configured to measure a feature point and obtain a measured coordinate value;
• a controller configured to control the robot;
• and
• an input unit configured to receive an input from a user toward the controller,
• wherein the controller obtains, via the input unit, setting information data on a determination point which is different from the feature point, and
• wherein the robot system uses a coordinate value of the determination point and the measured coordinate value, and determines whether the robot is taking a target position and orientation.