Calibration system for robot tool and calibration method for the same

A calibration system for robot tool, the calibration system comprising:

• a robot arm comprising a flange and adopting a robot arm coordinate system;
• a tool installed on the flange and comprising a tool working point (TWP);
• an imaging device setting an image sensing area within a movable range of the robot arm and adopting imaging device coordinate system, comprising:
• a light-source device emitting a light outward;
• and
• a photographing device arranged parallel to the light-source device and receiving the light emitted from the light-source device,
• wherein the imaging device sets the image sensing area by the emitted light;
• and
• a robot controller electrically connected to the robot arm, the robot controller configured to move the robot arm such that the TWP enters the image sensing area and to record a current gesture of the robot arm and a specific coordinate of the TWP of the tool in the imaging device coordinate system, whereby, when the TWP is within the imaging sensing area, the imaging device obtains the specific coordinate of the TWP in the imaging device coordinate system based on an interrupt information received by the photographing device;
• wherein the robot controller imports the current gesture and the specific coordinate to a pre-established transformation matrix to obtain an absolute coordinate of the TWP in the robot arm coordinate system, the transformation matrix recording a relationship between the robot arm coordinate system and the imaging device coordinate system;
• wherein, when the robot arm is not installed with the tool:
• the robot controller is configured to move the robot arm such that the flange is moved in the image sensing area and to record a gesture data of the robot arm, wherein the gesture data at least comprises the coordinate data of the flange in the robot arm coordinate system when the flange is placed at a plurality of positions, and an X-axis rotation amount, a Y-axis rotation amount, and a Z-axis rotation amount for the flange when the flange is placed at each of the positions, wherein the robot controller is configured to set the flange to be parallel to the coordinate plane in the imaging device coordinate system, and to set a Z-axis height of the flange when the imaging device first time senses the flange as z=0 height in the imaging device coordinate system;
• the robot controller is configured to move the flange to a first position in the image sensing area and define the coordinate data of the flange in the robot arm coordinate system when the flange is at the first position as a basic positioning point in the imaging device coordinate system;
• the robot controller is then configured to move the flange to a second position in the image sensing area with Z-axis height keeping unchanged, and define an X-axis direction or a Y-axis direction based on a relationship between the first position and the second position;
• the robot controller is then configured to move the flange to a third position in the image sensing area with Z-axis height keeping unchanged, and define a coordinate plane based on a relationship among the first position, the second position and the third position;
• and
• the robot controller is then configured to establish the imaging device coordinate system based on the coordinate plane and a Z-axis direction vertical to the coordinate plane;
• and
• the robot controller is configured to establish the transformation matrix based on the robot arm coordinate system, the imaging device coordinate system and the gesture data.