Calibration apparatus and calibration method for coordinate system of robotic arm

A calibration apparatus for a coordinate system of a robotic arm, the calibration apparatus comprising:

• an alignment device, capturing an image in a field of view (FoV), wherein the FoV is a three-dimensional space, and the alignment device uses an alignment device coordinate system, where the alignment device is immovable and the alignment device coordinate system is fixed;
• a robotic arm, one end of the robotic arm being arranged with a flange thereon, wherein the robotic arm uses a robot coordinate system, and the flange uses an end-effector coordinate system, and the robotic arm and the alignment device are arranged individually;
• a tool, one end of the tool being arranged on the flange, the other end of the tool comprising a tool center point (TCP), wherein the tool uses a tool coordinate system;
• and
• a processor, electrically connected with the alignment device and the robotic arm, recording a first homogeneous matrix indicating a transforming relationship between the end-effector coordinate system and the robot coordinate system, wherein the processor is configured to control the tool to move in the three-dimensional space generated by the alignment device under multiple gestures for performing a tool calibration procedure, and to compute a second homogeneous matrix indicating a transforming relationship between the tool coordinate system and the end-effector coordinate system according to data obtained from the tool calibration procedure;
• wherein, the processor is configured to compute a third homogeneous matrix indicating a transforming relationship between the tool coordinate system and the robot coordinate system according to the first homogeneous matrix and the second homogeneous matrix, and to compute the relative position of the TCP in the robot coordinate system based on the third homogeneous matrix;
• wherein, the processor is configured to control the TCP to perform a three-point fix procedure in the three-dimensional space for regarding points in the alignment device coordinate system as points of the TCP, the processor is configured to compute a fourth homogeneous matrix indicating a transforming relationship between the alignment device coordinate system and the robot coordinate system based on the third homogeneous matrix, and to compute the relative positions of points in the alignment device coordinate system and in the robot coordinate system according to the fourth homogeneous matrix.