Calibration method and device for robotic arm system

A calibration method for a robotic arm system, wherein the robotic arm system comprises a robotic arm, a calibration object, a visual device and a computing device, the method comprising:

• capturing, by the visual device, an image of the calibration object fixed to a front end of the robotic arm, wherein a pedestal of the robotic arm has a pedestal coordinate system, and the front end of the robotic arm has a first relative relationship with the pedestal, the front end of the robotic arm has a second relative relationship with the calibration object;
• receiving, by the computing device, the image, and obtaining three-dimensional feature data of the calibration object according to the image;
• and
• computing, by the computing device, a third relative relationship between the visual device and the pedestal of the robotic arm according to the three-dimensional feature data, the first relative relationship, and the second relative relationship to calibrate a position error between a physical location of the calibration object and a predictive positioning-location generated by the visual device,
• wherein the calibration object is a three-dimensional object that does not have any positioning marks.