A novel calibration method for robotic arm tool center point without a physical tool apex

With the manufacturing industry shifting toward small-batch, high-precision production, the need for accurate calibration of the center point of tools used in robotic arms, especially tools without a defined apex, has increased. Traditional calibration methods are unsuitable for tools without a defined apex because they involve errors introduced by tool replacement and fixture misalignment. Therefore, this study developed a calibration method that involves mounting a two-dimensional (2D) contour sensor and a 2D vision sensor on a rotary table to directly measure a tool’s relative position and orientation, thus achieving precise calibration of the tool center point and tool axis orientation without the need for tool replacement. Experimental results indicated that the proposed method can achieve a calibration accuracy of less than 0.36 mm and a calibration time per tool of less than 2 min. The proposed efficient, precise approach effectively reduces sensor alignment errors compared with traditional calibration methods and can be employed in diverse production environments with varying demands. Moreover, it ensures stability and repeatability of the manufacturing process in various high-precision applications.