Optimization methods for end-point accuracy of seven-axis articulated 3D scanning measurement arm

The measurement accuracy of the end effector point cloud of an Articulated Arm Coordinate Measuring Machine(AACMM) is influenced by factors such as joint structure, temperature compensation parameters, mechanical compensation parameters, end joint G modeling, and G joint rotation axis calibration algorithms. This study analyzes the end effector accuracy loss model of a seven-axis articulated 3D scanning measurement arm, focusing on the aforementioned factors. A nonlinear temperature compensation and mechanical compensation model based on a dual-suspension joint structure is proposed, along with a calibration method for the axis offset of the G joint. By evaluating the accuracy indices of single-point accuracy (SPAT), length error (EUMI), size error (PSIZE), form error (PFORM), and sphere position error (LDIS) in over 80% of the device's measurement range within a temperature environment of10°C to 40°C, this study demonstrates that the proposed method can improve the end position accuracy of a 3-meterrange AACMM by ±0.02mm under varying temperature and dynamic motion conditions.