一种电磁定位系统工作空间拓展方法

Aimed at the problem of limited workspace and inconsistent measurement accuracy of NDI electromagnetic tracking equipment, a method for expanding the workspace of electromagnetic tracking system and guaranteeing measurement accuracy by moving magnetic field generator is proposed. This method uses the indicator value returned by NDI system as the measurement of accuracy. When the indicator value exceeds the set threshold, the magnetic field generator connected with the manipulator is moved to relocate the sensor in the optimum working area, and the position and attitude measured by the system are unified into the coordinate system of the manipulator base through spatial transformation. In order to verify the effectiveness of the proposed method, experiments are conducted to verify that the measurement error is positively correlated with the indicator value and the distance between the sensor and the center of the magnetic field generator. Then, by comparing the errors before and after the expansion, it is shown that the mean position error can be reduced from 2.61 mm to 1.34 mm, and the mean orientation error can be reduced from 2.42° to 1.37°. This method can be used to locate and track large-scale moving instruments such as vascular interventional catheters.