Abstract: Relying on the bogie’s parameters test bench developed by Jilin University， the spatial coordinates determination method of the bogie’s gravity center was put forward based on the moment balance principle. The test models for spatial coordinates were also established. The longitudinal and the lateral coordinates were tested with keeping the bogie still. But when test the vertical coordinate， the bogie should be inclined via the actuators of the test bench to analyze the moment balance at an angle. The inverse displacement analysis model of the multiplesixDOF simulation platform with complex coupling motions was established， and the vertical coordinate was tested based on the coordinated control commands of the actuators. Coordinates of the gravity center of a certain bogie were measured and compared with the theoretical coordinates. The result shows that measured values are consistent with the theoretical ones， which proves the accuracy and feasibility of the test method.

Key words: bogie, coordinate of center of gravity, spatial coordinate, inverse displacement analysis, transformation in homogeneous coordinate