Research on the Flexible Measurement Method of the Center of Gravity of Ultra-Long Carrier Rockets Based on Four-Vehicle Support

For super-long launch vehicles (>50 meters), traditional methods of measuring the center of mass have issues such as significant body deflection and insufficient accuracy. This paper proposes an innovative four-vehicle joint support flexible measurement method for the center of mass. This method reduces the deformation of the vehicle body through multi-point support, combines a laser tracker to achieve system joint leveling and spatial positioning, then uses group unloaded measurement followed by loaded measurement of mass, and finally calculates the center of mass using the principle of static moment balance. The center of mass coordinates are then transformed to the required product coordinate system through multi-coordinate system conversion technology. Experimental verification shows that this method significantly improves measurement accuracy. The relative standard uncertainty of mass measurement is 0.078%, and the relative standard uncertainties of the center of mass in the X, Y, and Z directions are 0.015%, 0.087%, and 0.079%, respectively.