Abstract: Spacecraft in-orbit maneuver can lead to complex dynamic behaviors of liquid fuel，including nonlinear sloshing.The moving pulsation ball model（MPBM） was used to study the nonlinear rotary sloshing of liquid.The accuracy of MPBM was verified by ground sloshing experiment.Firstly，the influence of gravity was considered as the form of sloshing recovery force during the modeling process of MPBM.Specifically，the effect of gravity was introduced into the energy change process of the pulsating sphere based on virtual work principle.Secondly，the ground sloshing experiment platform was built to realize the accurate observation of the sloshing phenomenon of the spherical tank and the real-time measurement of the sloshing force and the sloshing moment.Finally，based on the acceleration excitation and sloshing force measured in the experiment，MPBM was used to simulate and compare the simulation results.The simulation results matched the experimental results well.The reasonable abstraction of liquid sloshing in this paper further improves the simulation ability of the equivalent mechanical model for complex sloshing behaviors，and provides basis for the realization of more efficient and accurate in-orbit control.

Key words: moving pulsating ball model（MPBM）, nonlinear rotary sloshing, ground sloshing experiment, sloshing force , numerical simulation