Investigation on soft-landing dynamics of four-legged lunar lander

•Seven degrees of freedom soft landing dynamic model of a lunar lander is proposed.•Calculation efficiency and accuracy of soft landing dynamics are optimized.•Soft landing test platform for scaled lunar lander model is developed.•Soft landing tests of the scaled lunar lander are conducted.•The results come from the dynamic model and tests match each other quite well.

In order to improve the efficiency and accuracy of soft-landing dynamic calculation of lunar lander, this paper proposed a new soft-landing dynamic model with seven free degrees and the inertia force was also taken into consideration during the landing process. The force condition of lander during soft-landing was investigated; moreover dynamics and kinematics equations were deduced. Besides, the landing process was studied by mathematical model, which is verified by results of scale lander prototype and landing test platform. The result shows that the calculation could match the test results effectively, which verifies accuracy and availability of seven free degrees soft-landing dynamic model.