Current passive anti-rollover systems exhibit inadequate adaptability to complex operational environments. Additionally, due to unidentified critical factors driving rollover incidents during landing, the design of active anti-tipping systems for airdrop remains constrained. Given the foregoing circumstances, this paper divides the landing impact process of the vehicle into the airbag cushioning stage and the rigid collision stage. In the airbag cushioning stage, a vertical impact test bench and a fluid–structure interaction (FSI) model is built up to obtain the terminal impact velocity when the airbag’s touching down speed is set as around 8 m/s. An oblique impact test bench and a dynamic model are proposed to investigate the influence of terminal sideslip angles and impact velocities on the vehicle’s roll/pitch stability during the rigid collision phase. Experimental and numerical analyses reveal that the peak overload during the airbag cushioning stage reaches approximately 11 g while the terminal impact velocity in this stage is around 2 m/s. In the rigid collision stage, higher initial descent velocities amplify the peak roll angles and significantly compromise the roll stability. Notably, adjusting the terminal sideslip angle from 90° to 0°/180° triples the critical horizontal velocity threshold from 5.3 m/s to 14.7 m/s which markedly enhances the vehicle’s stability. To address this, an active sideslip angle control system activated at a 250 m altitude is developed to align the vehicle’s horizontal velocity vector with its longitudinal axis to nearly 0°/180° and thus improves the roll/pitch stability. This study establishes a technical foundation for the design of a highly reliable anti-rollover device for the airdrop vehicle.

The breathing oscillation of cross parachutes has received limited attention in previous studies, although it represents a physically important transitional state between stable inflation and severe deployment instabilities such as canopy collapse or inversion. In this study, the inflation dynamics and breathing oscillation behavior of a small cross parachute are investigated using a three-dimensional fluid-structure interaction simulation based on the Arbitrary Lagrangian-Eulerian (ALE) framework. The aerodynamic response and structural deformation of the canopy are analyzed under two representative inflow velocities of 20 m/s and 40 m/s to evaluate the influence of inflow conditions on unsteady loading characteristics. The results show that at 20 m/s the parachute undergoes a smooth inflation process and reaches a quasi-steady post-inflation state, with the axial aerodynamic force stabilizing at approximately 101.2 N. At 40 m/s, pronounced breathing oscillations are observed during both the inflation and post-inflation stages, characterized by periodic expansion and contraction of the canopy. The axial force exhibits large-amplitude oscillations with a mean value of 444.6 N, a maximum of 650.4 N, and a minimum of 293.4 N. The time-averaged force accounts for about 94% of the mid-oscillation level, indicating a clearly asymmetric oscillatory behavior. Further analysis of velocity fields demonstrates that this response is closely related to a strongly unsteady wake, in which a periodically varying axial jet and recurrent low-velocity and recirculation regions develop downstream of the canopy. These results elucidate the fluid-structure interaction mechanisms responsible for breathing oscillation and establish a theoretical basis for evaluating the aerodynamic response and deployment stability of cross parachutes under high inflow velocities.