Landing cushioning performance and uncertainty interval analysis of heavy airdrop equipment

Purpose The complex and variable landing environment significantly influences the landing cushioning performance of heavy-load airdrop systems. These uncertainties obscure the relationships between landing responses and environmental parameters. This paper aims to propose a reliable landing cushioning system for heavy airdrop equipment and to present a method for analyzing the landing cushioning response range of the heavy airdrop equipment under uncertain conditions. Design/methodology/approach A fully flexible dynamic model of the equipment’s landing cushioning system is established, incorporating the nonlinear walking system and the combined airbag structure, the cushioning performance under various operating conditions was analyzed by test and simulation. An interval analysis algorithm for the multi-dimensions dynamic system was developed based on Chebyshev polynomials. By utilizing simulation results at interpolation points, the acceleration response intervals of the equipment landing were determined under 5% and 10% uncertainty intervals. Drop tests were conducted to further validate the accuracy of the interval algorithm. Findings The results demonstrate that the cushioning system exhibits excellent performance across the entire parameter range. The proposed interval analysis method provides high computational accuracy with low computational cost. In the uncertain intervals of 5% and 10%, the average R² values of the upper and lower bounds of the test points compared to the baseline are 0.91 and 0.813, respectively. The obtained acceleration upper and lower bounds fully encompass the results from both the scanning method and drop tests, with effective control over interval magnification. A clear mapping relationship has been established between the environmental parameters and the airdrop landing response. Originality/value This work provides a reliable cushioning system for heavy airdrop equipment while it holds significant implications for the landing cushioning and evaluating the uncertainties in the process of airdrop equipment.