Stability analysis and optimization for pneumatic cabin pressure regulating system

Pressure oscillation arises in cabin of aircraft equipped with the considered pressure regulating system. To solve the problem, the scheme of cabin pressure regulating system was introduced and analyzed. The system in differential pressure flight phase is simplified according to actual components participating in the pressure modulating. The simplified system was taken as an example for stability analysis. The nonlinearity of the system was analyzed in details. The describing function was obtained and the negative inverse describing function curve was plotted. The charging and discharging dynamic of hole-container structure was studied, and it was found that the charging and discharging transient was almost same in the condition. Then the transfer function of hole-container structure was built as first-order element, and the similarities and differences between them were pointed out. Describing function method was employed to analyze stability of the system, and a way of achieving stability was proposed. Full-physical simulation result shows that the required stability is achieved by this way.