一种飞行控制混合指令故障气动伺服弹性分析方法

Aeroservoelastic Analysis Method for Flight Control System Mixed-Command Fault

摘要:

大型民用飞机电传飞行控制系统会出现正常模式和直接模式控制指令同时输出的故障情况，需要表明该故障下飞机气动伺服弹性的适航符合性方法，目前关于故障情况系统结构耦合适航符合性的研究都以验 证思路为主，未给出针对具体故障的验证方法。提出一种飞行控制混合指令故障下的气动伺服弹性分析方法，给出正常模式和直接模式混合控制指令等效假设及等效方法，基于该等效假设给出混合指令下气动伺服弹性分析原理；设计铁鸟试验，对混合控制指令等效假设进行验证，开展故障状态的气动伺服弹性分析。结果表明：相比于正常模式，混合指令故障下飞机气动伺服弹性稳定性提高，满足设计要求，该分析方法可用于飞机故障状态的气动伺服弹性设计与验证工作。

Abstract:

Large civil aircraft fly-by-wire flight control systems may experience a fault condition where both normal mode and direct mode control commands are output simultaneously. It is necessary to propose a method to demonstrate the airworthiness compliance of the aircraft"s aeroservoelasticity under this fault condition. Current research on the airworthiness compliance of system structural coupling under fault conditions primarily focuses on verification concepts and does not provide specific verification methods for particular faults. This paper proposes an aeroservoelastic analysis method for the mixed command fault in flight control systems. First, an equivalent assumption for the mixed control commands from the normal and direct modes is proposed, and an equivalent method is provided. Based on this assumption, the principle for aeroservoelastic analysis under mixed commands is presented. Second, an iron bird test was designed to verify the equivalent assumption for the mixed control commands. Finally, an aeroservoelastic analysis of the fault state was conducted. The study shows that, compared to the normal mode, the aeroservoelastic stability of the aircraft improves under the mixed command fault, meeting the design requirements. This analysis method can be used for the design and verification of aeroservoelasticity in aircraft fault states.