机翼前缘积冰对大飞机操稳特性的影响

机翼结冰影响飞机的操稳特性和飞行性能，对飞行安全造成危害。基于实验数据构建了典型的不同结冰严重程度的机翼前缘积冰冰形，采用高精度数值模拟方法得到背景飞机机翼前缘积冰的气动数据，建立了飞机六自由度非线性动力学模型，在此基础上设计了俯仰角保持、滚转角保持及高度保持模式的自动驾驶仪闭环仿真系统。通过开环仿真，分析了不同程度积冰对飞机配平特性、纵向长短周期模态及横航向模态的影响，比较了不同程度积冰情形下飞机动态响应的差异。通过闭环仿真，研究了积冰对3种模式下自动驾驶性能的影响。仿真结果表明:积冰对飞机配平特性、模态特性及开环动态响应特性均会造成一定的不良影响，威胁飞行安全。 

Influence of ice accretion on leading edge of wings on stability and controllability of large aircraft

Ice accretion on the wings can affect the operational characteristics and flight performance of the aircraft, posing a hazard to flight safety. Based on the experimental data, the typical ice shapes with different icing severity on the leading edge of wings are constructed. The high-precision numerical simulation method is used to obtain the aerodynamic data of the background aircraft due to ice accretion, and the aircraft six-degree-of-freedom nonlinear dynamics model is established. On this basis, an autopilot closed-loop simulation system with three modes, namely, pitch attitude hold mode, roll attitude hold mode and altitude hold mode, is designed. Through the open-loop simulation, the different severity of ice accretion effects on aircraft trimming characteristics, longitudinal long and short period modal and lateral modal are analyzed, and the differences of aircraft dynamic response under different severity of ice accretion are compared. By using the closed-loop simulation, the influence of ice accretion on the autopilot performance under three modes is studied. The simulation results show that the ice accretion has an adverse effect on the stability and controllability of aircraft, including trimming characteristics, modal characteristics and open-loop dynamic response characteristics of aircraft, and threatens the flight safety.