基于喘振裕度估计模型的发动机高稳定性控制

为解决超机动飞行中发动机喘振裕度不可测量的难题,提出一种发动机喘振裕度的建模方法.喘振裕度的模型分为常规飞行时的无畸变模型与超机动飞行时的损失量模型两部分.无畸变模型是基于喘振裕度特征选择算法筛选最优模型输入,以非线性拟合方法建模实现;损失量模型则基于在线攻角预测模型实时评估发动机进口畸变度,进而计算获得.而后利用上述估计模型对发动机的稳定性进行实时预测,在不改变发动机原控制回路的基础上,对涡轮落压比控制指令进行喘振损失补偿,实现高稳定性控制.最后,通过大攻角机动飞行的数字仿真,验证了上述方案可以准确控制发动机喘振裕度在11%~13%,保证了发动机工作的稳定性和高效性.

High stability control of engine based on surge margin estimation model

In order to solve the immeasurable problem of engine surge margin in super-maneuvering flight,an approach to build an engine surge margin estimation model was proposed.The modeling process consists of two parts:surge margin benchmark value model under routine flight condition and surge margin loss value model under super-maneuvering flight condition.The benchmark value model was developed using nonlinear fitting method,and the input of model was fixed by surge margin feature selection algorithm.The surge margin loss value was obtained by an angel of attack predictive model which can be used to real-timely estimate engine inlet distortion index.Based on the predictive messages of surge margin estimation model,a scheme of high stability engine control through correcting turbine expansion ratio command was designed for super-maneuvering flight.In this way, the great advantage is that the original closed-loop doesn't need changes.Finally,some surer-maneuvering flight missions with large angle of attack were imitated.The simulation results show that surge margin ranges between 11% and 13% with above stability control concept,ensuring that engine can work safely and efficiently.