航空发动机分布式控制系统不确定性鲁棒H∞容错控制

Uncertain Robust H∞ Fault-tolerant Control for Aero-engine Distributed Control System

关键词:  航空发动机  分布式控制系统  不确定性  H∞容错控制  马尔可夫时延 

Key words:  Aero-engine  Distributed control system  Uncertainty  H∞fault-tolerant control  Markov time-delay

摘要:

为减小不确定性对航空发动机分布式控制系统性能的影响,针对具有参数摄动、不确定时延、执行机构动态故障、外部噪声干扰四种不确定性的航空发动机分布式控制系统,提出了一种基于鲁棒H∞理论的容错控制方法。首先对系统不确定性进行数学描述,将不确定时延视为服从齐次Markov链分布的随机变量,将执行机构故障等效为存在均值和方差约束的随机变量,并在此基础上建立整个闭环系统的增广模型；其次证明了该增广模型保持均方渐进稳定且具备H∞性能的充分条件；最后利用线性矩阵不等式(LMI)理论给出闭环系统鲁棒H∞容错控制器的设计方法。仿真结果表明该方法能够保证控制系统均方渐进稳定,并对以上四种不确定因素具有鲁棒性,同时对于飞行包线其他各点具有较好的动态响应。 

Abstract:

To reduce the effects of uncertainty on aero-engine distributed control system (DCS), a robust H∞ fault-tolerant controller was proposed for uncertain aero-engine DCS with parameter perturbation, uncertain time-delay, external disturbance and dynamic fault of actuators. Assume that the time-delays obeyed a homogenous Markov distribution. The actuator fault was regarded as random parameter with mean and variance constraints. Based on the assumption a closed-loop augmented model was established and a sufficient condition was derived for the augmented system. Under this condition the augmented system will be mean-square asymptotically stable and fulfill H∞ disturbance restraint. Finally, the design approach of robust fault-tolerant controller was proposed by means of linear matrix inequality (LMI). Simulation results show that the controller is robust to the above four uncertainties. The controller also ensures closed-loop system to be mean-square asymptotically stable. Besides, the controller has a favorable dynamic response at other flight conditions. 