未知故障下的飞机自适应控制

摘要

Changes in aircraft dynamic model caused by body damage or other unknown faults may cause pre⁃designed control laws unsuitable for maintaining steady flight and adaptive control methods are needed to ensure flight safety. For this study, based on the nonlinear NASA Generic Transport Model ( NASA_GTM) , retrospective cost adaptive control ( RCAC) is applied to maintain steady flight with unknown faults, including icing and control surfaces faults. With knowledge of Markov parameters which are calculated from the linearized version of NASA_GTM, output feedback RCAC controller is designed. Retrospective cost function is further optimized to update adaptive gains of RCAC controller and the thrust and control surfaces are adaptively modified to compensate for the impacts of unknown faults. The results show that RCAC controller is able to adapt its gains in order to maintain the steady flight and follow control commands.%飞机动力学模型因受损或者其他未知故障时，预先设计的飞机控制律可能会无法满足飞机的稳定飞行，从而需要设计自适应控制律以保证飞行安全。本文以非线性的NASA－GTM通用飞机模型为对象，运用基于回顾成本的自适应控制方法（ RCAC）进行飞机未知故障情况下的平稳飞行控制，包括机体结冰与控制舵面卡死两种故障情况。根据飞机局部线性化模型得到系统马尔科夫参数来设计基于输出反馈的RCAC控制器。通过最优化回顾代价函数来更新RCAC控制器增益，从而调节飞机引擎与控制舵面的输出来补偿由未知故障带来的影响。仿真结果表明在未知故障情况下，RCAC能够很好地通过自适应调整控制器的增益来保证飞机的平稳飞行和控制指令跟踪。