直升机执行器故障的双时标容错控制系统设计

针对直升机的执行器故障,本文提出了一种基于双时标模型的自适应容错控制方法.根据直升机的不同状态变量响应时间不同的特点和时标分离理论,将直升机模型划分为快速(姿态动力学)和慢速(平移动力学)两种时标模型.反步控制方法和逆动力学控制方法分别被用于进行快慢两种模型控制器的设计,并在控制过程中采用了不同的控制周期.在双时标模型中,引入了执行器效率因子(actuator effectiveness factors,AEFs)用于表示执行器的健康情况.利用无色卡尔曼滤波(unscented Kalman filter,UKF)对AEFs进行了在线估计,估计结果用于快速和慢速模型控制器的自适应重构.仿真结果表明,该自适应容错控制方法,能够有效的消除执行器故障(包括常值和时变故障)对直升机飞行性能的影响,并取得良好的控制效果.

Two time-scale fault tolerant control system design against actuator faults for a helicopter

A two-time-scale model-based adaptive fault tolerant control method is proposed to deal with faults of actuator for a helicopter. According to the characteristics of the helicopter in which different states with different settling times, and based on the time-scale separation principle, the helicopter model is divided into the fast model (i.e., the attitude dynamics) and the slow model (i.e., the translational dynamics). The backstepping control and the inverse dynamic control are independently used to design the controllers for the fast model and the slow model in which different control intervals are used. Actuator effectiveness factors (AEFs) are introduced into the two-time-scale model to show the healthy conditions of the actuator. An unscented Kalman filter (UKF) is used for the online estimation of the AEFs. The results from UKF are used for the adaptive reconfiguration of controllers for the fast model and the slow model. Simulation results show that the proposed adaptive fault tolerant control method can eliminate the impact of actuator faults (including constant and time-varying fault) on helicopter. Desirable flight performances and good control effects are achieved.