基于干扰观测器的二元机翼颤振抑制及阵风载荷减缓方法研究

针对大展弦比柔性飞机在飞行过程中面临的两类气动弹性问题:颤振抑制与阵风载荷减缓开展研究。首先,建立以飞行速度为时变参数的柔性二元机翼结构动力学模型。其次,提出了基于鲁棒预测控制方法的变参数柔性机翼颤振抑制;同时,引入干扰观测器对阵风扰动进行观测,以干扰估计作为抗干扰控制输入,实现阵风载荷减缓。然后,根据对偶原理,将控制器与观测器独立设计。运用极点配置方法,设计了离散系统干扰观测器。根据Lyapunov理论将变参数系统的鲁棒镇定与颤振抑制问题转换为极大/极小动态规划问题。通过线性矩阵不等式方法求解出相应的预测控制律,并证明了整个闭环系统的稳定性。最后,以某型柔性变参数二元机翼对象为例,进行仿真。结果表明,设计的鲁棒预测控制器可提高约20%的临界颤振速度,且阵风载荷减缓率达到90%。

Research on flutter suppression and gust load alleviationof a two - dimensional wing based on disturbance observer

In this paper, two types of aeroelastic problems for the high-aspect-ratio flexible aircraft were discussed: the flutter suppression and the gust load alleviation. Firstly, the structural dynamic model of a two-dimensional flexible wing with time-varying parameters was established. Secondly, a robust predictive control method was proposed to suppress the flutter of flexible wings with varying parameters. At the same time, disturbance observer was introduced to estimate the gust disturbance, and the estimated values were used as the rejected-disturb control input to realize gust load alleviation. According to the principle of duality, the controller and the observer can be designed independently. The disturbance observer of the discrete system was designed by using pole-placement method. According to, the robust stabilization and flutter suppression problem of variable parameter systems was transformed into maximal / minimal dynamic programming problem. The corresponding predictive control law was obtained by solving linear matrix inequalities. The stability of the overall closed-loop system was proved by using Lyapunov theory. The simulation results show that the robust predictor controller can increase the critical flutter speed by about 20% and the gust load alleviation rate is 90%.