基于动态逆的直升机多变量鲁棒控制

Robust multivariable control of helicopter based on dynamic inversion

针对UH-60黑鹰直升机悬停和低速飞行时轴间强耦合现象、难以获得飞行速度精确测量值以及动态逆的鲁棒性问题,在以速度为参数的增益调度线性动态逆控制器基础上进行改进,将表征空气动力学参数、质量特性和工作点摄动的有界不确定性被包含在具有物理意义的线性分式变化(LFT)模型中,进而与多变量鲁棒综合/分析相结合.针对鲁棒综合设计中遇到的问题,如控制器结构、加权函数和对象不确定性类型的选择进行了研究.非线性仿真和鲁棒分析结果表明:鲁棒动态逆控制系统具备良好跟踪和解耦效果,满足鲁棒稳定性要求,并且其鲁棒性能远优于传统动态逆.

For the strong cross-axis coupling in hovering and low-speed flight of U H-60 Black Haw k helicopter ,gain-scheduled linear dynamic inversion controller ,w hich is mainly determined by total airspeed ,was obtained through states approximation and transformation .The system was divided into two parts :attitude command attitude hold (ACAH) controller for the roll and pitch channel ;rate command (RC) controller for yaw and attitude channel .Considering the strong cross-axis coupling , difficulty in obtaining accurate airspeed measurements and robustness of dynamic inversion for hove-ring and low speed flight regime ,gain-scheduled linear dynamic inversion controller ,w hich is mainly determined by total airspeed ,was improved .Bounded uncertainty ,which represents the perturbation of aerodynamic parameter ,mass property and operating point ,is included in the physically meaningful linear fractional transformation (LFT ) model .And the LFT model is combined with robustness syn-thesis and analysis .Construction of controller structure ,selection of weighting functions and defini-tion of uncertainties were considered in robustness synthesis .The nonlinear simulation and robustness analysis results show that the robust dynamic inversion control system guarantees the effectiveness of tracking and decoupling ,w hich satisfies robust stability ,and the robust performance level is much better than that of classic dynamic inversion .