基于非线性干扰观测器的高超声速飞行器滑模反演控制

针对高超声速飞行器非线性、强耦合和参数不确定弹性体模型,提出了一种基于非线性干扰观测器的滑模反演控制方法.将飞行器曲线拟合模型分解为速度子系统和高度相关子系统并表示为严格反馈形式,分别采用滑模和反演方法设计实际控制量与虚拟控制量.采用1阶低通滤波器获取虚拟控制量的导数,解决了传统反演控制方法"微分项膨胀"问题.基于改进滑模微分器设计了一种新型非线性干扰观测器,以此对模型不确定项进行估计和补偿.仿真结果表明,该控制器对模型不确定性和气动弹性影响具有鲁棒性,且实现了对速度和高度参考输入的稳定跟踪.

Nonlinear-disturbance-observer-based sliding mode backstepping control of hypersonic vehicles

A nonlinear-disturbance-observer-based sliding mode backstepping controller is designed for flexible hypersonic vehicles with the characters of nonlinearity, strong couplings and parameter uncertainties. The vehicle curve-fitted model is decomposed as velocity subsystem and altitude-related subsystem, and is expressed as strict feedback form. The actual control laws and virtual control laws are designed based on the design procedures of sliding mode control and backstepping control, respectively. Low-pass first order filter is introduced to obtain the derivatives of virtual control laws, which avoids the explosion of differentiation terms in the traditional backstepping control. A new nonlinear disturbance observer designed based on improved sliding mode differentiator is introduced to estimate and compensate the model uncertainties. Simulation results demonstrate the effectiveness of this controller in tracking velocity and altitude commands in the presence of model uncertainty and aeroelasticity.