基于干扰观测器的导引头稳定平台滑模控制

针对导引头稳定平台存在不确定弹体速度干扰以及非线性摩擦干扰的问题,结合滑模控制和非线性干扰观测器理论,提出一种基于非线性干扰观测器的二阶滑模控制方法。针对系统模型中的多个不确定干扰项,首先,采用新型微分跟踪器对状态量的导数值进行估计,进而得到干扰项的估计值,通过坐标变换,将系统中的不确定项进行归一化处理,便于控制器设计;其次,基于新型微分跟踪器设计了新型非线性干扰观测器,以实现对归一化后系统干扰项的精确估计;最后,采用二阶滑模控制算法进行控制器设计。仿真实验证明,新型非线性干扰观测器精度高、响应快,基于干扰观测器的二阶滑模控制方法能够有效隔离弹体扰动与非线性摩擦对导引头稳定平台的干扰,提高了稳定平台的鲁棒性和跟踪精度。

Sliding mode control of seeker stabilized platform based on disturbance observer

To solve the uncertain projectile velocity disturbance and nonlinear friction problems of the stabilizer, combining with sliding mode control and observer theory, a second-order sliding mode control based on nonlinear disturbance observer is proposed. A differential tracker is adopted to estimate the derivation of the state value, and furthermore, the first disturbance is acquired. Through the coordinate transformation, disturbance in the system is normalized, which simplifies the controller design. Secondly, an observer is designed based on the differential tracker, and the controller aims to achieve precise estimation of normalized disturbance. Finally, a second-order sliding mode control is adopted. The simulation results show that the new nonlinear disturbance observer estimates accurately and responses quickly, and the proposed second-order sliding mode control based on disturbance observer is able to isolate the disturbance of the missile motion and nonlinear friction of the seeker stabilized platform. The method further improves the robustness and tracking accuracy of the stabilization.