基于鲁棒微分器的全阶非奇异终端滑模再入姿态控制

Robust Exact Differentiator Based Full-Order Nonsingular Terminal Sliding Mode for Re-Entry Attitude Control

针对飞行器再入段的强耦合和非线性的问题,提出了一种基于鲁棒微分器(robust exact differentiator,RED)的全阶非奇异终端滑模控制(full-order nonsingular terminal sliding mode control,FONTSMC)方法.首先,设计了一种新的全阶非奇异终端滑模函数,保证在控制器中不存在带有分数次幂项的状态量的导数,同时证明了跟踪误差可以在有限时间内收敛到0;然后,针对该滑模运动方程存在误差二阶导数的特殊情况,引入了超螺旋算法(super-twisting algorithm,STA)作为鲁棒微分器(RED),避免了由直接采用普通微分器引入的干扰噪声.进一步为了避免滑模控制的抖振问题,采用边界层技术与低通滤波技术共同消除控制量的抖振.最后,仿真结果验证了所设计的控制器可以实现有限时间姿态跟踪控制,且具有较好的鲁棒性.

Considering the reentry vehicle with strong inherent coupling and highly nonlinear, a full-order nonlinear terminal sliding mode control scheme was proposed based on terminal sliding mode and robust exact differentiator （RED）. Firstly, a novel full-order nonsingular terminal sliding mode control function was designed so that thederivatives of terms with fractional powers could not appear in the controller. Thus the control singularities could be avoided. Moreover, the tracking errors could be converged to 0 in finite time. Then, to obtain the derivatives of the angular velocity signal in the sliding mode manifold, a super-twisting algorithm （STA） was applied as robust exact differentiator. The interfering noise magnified with the common differentiator could be avoided because of the robustness of the RED. Furthermore, the filter and boundary layer technique were combined to alleviate chattering of the sliding mode controller. Finally, simulations were provided for the reentry vehicle with uncertain parameters and external disturbances to illustrate the effectiveness and robustness of the attitude control system.