四旋翼无人机执行器可重构性量化评价方法研究

随着对系统安全性和可靠性要求的不断提高，故障系统的自主恢复能力即系统的可重构性受到高度关注，然而现有对于控制系统可重构性量化评价的方法主要针对线性系统，因此以具有强耦合、欠驱动、强非线性的四旋翼无人机（quadrotor UAV）为被控对象，提出了一种基于双滑模面鲁棒观测器与马氏距离结合的非线性系统可重构性量化评价方法。首先，在四旋翼无人机非线性模型的基础上，设计了具有对扰动和故障均不敏感的双滑模面鲁棒观测器，用于实现对系统状态的准确估计；其次，在执行器饱和及系统状态误差指标双约束条件下，采用基于马氏距离的相似度法，对非线性系统可重构性进行量化评价；最后，通过四旋翼无人机仿真实验验证了所提方法的有效性。结果表明，所提方法能够真实反映不同故障程度下系统的可重构性量化水平，为非线性故障系统控制策略调整补偿提供了重要依据。 

Quantitative reconfigurability evaluation method of actuator for quadrotor UAV

The reconfigurability of system, that is, the ability of autonomous recovery of fault system, has been highly concerned by scholars with the continuous improvement of system security and reliability requirements. However, the existing quantitative evaluation methods for the reconfigurability of control system mainly focus on linear system. Therefore, this paper proposes a quantitative evaluation method of reconfigurability for nonlinear system based on the combination of robust observer of double sliding surfaces and Mahalanobis distance, which chooses the quadrotors Unmanned Aerial Vehicle (quadrotor UAV) with strong coupling, underdrive and strong nonlinearity as the controlled object. Firstly, in order to obtain accurate estimation of system state, a double sliding surface robust observer is designed based on the nonlinear model of quadrotor UAV, which is insensitive to disturbance and failure. Secondly, the similarity method based on Mahalanobis distance is used to quantitatively evaluate the reconfigurability for nonlinear system under the double constraints of actuator saturation and system state error. Finally, the effectiveness of the proposed method is verified by the quadrotor UAV simulation experiment. The results show that the method can truly reflect the system reconfigurability quantification level under different failure levels, which provides an important basis of the control strategy adjustment and compensation for nonlinear fault systems.