This paper investigates command filter backstepping fault-tolerant control for a class of nonlinear systems with nonlinear faults. In particular, the system nonlinear faults are non-affine, which are handled by the filtered signal and fuzzy logic systems approximate Lemma. Command filter is used in this paper, which eliminates the “explosion of complexity” of the classical backstepping and compensates the output of the filter to the derivative of the virtual control. In addition, the controller design procedure has been shown in detail, while the stability of the closed-loop system and the convergence of the tracking error are proved via Lyapunov Theorem. Simulation examples are given to illustrate the feasibility and effectiveness of the proposed scheme.

Aiming at the accuracy problem of pose estimation under complex pose of indoor UAV, this paper proposes a dynamic threshold setting method based on vision sensor pose detection for adaptive selection of keyframes. Due to the uncertainty of camera pose estimation, this paper uses statistical theory to analyze the pose difference between camera frames to characterize the camera motion characteristics, innovatively employs a multi-layered fuzzy inference mechanism for joint judgment to derive dynamic thresholds, and applies this method to ORB-SLAM3 system to construct a new system called Fuzzy-ORB-SLAM3 for the purpose of achieving adaptive compensation in keyframe creation. Finally, the new system is validated on TUM and EuRoc public datasets. The results compared with ORB-SLAM3 and other typical SLAM systems show that the proposed system has higher positioning accuracy and can better adapt to the pose estimation of UAVs in complex motion states.

This paper presents an adaptive finite-time fault-tolerant control strategy for non-strict feedback nonlinear systems, addressing infinite time-varying actuator faults and output constraints. It introduces a fuzzy adaptive updating law to compensated actuator faults and uses a barrier Lyapunov function (BLF) to handle output constraints in both constrained and unconstrained systems. The method integrates adaptive backstepping and fuzzy logic to manage non-strict feedback challenges and incorporates projection adaptation techniques. The approach incorporates projection adaptation design techniques in its scheme. The controller designed through this method not only ensures finite-time convergence of the system’s output tracking error to the origin but also guarantees compliance with output constraints, even in the face of potentially infinite time-varying actuator failures. The efficacy of this proposed method is corroborated by simulation examples, showcasing its proficiency in managing both actuator faults and output constraints.