Xiaozhao Fan

Bio: Xiaozhao Fan is an academic researcher from Yanshan University. The author has contributed to research in topics: Parallel manipulator & Nonlinear system. The author has an hindex of 1, co-authored 1 publications receiving 44 citations.

Tracking differentiator and extended state observer-based nonsingular fast terminal sliding mode attitude control for a quadrotor

Abstract: The attitude control problem is addressed for a quadrotor system subject to the modeling uncertainties and unknown disturbances. A novel attitude control scheme is proposed based on nonsingular fast terminal sliding mode (NFTSM) technique. First, the tracking differentiator (TD) is designed to obtain the smooth tracking signal and its derivative. Then, the extended state observer (ESO) is constructed to provide the estimate of the modeling uncertainties and unknown disturbances. With the designed TD and ESO, a novel NFTSM controller is developed such that tracking error converges to zero in finite time. The transient-state and the steady-state performances are both achieved with the new controller. Finally, the simulation and real experiment results verify the effectiveness and superiority of the proposed control method.

Adaptive fuzzy backstepping output constraint control of flexible manipulator with actuator saturation

Abstract: This paper deals with the problem of adaptive fuzzy tracking control for a single-link robotic manipulator coupled to a brushed direct current motor with actuator saturation. Fuzzy logic systems are used to approximate the unknown nonlinear systems. The filtered signals are introduced to eliminate the interference of high-frequency signals. The virtual/actual control inputs are derived from the solutions of a series of dynamical equations. Under the framework of the backstepping control design, an observer-based output feedback control design scheme is proposed. It is proved that the control approach can guarantee that all the signals in the closed-loop system are bounded.

Speed Control of Permanent Magnet DC Motor with Friction and Measurement Noise Using Novel Nonlinear Extended State Observer-Based Anti-Disturbance Control

Abstract: In this paper, a novel finite-time nonlinear extended state observer (NLESO) is proposed and employed in active disturbance rejection control (ADRC) to stabilize a nonlinear system against system’s uncertainties and discontinuous disturbances using output feedback based control. The first task was to aggregate the uncertainties, disturbances, and any other undesired nonlinearities in the system into a single term called the “generalized disturbance”. Consequently, the NLESO estimates the generalized disturbance and cancel it from the input channel in an online fashion. A peaking phenomenon that existed in linear ESO (LESO) has been reduced significantly by adopting a saturation-like nonlinear function in the proposed nonlinear ESO (NLESO). Stability analysis of the NLEO is studied using finite-time Lyapunov theory, and the comparisons are presented over simulations on permanent magnet DC (PMDC) motor to confirm the effectiveness of the proposed observer concerning LESO.