Antidisturbance Vibration Suppression of the Aerial Refueling Hose during the Coupling Process

Abstract

In autonomous aerial refueling (AAR), the vibration of the flexible refueling hose caused by the receiver aircraft's excessive closure speed should be suppressed once it appears. This paper proposed an active control strategy based on the permanent magnet synchronous motor (PMSM) angular control for the timely and accurate vibration suppression of the flexible refueling hose. A nonsingular fast terminal sliding-mode (NFTSM) control scheme with adaptive extended state observer (AESO) is proposed for PMSM take-up system under multiple disturbances. The states and the "total disturbance" of the PMSM system are firstly reconstituted using the AESO under the uncertainties and measurement noise. Then, a faster sliding variable with tracking error exponential term is proposed together with a special designed reaching law to enhance the global convergence speed and precision of the controller. The proposed control scheme provides a more comprehensive solution to rapidly suppress the flexible refueling hose vibration in AAR. Compared to other methods, the scheme can suppress the flexible hose vibration more fleetly and accurately even when the system is exposed to multiple disturbances and measurement noise. Simulation results show that the proposed scheme is competitive in accuracy, global rapidity, and robustness.

Finite‐time control for a quadcopter UAV in the application of wildfire monitoring

“…\end{equation}$$Furthermore, $$x(0)\ge 0$$ and $$x(T_1) = 0$$; then we integrate both sides of Equation (23) to obtain the settling time of the dynamics (20) as: $$$$\begin{equation} T_1=\int\limits _0^{|x(0)|} \frac{k_2^{1 / \eta _2}}{{\left(x+k_1 x^{\eta _1}\right)}^{1 / \eta _2}} d x. \end{equation}$$$$To improve the convergence rate of the conventional NFTSM, authors in [40] proposed the following sliding surface: $$$$\begin{equation} S_2 = x +k_1\left\lceil x\right\rfloor ^{\eta _1}+k_2\left\lceil \dot{x}\right\rfloor ^{\eta _2}+k_3\operatorname{exp}{\left({\left|x\right|}\right)}{\left|x\right|} = 0, \end{equation}$$$$where $$k_3>0$$. The settling time of the dynamics in Equation (25) as: …”

Finite-time control for UA quadcopter in application of wildfire monitoring

“…To improve the convergence rate of the conventional NFTSM surface [20] proposed the following sliding surface:…”

“…Thus, due to its remarkable benefits, the NFTSM control scheme gained wide acceptance and application in several nonlinear systems. To further improve the convergence speed of the NFTSM control, authors in [20] added an exponential term on the nonlinear sliding surface of the NFTSM control method. The control scheme was implemented to suppress vibrations in autonomous aerial refuelling.…”

“…• Design of a HOSMO which will estimate UA quadcopter's state variables and unknown uncertainties and disturbances. • Development of an improved NFTSM control scheme with quicker convergence speed compared to [19] and [20] that further improves the tracking speed and accuracy of a UA quadcopter's position and attitude dynamics. • A novel control scheme based on the improved NFTSMC and HOSMO is designed and applied to a practical problem of wildfire monitoring using a UA quadcopter.…”

Vibration suppression and fault‐tolerant control of an aerial refueling hose with multiple actuators

“…Vibration control of the refueling hose has been a widely concerned topic [8][9][10][11]. After being released from the refueling pod, the flexible hose is exposed to the complex air environment and moves along with the tanker.…”