scholarly journals Stabilisation of a Flexible Spacecraft Subject to External Disturbance and Uncertainties

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yun Fu ◽  
Yu Liu ◽  
Lingyan Hu ◽  
Lingxi Peng
Keyword(s):  
Boundary Control ◽  
Semigroup Theory ◽  
Nonlinear Partial Differential Equation ◽  
Flexible Spacecraft ◽  
Original Position ◽  
External Disturbances ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Flexible Appendage ◽  
Adaptive Boundary Control

This paper addresses the problems of vibration reduction and attitude tracking for a flexible spacecraft subject to external disturbances and uncertainties. Based on Hamilton’s principle, flexible spacecraft is modelled by a coupled nonlinear partial differential equation with ordinary differential equations. Adaptive boundary control scheme is adopted to stabilize the vibration displacement of flexible appendage into a small neighbourhood of original position and simultaneously maintain attitude angle within the desired angle region. Two disturbance adaptive laws are constructed to attenuate the effect of unknown external disturbances. The well posedness of the controlled system is proven by using the semigroup theory. The proposed adaptive boundary control scheme can guarantee the uniform boundedness of the closed-loop system. Numerical simulation results illustrate the effectiveness of the proposed control scheme.

Boundary Control of an Axially Moving String Via Lyapunov Method

1999 ◽  
Vol 121 (1) ◽  
pp. 105-110 ◽  
Author(s):  
Rong-Fong Fung ◽  
Chun-Chang Tseng
Keyword(s):  
Boundary Control ◽  
Lyapunov Method ◽  
Sliding Mode ◽  
Semigroup Theory ◽  
Active Vibration Control ◽  
Nonlinear Partial Differential Equation ◽  
Distributed Parameter ◽  
Axially Moving String ◽  
Active Vibration ◽  
Axially Moving

This paper presents the active vibration control of an axially moving string system through a mass-damper-spring (MDS) controller at its right-hand side (RHS) boundary. A nonlinear partial differential equation (PDE) describes a distributed parameter system (DPS) and directly selected as the object to be controlled. A new boundary control law is designed by sliding mode associated with Lyapunov method. It is shown that the boundary feedback states only include the displacement, velocity, and slope of the string at RHS boundary. Asymptotical stability of the control system is proved by the semigroup theory. Finally, finite difference scheme is used to validate the theoretical results.

Adaptive boundary control and vibration suppression of a flexible satellite system with input saturation

2018 ◽  
Vol 41 (9) ◽  
pp. 2666-2677
Author(s):  
Yun Fu ◽  
Yu Liu ◽  
Daoping Huang
Keyword(s):  
Boundary Control ◽  
Closed Loop ◽  
Vibration Suppression ◽  
Input Saturation ◽  
Satellite System ◽  
Closed Loop System ◽  
Adaptive Law ◽  
Control Scheme ◽  
Boundary Disturbance ◽  
Adaptive Boundary Control

In this paper, the vibration suppression problem of a flexible satellite system is addressed. The dynamic model of the flexible satellite system is expressed by a set of non-homogeneous partial differential equations (PDEs). By using the theory of systems with uniform ultimate bounded (UUB) solutions and adaptive techniques, adaptive boundary control is presented to suppress the vibration of the flexible satellite with parametric uncertainties. A disturbance adaptive law is constructed to compensate for the effect of the boundary disturbance, and an auxiliary system is considered to mitigate the effect of input saturation. The well-posedness of the closed-loop system is discussed, and UUB stability can be ensured through a rigorous Lyapunov-like analysis. Numerical simulation results show the effectiveness of the proposed control scheme.

scholarly journals Robust attitude tracking control scheme for a multi-body spacecraft using a radial basis function network and terminal sliding mode

2014 ◽  
Vol 24 (5) ◽  
Author(s):  
CHANGQING YUAN ◽  
YANHUA ZHONG ◽  
JINGRUI ZHANG ◽  
HONGBUO LI ◽  
GUOJUN YANG ◽  
...  
Keyword(s):  
Basis Function ◽  
Sliding Mode ◽  
Radial Basis Function Network ◽  
Robust Controller ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Multi Body ◽  
Function Network

We present a novel robust control scheme that deals with multi-body spacecraft attitude tracking problems. The control scheme consists of a radial basis function network (RBFN) and a robust controller. By using the finite time convergence property of the terminal sliding mode (TSM), we derive a new online learning algorithm for updating all the parameters of the RBFN that ensures the RBFN has fast approximation for the parameter uncertainties and external disturbances. We design a robust controller to compensate RBFN approximation errors and realise the anticipative stability and performance properties. We can also achieve closed-loop system stability using Lyapunov stability theory.No detailed knowledge of the non-linear dynamics of the spacecraft is required at any point in the entire design process, and the proposed robust scheme is simple and effective and can be applied to more complex systems. Simulation results demonstrate the good tracking characteristics of the proposed control scheme in the presence of inertial uncertainties and external disturbances.

scholarly journals Backstepping Control of an Unmanned Helicopter Subjected to External Disturbance and Model Uncertainty

2021 ◽  
Vol 11 (12) ◽  
pp. 5331
Author(s):  
Wenlong Zhao ◽  
Zhijun Meng ◽  
Kaipeng Wang ◽  
Haoyu Zhang
Keyword(s):  
External Disturbance ◽  
Flight Test ◽  
Lyapunov Theory ◽  
Outdoor Environment ◽  
Wind Gust ◽  
External Disturbances ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Highly Nonlinear ◽  
The Stability

A helicopter is a highly nonlinear system. Its mathematical model is difficult to establish accurately, especially the complicated flapping dynamics. In addition, the forces and moments exerted on the fuselage are very vulnerable to external disturbances like wind gust when flying in the outdoor environment. This paper proposes a composite control scheme which consists of a nonlinear backstepping controller and an extended state observer (ESO) to handle the above problems. The stability of the closed-loop system can be guaranteed based on Lyapunov theory. The external disturbances and model nonlinearities are treated as a lumped disturbance. Meanwhile, the ESO is employed to compensate the influence by estimating the lumped disturbance in real-time. Numerical simulation results are presented to demonstrate that the algorithm can achieve accurate and agile attitude tracking under the external wind gust disturbances even with model uncertainties. When coming to the flight test, a block dropping device was designed to generate a quantifiable and replicable disturbance, and the experimental results indicate that the algorithm introduced above can reject the external disturbance rapidly and track the given attitude command precisely.

scholarly journals Anti-Unwinding Attitude Control with Fixed-Time Convergence for a Flexible Spacecraft

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Chutiphon Pukdeboon ◽  
Anuchit Jitpattanakul
Keyword(s):  
Attitude Control ◽  
Initial Conditions ◽  
Coupling Effect ◽  
Fixed Time ◽  
Upper Bounds ◽  
Flexible Spacecraft ◽  
External Disturbances ◽  
Attitude Tracking ◽  
Bounded Disturbances ◽  
Attitude Tracking Control

This paper investigates the fixed-time attitude tracking control problem for flexible spacecraft with unknown bounded disturbances. First, with the knowledge of norm upper bounds of external disturbances and the coupling effect of flexible modes, a novel robust fixed-time controller is designed to deal with this problem. Second, the controller is further enhanced by an adaptive law to avoid the knowledge of norm upper bounds of external disturbances and coupling effect of flexible modes. This control law guarantees the convergence of attitude tracking errors in fixed time where the settling time is bounded by a constant independent of initial conditions. Moreover, the proposed controllers can prevent the unwinding phenomenon. Simulation results are presented to demonstrate the performance of the proposed control scheme.

scholarly journals Disturbance Rejection Attitude Control for a Quadrotor: Theory and Experiment

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Li Ding ◽  
Qing He ◽  
Chengjun Wang ◽  
Rongzhi Qi
Keyword(s):  
Attitude Control ◽  
Disturbance Rejection ◽  
Sliding Mode ◽  
External Disturbances ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Aerial Vehicle ◽  
Linear Extended State Observer ◽  
The Stability ◽  
Theory And Experiment

In this article, an attitude tracking controller is designed for a quadrotor unmanned aerial vehicle (UAV) subject to lumped disturbances. Firstly, the attitude dynamical model of the quadrotor under external disturbances is established. Subsequently, an improved sliding mode control (SMC) strategy is designed based on the linear extended state observer (LESO). In this control scheme, the SMC will guarantee the sliding surface is finite time reachable and the LESO will estimate and compensate for the lumped disturbances. Then, the robustness and asymptotic stability of the proposed controller are proved by the stability analyses. Finally, three numerical simulation cases and comparative flight experiments validate the effectiveness of the developed controller.

Adaptive vibration control of a flexible marine riser via the backstepping technique and disturbance adaptation

2017 ◽  
Vol 40 (5) ◽  
pp. 1407-1416 ◽  
Author(s):  
Fang Guo ◽  
Yu Liu ◽  
Zhijia Zhao ◽  
Fei Luo
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Boundary Control ◽  
Vibration Suppression ◽  
Original Position ◽  
Backstepping Technique ◽  
Marine Riser ◽  
Partial Differential ◽  
Disturbance Adaptation ◽  
Adaptive Boundary Control

This paper proposes an adaptive boundary control for vibration suppression of a flexible marine riser system. The dynamic model of the riser system is described in the form of a nonlinear nonhomogeneous hyperbolic partial differential equation and four ordinary differential equations. In a proper mathematical manner, the backstepping technique, Lyapunov’s direct method, and the adaptive technique are utilized to design an adaptive boundary control for the vibration suppression of the riser system, and also for the global stabilization of the riser within a small neighbourhood of its original position. In addition, a parameter adaptive law is designed to compensate for the system parametric uncertainties and a disturbance adaptation law is proposed to eliminate the effects of boundary disturbance. The uniformly bounded stability of the closed-loop riser system is achieved through rigorous Lyapunov analysis with no discretization or simplification of the partial differential equation dynamics model of the system. Simulation results are presented to illustrate the effectiveness of the proposed control.

Robust fault-tolerant flight control of quadrotor against faults in multiple motors

2021 ◽  
pp. 095441002199954
Author(s):  
Dinesh D Dhadekar ◽  
S E Talole
Keyword(s):  
Flight Control ◽  
Tracking Control ◽  
Fault Tolerant ◽  
External Disturbances ◽  
Detection And Identification ◽  
Attitude Tracking ◽  
Fault Detection And Identification ◽  
Attitude Tracking Control ◽  
Disturbance Estimator

In this article, position and attitude tracking control of the quadrotor subject to complex nonlinearities, input couplings, aerodynamic uncertainties, and external disturbances coupled with faults in multiple motors is investigated. A robustified nonlinear dynamic inversion (NDI)-based fault-tolerant control (FTC) scheme is proposed for the purpose. The proposed scheme is not only robust against aforementioned nonlinearities, disturbances, and uncertainties but also tolerant to unexpected occurrence of faults in multiple motors. The proposed scheme employs uncertainty and disturbance estimator (UDE) technique to robustify the NDI-based controller by providing estimate of the lumped disturbance, thereby enabling rejection of the same. In addition, the UDE also plays the role of fault detection and identification module. The effectiveness and benefits of the proposed design are confirmed through 6-DOF simulations and experimentation on a 3-DOF Hover platform.

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