scholarly journals Fixed-time sliding mode attitude control of a flexible spacecraft with rotating appendages connected by magnetic bearing

2022 ◽  
Vol 19 (3) ◽  
pp. 2286-2309
Author(s):  
Gaowang Zhang ◽  
◽  
Feng Wang ◽  
Jian Chen ◽  
Huayi Li
Keyword(s):  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Fixed Time ◽  
Magnetic Bearing ◽  
Flexible Spacecraft ◽  
Active Magnetic Bearing ◽  
Connected Components ◽  
Solar Panels ◽  
Satellite Platform

<abstract> <p>This study focuses on the attitude control of a flexible spacecraft comprising rotating appendages, magnetic bearings, and a satellite platform capable of carrying flexible solar panels. The kinematic and dynamic models of the spacecraft were established using Lagrange methods to describe the translation and rotation of the spacecraft system and its connected components. A simplified model of the dynamics of a five-degrees-of-freedom (DOF) active magnetic bearing was developed using the equivalent stiffness and damping methods based on the magnetic gap variations in the magnetic bearing. Next, a fixed-time sliding mode control method was proposed for each component of the spacecraft to adjust the magnetic gap of the active magnetic bearing, realize a stable rotation of the flexible solar panels, obtain a high inertia for the appendage of the spacecraft, and accurately control the attitude. Finally, the numerical simulation results of the proposed fixed-time control method were compared with those of the proportional-derivative control method to demonstrate the superiority and effectiveness of the proposed control law.</p> </abstract>

scholarly journals Disturbance and uncertainty estimator-based cascaded position-current controller for active magnetic bearing system

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983535 ◽  
Author(s):  
Yao-Nan Wang ◽  
Tran Minh Hai
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
System State ◽  
Control Loop ◽  
Current Controller ◽  
Highly Nonlinear ◽  
Uncertainty Estimator ◽  
Bearing System

This article presents a robust control method; all of the unknown disturbances and uncertainty values will be rejected. Suspension of active magnetic bearing system is aimed to figure out that the proposed control method is implementable for highly nonlinear unstable system. First, system state is described by dynamic model, with unknown lump of uncertainty value. Subsequently, the cascade control with inner and outer loops is defined by sliding mode control based on disturbance and uncertainty estimator. The outer control loop is used to force the system state converge on the predefined surface, while inner control loop is used to control the current of electrical part of the system. Finally, the simulation results show that the proposed control method is good at tracking trajectory.

Fault-tolerant attitude control for flexible spacecraft subject to input and state constraint

2020 ◽  
Vol 42 (14) ◽  
pp. 2660-2674
Author(s):  
Mehdi Golestani ◽  
Seyed Majid Esmaeilzadeh ◽  
Bing Xiao
Keyword(s):  
Attitude Control ◽  
Actuator Saturation ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fixed Time ◽  
State Constraint ◽  
Flexible Spacecraft ◽  
Convergence Time ◽  
Prescribed Performance ◽  
High Attitude

This paper considers the problem of fault-tolerant attitude control for a flexible spacecraft subject to input and state constraint. Particularly, a new sliding mode-based attitude control with fixed-time convergent for the flexible spacecraft is developed in which the convergence rate of the system state is improved both far from and at close range of the origin. In contrast to the existing complicated prescribed performance controls (PPC), the proposed PPC possesses a much simpler structure due to the use of a novel constraint concept without employing error transformation. It also introduces a modified prescribed performance function (MPPF) to explicitly determine the settling time. It is rigorously proved that the attitude variable is kept within the predefined constraint boundaries even when the actuator saturation is taken into account. Moreover, the proposed controller is inherently continuous and the chattering is effectively reduced. An adaptive mechanism is developed in which no prior knowledge of the lumped uncertainties is required. Finally, numerical simulations are presented to demonstrate that the proposed controller is able to successfully accomplish attitude control with high attitude pointing accuracy and stability. More specifically, it provides faster convergence (improvement percentage of convergence time (IP_CT) is about 18%) and more accurate control (improvement percentages of MRPs (IP_MRPs) and angular velocity (IP_AV) are about 60% and 80%, respectively) under healthy actuators. Values of IP_CT, IP_CT, and IP_AV are 50%, 99.9% and 99.9% under faulty actuators, respectively.

scholarly journals Active Fractional-Order Sliding Mode Control of Flexible Spacecraft Under Actuators Saturation

2021 ◽  
Author(s):  
milad alipour ◽  
Maryam Malekzadeh ◽  
alireza ariaei
Keyword(s):  
Fractional Order ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Sliding Mode ◽  
Fixed Time ◽  
Flexible Spacecraft ◽  
Terminal Sliding Mode ◽  
Damping Matrix ◽  
Active Vibration Suppression ◽  
Active Vibration

Abstract In this article, a novel multi-purpose modified fractional-order nonsingular terminal sliding mode (MFONTSM) controller is designed for the flexible spacecraft attitude control and appendages passive vibration suppression, assuming the control torque saturation in the system dynamics. Furthermore, an active FONTSM controller is proposed separately to perform active vibration suppression of the flexible appendages using piezoelectric actuators. The fixed-time stability of the closed-loop system for both the passive and active controllers is analyzed and proved using the Lyapunov theorem. Finally, the performance of the proposed controllers has been tested in the presence of uncertainties, external disturbances, and the absence of the damping matrix in order to study the effectiveness of the proposed method.

scholarly journals Finite-Time Adaptive Higher-Order SMC for the Nonlinear Five DOF Active Magnetic Bearing System

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1333
Author(s):  
Sudipta Saha ◽  
Syed Muhammad Amrr ◽  
Abdelaziz Salah Saidi ◽  
Arunava Banerjee ◽  
M. Nabi
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Sliding Mode ◽  
A Priori ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Mode Control ◽  
Adaptive Laws ◽  
Effective Performance ◽  
Unknown Disturbances

The active magnetic bearings (AMB) play an essential role in supporting the shaft of fast rotating machines and controlling the displacements in the rotors due to the deviation in the shaft. In this paper, an adaptive integral third-order sliding mode control (AITOSMC) is proposed. The controller suppresses the deviations in the rotor and rejects the system uncertainties and unknown disturbances present in the five DOF AMB system. The application of AITOSMC alleviates the problem of high-frequency switching called chattering, which would otherwise restrict the practical application of sliding mode control (SMC). Moreover, adaptive laws are also incorporated in the proposed approach for estimating the controller gains. Further, it also prevents the problem of overestimation and avoids the use of a priori assumption about the upper bound knowledge of total disturbance. The Lyapunov and homogeneity theories are exploited for the stability proof, which guarantees the finite-time convergence of closed-loop and output signals. The numerical analysis of the proposed strategy illustrates the effective performance. Furthermore, the comparative analysis with the existing control schemes demonstrates the efficacy of the proposed controller.

Integral Sliding Mode Control Approach for 3-Pole Active Magnetic Bearing System

2016 ◽  
Vol 829 ◽  
pp. 128-132 ◽  
Author(s):  
Van Van Huynh ◽  
Minh Hoang Quang Tran
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Sliding Surface ◽  
Integral Sliding Mode Control ◽  
Integral Sliding Mode ◽  
Mode Control ◽  
Integral Sliding Surface ◽  
Bearing System

In this paper, a new integral sliding mode control scheme is designed for the 3-pole active magnetic bearing system. First, a new integral sliding surface is designed such that the 3-pole active magnetic bearing system in the sliding mode is asymptotically stable under certain conditions. Then, an adaptive controller is designed to solve the unknown upper bound of matched uncertainty and guarantee the reachability of the integral sliding surface. Finally, the performance of the proposed integral sliding mode controller is applied to 3-pole active magnetic bearing system to demonstrate the efficacy of the proposed method.

Fixed-time fractional-order sliding mode control for nonlinear power systems

2020 ◽  
Vol 26 (17-18) ◽  
pp. 1425-1434 ◽  
Author(s):  
Sunhua Huang ◽  
Jie Wang
Keyword(s):  
Sliding Mode Control ◽  
Power System ◽  
Fractional Order ◽  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Fixed Time ◽  
Sliding Mode Controller ◽  
Mode Control ◽  
Time Control

In this study, a fractional-order sliding mode controller is effectively proposed to stabilize a nonlinear power system in a fixed time. State trajectories of a nonlinear power system show nonlinear behaviors on the angle and frequency of the generator, phase angle, and magnitude of the load voltage, which would seriously affect the safe and stable operation of the power grid. Therefore, fractional calculus is applied to design a fractional-order sliding mode controller which can effectively suppress the inherent chattering phenomenon in sliding mode control to make the nonlinear power system converge to the equilibrium point in a fixed time based on the fixed-time stability theory. Compared with the finite-time control method, the convergence time of the proposed fixed-time fractional-order sliding mode controller is not dependent on the initial conditions and can be exactly evaluated, thus overcoming the shortcomings of the finite-time control method. Finally, superior performances of the fractional-order sliding mode controller are effectively verified by comparing with the existing finite-time control methods and integral order sliding mode control through numerical simulations.

scholarly journals Research on Trajectory Planning and Tracking of Hexa-copter

2018 ◽  
Vol 173 ◽  
pp. 02008
Author(s):  
Qiyu Wang ◽  
Huijie Zhang ◽  
Jinrong Han
Keyword(s):  
Trajectory Planning ◽  
Flight Control ◽  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Interpolation Method ◽  
Spline Interpolation ◽  
Variable Structure ◽  
Flight Trajectory ◽  
Attitude Stability

In this paper, the flight control problem of hexa-copter is studied in detail from threedimensional trajectory planning to tracking. Then the cubic spline interpolation method is used to generate the trajectory by using these time marked waypoints. The flight trajectory curve produced by this method is smooth, twice differentiable, and it is easy to control implementation. The flight dynamics model of the UAV has the characteristics of multi-input multi-output, strong coupling, under-actuation, severe nonlinearity and external environmental disturbance. In order to improve the accuracy of flight trajectory and the stability of attitude control, a multi-loop sliding mode variable structure control method is proposed to achieve the hexa-copter flight trajectory tracking. The simulation results show that this method can track the predetermined flight trajectory and keep the attitude stability of the UAV normally.

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