scholarly journals Disturbance Observer-Based Nonsingular Terminal Sliding Mode Control for Spacecraft Electromagnetic Docking

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Jinghui Zhang ◽  
Guoqiang Zeng ◽  
Shifeng Zhang
Keyword(s):  
Sliding Mode Control ◽  
Magnetic Moment ◽  
Disturbance Observer ◽  
Field Model ◽  
Sliding Mode ◽  
Far Field ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Control Scheme ◽  
On Line

This paper presents a novel nonlinear sliding mode control scheme that combines on-line model modification, a nonlinear sliding mode controller, and a disturbance observer to solve the essential problems in spacecraft electromagnetic docking control, such as model uncertainties, unknown external disturbances, and inherent strong nonlinearity and coupling. An improved far-field model of electromagnetic force which is much more accurate than the widely used far-field model is proposed to enable the model parameters to be on-line self-adjusting. Then, the relationship between magnetic moment allocation and energy consumption is derived, and the optimal direction of the magnetic moment vector is obtained. Based on the proposed improved far-field model and the research results of magnetic moment allocation law, a fast-nonsingular terminal mode controller driven by a disturbance observer is designed in the presence of model uncertainties and external disturbances. The proposed control method is guaranteed to be chattering-free and to possess superior properties such as finite-time convergence, high-precision tracking, and strong robustness. Two simulation scenarios are conducted to illustrate the necessity of modifying the far-field model and the effectiveness of the proposed control scheme. The simulation results indicate the realization of electromagnetic soft docking and validate the merits of the proposed control scheme. In the end of this paper, some conclusions are drawn.

scholarly journals Design of Composite Disturbance Observer and Continuous Terminal Sliding Mode Control for Piezoelectric Nanopositioning Stage

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2242
Author(s):  
Pengyu Qiao ◽  
Jun Yang ◽  
Chen Dai ◽  
Xi Xiao
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Accurate Estimation ◽  
Terminal Sliding Mode Control ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Composite Control ◽  
Mode Control

The nonlinearities of piezoelectric actuators and external disturbances of the piezoelectric nanopositioning stage impose great, undesirable influences on the positioning accuracy of nanopositioning stage systems. This paper considers nonlinearities and external disturbances as a lumped disturbance and designs a composite control strategy for the piezoelectric nanopositioning stage to realize ultra-high precision motion control. The proposed strategy contains a composite disturbance observer and a continuous terminal sliding mode controller. The composite disturbance observer can estimate both periodic and aperiodic disturbances so that the composite control strategy can deal with the disturbances with high accuracy. Meanwhile, the continuous terminal sliding mode control is employed to eliminate the chattering phenomenon and speed up the convergence rate. The simulation and experiment results show that the composite control strategy achieves accurate estimation of different forms of disturbances and excellent tracking performance.

Adaptive Sliding Mode Control of MEMS Vibrational Gyroscope

2006 ◽  
Author(s):  
J. Fei ◽  
C. Batur
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Angular Rate ◽  
External Disturbance ◽  
Adaptive Sliding Mode Control ◽  
Angular Velocity Vector ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Control Scheme ◽  
On Line

This paper presents a new sliding mode adaptive controller for MEMS z-axis gyroscope. The proposed adaptive sliding mode control algorithm can on-line estimate the component of the angular velocity vector, which is orthogonal to the plane of oscillation of the gyroscope (the z-axis) and the linear damping and stiffness model coefficients. The stability of the closed-loop system can be guaranteed with the proposed control strategy. The numerical simulation for MEMS Gyroscope is investigated to verify the effectiveness of the proposed adaptive sliding mode control scheme. It is shown that the proposed adaptive sliding mode control scheme offers several advantages such as on-line estimation of gyroscope parameters including angular rate and large robustness to parameter variations and external disturbance.

scholarly journals Fixed-Time Trajectory Tracking Control of Autonomous Surface Vehicle with Model Uncertainties and Disturbances

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jiawen Cui ◽  
Haibin Sun
Keyword(s):  
Trajectory Tracking ◽  
Tracking Control ◽  
Sliding Mode ◽  
Fixed Time ◽  
Convergence Time ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Trajectory Tracking Control ◽  
Integral Sliding Mode ◽  
Control Scheme

The issue of fixed-time trajectory tracking control for the autonomous surface vehicles (ASVs) system with model uncertainties and external disturbances is investigated in this paper. Particularly, convergence time does not depend on initial conditions. The major contributions include the following: (1) An integral sliding mode controller (ISMC) via integral sliding mode surface is first proposed, which can ensure that the system states can follow the desired trajectory within a fixed time. (2) Unknown external disturbances are absolutely estimated by means of designing a fixed-time disturbance observer (FTDO). By combining the FTDO and ISMC techniques, a new control scheme (FTDO-ISMC) is developed, which can achieve both disturbance compensation and chattering-free condition. (3) Aiming at reconstructing the unknown nonlinear dynamics and external disturbances, a fixed-time unknown observer (FTUO) is proposed, thus providing the FTUO-ISMC scheme that finally achieves trajectory tracking of ASVs with unknown parameters. Finally, simulation tests and detailed comparisons indicate the effectiveness of the proposed control scheme.

Robust output tracking of nonlinear systems with transient improvement via funnel-based sliding mode control

2020 ◽  
Vol 42 (16) ◽  
pp. 3225-3233
Author(s):  
Mehdi Zahedi ◽  
Tahereh Binazadeh
Keyword(s):  
Nonlinear Systems ◽  
Sliding Mode Control ◽  
Sliding Mode ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Output Tracking ◽  
Mode Control ◽  
Transient Improvement ◽  
The Face ◽  
Funnel Control

This paper studies a new procedure for robust tracking of nonlinear systems. This procedure is based on the combination of the sliding mode control and the funnel control, which in addition to the robust performance of the closed-loop system in the face of model uncertainties and/or external disturbances also leads to improvement of the characteristics of the transient responses. Using funnel control and the appropriate choice of the funnel can affect the convergence rate and overshoot. In this regard, a theorem has been presented and the effective performances of the suggested controller have been guaranteed in various respects based on exact mathematical analysis. Simulations have also been carried out to illustrate the efficiency of the proposed approach and to verify the theoretical achievements of the paper despite model uncertainties and external disturbances.

scholarly journals Integral sliding mode-based formation control of multiple unertain robots via nonlinear disturbane observer

2016 ◽  
Vol 13 (6) ◽  
pp. 172988141667769 ◽  
Author(s):  
Dianwei Qian ◽  
Chengdong Li ◽  
Shiwen Tong ◽  
Lu Yu
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Formation Control ◽  
Sliding Mode ◽  
Nonlinear Disturbance Observer ◽  
Integral Sliding Mode Control ◽  
Integral Sliding Mode ◽  
Mode Control ◽  
Control Scheme ◽  
Nonlinear Disturbance

This article proposes a control scheme for formation of maneuvers of a team of mobile robots. The control scheme integrates the integral sliding mode control method with the nonlinear disturbance observer technique. The leader–follower formation dynamics suffer from uncertainties originated from the individual robots. The uncertainties challenge the formation control of such robots. Assuming that the uncertainties are unknown but bounded, an nonlinear disturbance observer-based observer is utilized to approximate them. The observer outputs feed on an integral sliding mode control-based controller. The controller and observer are integrated into the control scheme to realize formation maneuvers despite uncertainties. The formation stability is analyzed by means of the Lyapunov’s theorem. In the sense of Lyapunov, not only the convergence of the approximation errors is guaranteed but also such a control scheme can asymptotically stabilize the formation system. Compared to the results by the sole integral sliding mode control, some simulations are presented to demonstrate the feasibility and performance of the control scheme.

Robust sliding mode control of uncertain nonlinear systems with chattering alleviating scheme

2021 ◽  
pp. 2140042
Author(s):  
Bhausaheb B. Musmade ◽  
Balasaheb M. Patre
Keyword(s):  
Nonlinear Systems ◽  
Sliding Mode Control ◽  
Uncertain Systems ◽  
Sliding Mode ◽  
External Disturbance ◽  
Uncertain Nonlinear Systems ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Controlled System ◽  
Mode Control

In this paper, a class of uncertain nonlinear systems is investigated and a sliding mode control (SMC) design is presented. The method is proposed for uncertain systems with model uncertainties, nonlinear dynamics and external disturbances. Using nominal system and related bounds of uncertainties, a chattering alleviating scheme is also proposed, which can ensure the robust SMC law. The performance and the significance of the controlled system are investigated under variation in system parameters and also in presence of an external disturbance. The simulation results indicate that performance of the proposed controller is effective compared to the existing controllers.

scholarly journals Terminal Sliding Mode Control with Unidirectional Auxiliary Surfaces for Hypersonic Vehicles Based on Adaptive Disturbance Observer

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Naibao He ◽  
Changsheng Jiang ◽  
Bin Jiang ◽  
Qian Gao
Keyword(s):  
Attitude Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Robust Adaptive Control ◽  
Hypersonic Vehicles ◽  
Control Performance ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Control Scheme ◽  
Observer Model

A novel flight control scheme is proposed using the terminal sliding mode technique, unidirectional auxiliary surfaces and the disturbance observer model. These proposed dynamic attitude control systems can improve control performance of hypersonic vehicles despite uncertainties and external disturbances. The terminal attractor is employed to improve the convergence rate associated with the critical damping characteristics problem noted in short-period motions of hypersonic vehicles. The proposed robust attitude control scheme uses a dynamic terminal sliding mode with unidirectional auxiliary surfaces. The nonlinear disturbance observer is designed to estimate system uncertainties and external disturbances. The output of the disturbance observer aids the robust adaptive control scheme and improves robust attitude control performance. Finally, simulation results are presented to illustrate the effectiveness of the proposed terminal sliding mode with unidirectional auxiliary surfaces.

Sign in / Sign up

Export Citation Format

Share Document