Robust Output Regulation Via Sliding Mode Control and Disturbance Observer: Application in a Forced Van Der Pol Chaotic Oscillator

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
F. Shiravani ◽  
M. H. Shafiei
Keyword(s):  
Disturbance Observer ◽  
Sliding Mode ◽  
Tracking Error ◽  
Output Regulation ◽  
Chaotic Oscillator ◽  
Model Uncertainties ◽  
Feedback Form ◽  
Van Der Pol ◽  
Effective Performance ◽  
Robust Output Regulation

This paper considers the problem of robust output regulation of nonlinear systems in semi strict-feedback form in the presence of model uncertainties and nonvanishing disturbances. In the proposed procedure, two exosystems are considered to generate the disturbance and reference signals. In order to reduce both the conservatism of the control law and the chattering phenomena, a disturbance observer is designed for disturbance estimation instead of assuming the known upper bound for the disturbance. Moreover, a novel sliding surface is designed based on the tracking error to guarantee that the output of the system tracks the output of the exosystem. In this regard, some theorems are given and according to the Lyapunov approach, it is proved that the robust output regulation is guaranteed in the presence of model uncertainties and external disturbances. Finally, in order to show the applicability of the proposed controller, it is applied to the Van der Pol chaotic oscillator. Computer simulations verify the theoretical results and also show the effective performance of the proposed controller.

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.

Strictly-lower-convex-function-constructing disturbance observer based adaptive back stepping control for hypersonic flight vehicles

2017 ◽  
Vol 232 (13) ◽  
pp. 2552-2564
Author(s):  
Jingxing Zuo ◽  
Yunjie Wu ◽  
Lianghua Sun
Keyword(s):  
Convex Function ◽  
Flight Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Tracking Error ◽  
Small Region ◽  
Control Laws ◽  
Hypersonic Flight ◽  
Flight Vehicles ◽  
Adaptive Laws

This study concerns with the attitude and velocity tracking control problem for the longitudinal model of hypersonic flight vehicles, which is nonlinear in aerodynamics with model uncertainties and external disturbances. By employing back stepping sliding mode method and the strictly-lower-convex-function-constructing nonlinear disturbance observer (SNDOB), a novel composite controller is proposed to guarantee the system tracking error to converge to a small region containing the origin. Besides, several proper adaptive laws are also introduced to make the controller avoid of the differential explosion problem and be chatter-free. Compared with other robust flight control approaches, key novelties of the developed method are that one new SNDOB is proposed and drawn into the virtual control laws at each step to compensate the disturbances and that adaptive laws are utilized to simplify the tedious and complicated differential operations. Finally, it is demonstrated by the simulation results that the new method exhibits not only an excellent robustness but also a better disturbance rejection performance than the convention approach.

scholarly journals Adaptive Sliding Mode Robust Control for Virtual Compound-Axis Servo System

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yan Ren ◽  
Zhenghua Liu ◽  
Le Chang ◽  
Nuan Wen
Keyword(s):  
Robust Control ◽  
High Frequency ◽  
Disturbance Observer ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Servo System ◽  
Adaptive Sliding Mode ◽  
Main System

A structure mode of virtual compound-axis servo system is proposed to improve the tracking accuracy of the ordinary optoelectric tracking platform. It is based on the structure and principles of compound-axis servo system. A hybrid position control scheme combining the PD controller and feed-forward controller is used in subsystem to track the tracking error of the main system. This paper analyzes the influences of the equivalent disturbance in main system and proposes an adaptive sliding mode robust control method based on the improved disturbance observer. The sliding mode technique helps this disturbance observer to deal with the uncompensated disturbance in high frequency by making use of the rapid switching control value, which is based on the subtle error of disturbance estimation. Besides, the high-frequency chattering is alleviated effectively in this proposal. The effectiveness of the proposal is confirmed by experiments on optoelectric tracking platform.

scholarly journals Disturbance Observer-Based Complementary Fractional-Order Sliding Mode Control for PMSM Drive System

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yong-Hong Lan ◽  
Li-Tao Zheng ◽  
Zhao-Hong Wang
Keyword(s):  
Sliding Mode Control ◽  
Permanent Magnet ◽  
Fractional Order ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Permanent Magnet Synchronous Motor ◽  
Tracking Error ◽  
Synchronous Motor ◽  
Drive System ◽  
Mode Control

In this paper, a disturbance observer-based complementary fractional-order sliding mode control (CFOSMC) scheme is proposed for the permanent magnet synchronous motor (PMSM) drive system. First, to reconstruct the load disturbance and parameter variations, a nonlinear disturbance observer is designed. Next, a disturbance observer-based fractional-order sliding mode with a saturation function control law is designed to reduce the chattering problem in the existing fractional-order sliding mode control (FOSMC) method. Furthermore, to reduce the thickness of the boundary layer, a CFOSMC scheme is designed. By using the fractional-order Lyapunov stability theorem, the existence condition and the chattering problem are analyzed. Compared with the existing FOSMC, the obtained CFOSMC law does not contain any high-order derivatives of tracking error, which is easier to implement. Finally, the numerical simulations and experimental results are provided to show the superiority of the proposed method. To improve the performance of the permanent magnet synchronous motor (PMSM) drive system in terms of tracking rapidity, accuracy, and robustness, a complementary fractional-order sliding mode control (CFOSMC) scheme with disturbance observer is proposed in this paper.

Disturbance observer based dynamic surface flight control for an uncertain aircraft

2017 ◽  
Vol 232 (4) ◽  
pp. 729-744 ◽  
Author(s):  
Jianjun Ma ◽  
Peng Li ◽  
Zhiqiang Zheng
Keyword(s):  
Flight Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Dynamic Surface ◽  
Nonlinear Disturbance Observer ◽  
Actuator Dynamics ◽  
Highly Nonlinear ◽  
Nonlinear Disturbance

To handle the flight control problem of an uncertain aircraft with highly nonlinear characteristics, internal uncertainties and external disturbances, an adaptive dynamic surface controller based on nonlinear disturbance observer is designed in this paper. A novel nonhomogeneous nonlinear disturbance observer is designed to approximate the uncertainties and disturbances, which can exactly estimate the disturbances in finite time. Dynamic surface control is utilized to avoid the explosion of complexity in traditional backstepping design. Through Lyapunov synthesis, the closed-loop control system is demonstrated to be semi-globally uniformly ultimately bounded and the tracking error converges to a small neighborhood of origin. Besides, actuator dynamics are taken into account, and the controller for actuator dynamics with consideration of limitation is developed based on sliding-mode control theory. The effectiveness of the proposed control is shown by simulation experiments.

scholarly journals Sliding Mode Control for NSVs with Input Constraint Using Neural Network and Disturbance Observer

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Yan-long Zhou ◽  
Mou Chen
Keyword(s):  
Sliding Mode Control ◽  
Flight Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Coupling Parameter ◽  
Tracking Error ◽  
Space Vehicles ◽  
Strong Nonlinearity ◽  
Observer Error ◽  
Mode Control

The sliding mode control (SMC) scheme is proposed for near space vehicles (NSVs) with strong nonlinearity, high coupling, parameter uncertainty, and unknown time-varying disturbance based on radial basis function neural networks (RBFNNs) and the nonlinear disturbance observer (NDO). Considering saturation characteristic of rudders, RBFNNs are constructed as a compensator to overcome the saturation nonlinearity. The stability of the closed-loop system is proved, and the tracking error as well as the disturbance observer error can converge to the origin through the Lyapunov analysis. Simulation results are presented to demonstrate the effectiveness of the proposed flight control scheme.

Robust Output Regulation Approach for Attitude Control and Momentum Management of the Space Station

2015 ◽  
Vol 719-720 ◽  
pp. 316-323
Author(s):  
Yong Liu ◽  
Wei Huo
Keyword(s):  
Attitude Control ◽  
Closed Loop ◽  
Space Station ◽  
Output Regulation ◽  
Management Problem ◽  
Closed Loop System ◽  
Model Uncertainties ◽  
Robust Output Regulation ◽  
Regulation Approach ◽  
Momentum Management

An novel methodology to solve the attitude control and momentum management problem of the space station with model uncertainties is developed. By the use of the robust output regulation theory, the attitude control and momentum management integrating model and the internal model of disturbances are combined to design a robust coupling controller such that the plant outputs track desired reference signals and the model uncertainties can be tolerated. It is proved that the designed controller guarantees stability of the closed-loop system and suppresses the disturbance well. Simulation results are provided to demonstrate the feasibility of the proposed method.

scholarly journals Research on control technology of tip-tilt mirror system in adaptive optics

2021 ◽  
Vol 2087 (1) ◽  
pp. 012056
Author(s):  
Dechun Zhao ◽  
Yansong Song ◽  
Yang Liu ◽  
Baishuo Zhang ◽  
Tianci Liu
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Mirror System ◽  
Nonlinear Observer ◽  
Nonlinear Disturbance Observer ◽  
Mode Control ◽  
Nonlinear Disturbance

Abstract In order to solve the control problem of the tip-tilt mirror under the unknown disturbance, a nonlinear disturbance observer with adaptive ability based on the sliding mode control is designed.Firstly, the sliding mode control method of the tip-tilt mirror system is established with Lyapunov functions. Secondly, an adaptive nonlinear disturbance observer is developed on a basis of observer model. Finally, the proposed sliding mode control method is combined with a nonlinear observer with adaptive capability to achieve the goal of improving the control accuracy of the system, while also reducing the chattering caused by the system. The experiment proves that this method is achievable. The experimental results show that the tracking error of the azimuth axis is reduced from 1.637μrad to 1.083μrad, and the accuracy is improved by about 51.2%. The tracking error of the pitch axis is reduced from 1.966μrad to 1.614μrad, and the accuracy is improved by about 21.8%. This method can greatly weaken the inherent chattering and external disturbance of the system, and improve the stability of the tip-tilt mirror system.

Robust Output Regulation of a Class of Nonlinear Systems Via Disturbance Observer in the Presence of Matched and Unmatched Uncertainties

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
F. Shiravani ◽  
M. H. Shafiei
Keyword(s):  
Nonlinear Systems ◽  
Upper Bound ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Model Uncertainties ◽  
Control Laws ◽  
Virtual Control ◽  
Reference Signals ◽  
Asymptotic Tracking ◽  
Matched And Unmatched Uncertainties

The purpose of this paper is to propose a controller for nonlinear systems to achieve robust asymptotic tracking of a class of reference signals, in the presence of matched and unmatched disturbances and model uncertainties. The disturbances and reference signals are generated using two linear exosystems. In the proposed controller, instead of using the upper bound of disturbances in the design process, their instantaneous values are estimated disturbance observer. Therefore, disturbance observer-based control (DOBC) methods are less conservative with respect to conventional approaches. In addition to the DOBC design, a new stepwise procedure based on backstepping technique and sliding mode control is proposed. In the proposed approach, in each step, estimations of disturbances and the upper bound of model uncertainties are used to compose virtual control laws; these virtual control laws compose the final control law. Finally, numerical and practical examples are simulated to show the efficiency of the proposed technique and also to verify the theoretical results.

Sign in / Sign up

Export Citation Format

Share Document