Disturbance observer–based fixed-time robust control for constrained air-breathing hypersonic vehicle

2021 ◽  
pp. 095965182110652
Author(s):  
Jicheng Liu ◽  
Ju Jiang ◽  
Chaojun Yu ◽  
Bing Han
Keyword(s):  
Robust Control ◽  
Feedback Linearization ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Uniform Boundedness ◽  
Fixed Time ◽  
External Disturbances ◽  
Simulation Experiments ◽  
Sliding Surfaces

This article studies the fixed-time robust control problem for the longitudinal dynamics of hypersonic vehicles in the presence of parametric uncertainties, external disturbances and input constraints. First, the dynamic model is transformed into two fourth-order integral chain subsystems by feedback linearization technology. Four novel fast integrating sliding surfaces are designed for each subsystem to guarantee the fixed time convergence of the errors and the derivatives. The double power reaching law is investigated to accelerate the convergence of sliding surfaces. Furthermore, the fixed-time disturbance observer technique is applied to estimate the lumped disturbance precisely. A novel fixed-time anti-saturation auxiliary system is designed to tackle the saturation caused by constraints of actuators. Then the semi-global uniform boundedness of the closed-loop system in a fixed time is proved by Lyapunov’s stability theory. Finally, comparison simulation experiments with the existing higher order sliding mode control method are carried out to verify the proposed method’s effectiveness and superiority.

Robust sliding mode control for a class of underactuated systems with mismatched uncertainties

2009 ◽  
Vol 223 (6) ◽  
pp. 785-795 ◽  
Author(s):  
D W Qian ◽  
X J Liu ◽  
J Q Yi
Keyword(s):  
Robust Control ◽  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Underactuated Systems ◽  
Sliding Surface ◽  
Nominal System ◽  
Sliding Surfaces ◽  
Mode Control ◽  
Mismatched Uncertainties

Based on the sliding mode control methodology, this paper presents a robust control strategy for underactuated systems with mismatched uncertainties. The system consists of a nominal system and the mismatched uncertainties. Since the nominal system can be considered to be made up of several subsystems, a hierarchical structure for the sliding surfaces is designed. This is achieved by taking the sliding surface of one of the subsystems as the first-layer sliding surface and using this sliding surface and the sliding surface of another subsystem to construct the second-layer sliding surface. This process continues till the sliding surfaces of all the subsystems are included. A lumped sliding mode compensator is designed at the last-layer sliding surface. The asymptotic stability of all of the layer sliding surfaces and the sliding surface of each subsystem is proven. Simulation results show the validity of this robust control method through stabilization control of a system consisting of two inverted pendulums and mismatched uncertainties.

scholarly journals Disturbance Observer-Based Integral Backstepping Control for a Two-Tank Liquid Level System Subject to External Disturbances

2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Xiangxiang Meng ◽  
Haisheng Yu ◽  
Herong Wu ◽  
Tao Xu
Keyword(s):  
Control Strategy ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Mass Conservation ◽  
Backstepping Control ◽  
Liquid Level ◽  
Level System ◽  
External Disturbances ◽  
Simulation And Experiment

A novel method of disturbance observer-based integral backstepping control is proposed for the two-tank liquid level system with external disturbances. The problem of external disturbances can be settled in this paper. Firstly, the mathematical model of the two-tank liquid level system is established based on fluid mechanics and principle of mass conservation. Secondly, an integral backstepping control strategy is designed in order to ensure liquid level tracking performance by making the tracking errors converge to zero in finite time. Thirdly, a disturbance observer is designed for the two-tank liquid level system with external disturbances. Finally, the validity of the proposed method is verified by simulation and experiment. By doing so, the simulation and experimental results prove that the scheme of disturbance observer-based integral backstepping control strategy can suppress external disturbances more effective than the disturbance observer-based sliding mode control method and has better dynamic and steady performance of the two-tank liquid level system.

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.

ROBUST CONTROL OF CHAOTIC VIBRATION OF COMPOSITE PLATE IN THE PRESENCE OF NOISE USING SLIDING MODE METHOD

2012 ◽  
Vol 22 (05) ◽  
pp. 1250106
Author(s):  
SHAMRAO ◽  
S. NARAYANAN
Keyword(s):  
Robust Control ◽  
Composite Plate ◽  
Control Method ◽  
Sliding Mode ◽  
Linear Quadratic ◽  
External Disturbances ◽  
Chaotic Vibration ◽  
Mode Method ◽  
Control Methodology ◽  
Cubic Stiffness

Robust control of chaotic vibration in composite plate in the presence of noise using sliding mode control methodology is considered in this paper. The composite plate system has a combination of linear, quadratic and cubic stiffness terms. Robustness of the controller is analyzed with reference to the parametric variations of the system and external disturbances due to noise and compared with Pyragas control method. The composite plate considered is a six-layered rectangular antisymmetric cross-ply plate with immovable edges. The plate is assumed to be viscously damped and harmonically excited.

scholarly journals Enhanced Nonlinear Robust Control for TCSC in Power System

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Chao Zhang ◽  
Xing Wang ◽  
Zhengfeng Ming ◽  
Zhuang Cai
Keyword(s):  
Adaptive Control ◽  
Time Delay ◽  
Robust Control ◽  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Uncertain Parameter ◽  
Adaptive Backstepping ◽  
External Disturbances ◽  
Backstepping Sliding Mode Control

This paper proposes an enhanced robust control method, which is for thyristor controlled series compensator (TCSC) in presences of time-delay nonlinearity, uncertain parameter, and external disturbances. Unlike conventional adaptive control methods, the uncertain parameter is estimated by using system immersion and manifold invariant (I&I) adaptive control. Thus, the oscillation of states caused by the coupling between parameter estimator and system states can be avoided. In addition, in order to overcome the influences of time-delay nonlinearity and external disturbances, backstepping sliding mode control is adopted to design control law recursively. Furthermore, robustness of TCSC control subsystem is achievable provided that dissipation inequality is satisfied in each step. Effectiveness and efficiencies of the proposed control method are verified by simulations. Compared with adaptive backstepping sliding mode control and adaptive backstepping control, the time of reaching steady state is shortened by at least 11% and the oscillation amplitudes of transient responses are reduced by at most 50%.

scholarly journals Backstepping Sliding Mode Robust Control for a Wire-Driven Parallel Robot Based on a Nonlinear Disturbance Observer

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yuqi Wang ◽  
Qi Lin ◽  
Lei Zhou ◽  
Xinxin Shi ◽  
Lei Wang
Keyword(s):  
Robust Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Design Method ◽  
Parallel Robot ◽  
Parallel Robots ◽  
End Effector ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance

Based on a nonlinear disturbance observer, a backstepping sliding mode robust control is proposed for a wire-driven parallel robot (WDPR) system used in the wind tunnel test to dominate the motion of the end effector. The control method combines both the merits of backstepping control and sliding mode robust control. The WDPR is subject to different types of disturbances, and these disturbances will affect the motion precision of the end effector. To overcome these problems, a nonlinear disturbance observer (NDO) is designed to reject such disturbances. In this study, the design method of the nonlinear disturbance observer does not require the reliable dynamic model of the WDPR. Moreover, the design method can be used not only in the WDPR but also in other parallel robots. Then, a backstepping design method is adopted and a sliding mode term is introduced to construct a desired controller, and the disturbances are compensated in the controller to reduce the switching gain and guarantee the robustness. For the sake of verifying the stabilization of the closed-loop system, the Lyapunov function is constructed to analyze the stabilization of the system. Finally, the feasibility and validity of the proposed control scheme are proved through both simulation and experimental results.

New Robust Control Method Applied to the Locomotion of a 5-Link Biped Robot

Robotica ◽  
2020 ◽  
Vol 38 (11) ◽  
pp. 2023-2038
Author(s):  
Mohammad Mehdi Kakaei ◽  
Hassan Salarieh
Keyword(s):  
Robust Control ◽  
Feedback Linearization ◽  
Control Method ◽  
Sliding Mode ◽  
Biped Robot ◽  
Zero Dynamics ◽  
Lyapunov Theorem ◽  
Free Response ◽  
Hybrid Zero Dynamics ◽  
Controller Performance

SUMMARYThis paper proposes a new design of robust control combining feedback linearization, backstepping, and sliding mode control called FLBS applied to the locomotion of five-link biped robot. Due to the underactuated robot’s model, the system has a hybrid nature, while the FLBS control can provide a stabilized walking movement even with the existence of large disturbances and uncertainties by implementing smooth chatter-free signals. Stability of the method is proven using the Lyapunov theorem based on the hybrid zero dynamics and Poincaré map. The simulations show the controller performance such as robustness and chatter-free response in the presence of uncertainty and disturbance.

Part 1: robust adaptive control of quadrotor with disturbance observer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nigar Ahmed ◽  
Abid Raza ◽  
Rameez Khan
Keyword(s):  
Adaptive Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
External Disturbance ◽  
Robust Adaptive Control ◽  
External Disturbances ◽  
Content Type ◽  
Control Objective ◽  
Robust Adaptive

Purpose The aim of this paper is to design a nonlinear disturbance observer-based control (DOBC) method obtained by patching a control method developed using a robust adaptive technique and a DO. Design/methodology/approach For designing a DOBC, initially a class of nonlinear system is considered with an external disturbance. First, a DO is designed to estimate the external disturbances. This estimate is combined with the controller to reject the disturbances and obtain the desired control objective. For designing a controller, the robust sliding mode control theory is used. Furthermore, instead of using a constant switching gain, an adaptive gain tuning criterion is designed using Lyapunov candidate function. To investigate the stability and effectiveness of the developed DOBC, stability analysis and simulation study are presented. Findings The major findings of this paper include the criteria of designing the robust adaptive control parameters and investigating the disturbance rejection when robust adaptive control based DOBC is developed. Practical implications In practice, the flight of quadrotor is affected by different kind of external disturbances, thus leading to the change in dynamics. Hence, it is necessary to design DOBCs based on robust adaptive controllers such that the quadrotor model adapts to the change in dynamics, as well as nullify the effect of disturbances. Originality/value Designing DOBCs based on robust control method is a common practice; however, the robust adaptive control method is rarely developed. This paper contributes in the domain of DOBC based on robust adaptive control methods such that the behavior of controller varies with the change in dynamics occurring due to external disturbances.

scholarly journals Sliding Mode Control Based on Disturbance Observer for Greenhouse Climate Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Lijun Chen ◽  
Shangfeng Du ◽  
Dan Xu ◽  
Yaofeng He ◽  
Meihui Liang
Keyword(s):  
Sliding Mode Control ◽  
Feedback Linearization ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Control Technique ◽  
Integral Sliding Mode ◽  
Greenhouse Climate ◽  
Mode Control ◽  
Temperature And Humidity

Greenhouses are closed environments that require careful climatic control, which can benefit from a system control method to cope with the high nonlinearity, complex coupling, and robustness of unknown disturbances. This paper presents a general framework for an integral sliding mode controller based on a disturbance observer combined with feedback linearization for a greenhouse temperature and humidity system. The first-principle greenhouse climate model is described as a standard affine nonlinear system. The feedback linearization control law is used to achieve a system consisting of two separate integrator channels for temperature and humidity. System compound disturbances are estimated by applying a sliding mode disturbance observer. Based on the observer, an integral sliding mode control is incorporated to enhance the robustness against uncertainties and guarantee satisfactory tracking performance even when there are unknown estimation errors. The validity and efficacy of the proposed control technique for greenhouse climate tracking were verified by comparison with simulation results obtained using the common sliding mode control method using feedback linearization without the disturbance observer. Based on this comparison, the developed controller shows a faster system response speed, higher control precision, and stronger anti-interference ability. This method can be applied to improve greenhouse climate control systems.

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