scholarly journals Disturbance observer–based super-twisting sliding mode control for formation tracking of multi-agent mobile robots

2020 ◽  
Vol 53 (5-6) ◽  
pp. 908-921 ◽  
Author(s):  
Guigang Zhang ◽  
Yun Wang ◽  
Jian Wang ◽  
Jiarong Chen ◽  
Dianwei Qian
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Mode Control ◽  
Formation Tracking ◽  
Multi Agent ◽  
Mode Formation ◽  
Robot Platform ◽  
Formation Design

This paper presents a super-twisting sliding mode control method for the formation maneuvers of multiple robots. In the real world of applications, the robots suffer from many uncertainties and disturbances that trouble the super-twisting sliding mode formation maneuvers very much. Especially, this issue has the adverse effects on the formation performance when the uncertainties and disturbances have an unknown bound. This paper focuses on this issue and utilizes the technique of disturbance observer to meet this challenge. In terms of the leader–follower framework, this paper investigates the integration of the super-twisting sliding mode control method and the disturbance observer technique. This kind of formation design has the guaranteed closed-loop stability in the sense of Lyapunov. Some simulations are implemented through a multi-robot platform. The results demonstrate that the superiority of the formation design regardless of uncertainties and disturbances.

scholarly journals Second-Order Sliding Mode Formation Control of Multiple Robots by Extreme Learning Machine

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1444 ◽  
Author(s):  
Qian ◽  
Zhang ◽  
Wang ◽  
Wu
Keyword(s):  
Sliding Mode Control ◽  
Extreme Learning Machine ◽  
Control Method ◽  
Sliding Mode ◽  
Second Order ◽  
Mode Control ◽  
Learning Machine ◽  
Second Order Sliding Mode ◽  
Mode Formation ◽  
Formation Design

This paper addresses a second-order sliding mode control method for the formation problem of multirobot systems. The formation patterns are usually symmetrical. This sliding mode control is based on the super-twisting law. In many real-world applications, the robots suffer from a great diversity of uncertainties and disturbances that greatly challenge super-twisting sliding mode formation maneuvers. In particular, such a challenge has adverse effects on the formation performance when the uncertainties and disturbances have an unknown bound. This paper focuses on this issue and utilizes the technique of an extreme learning machine to meet this challenge. Within the leader–follower framework, this paper investigates the integration of the super-twisting sliding mode control method and the extreme learning machine. The output weights of this extreme learning machine are adaptively adjusted so that this integrated formation design has guaranteed closed-loop stability in the sense of Lyaponov. In the end, some simulations are implemented via a multirobot platform, illustrating the superiority and effectiveness of the integrated formation design in spite of uncertainties and disturbances.

Global sliding mode control for the underactuated translational oscillator with rotational actuator system

2020 ◽  
pp. 095965182094613
Author(s):  
Xianqing Wu ◽  
Kexin Xu
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Nonlinear Disturbance Observer ◽  
Mode Control ◽  
Global Sliding Mode Control ◽  
Actuator System ◽  
Nonlinear Disturbance ◽  
Rotational Actuator

This article is motivated by the control issues of the translational oscillator with rotational actuator system in the existence of uncertain disturbances. A nonlinear disturbance observer and a global sliding mode control method are proposed for the disturbance estimation and stabilization of the translational oscillator with rotational actuator system. Compared with the existing control methods, uncertain disturbances are estimated by the proposed nonlinear disturbance observer. In addition, the sliding mode control method is continuous and global robustness with respect to disturbances. Specifically, to facilitate the controller design, the dynamics of the translational oscillator with rotational actuator system are rearranged as the cascade form first. Then, a virtual signal is constructed and corresponding error dynamics are derived. Subsequently, a nonlinear disturbance observer and a continuous global sliding mode control method are proposed for the disturbance rejection and stabilization of the translational oscillator with rotational actuator system. Finally, simulation results are provided to verify the effectiveness and robustness of the proposed controller.

A novel second-order sliding mode control based on the Lyapunov method

2018 ◽  
Vol 41 (4) ◽  
pp. 1068-1078 ◽  
Author(s):  
Lu Liu ◽  
Shihong Ding ◽  
Li Ma ◽  
Haibin Sun
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Second Order ◽  
Lyapunov Theory ◽  
Mode Control ◽  
Mismatched Disturbance ◽  
Second Order Sliding Mode

In this paper, a novel discontinuous second-order sliding mode control approach has been developed to handle sliding mode dynamics with a nonvanishing mismatched disturbance by using Lyapunov theory and a finite-time disturbance observer. Firstly, the finite-time disturbance observer is designed to estimate the nonvanishing mismatched disturbance. Secondly, a virtual controller has been constructed based on the estimated value such that the sliding variable can be stabilized to zero in a finite time. Then, the real discontinuous controller is designed to guarantee that the virtual controller can be well tracked in a finite time. Lyapunov analysis also verifies the finite-time stability of the closed-loop sliding mode control system. The developed discontinuous second-order sliding mode control method possesses two appealing features including strong robustness with respect to the matched and mismatched nonvanishing disturbances, and relaxation on the constant upper bound of uncertainties widely used in a conventional second-order sliding mode. Finally, an academic example is illustrated to verify the effectiveness of the proposed method.

scholarly journals Finite-Time Reentry Attitude Control Using Time-Varying Sliding Mode and Disturbance Observer

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Xuzhong Wu ◽  
Shengjing Tang ◽  
Jie Guo ◽  
Yao Zhang
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Attitude Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Time Varying ◽  
Control Methods ◽  
Mode Control ◽  
Attitude Controller

This paper presents the finite-time attitude control problem for reentry vehicle with redundant actuators in consideration of planet uncertainties and external disturbances. Firstly, feedback linearization technique is used to cancel the nonlinearities of equations of motion to construct a basic mode for attitude controller. Secondly, two kinds of time-varying sliding mode control methods with disturbance observer are integrated with the basic mode in order to enhance the control performance and system robustness. One method is designed based on boundary layer technique and the other is a novel second-order sliding model control method. The finite-time stability analyses of both resultant closed-loop systems are carried out. Furthermore, after attitude controller produces the torque commands, an optimization control allocation approach is introduced to allocate them into aerodynamic surface deflections and on-off reaction control system thrusts. Finally, the numerical simulation results demonstrate that both of the time-varying sliding mode control methods are robust to uncertainties and disturbances without chattering phenomenon. Moreover, the proposed second-order sliding mode control method possesses better control accuracy.

scholarly journals Nonsingular Terminal Sliding Mode Control of Uncertain Chaotic Gyroscope System Based on Disturbance Observer

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xin Ma ◽  
Yeguo Sun ◽  
Fang Zhu
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Sliding Mode ◽  
Estimation Error ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Gyroscope System ◽  
Nonsingular Terminal Sliding Mode

Based on disturbance observer, this paper develops a nonsingular terminal sliding mode control method for uncertain chaotic gyroscope system. Firstly, fuzzy logic system (FLS) is used to estimate the unknown function; then disturbance observer (DOB) is constructed to estimate the mixed disturbance, which consists of the fuzzy estimation error, external disturbance, and dead-zone input error. Subsequently, by using a nonsingular terminal sliding mode function, the control method proposed in this paper can achieve the sliding mode variable approaching a small neighborhood of zero and reduce chattering phenomenon of the tracking error and controller. Finally, comparative simulation results confirm the effectiveness of the method proposed in this paper.

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.

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