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.

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.

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.

scholarly journals Sliding Mode Robust Control of a Wire-Driven Parallel Robot Based on HJI Theory and a Disturbance Observer

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 215235-215245
Author(s):  
Yuqi Wang ◽  
Qi Lin ◽  
Jiacai Huang ◽  
Lei Zhou ◽  
Jinjiang Cao ◽  
...  
Keyword(s):  
Robust Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Parallel Robot

scholarly journals Sliding mode control of the automobile electro-coating conveying mechanism with a nonlinear disturbance observer

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879574 ◽  
Author(s):  
Wei Yuan ◽  
Guoqin Gao
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
High Performance ◽  
Sliding Mode ◽  
External Disturbance ◽  
Nonlinear Disturbance Observer ◽  
Control Approach ◽  
Mode Control ◽  
Highly Nonlinear ◽  
Nonlinear Disturbance

The trajectory-tracking performance of the automobile electro-coating conveying mechanism is severely interrupted by highly nonlinear crossing couplings, unmodeled dynamics, parameter variation, friction, and unknown external disturbance. In this article, a sliding mode control with a nonlinear disturbance observer is proposed for high-accuracy motion control of the conveying mechanism. The nonlinear disturbance observer is designed to estimate not only the internal/external disturbance but also the model uncertainties. Based on the output of the nonlinear disturbance observer, a sliding mode control approach is designed for the hybrid series–parallel mechanism. Then, the stability of the closed-loop system is proved by means of a Lyapunov analysis. Finally, simulations with typical desired trajectory are presented to demonstrate the high performance of the proposed composite control scheme.

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