scholarly journals Nonlinear disturbance observer design for robotic manipulators

2013 ◽  
Vol 21 (3) ◽  
pp. 253-267 ◽  
Author(s):  
A. Mohammadi ◽  
M. Tavakoli ◽  
H.J. Marquez ◽  
F. Hashemzadeh
Keyword(s):  
Disturbance Observer ◽  
Robotic Manipulators ◽  
Observer Design ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance

scholarly journals Suppression the Disturbance of Robotic Manipulators Based on Nonlinear Disturbance Observer and Fuzzy Logic System

2020 ◽  
Vol 24 (7) ◽  
pp. 846-854
Author(s):  
Wangyong He ◽  
Haogui Li ◽  
Yuanjiang Wang ◽  
Sanqiu Liu ◽  
◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Disturbance Observer ◽  
Robot Manipulator ◽  
Robotic Manipulators ◽  
Fuzzy Logic System ◽  
External Disturbances ◽  
Nonlinear Disturbance Observer ◽  
Coupling System ◽  
Nonlinear Disturbance ◽  
Logic System

Robotic Manipulators (RM) are nonlinear and coupling system with time-variant and model uncertainties. In addition, RM are subject to different types of disturbances in practice, such as joint frictions, unknown payloads, and interferences from external systems. In this paper, these adverse factors are regarded as disturbance, and classifies them into internal disturbances and external disturbances. In order to achieve high-precision control, a Nonlinear Disturbance Observer (NDO) is designed to suppress external disturbances, and a Fuzzy Logic System (FLS) is designed to compensate internal disturbances. The scheme can effectively suppress the disturbance and improve the control accuracy. The validity of the scheme is shown by computer simulations of a two-link robot manipulator.

scholarly journals A nonlinear disturbance observer for robotic manipulators

2000 ◽  
Vol 47 (4) ◽  
pp. 932-938 ◽  
Author(s):  
Wen-Hua Chen ◽  
D.J. Ballance ◽  
P.J. Gawthrop ◽  
J. O'Reilly
Keyword(s):  
Disturbance Observer ◽  
Robotic Manipulators ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance

A Novel Nonlinear Disturbance Observer embedded Second-Order Finite Time Tracking-based Controller for Robotic Manipulators

2021 ◽  
pp. 1-27
Author(s):  
Bin Ren ◽  
Yao Wang ◽  
Jiayu Chen ◽  
Silu Chen
Keyword(s):  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Tracking Error ◽  
Robotic Manipulators ◽  
Second Order ◽  
Terminal Sliding Mode ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance ◽  
Nonlinear Mechanical Systems

Abstract Robotic manipulators are complex and dynamic nonlinear mechanical systems subject to numerous uncertainties, such as payload variations, frictions, and unmodeled dynamics. To mitigate the uncertainty caused by these disturbances and minimize the tracking errors of the controllers, this study proposed a finite time tracking-based controller (FTC) that embeds a nonlinear disturbance observer (NDO) and a second-order sliding mode modifier (SOSM). The NDO was incorporated to compensate for the system's global bounded uncertainty and the SOSM employed a robust nonsingular terminal sliding-mode modifier to stabilize the controller. The theoretical analysis showed that the tracking error could quickly converge in finite time. Simulation on a typical robotics manipulator demonstrated the practical appeal of the proposed scheme.

Robust Nonlinear Disturbance Observer Design for Estimation of Ammonia Storage Ratio in Selective Catalytic Reduction Systems

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Jinbiao Ning ◽  
Fengjun Yan
Keyword(s):  
Selective Catalytic Reduction ◽  
Disturbance Observer ◽  
Catalytic Reduction ◽  
External Disturbance ◽  
Nox Reduction ◽  
Observer Design ◽  
Noise Attenuation ◽  
Nonlinear Disturbance Observer ◽  
Ammonia Storage ◽  
Nonlinear Disturbance

Urea-based selective catalytic reduction (SCR) system is a promising way to obtain high NOx reduction and commonly adopted in diesel engine aftertreatment systems. The ammonia storage ratio is critical for SCR feedback control but it is difficult to be directly measured by sensors. This paper aims to effectively estimate the ammonia storage ratio on line and reduce the cost of using ammonia sensors. In the proposed method, the ammonia storage ratio is treated as an external disturbance in the NOx dynamic model and estimated by the nonlinear disturbance observer (NDO) methods. Furthermore, to reduce estimation errors of ammonia storage ratio caused by the high-frequency measurement noises, a novel robust nonlinear disturbance observer (robust NDO) is proposed and compared with a typical design method (regular NDO). Both the NDOs are developed based on part of the three-state SCR model and cost-effective, since NOx sensors are only used. The stability and noise attenuation properties of both estimations were also analyzed in the paper. The simulation results based on the full-vehicle simulator of FTP-75 test demonstrate that the regular NDO and the robust NDO can effectively estimate the ammonia storage ratio even in cases where ammonia cross-sensitivity affects the response. Among the two observers, the robust NDO has better noise attenuation properties.

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