Repetitive Control based Disturbance Observer for Uncertain Communication Delays

2021 ◽  
Author(s):  
V. Artheec Kumar ◽  
Zhenwei Cao ◽  
Deshan Thayabaran ◽  
Don Bombuwela
Keyword(s):  
Disturbance Observer ◽  
Repetitive Control ◽  
Communication Delays

Delay Compensation for Teleoperation Systems Based on Communication Disturbance Observers

2016 ◽  
Vol 20 (7) ◽  
pp. 1044-1050
Author(s):  
Wen-An Zhang ◽  
◽  
Junkai Jin ◽  
Xiang Qiu ◽  
Li Yu
Keyword(s):  
Control Problem ◽  
Disturbance Rejection ◽  
Disturbance Observer ◽  
Controller Design ◽  
Design Method ◽  
Smith Predictor ◽  
Time Varying ◽  
Communication Delays ◽  
Delay Compensation ◽  
Teleoperation Systems

This paper investigates the control problem for a class of teleoperation systems with communication delays. The network-induced delays are usually inevitable in teleoperation systems, and may be time varying and unpredictable. Since the conventional Smith predictor is only useful for fixed delays, a novel delay compensation and controller design method is proposed in this paper. The proposed method combines a disturbance rejection controller and a communication disturbance observer (CDOB). Simulations are provided to show the effectiveness and superiority of the proposed delay compensation and controller design method.

Integrated Modified Repetitive Control With Disturbance Observer of Piezoelectric Nanopositioning Stages for High-Speed and Precision Motion

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Zhao Feng ◽  
Jie Ling ◽  
Min Ming ◽  
Xiaohui Xiao
Keyword(s):  
Disturbance Observer ◽  
High Speed ◽  
External Disturbance ◽  
Repetitive Control ◽  
Optimization Procedure ◽  
Tracking Performance ◽  
Hysteresis Nonlinearity ◽  
Control Scheme ◽  
The Stability ◽  
Precision Motion

The tracking performance of piezoelectric nanopositioning stages is vital in many applications, such as scanning probe microscopes (SPMs). Although modified repetitive control (MRC) can improve tracking performance for commonly used periodic reference input, it is sensitive to unexpected disturbances that deteriorate tracking precision, especially for high-speed motion. In order to achieve high-speed and precision motion, in this paper, a new composite control scheme by integrating MRC with disturbance observer (DOB) is developed. To simplify controller implementation, the hysteresis nonlinearity is treated as external disturbance and the proposed method is designed in frequency domain. The stability and robust stability are analyzed, and an optimization procedure to calculate the controller parameters is employed to enhance the performance to the maximum extent. To validate the effectiveness of the proposed method, comparative experiments are performed on a piezoelectric nanopositioning stage. Experimental results indicate that the hysteresis is suppressed effectively and the proposed method achieves high-speed and precision tracking with triangular waves references up to 25 Hz and improves the disturbance rejection ability with disturbances under different frequencies and robustness to model uncertainty through comparing with feedback controllers and MRC, respectively.

scholarly journals Disturbance observer-based predictive repetitive control with constraints

2020 ◽  
pp. 1-10
Author(s):  
Liuping Wang ◽  
Chris T. Freeman ◽  
Eric Rogers
Keyword(s):  
Disturbance Observer ◽  
Repetitive Control
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