Unknown time-varying input delay compensation for uncertain nonlinear systems

Automatica ◽  
2017 ◽  
Vol 76 ◽  
pp. 222-229 ◽  
Author(s):  
Serhat Obuz ◽  
Justin R. Klotz ◽  
Rushikesh Kamalapurkar ◽  
Warren Dixon
Author(s):  
W. X. Deng ◽  
J. Y. Yao

In this paper, a robust adaptive controller is proposed for a class of uncertain nonlinear systems subject to time-varying input delay, parametric uncertainties and additive bounded disturbances. The desired trajectory based adaptive feedforward technique and a predictor-like robust delay compensating term are integrated via backstepping in the controller design. The proposed controller theoretically ensures semi-global uniformly ultimately bounded tracking performance based on Lyapunov stability analysis by employing Lyapunov-Krasovskii (LK) functionals. Simulation results are obtained to illustrate the effectiveness of the proposed control strategy.


2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Ashish Kumar Jain ◽  
Shubhendu Bhasin

This paper proposes a robust compensator for a class of uncertain nonlinear systems subjected to unknown time-varying input delay. The proposed control law is based on the integral of past values of control and a novel filtered tracking error. Sufficient gain conditions dependent on the known bound of the delay are derived using a Lyapunov-based stability analysis, where Lyapunov–Krasovskii (LK) functionals are used to achieve a global uniformly ultimately bounded (GUUB) tracking result. Simulation results for a nonlinear system are used to evaluate the performance and robustness of the controller for different values of time-varying input delay.


2016 ◽  
Vol 61 (3) ◽  
pp. 834-839 ◽  
Author(s):  
Rushikesh Kamalapurkar ◽  
Nicholas Fischer ◽  
Serhat Obuz ◽  
Warren E. Dixon

Author(s):  
Seyed Hamid Hashemipour ◽  
Nastaran Vasegh ◽  
Ali Khaki Sedigh

This paper investigates the problem of decentralized model reference adaptive control (MRAC) for a class of large-scale systems with time-varying delays in the interconnected terms and state and input delays. The upper bounds of interconnection terms with time-varying delays and external disturbances are assumed to be completely unknown. By integrators inclusion, a dynamic input delay compensator is established for input delay compensation and it is used as a practical method for state calculation x(t + R). Also, a method is presented for a class of decentralized feedback controllers, which can evolve the closed-loop system error uniformly bounded stable. As a numerical example, the proposed technique is applied to an unstable open-loop system to show the feasibility and effectiveness of the method.


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