A Note on a Reduced-Order Observer Based Controller for a Class of Lipschitz Nonlinear Systems

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Mohamadreza Homayounzade ◽  
Mehdi Keshmiri
Keyword(s):  
Nonlinear Systems ◽  
Global Exponential Stability ◽  
Degrees Of Freedom ◽  
Large Range ◽  
Robot Manipulator ◽  
Tracking Error ◽  
Control Law ◽  
Reduced Order ◽  
Lipschitz Nonlinear Systems ◽  
Reduced Order Observer

This paper presents a novel reduced-order observer based controller for a class of Lipschitz nonlinear systems, described by a set of second order ordinary differential equations. The control law is designed based on the measured output and estimated states. The main features are: (1) The computation cost is reduced noticeably, since the observer is a reduced-order one; (2) The controller guarantees semi-global exponential stability for both estimation and tracking error; and (3) The proposed method can be used in a large range of applications, especially in mechanical systems. The effectiveness of the proposed method is investigated through the numerical simulation for a two-degrees-of-freedom robot manipulator acting on a horizontal worktable.

scholarly journals Adaptive output regulation for a class of nonlinear systems with guaranteed transient performance

2019 ◽  
Vol 42 (6) ◽  
pp. 1180-1190
Author(s):  
Weijie Sun ◽  
Zhenhua Zhu ◽  
Jianglin Lan ◽  
Yunjian Peng
Keyword(s):  
Nonlinear Systems ◽  
Tracking Error ◽  
High Gain ◽  
Output Regulation ◽  
Control Law ◽  
Stabilization Problem ◽  
Transient Performance ◽  
Adaptive Stabilization ◽  
Output Tracking ◽  
Output Constraints

This paper is dedicated to adaptive output regulation for a class of nonlinear systems with asymptotic output tracking and guarantee of prescribed transient performance. With the employment of internal model principle, we first transform this problem into a specific adaptive stabilization problem with output constraints. Then, by integrating the time-varying Barrier Lyapunov Function (BLF) technique together with the high gain feedback method, we develop an output-based control law to solve the constrained stabilization problem and consequently confine the output tracking error to a predefined arbitrary region. The output-based control law enables adaptive output regulation in the sense that, under unknown exosystem dynamics, all the closed-loop system signals are bounded whilst the controlled output constraints are not violated. Finally, efficacy of the proposed design is illustrated through a simulation example.

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