Operator-based external disturbance rejection of perturbed nonlinear systems by using robust right coprime factorization

2017 ◽  
Vol 40 (10) ◽  
pp. 3169-3178 ◽  
Author(s):  
Mengyang Li ◽  
Mingcong Deng
Keyword(s):  
Nonlinear Systems ◽  
Adverse Effects ◽  
Robust Stability ◽  
External Disturbance ◽  
Point Of View ◽  
Tracking Performance ◽  
Coprime Factorization ◽  
Output Tracking ◽  
Design Scheme ◽  
Internal Perturbation

In this paper, a class of nonlinear systems with external disturbance and internal perturbation are considered by using operator-based robust right coprime factorization for guaranteeing robust stability, rejecting adverse effects resulting from the existing disturbance and perturbation quantitatively and, meanwhile, realizing output tracking performance. In detail, firstly, robust stability is guaranteed based on a Lipschitz norm inequation using robust right coprime factorization. Secondly, based on the proposed design scheme, a convenient framework is obtained for discussing rejection issues for external disturbance and internal perturbation. Thirdly, from an error signal point of view, the adverse effects resulting from the external disturbance and internal perturbation of the nonlinear system are removed by the designed nonlinear operator. Moreover, output tracking performance is realized using the proposed design scheme simultaneously. Finally, a simulation example is given to confirm the effectiveness of the proposed design scheme of this paper.

Robust Control of Nonlinear System with Input and Output Nonlinear Constraints

2017 ◽  
Vol 29 (6) ◽  
pp. 1073-1081 ◽  
Author(s):  
Shuhui Bi ◽  
Lei Wang ◽  
Chunyan Han ◽  
◽  
Keyword(s):  
Robust Control ◽  
Nonlinear System ◽  
Robust Stability ◽  
System Structure ◽  
Tracking Performance ◽  
Nonlinear Constraints ◽  
Nonlinear Constraint ◽  
Output Tracking ◽  
Input And Output ◽  
Output Constraints

With the development of modern technology, actuators and sensors composed of smart materials, such as piezoceramic and magnetostrictive materials, have been widely used in practice owing to their various advantages. However, in the working process of a smart material based actuator and sensor, non-smooth nonlinear constraints in their output responses may induce inaccuracies and oscillations, which severely degrade system performance. Therefore, input and output nonlinear constraints brought about by actuators and sensors should be considered. Generally, the output nonlinear constraint, namely, non-smooth effects from sensors, has been ignored. Therefore, in this paper, a robust control for a system with an output constraint as well as with both input and output constraints will be considered. Firstly, the generalized Prandtl-Ishlinskii (PI) hysteresis model is used for describing the input and output nonlinearities owing to its excellent characteristics, the model has proved suitable in theoretical operator based settings. Further, a robust control for a nonlinear system with an output nonlinear constraint is considered by using operator based robust right coprime factorization approach. Here, operator based robust stability is considered, and the control system structure including feedforward and feedback controllers is presented with a derivation of sufficient conditions for stable controller operation. Based on the proposed conditions, the influence from an output nonlinear constraint is rejected, the systems are robustly stable, and output tracking performance can be realized. Moreover, robust stability and output tracking performance for a nonlinear system with both input and output nonlinear constraints are also analyzed.

Robust Tracking Control for a Class of Nonlinear Systems with L∞_Bouned Disturbance

2011 ◽  
Vol 211-212 ◽  
pp. 1167-1171
Author(s):  
Peng Guo ◽  
Hui Hu ◽  
Cheng Liu
Keyword(s):  
Nonlinear Systems ◽  
Simple Structure ◽  
External Disturbance ◽  
Tracking Error ◽  
Robust Tracking ◽  
Robust Tracking Control ◽  
Output Tracking ◽  
Mismatched Uncertainties ◽  
Affine Nonlinear Systems ◽  
Theoretical Developments

In the paper, a robust tracking controller is presented for a class of SISO affine nonlinear systems with unknown mismatched uncertainties and external disturbance in input channel.The designed controller has simple structure and concrete expression and include no Lyapunov function. So the proposed controller is easy to compute and complement.The practical stability of output tracking error and the states of the corresponding closed-loop system are demonstrated by Lyapunov stability theorem.Simulation results are presented throughout the paper to complement the theoretical developments.

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