Event-Triggered Control of Nonlinear Uncertain Systems in the Lower-Triangular Form

2020 ◽  
pp. 143-174
Author(s):  
Tengfei Liu ◽  
Pengpeng Zhang ◽  
Zhong-Ping Jiang
Keyword(s):  
Uncertain Systems ◽  
Triangular Form ◽  
Nonlinear Uncertain Systems ◽  
Lower Triangular ◽  
Event Triggered

scholarly journals On active disturbance rejection control for lower-triangular nonlinear uncertain systems with mismatched uncertainties and unknown control coefficients

2021 ◽  
Author(s):  
Ping Liu ◽  
Sen Chen ◽  
Zhi-Liang Zhao
Keyword(s):  
Disturbance Rejection ◽  
Uncertain Systems ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control ◽  
Mismatched Uncertainties ◽  
Nonlinear Uncertain Systems ◽  
Unknown Control Coefficients ◽  
Lower Triangular ◽  
Unknown Control ◽  
Control Coefficients

Abstract The paper investigates the control problem for a class of lower-triangular nonlinear uncertain systems with mismatched uncertainties and unknown values of control coefficients. Based on the signs of control coefficients rather than the nominal values or the approximative mathematical expressions, a new active disturbance rejection control is proposed. The design procedure can be concluded by three steps: determining the equivalent integrators chain form, constructing the extended state observer to estimate the total disturbance, and designing a dynamical system to let the actual input track the ideal input. Then under a mild assumption for mismatched uncertainties and unknown control coefficients, the paper rigorously analyzes the bounds of tracking error, estimating error and the error between the actual and ideal inputs. The presented theoretical results reveal the strong robustness of the proposed method to mismatched uncertainties and uncertain control input coefficients. Moreover, the tuning law of observer parameter and the parameter of dynamical input design is theoretically shown.

scholarly journals Fault Diagnosis of Nonlinear Uncertain Systems with Triangular Form

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Qi Ding ◽  
Xiafu Peng ◽  
Xunyu Zhong ◽  
Xiaoqiang Hu
Keyword(s):  
Fault Diagnosis ◽  
Uncertain Systems ◽  
Nonlinear Function ◽  
Parameter Tuning ◽  
Treatment Technique ◽  
Dynamic Compensation ◽  
Triangular Form ◽  
Novel Approach ◽  
Nonlinear Uncertain Systems ◽  
State Estimations

A novel approach to fault diagnosis for a class of nonlinear uncertain systems with triangular form is proposed in this paper. It is based on the extended state observer (ESO) of the active disturbance rejection controller and linearization of dynamic compensation. Firstly, an ESO is designed to jointly estimate the states and the combination of uncertainty, faults, and nonlinear function of nonlinear uncertain systems. It can derive the estimation of nonlinear function via the state estimations and system model. Then, linearization of dynamic compensation is employed to linearize the system by offsetting nonlinear function mandatorily using its estimation. An observer-based residual generator is designed on the basis of the prior linearized model for fault diagnosis. Moreover, threshold treatment technique is adopted to improve the robustness of fault diagnosis. This method is utilizable and simple in construction and parameter tuning. And also we show the construction of ESO and give the corresponding convergence proof succinctly. Finally, a numerical example is presented to illustrate the validity of the proposed fault diagnosis scheme.

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