Frequency Domain Identification of Multiple Input Multiple Output Nonlinear Systems

2006 ◽  
Author(s):  
Akshya K Swain ◽  
Cheng-Shun Lin ◽  
E.M.A.M. Mendes
Keyword(s):  
Nonlinear Systems ◽  
Frequency Domain ◽  
Multiple Input Multiple Output ◽  
Domain Identification ◽  
Frequency Domain Identification ◽  
Multiple Input ◽  
Input Multiple Output

scholarly journals Complex-Coefficient Frequency Domain Stability Analysis Method for a Class of Cross-Coupled Antisymmetrical Systems and Its Extension in MSR Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yuan Ren ◽  
Jiancheng Fang
Keyword(s):  
Stability Analysis ◽  
Frequency Domain ◽  
Stability Criterion ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Complex Coefficient ◽  
Analysis Method ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Domain Stability

This paper develops a complex-coefficient frequency domain stability analysis method for a class of cross-coupled two-dimensional antisymmetrical systems, which can greatly simplify the stability analysis of the multiple-input multiple-output (MIMO) system. Through variable reconstruction, the multiple-input multiple-output (MIMO) system is converted into a single-input single-output (SISO) system with complex coefficients. The pole locations law of the closed-loop system after the variable reconstruction has been revealed, and the controllability as well as observability of the controlled plants before and after the variable reconstruction has been studied too, and then the classical Nyquist stability criterion is extended to the complex-coefficient frequency domain. Combined with the rigid magnetically suspended rotor (MSR) system with heavy gyroscopic effects, corresponding stability criterion has been further developed. Compared with the existing methods, the developed criterion for the rigid MSR system not only accurately predicts the absolute stability of the different whirling modes, but also directly demonstrates their relative stability, which greatly simplifies the analysis, design, and debugging of the control system.

Adaptive finite-time neural backstepping control for multiple-input–multiple-output uncertain nonlinear systems with full state constraints

2021 ◽  
pp. 014233122198912
Author(s):  
Yan Wei ◽  
Pingfang Zhou ◽  
Yueying Wang ◽  
Dengping Duan ◽  
Jiwei Tang
Keyword(s):  
Nonlinear Systems ◽  
Finite Time ◽  
State Constraints ◽  
Multiple Input Multiple Output ◽  
Backstepping Control ◽  
Attitude Tracking ◽  
Multiple Input ◽  
Full State ◽  
Input Multiple Output ◽  
Full State Constraints

This paper investigates the issue of finite-time tracking control for multiple-input–multiple-output nonlinear systems subject to uncertainties and full state constraints. To deal with full state constraints directly, integral barrier Lyapunov functionals (iBLF) are introduced. By using finite-time stability theory, an iBLF-based adaptive finite-time neural control scheme is presented. To solve the problem of “explosion of complexity” in the design of traditional backstepping control, a new finite-time convergent differentiator is presented. Through stability analysis, all closed-loop signals are proved to be semi-globally uniformly ultimately bounded, the finite time convergence can be guaranteed, and the state constraints are never violated. Finally, the attitude tracking simulations for an autonomous airship are conducted to verify the effectiveness of the proposed scheme.

Application of a Fast-Stabilizing Frequency Domain Parameter Estimation Method

2001 ◽  
Vol 123 (4) ◽  
pp. 651-658 ◽  
Author(s):  
H. Van der Auweraer ◽  
P. Guillaume ◽  
P. Verboven ◽  
S. Vanlanduit
Keyword(s):  
Parameter Estimation ◽  
Frequency Domain ◽  
Multiple Input Multiple Output ◽  
Real Life ◽  
Estimation Method ◽  
Modal Testing ◽  
Multiple Input ◽  
Input Multiple Output ◽  
System Order ◽  
Least Squares Approach

A new noniterative frequency domain parameter estimation technique is proposed. It is based on a weighted total least squares approach, starting from multiple input multiple output frequency response functions. One of the specific advantages of the technique lies in the very stable identification of the system poles as a function of the specified system order, leading to easy-to-interpret stabilization diagrams. This implies a potential for automating the method and to apply it to “difficult” estimation cases. Several real-life case studies are discussed, one related to holographic modal analysis in the medium frequency range, one to the modal testing of a fully trimmed vehicle.

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