QFT Parameter-Scheduling control design for linear Time-Varying systems based on RBF networks

2003 ◽  
Vol 17 (4) ◽  
pp. 484-491
Author(s):  
Jae Weon Choi ◽  
Wan-Suk Yoo ◽  
Suk Lee ◽  
Ki Hong Im ◽  
Jin Young Choi
Author(s):  
S. Kalender ◽  
H. Flashner

This paper proposes a new design approach for periodically time-varying systems. The approach is based on the application of point-mapping technique to obtain an equivalent linear time invariant sampled data system for the linear periodically time varying system with parameterized control vector, thus allowing the known control design techniques for sampled data systems to be applied. An extension of the approach for analysis of robustness of the control design with respect to parametric uncertainties is also presented. The extension is based on retaining linear as well as higher order terms in the uncertain parameters in the point-mapping algorithm. To illustrate the approach, stabilization of the trivial equilibrium point for a mathematical model representing the dynamics for a double inverted pendulum with periodic forcing is considered. The effectiveness of the extension of the approach for robust stability analysis is demonstrated also by considering uncertain periodic forcing parameters for the double inverted pendulum example.


Eng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 99-125
Author(s):  
Edward W. Kamen

A transform approach based on a variable initial time (VIT) formulation is developed for discrete-time signals and linear time-varying discrete-time systems or digital filters. The VIT transform is a formal power series in z−1, which converts functions given by linear time-varying difference equations into left polynomial fractions with variable coefficients, and with initial conditions incorporated into the framework. It is shown that the transform satisfies a number of properties that are analogous to those of the ordinary z-transform, and that it is possible to do scaling of z−i by time functions, which results in left-fraction forms for the transform of a large class of functions including sinusoids with general time-varying amplitudes and frequencies. Using the extended right Euclidean algorithm in a skew polynomial ring with time-varying coefficients, it is shown that a sum of left polynomial fractions can be written as a single fraction, which results in linear time-varying recursions for the inverse transform of the combined fraction. The extraction of a first-order term from a given polynomial fraction is carried out in terms of the evaluation of zi at time functions. In the application to linear time-varying systems, it is proved that the VIT transform of the system output is equal to the product of the VIT transform of the input and the VIT transform of the unit-pulse response function. For systems given by a time-varying moving average or an autoregressive model, the transform framework is used to determine the steady-state output response resulting from various signal inputs such as the step and cosine functions.


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