STABILITY OF LINEAR TIME-INVARIANT OPEN-LOOP UNSTABLE SYSTEMS WITH INPUT SATURATION

2008 ◽  
Vol 6 (4) ◽  
pp. 496-506 ◽  
Author(s):  
Wen-Liang A. Wang ◽  
Hiro Mukai
Keyword(s):  
Linear Time ◽  
Input Saturation ◽  
Open Loop ◽  
Unstable Systems ◽  
Linear Time Invariant ◽  
Time Invariant

A Linear Time Varying Model for On-Off Valve Controlled Pneumatic Actuators

1990 ◽  
Vol 112 (4) ◽  
pp. 740-747 ◽  
Author(s):  
C. Kunt ◽  
R. Singh
Keyword(s):  
Linear Time ◽  
Digital Simulation ◽  
Control Valve ◽  
Open Loop ◽  
Rotary Valve ◽  
Pneumatic Actuators ◽  
Linear Time Invariant ◽  
Directional Control ◽  
Actuation Systems ◽  
Time Invariant

A new linear time varing (LTV) model has been developed for open loop, on-off valve controlled pneumatic actuation systems. This formulation is based on a periodic profile description for variable operating points and directional control valve flow variations. The dynamic behavior of the example case, a single acting cylinder controlled by a two way-two port rotary valve, under the cyclic pressure loading is obtained using the proposed LTV model. Experimental evidence and digital simulation predictions based on the nonlinear mathematical equations validate the analytical formulation. The proposed LTV model is found to be better and more applicable than linear time invariant (LTI) models used previously by many investigators.

scholarly journals Disturbance Observer-Based Offset-Free Global Tracking Control for Input-Constrained LTI Systems with DC/DC Buck Converter Applications

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4079
Author(s):  
Kyunghwan Choi ◽  
Dong Soo Kim ◽  
Seok-Kyoon Kim
Keyword(s):  
Tracking Control ◽  
Disturbance Observer ◽  
Linear Time ◽  
Estimation Error ◽  
Open Loop ◽  
Buck Converter ◽  
Invariance Property ◽  
Linear Time Invariant ◽  
Global Tracking ◽  
Time Invariant

This paper presents an offset-free global tracking control algorithm for the input-constrained plants modeled as controllable and open-loop strictly stable linear time invariant (LTI) systems. The contribution of this study is two-fold: First, a global tracking control law is devised in such a way that it not only leads to offset-free reference tracking but also handles the input constraints using the invariance property of a projection operator embedded in the proposed disturbance observer (DOB). Second, the offset-free tracking property is guaranteed against uncertainties caused by plant-model mismatch using the DOB’s integral action for the state estimation error. Simulation results are given in order to demonstrate the effectiveness of the proposed method by applying it to a DC/DC buck converter.

Decentralized control of discrete-time linear time invariant systems with input saturation

2009 ◽  
Vol 20 (12) ◽  
pp. 1353-1362
Author(s):  
Ciprian Deliu ◽  
Babak Malek ◽  
Sandip Roy ◽  
Ali Saberi ◽  
Anton A. Stoorvogel
Keyword(s):  
Decentralized Control ◽  
Discrete Time ◽  
Linear Time ◽  
Input Saturation ◽  
Linear Time Invariant ◽  
Linear Time Invariant Systems ◽  
Time Invariant ◽  
Time Linear

Evaluation of fractional order of the discrete integrator. Part II

2020 ◽  
Vol 23 (2) ◽  
pp. 408-426
Author(s):  
Piotr Ostalczyk ◽  
Marcin Bąkała ◽  
Jacek Nowakowski ◽  
Dominik Sankowski
Keyword(s):  
Fractional Order ◽  
Output Signal ◽  
Linear Time ◽  
Mathematical Problem ◽  
Simple Method ◽  
Linear Time Invariant ◽  
Input And Output ◽  
Order Difference Equation ◽  
Time Invariant ◽  
Discrete Integrator

AbstractThis is a continuation (Part II) of our previous paper [19]. In this paper we present a simple method of the fractional-order value calculation of the fractional-order discrete integration element. We assume that the input and output signals are known. The linear time-invariant fractional-order difference equation is reduced to the polynomial in a variable ν with coefficients depending on the measured input and output signal values. One should solve linear algebraic equation or find roots of a polynomial. This simple mathematical problem complicates when the measured output signal contains a noise. Then, the polynomial roots are unsettled because they are very sensitive to coefficients variability. In the paper we show that the discrete integrator fractional-order is very stiff due to the degree of the polynomial. The minimal number of samples guaranteeing the correct order is evaluated. The investigations are supported by a numerical example.

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