On the identification of high-order lightly-damped multivariable systems

1999 ◽  
Keyword(s):  
High Order ◽  
Multivariable Systems

Minimal Pade´ Model Reduction for Multivariable Systems

1984 ◽  
Vol 106 (4) ◽  
pp. 293-299 ◽  
Author(s):  
Y. Bistritz ◽  
U. Shaked
Keyword(s):  
Model Reduction ◽  
Minimal Model ◽  
High Order ◽  
Order System ◽  
Multivariable Systems ◽  
Minimal Order ◽  
Minimal Set ◽  
Order Linear ◽  
High Order System ◽  
Independent Parameters

The approximation of high order linear multivariable systems in the Pade´ sense is considered. A unified treatment is presented by which various models of minimal order are found which match given sequences of time moments and Markov matrices. The uniqueness of these models is investigated and in cases where there exist more than one minimal model for a given sequence the set of all the distinct models is characterized by a minimal set of independent parameters which can be assigned arbitrary values. The possible instability of Pade´ reduced models for stable systems is considered and a method is suggested which yields stable models that approximate the high order system, or at least its magnitude, in the Pade´ sense.

Two-channel pitch/yaw missile autopilot design using arbitrary order sliding modes based pole placement

2015 ◽  
Vol 119 (1216) ◽  
pp. 765-779
Author(s):  
B. Kada
Keyword(s):  
Arbitrary Order ◽  
Sliding Mode ◽  
High Order ◽  
Design Tool ◽  
Pole Placement ◽  
Multivariable Systems ◽  
Sliding Modes ◽  
Order Pole ◽  
Strong Robustness ◽  
And Control

AbstractThe paper presents a new missile autopilot system design. The design is achieved through the pole-placement in quasi-continuous high-order sliding mode gains adjustment. Enhanced performance, strong robustness and smooth control are obtained through arbitrary increase of the number of non-oscillatory stable poles. The target application of this technique the two-channel pitch/yaw missile autopilot system is considered. Numerical simulations indicate that the arbitrary-order sliding modes based pole placement’s performance compares favourably against recently proposed high-order pole placement schemes.The proposed arbitrary-order pole placement scheme presents a promising design tool for finite-time stabilisation and control of uncertain multivariable systems.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

The usefulness of high index low symmetry zone axes for holz line analysis

1987 ◽  
Vol 45 ◽  
pp. 384-385
Author(s):  
C. M. Sung ◽  
D. B. Williams
Keyword(s):  
Lattice Parameter ◽  
High Order ◽  
Zone Axis ◽  
High Index ◽  
High Symmetry ◽  
Second Phases ◽  
Line Patterns ◽  
Low Symmetry ◽  
Line Analysis

Researchers have tended to use high symmetry zone axes (e.g. <111> <114>) for High Order Laue Zone (HOLZ) line analysis since Jones et al reported the origin of HOLZ lines and described some of their applications. But it is not always easy to find HOLZ lines from a specific high symmetry zone axis during microscope operation, especially from second phases on a scale of tens of nanometers. Therefore it would be very convenient if we can use HOLZ lines from low symmetry zone axes and simulate these patterns in order to measure lattice parameter changes through HOLZ line shifts. HOLZ patterns of high index low symmetry zone axes are shown in Fig. 1, which were obtained from pure Al at -186°C using a double tilt cooling holder. Their corresponding simulated HOLZ line patterns are shown along with ten other low symmetry orientations in Fig. 2. The simulations were based upon kinematical diffraction conditions.

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