Methods of System Identification for Anisotropic Laminates

1995 ◽  
Author(s):  
Carlo Cinquini ◽  
Claudia Mariani ◽  
Paolo Venini
Keyword(s):  
Identification Algorithm ◽  
Structure Model ◽  
Single Input Single Output ◽  
Identification Methods ◽  
Single Output ◽  
Output Structure ◽  
Out Of Plane ◽  
Single Input ◽  
The Time Domain ◽  
Vector Differential Equation

Abstract The present paper is concerned with the identification of thin anisotropic laminates under transverse dynamic loads. A variational formulation of the problem governing the out-of-plane vibrations of the system is outlined allowing application of the Rayleigh-Ritz methodology for the spatial discretization. The resulting vector differential equation is then solved in the time domain with the objective of collecting enough input/output pairs so as to permit the selected identification algorithm to converge. A few identification methods of parametric type are described and applied to clamped anisotropic laminates under the assumption of a SISO (single-input single-output) structure model. The choice of the latter, of the relevant parameters and of the excitation capable of producing significant dynamics are among the keys for the success of the procedure. Extensions to other categories of identification methods as well as applications for the active control of the laminate are currently under development.

Comparative Study of Three Output-Error Multi-Input Multi-Output Identification Methods

2020 ◽  
Author(s):  
Renato A. L. de Andrade ◽  
Péricles R. Barros
Keyword(s):  
Least Squares ◽  
Mimo Systems ◽  
Single Input Single Output ◽  
Identification Methods ◽  
Output Error ◽  
Single Output ◽  
Regression Algorithms ◽  
Intrinsic Complexity ◽  
Order Of Magnitude ◽  
Single Input

Multi-input multi-output (MIMO) systems have been a major concern for decades. However, due to the intrinsic complexity raised by the process interactions and optimization issues, MIMO approaches have not been developed as extensively as the single-input single-output ones. Recently, nevertheless, several algorithms have been proposed to address this problem, most of them based on recursive algorithms and many dependent on the assumption that the transfer function denominator polynomials are the same for all subsystems. In this article, an iterative least-squares-based algorithm, a pseudolinear regression and a Gauss-Newton optimization-based algorithm are proposed to provide a continuous-time output-error multi-input single-output model by means of iterative strategies. The numerical simulations indicate the iterative least-squares-based and the pseudo-linear regression algorithms have similar performances and generate more accurate and precise estimates than the Gauss-Newton one, which presented averages and standard deviations of the parameters ranging from twice as large to one order of magnitude higher than those of the other two algorithms.

Series-Parallel and Parallel Identification Schemes for a Class of Continuous Nonlinear Systems

1977 ◽  
Vol 99 (2) ◽  
pp. 137-140
Author(s):  
Masayoshi Tomizuka
Keyword(s):  
Identification Algorithm ◽  
Input Output ◽  
Single Input Single Output ◽  
Identification Schemes ◽  
Linear Dynamic ◽  
Single Output ◽  
Single Input ◽  
Static Part ◽  
Nonlinear Static ◽  
The Stability

This technical brief deals with the identification of a single-input, single-output nonlinear system which is composed of a nonlinear static part and a linear dynamic part. A series-parallel identification algorithm and a parallel identification algorithm are presented; they require the input, output, and the order of the linear dynamic portion of the system. The stability of the algorithms is assured by Popov’s hyperstability theorem. The effectiveness of the identification schemes developed is demonstrated by computer simulation.

Design of Single-Input-Single-Output Compliant Mechanisms for Practical Applications Using Selection Maps

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Sudarshan Hegde ◽  
G. K. Ananthasuresh
Keyword(s):  
Compliant Mechanisms ◽  
Material Selection ◽  
Design Procedure ◽  
Single Input Single Output ◽  
Practical Applications ◽  
Beam Elements ◽  
Single Output ◽  
Out Of Plane ◽  
Single Input ◽  
Interactive Map

We present an interactive map-based technique for designing single-input-single-output compliant mechanisms that meet the requirements of practical applications. Our map juxtaposes user-specifications with the attributes of real compliant mechanisms stored in a database so that not only the practical feasibility of the specifications can be discerned quickly but also modifications can be done interactively to the existing compliant mechanisms. The practical utility of the method presented here exceeds that of shape and size optimizations because it accounts for manufacturing considerations, stress limits, and material selection. The premise for the method is the spring-leverage (SL) model, which characterizes the kinematic and elastostatic behavior of compliant mechanisms with only three SL constants. The user-specifications are met interactively using the beam-based 2D models of compliant mechanisms by changing their attributes such as: (i) overall size in two planar orthogonal directions, separately and together, (ii) uniform resizing of the in-plane widths of all the beam elements, (iii) uniform resizing of the out-of-plane thicknesses of the beam elements, and (iv) the material. We present a design software program with a graphical user interface for interactive design. A case-study that describes the design procedure in detail is also presented while additional case-studies are posted on a website.

Comparative analysis of SISO and wavelength diversity-based FSO systems at different transmitter power levels

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Varun Srivastava ◽  
Abhilash Mandloi ◽  
Dhiraj Kumar Patel
Keyword(s):  
Optical Signal ◽  
Free Space Optical ◽  
Optical Source ◽  
Transmit Power ◽  
Single Input Single Output ◽  
Transmitter Power ◽  
Single Output ◽  
Communication Links ◽  
Single Input ◽  
Matching Performance

AbstractFree space optical (FSO) communication refers to a line of sight technology, which comprises optical source and detector to create a link without the use of physical connections. Similar to other wireless communication links, these are severely affected by losses that emerged due to atmospheric turbulence and lead to deteriorated intensity of the optical signal at the receiver. This impairment can be compensated easily by enhancing the transmitter power. However, increasing the transmitter power has some limitations as per radiation regulations. The requirement of high transmit power can be reduced by employing diversity methods. This paper presents, a wavelength-based diversity method with equal gain combining receiver, an effective technique to provide matching performance to single input single output at a comparatively low transmit power.

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